摘要:

11 Cr Mo,and W By H. SLOAN Consulting Chemist 40 Wendan Road Newbury Berkshire RE14 7AF UK 1 introduction This report covers the chemistry of Clr Mo and W for the two years 1991 and 1992. It is organized in part by structural type and in part by the major ligand donor atom. Reviews have appeared on 19-electron organometallic adducts of molybdenum,' molybdenum and tungsten oxide zeolites, cubane and incomplete cubane-type Mo and W oxo/sulfido cluster^,^ cyclopentadienyl molybdenum and tungsten dihalide~,~ coordination chemistry and catalysis with oxygen-phosphorus ligand complexes of chromium,' two- or three-fold orientational disorder6 in [M2X8]"- [M2X,L4] and [M,X,(P-P),] and cubane Mo W clusters with [S,P(OC,H,),] -ligand~.~ Metalates are described in reviews of polyoxomolybdates and tungstates,8 the coordination chemistry of polyox~molybdates,~ nitrosyl-substituted anions," and thiometalate complexes'' of the Cu-Mo/W-S system.Aspects of the chemistry of this group are also included in wider reviews of transition metal hydrides' (tungsten) protonation of coordinated dinitrogen' (molybdenum and tungsten) nitrido complexes of transition metalsI4 (molybdenum and tungsten) transition metal fluoro compounds containing CO PR, AsR, SbR ligands," di- tri- and polyphosphine complexes of transition metals," ab initio calculations of transition metal organometallics' '(chromium),ab initio molecular orbital studies of catalytic reactions of transition metal complexes,'8 transition metal and enzyme- ' D.R. Tyler Ace. Chem. Res. 1991 24 325. G.A. Ozin S. Ozkar and R. A. Prokopowicz Ace. Chrm. Res. 1992 25. 553. T. Shibahara Adu. Inorg. Chem. 1991 37 143. M. L.H. Green and P. Mountford Chem. Soc. Rev. 1992. 21 29. ' A. Bader and E. Lindner Coord. Chem. Rev. :991 108 27 (pages 40-44). ' F.A. Cotton and J. L. Eglin Inorg. Chim. Acta 1992 198-200 13. ' S. Lu J. Huang H. Zhuang J. Li D. Wu Z. Huang C. Lu J. Huang and J. Lu Polyhedron 1991,10,2203. ' M. T. Pope and A. Muller Angew. Chem. Int. Ed. Engl. 1991 30. 34. ' Q. Chen and J. Zubieta Coord. Chem. Rev. 1992 114 107. lo Y. Jeannin G. Herve and A. Proust Inorg. Chim. Acta 1991 198-200 319. " Y. Jeannin F. Secheresse S. Bernes and F. Robert Inorg. Chim. Acta 1991 198-200 493. 'Transition Metal Hydrides' ed.A. Dedieu VCH 1992. l3 G.J. Leigh. Ace. Chem. Res. 1992. 25 177. K. Dehnicke and J. Strahle Angew. Chem. Int. Ed. Engl. 1992. 31 955. N. M. Doherty and N. W. Hoffman Chem. Rep. 1991 91 553. Ib A.-M. Caminade J.-P. Majoral and R. Mathieu Chem. Rep. 1991 91 575. A. Veillard Chem. Rev. 1991 91 743. N. Koga and K. Morokurna Chem. Rev. 1991. 91 823. 127 128 H. Sloan catalysed reactions involving NH and amines,” solid state NMR of coordination compounds,20 hydrogen isotope exchange rates for polyamines bound to inert complexes2’ (chromium) optically-detected magnetic resonance spectroscopy of coordination compounds22 (chromium and molybdenum) reactions of transition metal dihydrogen complexes23 and complexes of silylenes silenes etc.24 2 Bond Stretch Isomers The existence of bond-stretch isomers has been the subject of a number of reviews2’ Reinvestigation has provided evidence in some cases that the apparent bond length isomerism is associated26 with co-crystallization of two compounds often where the difference in composition relates only to a metal-chloro or metal-oxo bond. Two forms of [MoOCI,(PMe,Ph),] and the dibromo analogue are reported2’ where differences of angles as well as some bond lengths occur though other investigators have disagreed.28 Ab initio calculations for [WOCl,(Me,tacn)] indicate29 that there is only one ground state and an orbital crossing mechanism cannot explain the occurrence of two isomers. For cis,mer-[Mo0C1,(PR3),] the second order Jahn-Teller effect is too weak to cause the bond-stretch phenomenon.In both cases calculations support the shorter bond as the stable form. Similar problems in distinguishing between Mo-0 and Mo-C1 bonds are de- scribed3’ in a structural determination of mer,~is-[MoOC1~(OPPh,)~] (1) where there is disorder between oxygen and chlorine atoms related by a crystallographic two-fold axis. This form is isomorphous with the corresponding W compound. A previous structural determination of a different form of (1) showed31 significantly different Mo-Cl and Mo-0 bond lengths for an ordered structure. 3 Metalates Topological aspects of polyoxometalates have been discussed.32 Polytungstate anions are often studied with regard to reductive and catalytic potential.The most frequently studied Keggin-type anions with varied central heteroatom and with substitution of a few tungsten atoms by other transition metals on the surface of the anion show variations in anionic charge and charge distribution that affects this potential. Though the surface substitution often leads to disorder in the l9 D. M. Roundhill Chem. Rec. 1992 92 1. ’” J. A. Davies and S. Dutremez Coord. Chem. Rw. 1992 114 201. ” D.A. House Coord. Chem. Reu. 1992 114 249. 22 A. L. Kanyshny A. P. Suisalu and L.A. Aslanov Coord. Chem. Rev. 1992 117 1. 23 P. G. Jessop and R. H. Morris. Coord. Chem. Rev.. 1992 121 155. 24 P.D. Lickiss Chem. SOL..R~L,., 1992 21 271. 25 G. Parkin Acc. Chem. Res. 1992,25,455;J. M. Mayer Angew. Chem. Int. Ed.Engl. 1992,31,286; V.C. Gibson and M. McPartlin. J. Chem. Soc. Dalton Trans.. 1992 947. 26 K. Yoon G. Parkin. D. L. Hughes and G.J. Leigh. J. Chem. Soc. Dalton Trans. 1992 769. 27 A. P. Bashall S. W. A. Bligh. A. J. Edwards V. C. Gibson M. McPartlin and 0.B. Robinson Angew. Chem.. Int. Ed. Enyl. 1992 31. 1607. K. Yoon G. Parkin and A. L. Rheingold J. Am. Chem. Soc. 1991 113 1437; K. Yoon. G. Parkin and A.L. Rheingold J. Am. Chem. Soc. 1992 114 2210. 29 J. Song and M. B. Hall Inorg. Chem. 1991 30 4433. 3” B. E. Owens and R. Poli. Acta Crystullogr. Sect. C 1992 48 2137. 3’ C. D. Garner N. C. Howlader F. E. Mabbs A. T. McPhail and K. D. Onan J. Chem.Soc. Dalton Trans. 1978. 1848. 32 R. B. King Inorg. Chem.. 1991 30 4437. Cr Mo and W 129 crystal state making identification of the substituted sites difficult the anion [PTi,W 10040]7 -showed3 a preferred orientation and location of the titanium atoms as a c isomer.The isomorphous ammonium salts of [MW,,O,,F,NaH,]"-(M = Co n = 9; M = Fe n = 8) have 34 Dawson-type structures. Tandem MS was shown to be a useful technique for the characterization of large inorganic complexes. Reaction of Na,MoO with A-Na,[PW,O,,] gave3 [PMo,W,O,,]~- which is an A-type trisubstituted p-isomer with the three MOO moieties linked together in a triangle on one side of the anion. Addition of sodium metavanadate to the divacant anion y-[HSiW 10036]7 -gave,3h quantitatively the 1,2-divanado-compound Cs,H,[y-SiV W ,OO,O]. This complex is stable in non-aqueous solutions but isomerizes in water to the ,&structured (8,12) (3,12) or (3,8) divanado-isomers.The anion of K,Na4H,[TbWlo0,,] is made37 from two W,Oy groups chelating the central terbium atom. The W,Oy groups are derived from the [W,0,,]2 -ion by removal of a W04+ unit. Two of the potassium ions are coordinated to the anion in the crystal playing a stabilizing r61e that apparently cannot be provided by sodium ions; the all-sodium salt could not be prepared. The ;I-octamolybdate [M~,N(CH,),NM~,][MO,~~~] from a slightly ~rystallized,~ acidic aqueous solution of sodium molybdate and [Me,N(CH,),NMe,]CI,. The anions contain six edge-sharing MOO octahedra and two MOO trigonal bipyramids contrasting with the a-form (six octahedra and two MOO tetrahedra) and p-form (eight octahedra).Reaction of [NBU,],[MO~~PO,~] with PPh in MeCN gave39 the two- and four-electron reduced compounds containing one or two molybdenum(v) pairs where a bridging oxygen atom has been eliminated. The anion retains the Keggin-type structure. An exchange reaction involving transfer of a bridging oxygen atom between [Mo~~Mo~PO,,]~-occurs in solution within the NMR and [Mo~'Mo~PO,,]~- timescale. The aluminomolybdate K3H6[AlMo,0,,]~7H20 has4' a typical Anderson-type anion with MOO octahedra sharing edges with an almost regular central A10 octahedron. [NBuf;],[TeMo,O,,(OH,)] was prepared4 by the reaction of Te(OH) and [NBuf;],[Mo,O,,]. The X-ray crystal structure revealed the presence of discrete anions containing a distorted square-pyramidal MoV' atom.This contrasts with the only other structurally characterized five-coordinate MoV1 compound [MoO,{C,H,N(CH,P~,S)~)] which is trigonal bipyramidal. The isostructural arsenometalates Na,[As,M,O,,]~lOH,O (M = Mo W) have4 an M30, block stabilized by a linear triarsenate moiety. The arsenomolybdate anion reacts with Co2 + 33 T. Ozeki and T. Yamase Acta Crystallogr. Sect. C 1991 47 693. 34 S. H. Wasfi C. E. Costello A. L. Rheingold and B. S. Haggerty. Inory. Chem.. 1991. 30 1788. 35 I. Kawafune and G. Matsubayashi Chem. Lrrt.. 1992 1869. 36 J. Canny R. Thouvenot A. Teze G. Herbe. M. Leparulo-Loftus and M. T. Pope Inorg. Chmi.. 1991.30 976. " T. Ozeki. M. Takahashi and T. Yamase. Acfu Crystallogr. Sect. C. 1992 48 1370. 38 M.L. Niven J. J. Cruywagen and J. B. B. Heyns J. Chem. Soc. Dulron Truns. 1991 2007. 39 I. Kawafune and G. Matsubayashi Inorg. Chim. Actu. 1991 188. 33. 40 H.Y. Lee K. M. Park U. Lee and H. Ichida. Acfa Crystalloqr. Sect. C 1991,47 1959. 41 H. Ichida and A. Yagasaki. J. Chem. Soc.. Chern. Commun.. 1991. 27. 42 J. Martin-Frere Y. Jeanin F. Robert and J. Vaissermann. Inory. Chem. 1991. 30. 3635. 130 If. Sloan to give [C~(H,O),]I(,[A~,M~,~O~~~] which has an Anderson-type structure with the top and bottom of the anion having a tripod of corner-sharing AsO moieties on an equatorial band of MOO octahedral around a central cobalt atom. Bridging molybdate groups occur43 in the neutral complex [LF~(MOO,)~F~L]CH,C~~-H~O l2 -consisting of (L = Me,tacn) (2).The anion [Te,Mo 2060]has a novel ~tructure,4~ a ring of distorted TeO octahedra with pairs of MOO octahedra sharing one oxygen (3).Adjacent pairs of MOO octahedra share oxygen atoms with each other and with TeO only so there is no continuous -0-Mo-0-Mo-0-Mo-pathway. (Reproduced by permission from J. Chem. SOC. Chem. Commun. 1992 248) Another route to modification of catalytic properties with possible intermediates from catalytic reactions in mind is the attachment of ligands to the surface transition metal atoms in place of terminal 0x0 groups. The hexamolybdate anion [Mo,O J2 -reacted45 with Ph,P=Ntol to give an imido ligand (Mo=Ntol group). This is easily 43 K.Lettko S. Liu. and J. Zubieta. Actu Crysrulloqr. Sect. C. 1991 47. 1723.44 C. Rob1 and M. Frost. J. Chem. Soc,.. Chem. Commun.. 1992. 248. 45 Y. Du. A. L. Rheingold and E.A. Maatta. J. Am. Chem. So(,..1992 113 345. Cr Mo and W 131 hydrolysed to p-toluidine and the original molybdate anion. The Mo-0 bonds adjacent to the imido ligand are significantly shortened. 4 Cubane-type Structures A cuboidal arrangement M,X, of four metal and four Iigand donor atoms with each of these groups of four occupying alternating corners of the cube has become a well-recognized structural type. The X atoms are often oxygen or sulfur either as the single atom or as part of a ligand or halogen and are not always identical. Heterometal derivatives incomplete cubanes and linked cubanes are also known. While the structure is often distorted from a simple cube the term 'cubane' is often used for convenience.The chromium hydride cubane (4) was obtained46 as in Scheme 1. The Cr-Cr distances are long (2.715A) compared with 2.642A for (5) and 2.263A for (6). The decrease from (5) to (6) is expected for the change from four-electron chloro bridges to the two-electron methyl bridges and the stronger Cr-Cr bonding is consistent with the reduction in pefffrom 2.0,~~ to 0.9 pB.Compound (4) exhibits almost ideal Curie-type paramagnetism with peff= 2.83~~ down to 15K. While structural parameters for hydrogen are often uncertain from X-ray diffraction studies there is sufficient evidence to point to hydride ligands capping the faces of the chromium tetrahedron. (5) (R = Me Bun,CHzSiMe3) ,SP* (6) R = Me Scheme 1 A central cubic structure (7) of alternating molybdenum and oxygen atoms was found4' in [(Mo0,Cr(bispictn)),][C10,],.The configuration around chromium is alternately A and A. The minor product [Mo,0,(p3-O),(OSiMe3),(NHMe,),] from the co-condensation of MOO and Me,SiNMe a cubane structure with molybdenum(v) supported by monodentate ligands only. 46 R. A. Heintz B. S. Haggerty H. Wan A. L. Rheingold and K. H. Theopold. At~qew.Chern. Int. Ed. Enql.. 1992 31 1077. 47 J. Glerup A. Hazell and K. Michelsen Actu Chern. Scand. 1991 45. 1025. 4x G.S. Kim D. A. Keszler and C. W. DeKock. Inorg. Chem. 1991. 30 574. 132 H. Sloan (7) L = tetradentatebispictii The kinetics of the substitution by thiocyanate at molybdenum in the cubane [Mo~'S,(H,O),,]~+ showed4' two consecutive reaction steps an equilibrium for substitution at each of the four Mo centres by NCS- followed by an isomerization.For the mixed-valence cation [Mo,S,(H,O) ,I5+ ,two concurrent substitutions occur having statistical factors consistent with the presence of three Mo centres different from the fourth. Kinetic studies provide evidence for electron distribution corresponding to three Mo"' and one Mo" centres. An extensive series of Mo-S cubanes has been prepared5' with various mono-anionic dithiolate ligands [R,NCS, (RO),PS, ROCS, RSCS,] providing the sulfur atoms of the cube. The relative ease of reduction of these cubanes is RSCS > ROCS > (RO),PS > R,NCS,. Facile preparative techniques and crystal structures are reported5 for the incom- plete cubanes [M3(p3-S)(p-S),(H,0)9]4+ (M = Mo W) and derivatives with other ligands (NCS- tridentate Hnta) in place of water.Treatment of the trinuclear incomplete cubanes [MO~S~O~-,,(H,O)~]~'= 2 3 4) with borohydride (8 n caused5 replacement of the p2-S by p2-0,but further reaction with (8 n = 1) resulted in loss of the trinuclear structure rather than replacement of the p3-S by oxygen. The distorted cubane [WV(Ntol)(S,P(OEt),)(p3-S)] (9) has53 the tetrameric structure in the solid and this is also the dominant form in solution. The visible spectra are consistent with a dissociative equilibrium (more favourable for the W complex than for Mo) further evidence for which was obtained by the formation of a mixed cubane core [Mo2W2S4]on mixing solutions of the tungsten and molybdenum analogues.The mixed Mo-W incomplete cubanes [M,M'S,(H,0)9](ptolS03),~9H,0 (M = Mo M' = W; M = W M' = Mo) have the molybdenum and tungsten atoms statistically di~ordered;~~ they are both isomorphous with the analogous all-molybdenum (M = M' = Mo) or all-tungsten (M = M' = W) analogues. 49 Y. J. Li M. Nasreldin M. Hurnzres and A. G. Sykes Inorg. Chem.. 1992 31 301 1. 50 C. L. Coyle K. A. Eriksen S. Farina J. Francis Y. Gea M. A. Greaney P.J. Guzi. T. R. Halbert H. H. Murray and E.I. Stiefel Inorg. Chim. Acta. 1991 198-200 565. 51 T. Shibahara M. Yarnasaki. G. Sakane K. Minarni T. Yabuki and A. Ichimura Inorg. Chem. 1992,31 640. 52 Q.-T. Liu J. Lu and A.G.Sykes. Inory. Chrm. Actu. 1991 19&200. 623. 53 M.L. Sarnpson J. F. Richardson and M. E. Noble. Inorg. Chem.. 1992 31 2726. 54 T. Shibahara and M. Yarnasaki. Inorg. Chem. 1991 30. 1687. Cr Mo and W [Groupsp-tolyl and (EtO),PS not shown for clarity] The mixed-metal cubane [MO~MS,(H~O),~]~+ Fe Ni) reacted55 with Cu2+ (M = in aqueous media to give replacement of M by Cu. The Mo3S part of the central moiety is unchanged. Reaction of the incomplete cubane [Mo~S,(H,O),]~+ (10)with metallic cobalt gave56 a double cubane [(H,0),Mo3S,CoCoS,Mo,(H,0),1 [ptolSO3].l8H,O in which two Mo,S,Co moieties are joined through two Co-S bonds. Reaction with Hg gave [(H,0),Mo,S,HgS,Mo3(H20),][pto1S0,]-20H20 in which the mercury atom is sandwiched between two Mo3S4 units through six Hg-S bonds.A similar reaction with Ni gave5' [Mo3NiS,(H,0),,][pto1S0,1 .7H20 with a very low magnetic moment. This was reacted further with nitriloacetate in aqueous KOH to give [Mo3NiS,(Hnta)(nta),C1l5 -. In [W,Cu,S,(SCH,CH,S),(PPh3)2],the tungsten atoms are5* five-coordinate and bound to the sulfur atoms of the cubane moiety and chelating dithiolato ligand. The distorted cubane structure of [{WCU,S,CI)(S)(PP~,)~] was found to have5 tungsten tetrahedrally coordinated to the four S atoms. Similar tetrahedral WOS moieties The occur6* in [( WCU,S~(S,COE~))(O)(PP~~)~].related selenium cubane [{ WCu,Se3C1)(Se)(PPh,),1 has been prepared61 and used to give complexes contain- ing bridging WSe ligands. Heptanuclear [PPh,] ,[ W ,Cu,O,S,(S,CNEt ,),]-dmf has6' an anion containing two defective cubane units OWS3Cu2 and OWS,Cu, linked by bridging S,CNEt2 ligands and weak Cu-S bonds.5 Quadruple Metal-Metal Bonds Dinuclear complexes of general form [M2X,] with an M-M quadruple bond show a cubic arrangement of ligands. The possible motion of the M-M unit within the cube has been considered6 by means of Fenske-Hall-type molecular orbital calculations. Similar calculations were made for octahedral or [M2X6] complexes where the change '' T. Shibahara T. Asano and G. Sakane Polyhedron 1991. 10 2351. s6 T. Shihahara H. Akashi M. Yamasaki and K. Hashimoto Chem. Lett. 1991 689. " T. Shibahara M. Yarnasaki H. Akashi and T. Katayama. Inorg. Chem.. 1991. 30 2693. '' N. Zhu R. Wu and X.Wu Acta Crystallogr. Sect. C 1991 47 1537. '')N. Zhu J. Wu and X. Wu. Acta Crystullogr. Sect. C. 1991 47 856. S. Du N. Zhu P. Chen and X. Wu. Angew. Chern. Int. Ed. Enyl.. 1992. 31 1085. 61 C.C. Christuk M.A. Ansari. and J.A. Ibers Angew. Chem. Int. Ed. Engl.. 1992 31 1477. 62 R. Cao X. Lei. and H. Liu Actu Crystallogr. Secr. C. 1991. 47. 876. 63 R. H. Cayton and M. H. Chisholm Inory. Chem.. 1991 30. 1422. 134 H. Sloun does not appear to be of sufficiently low energy to be operative as an isomerization step though it is not disallowed on symmetry grounds. The Cr-Cr quadruple bond in [Cr,(p-bet),(H,O),] has6 symmetric bridging zwitterionic betaine ligands and weakly bound terminal aquo groups. The tempera- ture-dependent partial paramagnetism of [Cr,(O,CR),L,] (R = Me CF,; L = MeOH H,O py MeCN) and related compounds has been shown65 to reflect a distribution of electrons between a ground state with S = 0 and a low-lying state with S = 1.For R = Me the singlet-triplet separation varies inversely with the Cr-Cr distance as L is changed. The corresponding carbamato compounds (R = NEt, L = NHEt,) show smaller singlet-triplet gaps for similar Cr-Cr distances possibly due to different interaction with the 6 orbital. The complexes [Mo,X,(PR,),] (X = F R = Me, Me,Ph) prepared66 by reacting [Mo,Me,(PR,),] with Olah’s reagent (py-xHF) have a Mo core disordered in three directions within a symmetric cube of the eight ligands. Correlations were found between 6-6* transitions ligand-to-metal charge transfer bands Mo-X distances and NMR shifts for many known compounds with X = F Cl Br or I.Assignments of the far IR frequencies have been made67 for a number of [Mo,X,L,] complexes [X = C1 Br I; L = AsMe, PR (R = Me Et Pr Bu)] with the aid of a vector addition model. Complications arise from the presence of internal ligand deformation modes in the same spectral region. The determination of the energy separations from the magnetic susceptibility of the solid has been widely used over a wide temperature range and with considerable accuracy. The alternative method via the 31P chemical shifts is reported6* for quadruply-bonded complexes of type [Mo,Cl,(L-L),] [L-L = dmpe depe dppe dppee dppp (PMe,),]. The barrier to rotation of the Mo-Mo unit within the cubic array of the ligands was determined to be 9.9kcal/mole.[Mo,(pyphos),] (11) has69 Mo-Mo 2.103A indicating a bond order of four. Reaction of (1 1) with [Mo(CO),(NCMe),] [PdCl,(NCPh),] or [PtBr,(cod)] gave (12 a,b,c). Complexes (12 b,c) exhibit intense absorptions at 645 and 660 nm respectively suggesting dative Mo -+ M (M = Pd Pt) bonding. The reaction of the molybdenum(I1) complex [Mo,(O,CCF,),] with anthraquinone (AQ) in benzene gave” achain polymer [(Mo,(O,CCF,),~AQ},]. X-Ray and spectral studies show two differently bonded AQ moieties linking the dinuclear molybdenum entities. However the interaction has little significant effect on the electronic structure of the Mo core. Reaction of [Mo,(B,CR) (R = Me Ph) with [NRk],[WS,] (R‘ = Et Pr) gave71 thecomplex [NR4]2[Mo2(0,CR),(WS4)2] in which the quadruply bonded Mo-Mo is bridged by all four ligands; pairs of like ligands are mutually trans.There is some lengthening of the Mo-Mo bond compared with the starting complex. The WS moieties in the benzoate complex (R = Ph) are tilted so that one of the non-ligating sulfur atoms is directed towards the aromatic ring of the adjacent benzoate ligand. 64 W. Clegg B. P. Straughan and A. R. Yusoff Acru Crystullogr. Sect. C 1992 48. 1896. ‘’ F.A. Cotton H. Chen L. M. Daniels and X. Feng J. Am. Chem. Soc. 1992 114 8980. “ F. A. Cotton and K. J. Wiesinger Inorg. Chem. 1992 31 920. ‘’ M. D. Hopkins V. M. Miskowski. P. M. Killough A. P. Sattelberger W. H. Woodruff. and H. B. Gray Inorq. Chem. 1992 31 5368.‘’ F. A. Cotton J. L. Eglin B. Hong and C. A. James J. Am. Chem. Soc,.. 1992 114 4915. 69 K. Mashima H. Nakano. T. Mori H. Takaya and A. Nakamura Chem. Lett. 1992 185. ’” M. Handa H. Sono K. Kasamatsu K. Kasuga M. Mikuriya and S. Ikenoue Chem. Left. 1992 453. ” M. A. Greaney and E. I. Stiefel. J. Chrm. Six. Chem. C’ommun.. 1992 1679. Cr Mo and W 135 0-N-P O-N-P P- N- 0 P- N- 0 (11j P-N-O = pyphos (12) a ML = Mo(CO),; b ML = PdCl,; c ML,=PdBrz Reaction of [Mo,Me,(PMe,),] and C,F,OH gave72 [Mo,(OC,H,),(PMe3),] with the evolution of methane. This is the first example of a 1,2,7,8 isomer with unidentate ligands for the square prismatic structure [positions labelled as in (13)] though it may not be the thermodynamically most stable isomer due to the rapid precipitation of the product.[Mo,(O,CCF,),] reacted7 readily with bipy in MeCN giving the salt [Mo2(p-02CCF3)2(bipy),][02CCF,I whose structure was confirmed by X-ray diffraction. The IR and NMR spectra confirmed the presence of both ionic and ligated tri- fluoroacetate groups but temperature and solvent dependent isomerization occurred. The independent preparation of [M0,(q~-O,CCF,),(bipy)~]-2Me,C0 showed this to be the isomerization product having a very short unsupported Mo-Mo quadruple bond (2.077A). The isomerization also occurred photochemically. Binuclear compounds with weakly coordinated ligands are of interest for catalysis and preparative studies. The highly reactive salt [Mo,(NCM~),(UX-NCM~)~][BF,I -2MeCN was prepared7 from [Mo,(OAc),] and [OEt,][BF,] in acetonitrile; the centrosymmetric cation has linear Mo-N-C groupings except at the axial positions where the bent Mo-N-C angles appear to arise from interactions with the solvate molecules.The Mo-Mo distance is unusually long (2.187 A) for a quadruple bond. 'H NMR spectroscopy shows labile acetonitrile ligands undergoing rapid exchange with solvent. A comparison of the structures of [M,(dfm),] (M = Cr W) with those of the 72 F. A. Cotton and K. J. Wiesinger. Inorg. Chem. 1991 30 750. 73 J. H. Matonic S.-J. Chen. S. P. Perlepes K. R. Dunbar and G. Christou J. Am. Chem. Soc.. 1991 113 8169. 74 F.A. Cotton and K. J. Wiesinger Inory. Chrrn. 1991 30 871. 136 H. Sloan molybdenum analogue and other similar quadruply bonded complexes that the M-M bond lengths are insensitive to the use of more basic chelating ligands unlike the situation for Ru" 0s"'.Several quadruply-bonded heterobimetallic complexes [MoWCl,(L-L),] (L-L = bidentate phosphine) have been prepared.76 These gen- erally show the increased sensitivity towards oxidation typical of the homobimetallic tungsten analogues compared with the molybdenum analogues. However there is reduced reactivity towards alcohols comparable with the molybdenum analogues. Some of these complexes have chelating (designated 2) as opposed to bridging (designated p) diphosphines. The diamagnetic anisotropy of the Mo-W quadruple bond was essentially the same as that for the Mo-Mo bond. 6 Triple Metal-Metal Bonds The molybdenum-molybdenum triple bond is bridged77 by two (2S,3S)-2,3-bis(dipheny1phosphino)butane ligands in the symmetrical complex p-[Mo,(NCS),(dppb),]MeNO where the thiocyanate groups are N-coordinated.Reaction of symmetric [W,Cl,(NMe,),] with LiPR (R = Et Cy Bu' Ph SiMe, ptol p-C,H,F) at temperatures below 0°C resulted in substitution of the chloro ligands by PR,78 with retention of the W-W triple bond. These complexes occur in anti and gauche forms. On warming to over O'C or by direct reaction at higher temperatures further isomers are formed with bridging PR ligands. The 31P NMR spectra showed chemical shifts in the order anti < gauche < bridged. Crystal structure determinations of several of these comFounds gave W-W bond lengths consistent with the retention of the triple bond.A labile leaving group the trifluoromethanesulfonate ligand in [W,-(NMe,),(O,SCF,),] was introduced79 by reacting [W,(NMe,),] with Me,SiO,SCF,. This product has a symmetric anti-W,O,N core and reacted with PMe to give [W,(NMe,),(03SCF3)3(PMe3)2]. The latter contains roughly square planar WON,P and W0,NP units connected by a tungsten-tungsten triple bond in a staggered conformation. The W-0 and W-N distances C2.205 8 and 2.008 (ave) respectively] in the WON,P moiety are longer than those in the W0,NP moiety (average 2.13 8 and 1.928 respectively). The reaction of [W,(OR),] (14 R = SiMe,Bu') and NO in the presence of pyridine in a hydrocarbon solvent resulted inEo cleavage of the W-W triple bond and formation of a [W(NO)(OR),(py),] at low temperature (-72 "C) a reaction analogous to that of the complex (14 R = Bu').At higher temperatures however the NO bond of the siloxy complex cleaved giving CW(O)(OR),(PY,l and CW,(O),(OR),(PY),I* 7 Face- and Edge-sharing Bioctahedral Complexes The formation of binuclear complexes raises the question of the existence and order of l5 F.A. Cotton and T. Ren J. Am. Chem. Soc.. 1992 114 2231. 76 F. A. Cotton and C. A. James Inorg. Chem. 1992. 31 5298. 77 A. A. Aitchison L. J. Farrugia and R. D. Peacock Acta Crystallogr.,Sect. C 1991 47. 2556. l8 W. E. Buhro M. H. Chisholm. K. Folting J. C. Huffman J. D. Martin,and W. E. Streib J. Am. Chem. SOC. 1992 114 557. 79 M. H. Chrisholm K. S. Kramer J. D. Martin J.C. Huffman E.B. Lobkovsky and W. E. Streib Inorg. Chem. 1992 31 4469. '"M. H. Chisholm. C.M. Cook. K. Folting and W. E. Streib Inorg. Chim. Acta 1992 198-200 63. cr Mo and w 137 direct metal-metal bonding. The properties of these compounds often depend subtly on the electronic interaction between the metal centres whether through the direct link or through the bridging ligands. The mer configuration in solution of octahedral [MoX,L,] (X = Cl Br I; L = PMe, PEt, PMe,Ph) was established” from NMR spectroscopy. For the chloro complexes and the corresponding face-sharing [Mo,CI,L,] and the edge- sharing [Mo,Cl,L,] binuclear species the relative stability sequence face-sharing < edge-sharing << monomer holds in a phosphine-rich environment. The edge-sharing bioctahedral heterobimetallic complex [MoWCl,(p-CI)(p-H)(p- dppm),].2thf.C,H6 is formeds2 by the reaction of [MoWCl,(PMePh,),] with dppm.The complex contains trans dppm ligands. The Mo-W distance is consistent with multiple bonding and is unusually short for a (111)-(III) core. The oxidative addition of Y (Y = C1 Br I) to the quadruply bonded [Mo,X,(dppm),] (X = C1 Br I) forms nine edge-sharing bioctahedral complexes [Mo,X,Y,(dppm),]. Their structural and magnetic susceptibility properties indicated8 that both direct M-M coupling and indirect coupling across the p-X atoms occurs. Addition of lithium powder to cis-[WF,(OMe),] followed by excess NaOMe in thf gave84 edge-sharing bioctahed- ral [W,(OMe),,] where the W-W distance is consistent with single bonding.The use of resonance patterns in the ‘H NMR spectra of face- and edge-sharing bioctahedral complexes [Mo,Cl,L,] and [Mo,Cl,L,-,,L’], (L,L’ = phosphines) has been developed8’ to provide precise information on chemical identity and stereochem- istry. The mechanism of the transformation of edge- to face-sharing compounds has been studied. A large effect on the magnetic properties of the edge-sharing compounds is observed on quite simple substitutional interchange of PMe and PEt,. A logarithmic relationship has been determined8 between the spin exchange coupling constant and the metal-metal distance mainly for chromium face-sharing octahedral binuclear complexes. The bridging ligands include 0x0 hydroxo alkoxo and halo groups. The reaction of [W,(NMe,),] and ROH (R = cyclopentyl) in hexane initially formed [W,(OR),(NHMe,),] which converted8’ on standing to [W,(p-H)(p-OR),(OR),(NHMe,)] (15).This has a confacial bioctahedral structure; the position of the hydrido bridge is inferred to be trans to the NHMe ligand to form the (OOH) common face. The dimethylamine is readily replaced by PMe and in solution (15) is in equilibrium with [W,H(OR)J and free amine or phosphine. The face-sharing bioctahedral complexes [Mo,X,(PMe,Ph),] (X = Br I) were obtaineds8 by reacting [MoX,(thf),] with PMe,Ph in a 2 :3 ratio in refluxing toluene. Like the known complex with X = C1 they have three bridging halogen atoms; the R. Poli and H.D. Mui Inorg. Chem. 1991 30 65. F. A. Cotton C. A. James and R. L. Luck Inory.Chern. 1991 30 4370. 83 F. A. Cotton L. M. Daniels K. R. Dunbar L. R. Falvello C. J. O’Connor and A. C. Price Inory. Chrm . 1991 30 2509. 84 J. C. Bryan,D. R. Wheeler D. L. Clark J. C. Huffman,and A. P. Sattelberger,J. Am. Chem.Soc.. 1991.113 3184. ” R. Poli and J.C. Gordon J. Am. Chem. Soc. 1992 114 6723. n6 A. Niemann U. Bossek K. Wieghardt C. Butzlaff. A. X.Trautwein and B. Nuber Angrw. Chem.,Int. Ed. Engi.. 1992 31 311. ’’ S.T.Chacon M. H. Chisholm K. Folting M. J. Hampden-Smith and J. C. Huffman Inory. Chrm. 1991 30 3122. ** J.C. Gordon. H.D. Mui R. Poli and K.J. Ahmed Polyhedron 1991 10 1667. 138 H. Sloan other ligands were shared so that two halogen atoms and one phosphine are at one metal centre while one halogen and two phosphines are bound to the other.The inter-metal distance increases in the order CI < Br < I and the paramagnetism increases similarly as shown by solid-state magnetic susceptibility measurements and by solution NMR spectroscopy. The latter also showed an equilibrium between the anti and gauche forms. Reduction of WCl with Na/Hg (or NaBEt,H) followed by treatment with 1 or 1.5 equivalents of PMe2Ph gaves9 edge-sharing [W2C16(PMe2Ph),] and face-sharing [W2C16(PMe2Ph)3] respectively. Similar reactions with WBr gave the first bromo- bridged face-sharing complexes [W,Br,(PR,),] (R3 = Me2Ph Me,). The W-W bond distances of these four complexes are 2.6950,2.4433,2.4768 and 2.4496 8 respectively indicating strong metal-metal bonding. They are the shortest such bonds in neutral halogen bridged complexes so far described.8 Triangular Cluster Complexes Triangular clusters are known with 6 7 8 and 9 valence electrons involved in the metal-metal bonding and with combinations of doubly and triply bridging ligands usually oxygen sulfur or halogen donors. SCF-X,-SW calculations have been madeg0 for various trinuclear molybdenum and tungsten cluster compounds of the form [M3XI3] (X = one or two of 0,S Cl). Salts of [M~,(p~-s)(p,-s,),X~]~- (X = C1 Br I) reacted” with KSeCN in MeCN to form [Mo3(p3-S)(p2-SSe)3(Ncs)6]2 where substitution of sulfur by selenium has occurred only at the equatorial S atoms. The cluster complex [MO~(~~-S)~(~- S),(PMe,),] preparedg2 by treatment of [NH,],[MO,S,,] with excess PMe in thf has a three-fold axis of symmetry through the centre of the Mo triangle.The subtle Jahn-Teller effects that may occur in such eight-electron cluster complexes is emphasized by the contrasting isosceles triangular metal moieties of [Mo~(,u~--(shorter base) and [cr,(,~~-S)~(p-S s)2(,kcI)3c16]3 j,(dppe),] (longer base). The reaction of excess PEt with [Mo,S,Cl,] [Mo,S,Br,] or [W,S,Br,] gave’ [Mo3 (p3-s )(p-s)3c14(PEt3)3 (H20)21‘OPEt 3 [Mo 3 (p3-S)b-sj 3Br4(PEt 3 )3 (OPEtzH) (H 0)] .2 t h f or [W,(p,-S)(p-S) B r ,(P E t ) (0P E t H)(H 0)] .2 t h f re spec t ivel y . These have similar structures though the three metal atoms in each compound have a different coordination sphere. It is proposed that the OPEt2H ligand arises by oxidation of PEt, coordination hydrogen abstraction by a metal atom from an ethyl group and subsequent elimination of ethene and transfer of the hydrogen to phosphorus (Scheme 2).Compounds containing the ions [M 3(p3-O)(p-Cl)3(p- OAc),Cl,]-(M = Mo W) were prepared9 by the reaction of MoC13.3H20 or [NEt,],[W,CI,] with excess Ac20 and AcOH or 1 M hydrochloric acid respectively. While six-electron triangular clusters are well known these are eight-electron clusters of which there are few examples. The relative stabilities of the different oxidation levels 89 F. A. Cotton and S. K. Mandal Inorg. Chrm. 1992 31,1267. F.A. Cotton and X. Feng Inorg. Chem.. 1991 30 3666. 91 V. P. Fedin M. N. Sokolov. V. Ye. Fedorov D. S. Yufit and Yu.T. Struchkov Inorg. Chim. Actu 1991 179 35.92 K. Tsuge S. Yajima H. Imoto and T. Saito J. Am. Chem. Soc. 1992 114 7910. 93 F.A. Cotton P. A. Kibala and C. S. Miertschin Inorq. Chrm. 1991. 30 548. 94 F. A. Cotton M. Shang and Z. S. Sun J. Am. Chem. Soc. 1991 113 3007. Cr Mo aiid W are strongly affected by the bridging ligands. Chloro rather than 0x0 groups favour eight- rather than six-electron clusters and the redox behaviour of Mo/W homologues can be remarkably different. When Mo is not bound to a phosphine ligand in the nine-electron clusters [MO~(~~-O)(~-C~),(~-OAC)~C~~(PR~)~ -,,I' -'(n = 1-3) the Mo-Mo bond lengths95 are longer than in the eight-electron compounds mentioned above; the other Mo-Mo bonds are similar in length. The Mo-Cltermi,, bond lengths become shorter with increasing value of n.M -OPEt -M-OPEt + GH, I CH2-CH2 H Scheme 2 The reaction of nitrous oxide (as an oxygen source) with [W,(OR),] (R = Bu') in pentane at -15 ''C gave9 the triangular six-electron cluster [w,o,(oR),] with no capping ligand; one of the W-W bonds has no bridging 0x0 ligand. NMR spectroscopy indicates that each of the tungsten atoms has a different coordination sphere. On carrying out the reaction at higher temperatures or on warming the product disproportionation occurs to [W2(0R),] and [WO,(OR),]. 9 Hydride and Dihydrogen Complexes Conclusive evidence for the existence ofpu,-H in [MO~(~~-I)(~~-H)(~-I)~I~L~] has been provided9' by the observation of 1 3 3 1 quartets in the 'H NMR spectrum. Variable temperature ' and ,' P CP/MAS NMR spectroscopy of the nine-coordinate complex [WH,(PMe,),] showed9 it has a tricapped trigonal prismatic structure.Two of the phosphine ligands are in eclipsed but inequivalent prismatic sites and the third caps the prismatic face opposite the other two. Ligand functionality interchange between the phosphine sites occurred above 340 K. The formally 14-electron complexes [MH(SC,H,R,),(PMe,Ph),] (M = Mo W; R = Me Prl) have99 a distorted trigonal bipyramidal geometry with respect to the non-hydride ligands; the phosphines are essentially trans in the apical positions. NMR studies of the hydrides and their deuteride analogues show low-field hydride shifts. There is a large coupling to one of the phosphorus donors indicating an asymmetric location of the hydride ligand with respect to the phosphine ligands.Several polyhydride derivatives of tungsten and molybdenum are reported,' O0 including [M(n-crown-n')][WH5(PMe,),] (M = K n = 18 n' = 6; M = Na n = 15 n' = 5)and [(W(PMe,),H,Lii,] where crystal structure and spectroscopic data show considerable covalent bonding W-H . . . M for the lithium sodium and potassium compounds. '' F.A. Cotton M. Shang. and Z.S. Sun J. Am. Chem. Soc. 1991 113 6917. Yh M. H. Chisholm C. M. Cook and K. Folting J. Am. Chem. Soc.. 1992 114. 2721. A. Burini F.A. Cotton and J. Czuchajowska Polyhedron. 1991. 10. 2145. YH S. J. Heyes M. L. H. Green and C. M. Dobson. Inorg. Chrm. 1991 30 1930. YY T. E. Burrow. A. Hills D. L. Hughes J. D Lane. R. H. Morris and R.L. Richards. J. Chum. Soc. Dalton Trans.. 1991 1813. loo A. Berry M.L. H. Green J.A. Bandy. and K. Prout. J. Chun. Soc. Dnlron 7rans.. 1991 2185. 140 H. Sloan Reaction of the basic hydrides trans,trans-[WH(CO),(NO)(PR,),] (R = Me Et Ph OPr') with the Lewis acidic BH,-L (L = thf or SMe,) gave"' air sensitive trans-[W(q2-BH,)(CO)(NO)(PR,),] as the main product; the more acidic hydrides (R = OMe OPh) did not give such a borohydride. In general these compounds are unstable with respect to elimination of BH,-PR and were characterized by spectral methods. However a structural study of the complex (R = Me) was possible showing a distorted octahedron. trans,trans-[WH(CO),(NO)(PMe,),] reacted" readily with pyridin-2-yl aldehydes and ketones. Insertion of the C=O bond into the W-H bond led to the formation of tungsten alkoxides and rapid extrusion of CO followed to give 0,N-chelates.The barrier to rotation of dihydrogen in [Cr(CO),(PCy,),(q'-H,)] has been foundlo3 to be 1.5 kcal/mol by an inelastic neutron scattering method which also provided unambiguous proof of the dihydrogen binding. There is a contrast in the solid and solution stabilities of this complex where loss of hydrogen in solution is assisted by the agostic interaction of a hydrogen in the 2-position of a cyclohexyl substituent. The reaction of arachno-[B,H,,]- with [M"I,(CO),L,] (M = Mo W; L = PPh, PPh,Me PPhMe,) gavelo4 6,6,6,6-(CO),(PR3),,-6-M-B9H1 [M = Mo x = y = 2 (known previously); M = W x = 3 y = 13. The tungsten compound has structure (16).(16) Each boron atom also bears an exo-hydrogen atom 10 Carbon-donor Ligands In an unusual redox elimination reaction (17) loseslo5 CO and ethylene to give the Mo'" complex (18). Such high-valent carbonyl complexes are rare. IR and NMR spectroscopy show symmetrically oriented dithiolate ligands with cis carbonyl groups. Similar elimination of CO and ethylene from the PPh derivative (19) gave the corresponding complex (20). The high frequency CO absorption in the IR spectrum and the observed Mo-CO distance are consistent with bonding to an electron-deficient Mo centre. Protonation of [W(CO),(PCy,),] with HBF;OEt in toluene gavelo6 A.A.H.van der Zeijden. V. Shklover and H.Berke Inory. Chem. 1991 30 4393. A.A.H. van der Zeijden and H.Berke. Helv. Chim. Acta 1992 75 513. J. Eckert G. J. Kubas and R. P. White Inorg. Chrm. 1992 31 1550. '04 P. K. Baker M. A. Beckett and L. M. Severs. Polyhedron. 1991 10. 1663. 10s D. Sellmann F. Grasser F. Knoch. and M. Moll Anyew. Chem. Int. Ed. Engl.. 1991 30 131 1. L. S. Van Der Sluys K.A. Kubat-Martin G.J. Kubas and K. G. Caulton. Inory. Chem. 1991 30. 306. Cr Mo and W a b + C2H4 + CO (17) R=CO (18) R= CO (19) R = PPh3 (20) R = PPh3 a R = CO 25 "C vacuum 15 days b R = PPh, 65"C thf 75 min [WH(CO),(BF,)(PCy,),] (21). X-Ray diffraction shows disorder in the oxygen atom of the CO group trans to the BF ligand; the W-C-0 linkage is definitely non-linear. The 'H and 31PNMR spectra show inequivalent phosphine ligands; disorder in the hydride position is also proposed as shown.The very long W-W bond (3.288 A) in [W,(CO),Cp;] has' O7 some support from two semi-bridging carbonyl groups with the W-C-0 angle at 170.4'. CY3 (21) O' H' and 02,H2 represent alternative positions for the oxygen of the carbonyl and the hydride ligands. Mononuclear compounds containing the cylindrically symmetrical but electroni- cally disparate carbonyl r-acid and 0x0 r-base ligands are rare. Oxidation of [NE~,][W(CO),{HB(M~,~Z)~)] by iodine or bromine in CH,CI or MeCN gave [WX(CO),(HB(Me,pz),)] (X = I Br) which may be further oxidized"' by dioxygen in refluxing toluene or hot MeCN to give [WXO(CO){HB(Me,pz),>]. The latter has an unusually low-field 13C signal near 280ppm assigned to the CO ligand.Further oxidation to the more thermodynamically stable cis-dioxo complex lo' A. L. Rheingold and J. R. Harper Acra Crpralloqr. Srcr. C. 1991 47 184. 10R S.G.Feng. L. Luan P. White M.S. Brookhart J. L. Templeton and C. G. Young lnorq.Chrm. 1991.30 2582. 142 H. Sloan [WO,X{HB(Me,pz),)] occurs. The intermediate iodotricarbonyl also reacted with aniline to form the nitrene complex [W(NPh)I(CO){ HB(Me,pz),)] for which vco and the 13C chemical shift for the carbonyl carbon indicate the greater electron density available for back-bonding compared with the 0x0 analogue. Evidence for a bent nitrene intermediate was obtained"' from the reaction offac-[Mo(CO),(NCMe),L1 [L = PPh, MeCN P(OMe,), P(OEt,),] and 8-azidoquinoline.In particular the reaction when L = PPh gave as major products (22) and (23). (22) z= co (23) Z = PPh3 Attempts to prepare [Cr(CO),(CNH)] (24)showed"' that the hydrogen isocyanide ligand forms strong hydrogen bonds to cyclic ethers and crown ethers. The adduct with thf for example is sufficiently stable to be sublimed. Crystallization from ether-layered CH,CI solutions of equimolar amounts of (24) and [ER,][Cr(CO),(CN)] (ER = NEt or AsPh,) gave the [AHA]- type ion (25); a strong possibly symmetric hydrogen bond is shown by single I3C NMR signals for each of CN COcis and COfrans and band deficient IR and Raman spectra. X-Ray structure analysis supports a strong hydrogen bond with an N(H)..-N distance of 2.569A as does the "N-CPMAS- NMR spectrum of (25 ER = AsPh,) which shows only a single line for the equivalent N atoms.By contrast the "N-CPMAS-NMR spectrum of (25 ER = NEt,) gave two signals. The asymmetric complex [Cr(CO) {CNHNC)Fe(dppe)Cp] shows markedly different CN bands in the IR and different CN signals in the NMR spectra. 11 Carbon Dioxide and Carbonate Ligands The reaction of CO with cis-[Mo(N,),(PMe,),] in coordinating solvents gave" * the carbonyl-carbonate complexes [{Mo(~(,-~~,~~-CO,)(CO)(PM~,),}~] (26) and [Mo(CO,)(CO)(PMe,),] (27)derived from the reductive disproportionation of CO,. J.L. Fourquet M. Leblanc A. Saravanamuthu M. R. M. Bruce and A. E. Bruce Inorg. Churn.. 1991,30 3241. 'lo E. Bar J. Fuchs D. Rieger F. Aguilar-Parrilla. H.-H. Limbach.and W. P. Fehlhammer Angrw. Chum.. In?. Ed. Engl. 1991 30 88. 'I' R. Alvarez J. L. Atwood E. Carmona P.J. Perez M. L. Poveda and R. D. Rogers Inorq. Chem. 1991.30 1493 Cr Mo and W Ether or thf as solvent led to the preferential formation of (26)while acetone gave (27). The two products interconvert readily by association or dissociation of PMe, and solution stability is strongly solvent dependent. Further reaction with chelating phosphines gave [Mo(CO,)(CO)(P-P)(PMe,),] (P-P = dmpe dmpm) and [Mo(CO,)(CO)(dmpe),]. Both (26) and (27) react with water giving the Mo"-MoV complex (28) where the carbonate ligand is engaged in a novel type of bonding. (26) R= Me (27) R=Me Carbonate provides' l2 the sole link between the chromium(m) centres in a notably robust complex trans-[(Cr(NH,)(~yclam)),(p-CO,)]~', which is unaffected by hot 6M hydrochloric acid.There is antiferromagnetic coupling between the chromium centres. Excess methanol or NR,H [R = Me Et; R = (CH,), (CH,), (CH,),O(CH,),] reacted' ' with trans-[W(CO)(N,)(dppe),] under CO to give hydrido-carbonato [WH(y'-OCO,Me)(CO)(dppe),] or hydrido-carbamato complexes [WH(q2-O,CNR,)(CO)(y '-dppe)(y2-dppe)] respectively. The carbamato complex [R = (CH,),] treated with AIEt under CO gave trans-[W(CO)(CO,)(dppe),] with a C,O-coordinated y2-CO ligand. Detailed vibrational studies of trans-[Mo(CO,),(PMe,),] showed' ' that the CO ligands are bound side-on through carbon and one of the oxygen atoms. Exchange reactions between trans-[Mo(CO,),(PMe,),] with diphosphines (dmpm dmpe depe dppe) gave' '' mono-and di-chelated substitution of the simple phosphines.The existence of a number of conformations in solution depending on the variations in CO orientation was demonstrated and mechanisms for their interconversion considered. Complexes obtained by further substitution of PMe by RNC were also studied. E. Bang J. Eriksen J. Glerup L. Msnsted 0.Msnsted and H. Weihe Actu Chrm.Sund. 1991.45 367. 'I3 T. Ishida. T. Hayashi Y. Mizobe. and M. Hidai Inorg. Chern. 1992 31. 4481. I I4 C. Jegat M. Fouassier. and J. Mascetti Inory. Chrm. 1991. 30 1521. 'Is E. Carmona A. K. Hughes M. A. Muiioz. D. M. O'Hare P. J. Perez,and M.L. P0veda.J. Am. Chrm.Soc.. 1991 113. 9210. 144 H. Sloan 12 Silicon-donor Ligands Reaction of (29a) or (29b) with Na,[Cr(CO),] gave116 (30) with intramolecular base stabilization of the low-coordinate Si atom.In (30a) there is evidence from NMR spectroscopy for the alternating dynamical coordination of the NMe moieties to Si. The Cr-Si bond is noticeably short. The coordinated Si-N bond of (30a) is shorter than that in (29a). \ (29) a R = CH,NMq; (30) a R = CH,NMq; b,R=H b,R=H 13 Nitrogen-donor Ligands A correlation of calculated electron density shifts with the experimentally observed leaving groups in the photochemistry of chromium(Ii1)-ammine complexes has been observed.' l7 Ab initio calculations have been made' for [Cr(NH3)J3+ and a number of mono- and di-substituted chromium ammine complexes in a detailed analysis of their ligand field spectra.While spin-forbidden excitations are calculated to be too large results are generally in good agreement with experimental data. Pulsed photoacoustic microcalorimetry was used' ' to determine bond dissociation energies in [Cr(NH3),l3+ and [CrCl(NH3),]2f. A simple angular overlap model was in reasonable agreement with the results. Characteristic IR spectral properties have been identified' 2o for Cr-propylenediamine complexes. Linear correlations with Gutmann's acceptor numbers are found' ,' for the solvatochromic effects and solvent dependence of I3C NMR shifts of trans and cis-[Cr(N),(O),] type complexes. The p-cyano- bis[pentaamminechromium(r~~)] ion is antiferromagnetic. '22 One-electron oxidation of the anion [Cr(CO),(NO)] -with trityl hexafluorophos-phate gave'23 [Cr2(CO)a(NO)2] (31 )which has a molecular structure (Cr-Cr = 3.020 and 3.001 A two crystallographically independent molecules) analogous to that of 'I6 R.Probst C.Leis S. Gamper. E. Herdtweck. C. Zybill. and N. Auner. Anyrw. Chrm. Inr. Ed. Enyl. 1991. 30 1132. L. G. Vanquickenborne B. Coussens. D. Postelmans. A. Ceulemans and K. Pierloot. Inory. Chrm.. 1992 31 539. 'IxL.G. Vanquickenborne. B. Coussens D. Postelmans A. Ceulemans and K. Pierloot. Inory. Chrm. 1991. 30 2978. I") X. Song and J. F. Endicott. Inorc;. Chem.. 1991. 30. 2214. 12' Y. Sakabe and H. Ogura And. Sci, 1992. 8 63. ''I S. Kaizaki N. Koine. and N. Sakagami Bull. Chrm. Soc. Jpn.. 1991. 64. 2058. '22 J. Glerup and H. Weihe.Acru Chrm. Sund.. 1991 45 444. A. P. Masters M. Parvez and T. S. Sorensen. Curi. J. Chrm.. 1991 69 2136. Cr Mo and W [Mn,(CO),,] (Mn-Mn = 2.904 A) and isoelectronic [Cr,(C0)l,]2-. The NO groups are trans to Cr in both (31) and the anion [Cr,(CO),(NO)]- (Cr-Cr = 2.995A). [W(CO),(Benzo[c]cinnoline)] is octahedral with the benzocinnoline coordinated through one nitrogen atom only. The N-N bond order is significantly reduced contrasting with a benzocinnoline complex of iron where the N-N bond remains at its double bond length. Three-coordinate compounds of third row transition metals are rare. The first example for tungsten (32) prepared'24 as in Scheme 3 is diamagnetic and monomeric. It is stable in the solid form but decomposes slowly in solution.An X-ray structural determination showed it to be planar trigonal slightly distorted to a T-shape with relatively short W-N and W-0 bonds. Simple o-donors such as thfdo not bind to (32) but alkenes will do so readily. [(ButNH)2W(=NBu')2] + 2Bd3SiOH -[(Bu'$i0)2W(=NBut)2] + 2NBu'H2 benzene 3HC1 1IOOC 3.5 d1 - [(But3Si0)2W=NBu'] + MgCl Mg dust,Et2P [(Bu'~S~O),CI,W= NBu'] + [NBu'H3]CI 25"c,7 (32) Scheme 3 Fast time-resolved IR spectroscopy was to probe the metal to 4-cyanopyridine charge transfer excited state of [W(C0),(4-CNpy)]. On visible light irradiation the CO stretching vibrations shift to higher frequency confirming that in this excited state the metal centre is oxidized. The silylcobalt complexes [Co(CO),(SiR,R')] (R R' = Ph Me) reacted'26 with the dinitrogen complexes [M(N2),L4] (M = Mo W L = tertiary phosphine) to give the silyldiazenido complexes trans-[M(NNSiR,R' )L,(p-OC)Co(CO),] which were fur- ther converted to silylhydrazido(2 -) complexes such as [WX(NNHSiR,R' )(dppe),] [Co(CO),] by treatment with HX (X = OH OMe Br).In the diazenido complex (M = Mo R = Ph R' = Me) Mo-N-N is linear and the angle N-N-Si is 152.2". The Mo-0 bond in the Mo-0-C-Co chain is long (2.25681) and the angle Mo-0-C is 164.9'. Dinitrogen complexes of Moo and Wo are known to react with strong acids to give ammonia or hydrazine or ammonia and hydrazine uia disproportionation of a hydrazido(2 -) complex. The presence of SnCl or GeI increasesI2' the formation of ammonia in such reactions and decreases the yield of nitrogen.One of the coordinated dinitrogen ligands in [W(N,),(dppe),] is protonated' 28 quantitatively at room temperature by the strongly acidic [Ru(q2-H2)(dtfpe)Cp]+in thf to give the hydrazido(2 -) complex [W(NNH,)F(dppe),][BF,]. 1 ,I-Diphenyl hydrazine reacted' 29 with [MoO,(acac),] in methanol to give 124 D. F. Eppley P.T. Wolczanski and G.D. Vanduyne Angew. Chem.. Int. Ed. Engl. 1991. 30. 584. I25 P. Glyn F. P. A. Johnson M. W. George. A. J. Lees and J. J. Turner Inorg. Chem. 1991. 30. 3543. 126 A.C. Street Y. Mizobe. F. Gotoh 1. Mega. H. Oshita. and M. Hidai Chem. Lett. 1991 383. T.A. George and B. B. Kaul. Inory. Chem. 1991. 30. 882; T. A. George M.A. Jackson and B. B. Kaul Polyhedron. 1991. 10 461. 1 ZX G. Jia R. H. Morris and C.T. Schweitzer Innrg. Chem. 1991 30. 593. I29 C. Bustos C. Manzur H. Gonzalez R. Schrebler D. Carrillo C. Bois. Y. Jeannin and P. Gouzerh Inorg. Chim. Acta 1991. 185 25. 146 H. Sloan [MoO(NNPh,)(acac),] (33) or [(MoO(NNPh,)(acac)(p-OR)),] (34 R = Me) de- pending on the temperature. Complex (33) reacted in refluxing ROH (R = Me Et Pr) to give alkoxy-bridged (34). The geometry of the hydrazido(2 -) ligand is consistent with extensive delocalization through the Mo-N-N unit. Similar compounds result- ed' ,'with 1-methyl-1-phenylhydrazine. Cyanamide reacted',' with trans-[M(N,),(dppe),] (M = Mo W) to give trans- [M(NCN),(dppe),] which has a near linear Mo-N-C-N system and an Mo-N bond length consistent with a bond order greater than one.The dehydrogenation of cyanamide does not occur with less electron-rich cationic centres. The 'H NMR spectrum of [M,(OEPh,),(NMe,),] (M = Mo W E = C; M = W E = Si) showed13* a temperature-dependent mixture of anti and guuche forms. The structures are exclusively anti for molybdenum and gauche for tungsten in the methoxide derivatives and anti for the tungsten-silicon complex. The tungsten atom of [NBu,][WCl,(Nptol)]- one of the products of the reaction of [NBu,][H,PW ,O,,] and [WCI,(Nptol)], is 0.43A out of the plane*33 of four chlorine atoms in the distorted octahedral structure. The W-N bond (1.43 A) is consistent with a double bond and the W-N-C bonds are almost linear. The other product the anion [W,(p-O)Cl,(Npt~l),]~-with the p-tolylimido groups cis to the bridging 0x0 ligand is slightly folded to separate the aryl groups; variations in the W-N distances are consistent with the possible trans effects present.Treatment of [( WCl,) ,(/I-NC,H,N-1,4)] obtained from WOCl and C,H,(NCO),-I ,4 with PMe,Ph gave' 34 [{WC1,(PMe,Ph),),(p-NC6H4N-I ,4)]. The linear n-bonded 1,4-phenylenediimido bridge joins the mer,trans-{ WCl,(PMe,Ph),) fragments in an eclipsed conformation. 14 Phosphorus-donor Ligands Phosphorus reacts'35 with WO to give a mixture of WP WP, WPO, and the novel WP,O,. The compounds are readily separated in pure form by chemical vapour transport reactions. Heating solutions of the pentaphosphacyclopentadienyl anion P; in dme with [M(CO),(NCR),] or [M(CO),] (M = Cr Mo W) gave', the first mixed carbonyl(pentaphosphacyclopentadieny1)metal complexes [M(CO),(q5-P,)] -.The tungsten complex shows a remarkably small 13C-'83W coupling in the NMR spectrum; the IR spectrum shows the two CO absorption pattern typical of local C,, symmetry. The tungsten complex reacts with SiClMe, giving [W(SiMe,)(CO)(q'- P,)] where the 'H NMR signal of SiMe is similar to that in the corresponding cyclopentadienyl complex. The isomorphous and isostructural [M(CO),(dppb)] (M = Cr W and the previously reported M = Mo) show'37 the expected shorter bond lengths to chro- mium and the longer M-C bond for the rrans carbonyl groups. The chromium complex has a larger P-M-P angle. The structures of a series of bis(dipheny1phosphino)alkane 130 D. Carrillo F. Robert and P.Gouzerh Inorg. Chirn. Acru 1992. 197 209. 13' A. J. L. Pombiero Inorg. Chim. Acra 1991. 198 200 179. 132 M. H. Chisholm I. P. Parkin. J. C. Huffman. E. M. Lobkovsky. and K. Folting Polyhedron. 1991.10.2839. 133 Q. Chen D. McClinton and J. Zubieta Inorg. Chim. Acfa. 1992 195 163. 134 W. Clegg R. J. Errington D.C. R. Hockless. J. M. Kirk and C. Redshaw. Po/.phedron 1992 11. 381. 135 H. Mathis R. Glaum and R. Gruehn Acru Chem. Scand.. 1991. 45. 781. 136 M. Baudler and T. Etzbach Angew. Chem. Int. Ed. Engl.. 1991 30 580. 13' C.-H. Ueng and G.-Y. Shih Acta Crysfallogr.. Sect. C 1992 48 988. Cr Mo and W 147 carbonyl complexes of molybdenum have been determined138 in order to elucidate effects of chelate and carbonyl ligands. Despite the greater steric requirement of the phosphine ligand in the water-soluble [Na-kryptofix-22I],[W(CO),(PR3)] (R = C,H,SO,-rn) compared with PPh, there is close ~irnilarity'~~ with the related PPh complex.On further reaction interligand interactions via the Na+ ion are considered to facilitate the exclusive formation of the cis isomer of [W(CO),(PR,),]6-. Oxidation of (35) gavel4' the compound (36) containing triply-bridging PO ligands. An unusual form of phosphinidene bridging has been obtainedl4* in (37)with a double and a single bond to tungsten atoms of different oxidation numbers. While the cyclopentadienyl complex is thermally very stable the pentamethylcyclopentadienyl homologue readily eliminates PH,mes to give the more common form of the cyclic symmetrical phosphinidene complex (38).(E,E)-3,4-bis(2,4,6-Tributylphenylphos-phinidene)-(1,2-trimethylsilyl)cyclobutene (39) reacted'42 with Group 6 hexacar- bonyls or [M(CO),(thf)] or [M(CO),(nbd)] to give the stable complexes [M(CO),L]. There is a linear relationship between 31P NMR chemical shifts and the mass of the metal atom. (35) Mes I (L= Cp') * L (37) L = cp cp* 2,2'-bis(3,4-DimethyIphosphinine)reacted', with [Cr(CO),(thf)] to give the symmetrical complex (40).The P-CI bond is longer than the P-C-6 bond within each phosphinine ring in contrast to both of the analogous bipy and 2-phosphinine- 2'-pyridine complexes where the corresponding bonds are closely similar in length. Titration calorimetry has been to determine the heats of protonation of cis-[M(CO),(L-L),] (M = Cr Mo W; L-L = dppm dppe dppp arphos dmpe) 13R C.-H.Ueng and G.-Y. Hwang Acra Crystallogr. Sect. C. 1991,47 522; C.-H. Ueng and L.-C. Leu Acra Crystallogr. Ser. C 1991 47 725. 13Y D. J. Darensbourg C. J. Bischoff. and J. H. Reibenspies Inorg. Chem. 1991. 30 1144. 140 0.J. Scherer J. Braun P. Walther G. Heckmann and G. Wolmershaeuser. Angel?. Chem. 1991,103.861. 141 W. Malisch U.-A. Hirth T.A. Bright H. Kab T. S. Ertal S. Huckmann and H. Bertagnolli. Angrw. Chem. Int. Ed. Engl. 1992 31 1525. 142 K. Toyota K. Tashiro. and M. Yoshifuji Chem. Lett. 1991. 2079. 143 P. Le Floch D. Carmichael L. Ricard and F. Mathey J. Am. Chem. SOL..,1991 113 667. 144 J. R.Sowa Jr. J. 9. Bonanno V. Zanotti.and R. J. Angelici Inorg. Chem. 1992 31. 1370. 148 H. Sloan Ar I SiMe3 %Me3 I Ar oc co (39) Ar = 2,4,6-ti-ibutylphenyl (40) with CF,SO,H in 1,2-dichloroethane. Spectroscopic studies showed protonation at the metal and the heat of protonation becomes less exothermic implying greater basicity as the chelate ring size increases. Replacing phenyl by methyl substituents increases basicity as the ligand becomes a better o-donor. The arsenic complex has a greater heat of protonation in line with the weaker bonding. The effect of changing the metal is to increase basicity and heat of protonation in the order Cr << Mo < W for the dppm series but there is some reversal (Mo > W) for the dppe complexes. An investigation by 'H NMR spectroscopy in CDCI or CD,Cl of the reactions of mer-[MoCl,(thf),] with phosphines has shown145 a clear trans effect in that the thf trans to a chloro ligand is replaced more rapidly than thf opposite to thf.Final products are the trichlorotrisphosphines except for bulkier phosphines which give dinuclear complexes. The most nucleophilic phosphines react with solvent to give additional chloro ligands in tetrachloro complexes. The 95M~ NMR shifts serve146 as a sensitive probe of the nature of PR ligands for a wide range of R types. Correlation with the Kabachnik electronic parameter allows differentiation of (T and zeffects though steric effects may interfere. For chlorophosphines results suggested poor n-acceptor properties in contrast to the view based on IR carbonyl frequencies.While the relative strength of alkylphosphite ligands as z-acceptors is well established that of alkylphos- phines remains poorly understood. The '0 NMR-derived quadrupole coupling constants have been determined147 in a comparative study of the axial and equatorial carbonyl ligands in [W(C0)5{P(OMe),)] [W(CO),(PMe,)] and [W(CO),(NMe,)] and the results provide a quantitative comparison of the n-acceptor properties of the trimethylphosphine ligand. 15 Arsenic-donor Ligands The seven-coordinate complex [WBr,(CO),(PMe,)(dtmah)] has notably shorten- ed148 W-As bonds possibly due to d,-d back donation from tungsten. The differences between these two bonds are ascribed to trans effects in the distorted monocapped trigonal prismatic structure.Chemically imposed disorder occurs149 in the crystal structure offac,fac-[Mo2(C0),(ape),l. One ape ligand bridges the two molybdenum atoms and the facial arrangement of the (CO) moieties leads to the disorder so that it is not possible to distinguish As and P atoms. 145 R. Poli and J.C. Gordon Itiorg. Chem. 1991. 30 4550. 14' E.C. Alyea and S. Song Inorg. Chrm.. 1992 31. 4909. 147 S. P. Wang M. G. Richmond and M. Schwartz J. Am. Chem. Soc.. 1992. 114 7595. i4x S. K. Manocha L. M. Mihichuk R. J. Barton. and B. E. Robertson Acrci Crystcdlogr. Sect. C. 1991 47 722. 149 6. F. Abrahams. R. Colton 6.F. Hoskins and K. McGregor. Ausr. J. Chrm. 1992. 45 941. Cr Mo atid W 149 16 Oxygen-donor Ligands The hexaaquachromium(r1r) cation in [Cr(H2O),]NO,.3H,O is distorted' 50 from octahedral geometry with Cr-0 distances varying from 1.46 to 1.72 A; the 0-Cr-0 angles are all close to but significantly vary from 90".The ESR spectrum of hexaaquomolybdenum(m) has been reinvestigated,' ' with significant differences from a previous report. A neutron diffraction study of the fully deuterated Tutton salt [ND4],[Cr(SO,),]-6D,O shows' 52 a large Jahn-Teller distortion of the cation [Cr(D,O),]". A contribution to the debate over the splitting in the sharp line transitions due to the anisotropic nature of the n-donor interaction of the hydroxyl ligand in [Cr(NH,)5(OH)]2' has been made' 53 with studies of the deuterated and undeuterated complex. Some re-assignment of bands is suggested.Neutron diffraction has provided' 54 improved definition of the disorder of both aquo and cyano ligands in [Co(NH,),(H,O)][Cr(CN),] with both ions of strongly regular octahedral form. The gas phase electron diffraction of chromyl nitrate [CrO,(NO,),] indicated' 55 a severely distorted octahedral structure in that the nitrate groups act as chelating ligands with one short and one long Cr-0 bond (estimated bond order of0.19-0.29 for the long bond). The 0x0 ligands are mutually cis. Outer sphere coordination of organic solvents to [Cr(acac),] and to [Cr(trop),] shows similar effects' 56 in their 'H and '3C NMR spectra suggesting interaction with the inner coordination environment of the metal and oxygen atoms. The structure of trans-[(Cr(en),(ONO)}2(H302)][C104]3 has' 57 two unusual features.As well as the 0-bound nitrito group with the other oxygen directed away from the chromium atom the two metal centres are bridged by an (OH)-H-(OH) chain with the middle H on a centre of inversion for the cation. Photochemical reaction of [W(CO),(thf)] with [NEt,][catH] gavel5* [NEt,],[W(CO),(cat)]-catH for which diffraction studies show continuous hydrogen bonding between bridging catechol and adjacent anions. Hydrogen bonding is present also in solution in MeCN deduced from the higher frequency CO vibrations in the IR and the downfield shift of the I3C NMR peaks. In the complex without the 'solvating' catH, the carbonyl ligands are fluxional and the NMR peaks coalesce at 23°C. The coalescence temperature is reduced by electron-releasing But groups on the cat ligand.Loss of CO occurs in the equilibrium of Scheme 4. The reaction of [CrCl,(thf),] with NaOPr' initially gave' 59 the polymer [{Cr(OPri)2]n] followed by further reaction as in Scheme 5; the final product has to have an octahedral arrangement of Cr,Na with the two chromium atoms in trans 15') D. Lazar B. Ribar V. Divjakovic. and C. Meszaros Actu Crystrullogr.. Sect. C 1991. 47 1060. 15' C.J. H. Jacobsen and E. Pedersen Inorg. Chem. 1991 30 4477. Is.? B . N . F'iggis E. S. Kucharski and J. B. Forsyth. Acta Crystallogr.. Sect. C. 1991 47 419. 153 K.-W. Lee and P. E. Hoggard Inorg. Chm. 1991 30 264. IS4 B. N. Figgis E. S. Kucharski and M. Vrtis Actu Crystullogr. Sect. B. 1991 47. 858. 15' C.J.Marsden K. Hedberg M. M. Ludwig and G. L. Card. Inorg. Chem. 1991 30 4761. 15' A. N. Kitaigorodski and U. Edlund. Actu Chern. Scund.. 1991 45. 534. A.G. McKenna W.T. Pennington and J.C. Fanning Inorg. Chim. Acta 1991 183 127. lSxD. J. Darensbourg K. K. Klausmeyer. B. L. Mueller and J. H. Reibenspies Angew. Chem. Int. Ed. EngI. 1992 31 1503. Is' J.J. H. Edema. S. Garnbarotta W.J.J. Snieets. and A. L. Spek. Inorg. Chem. 1991. 30 1380. 150 H. Sloan R = H Bu' Scheme 4 Scheme 5 positions and a propoxide capping each CrNa face. One thf molecule is ligated to each sodium atom. The influence of ligand and alkali metal counter-ions on the molecular complexity of chromium(I1) aryloxides has been examined.' 6o The products of the reaction of WCl with o-phenylenediamine are affected161 by the nature of the solvent; isopropanol gave binuclear [{ WCl,(Hpda)},(q-pda)] (41) whereas methanol led to the unsymmetric methoxide [W,Cl,(OMe),(p-OMe)2].Complex (41) has different bond lengths for the W-amino (2.2981) and W-amido (1.92 81) bonds in the chelated Hpda; the bridging pda is symmetric with W=N double bonds (1.75 A). The reaction in thf of WOCl, o-phenylenediamine and LiNMe (prepared in situ from Me,NH and commercial BuLi in hexanes) gave the anion [W2Cl,0(ONMe,),] -which has bridging 0x0 and one bridging hydroxylaminato groups both of which are symmetric. X-Ray diffraction studies showed162 that [(W(N-ptol)(OR),},] (R = Me Pr') have alkoxide bridged structures. The bridges are asymmetric (W-0 = 2.072 2.181 A) with the longer bond trans to the terminal arylimido ligands.Proton NMR shows the arylimido ligands to be dynamic in solution though less so than the 0x0 analogues. Anti-ferromagnetic [Cr,(a~ac),(p-0C,H,R)~] (R = H Me C1 OMe NO,) showed163 a magnetic interaction increasing with the pK of the phenate ligands but no significant differences in the UV/visible spectra. X-Ray diffraction studies (R = H Me) indicated a racemic mixture rather than the more common meso form. Thiophenate analogues are also reported. Straight W-O-Cphenoxy bond dispositions were found16' in [WCl,_,(OAr),] (n = I 2; Ar = 2,6-dimethylphenyl) though such bonds are known with angles as small as 117". The complex [Mo,O,(HCO,),]~- with one bridging formato and two bridging 0x0 groups is a useful source165 of aquo-molybdenum ions without the common problem of chloride contamination.The general rule of lengthening of bonds trans to a I60 J. J. H. Edema A. Meetsma. S.Gambarotta S. I. Khan W. J. J. Smeets and A. L. Spek Inorg. Chem.. 1991 30 3639. 16' C. Redshaw G. Wilkinson B. Hussain-Bates and M. B. Hursthouse. J. Chem. Soc.,Dmlton Trans. 1992 555. 162 W. Clegg R. J. Errington and C. Redshaw J. Chem. Soc. Dulton Truns.. 1992. 3189. 163 M. Nakahanada T. Fujihara A. Fuyuhiro and S. KaiLaki Inorg. Chem. 1992. 31 1315. 164 N. Kanehisa Y. Kai. N. Kasai H. Yasuda Y. Nakayama and A. Nakamura Bull. Chrm. Soc. Jpn. 1992 65 1197. M. Brorson and A. Hazell Actu Chem. Scund. 1991 45 758. Cr Mo and W terminal 0x0 ligand in binuclear molybdenum(v) complexes with two bridging oxygen atoms was confirmed but no such effect was found'66 from structural determinations where the bridging atoms are sulfur.The 18,W NMR chemical shifts of a number of 0x0- sulfido- and nitrido-tungsten(v1) complexes have been measured' 67 by indirect methods. The tungsten nuclei become more de-shielded with increasing ligand polarizibility and bond multiplicity. Ligand substitution of rac-1,l'-binaphth-2-01 (H,bino) with [W,(OBu\),] gave'68 mainly anti-(R,S) compound (42) whereas (R)-H,bino gave the gauche-(S,S) form. The distribution of the various products suggested a high stereospecificity in the reaction. But BU' An unusual oxidation which may involve nucleophilic (pyridine-N-oxide) or electrophilic (HOCl or C1,O) sources of oxygen occurred' 69 when [WCl,(NPR,)] (R =Me Ph) was converted to [WCl,(NCI)(OPR,)].The binuclear Mov complex (43) may be formed17' in several ways (Scheme 6) uia the mononuclear (44). The 0x0 group in (43) comes from the methoxy group in (44). [W(CO),(solvent)] reacted17' readily with oxalate dianion in 1 :1 ratio to form a simple chelated octahedral complex [W(CO),(C,O,)]' -. Reaction with a further equivalent of [W(CO),(solvent)] gave the stable binuclear [W,(CO),(C,O,)]'- in which the oxalate ligand bridges the two tungsten centres simultaneously chelating each tungsten. The latter dinuclear anion can be formed via the intermediate [W2(C0),,(C20,)]' with subsequent loss of CO. ~ The [Mo0,{0,CC(S)Ph,),]2 -anion where the phenyl groups provide sufficient steric hindrance to prevent dimerization reacted'72 with thiols at acid pH to give mononuclear [MoO(O,CC(S)Ph,},] - which has an almost square pyramidal structure and an ESR spectrum typical of oxomolybdenum(v) complexes.Trinuclear compounds with a triangle of three metal atoms around a central oxygen atom are well known in this and other transition metal groups. The complex [Cr,(p3-O)(p-0,0'-L-valine)6(H20),]7+has' 73 a planar trigonal disposition of 1hh B. Karnenar B. Kaitner and N. Strukan. Craut. Chem. Actu. 1991 64. 329. 167 Y. Ma P. Demou and J. W. Faller Inory. Chem. 1991 30 62. 168 S.D. Dietz. N. W. Eilerts and J. A. Heppert .4nyetv. Chem. Int. Ed. Engl. 1992. 31. 66. 169 J.D. Lichtenhan J. W. Ziller and N. M. Doherty Inorg. Chem.. 1992 31 4210. I 70 M. Minelli R. L. Kuhlrnan S.J. Shaffer and M. Y. Chiang Inorg. Chem. 1992 31 3891. 171 D.J. Darensbourg J.A. Chojnacki and J. H. Reibenspies Inory. Chrm. 1992 31. 3428. 172 V. Sanz T. Picher P. Palanca P. Gomez-Romero E. Llopis. J. A. Ramirez D. Beltran and A. Cervilla. Inorg. Chem. 1991 30. 3113. I73 H. Kato. K. Nakata A. Nagasawa T. Yamaguchi Y. Sasaki and T. Ito Bull. Chem. SOC.Jpn. 1991,64. 3463. 152 H. Sloan 0 FF t B; Br t N. / OMe (44) 0 Z = o-HS.C,H,.NH2 in MeOH + 2NF13. S-S = Et,NCS; Scheme 6 chromium atoms about a central oxygen atom. The electronic spectra and magnetic moments show that this and other analogous amino acid complexes are weakly anti-ferromagnetic.Compounds with two such edge-sharing triangles in an M40z core are now being explored. Dissolution of [Cr(H,O),](OAc) or [Cr,O(OAc),(H,O),]Cl in molten bipy at 80 ^C followed by addition of water and KPF, gave” [Cr,O,(OAc),(bipy ),][PF,]. The central Cr,O core of this compound is bent in the ‘butterfly’ mode previously found in analogous Mn and Fe carboxylates. Three acetato ligands bridge the terminal to central chromium atoms while the seventh acetato ligand bridges the two central chromium atoms. The adamantane-like Mo,P,O cage is retained’” unchanged during the reaction of (45) with halogens as in Scheme 7. Bromination contrasts with other halogenations in that a dibromo intermediate is not obtained in the direct reaction with (45).X-Ray diffraction studies of (46 X = I) show a trigonal prismatic structure around each 16-electron molybdenum(r1); NMR spectroscopy shows retention of this configuration by (46) and (47) in non-polar solvents. At low temperatures intermediate (48) was observed. When the NPr’ substituent is replaced by Ph similar reaction conditions give products (49) and (50) which are of low stability and lose CO readily. ”‘A. Bino. R. Chayat. E. Pedersen. and A. Schneider. Inorq. Cheni.. 1991. 30. X56. 1’5 M. M. Turnbull. C. Valdez. E. H. Wonp. E. J. Gabe. and F. L. Lee Itrory. Chmi. 1992. 31. 208. Cr Mo and W X = 1 R = NMeZ X2(C0)2Mo[RPO]4M~(C0)2X2 (46) X = Br low temp. or X = CI Br. I; R = Ph (47) I (48) X = I R = NMe2 (50) X = (31 Br I (49) X = C1 Br I R = Ph Scheme 7 17 Sulfur-donor Ligands and Sulfides Simple ligand substitution of [MoO,(acac),] gives' 76 cis-[Mo02(2-pymS),] (51) and cis-[Mo02(2-pyS),].These Mo"' complexes are quantitatively converted to the binuclear MoV compounds [Mo20,(2-pymS),] and [Mo20,(2-pyS),] by oxygen abstraction with PPh,. Compound (51) is distorted octahedral with cis-0x0 and trans-thio groups having different Mo-S distances. The crystal structures of a number of sterically hindered molybdenum-pyridine-2-thiol complexes show' 77 various coordination modes including unidentate-S chelate-(N,S) or bridging-S. In [NEt,][MoO(~,2-toluenedithiolato)~] the MOOS core is a distorted tetragonal pyramid178 with trans-chelating ligands.Dithiocarbonates reacted' 79 with tet-rathiometalates to give 1,2-dithiolene complexes (Scheme 8). Electrochemical studies show that these undergo two one-electron oxidations at mild potentials. [Mo(S,C,S,CO),] was prepared by oxidation of the corresponding dianion with nitrosonium or ferrocenium salts. Aqueous [Mo0,12 -and polysulfide reacted' 8o on heating to form the dinuclear anion (52a). Tungstate required preliminary reduction before undergoing a similar reaction to give (52b) and (53). The disodium dithiolate Na,(mnt) reacted' 81 with [Mo,(O,CMe),] to replace completely the acetate ligands and reduce the multiplicity of the quadruple Mo-Mo bond giving (54). The molybdenum atoms of this complex are within a distorted square pyramid with terminal 0or Sat the apex and in a syn conformation.The similar complex [Mo2(p-O),O2C1,(dmbip~),](55)was prepared by reaction of dmbipy and I76 P. R. Traill. A.G. Wedd and E. R.T. Tiekink ..lust. J. Chrm. 1992 45. 1933. 177 E. Block M. Gernon. H. Kang G. Ofori-Okai and J. Zubieta Inorg. Chern. 1991 30 1736. 178 N Ueyama N. Yoshinaga. A. Kajiwara A. Nakamura. and M. Kusunoki Bull. Chrm.Soc. Jpn.. 1991.64. 2458. I79 X. Yang. G. K. W. Freeman T. 9. Rauchfuss and S. R. Wilson Inorg. Chem.. 1991 30. 3034. I80 R. Bhattacharyya P. K. Chakrabarty P.N. Ghosh. A. K. Mukherjee D. Podder and M. Mukherjee. Inorg. Chem. 1991 30. 3948. in1 J. I. Dulebohn T.C. Stamatakos D. L. Ward and D.G. Nocera. Polyhedron. 1991 10. 2813. 154 H.Sloan Scheme 8 [Mo,Cl,(NCMe),] or by oxidation with dioxygen of [Mo,Cl,(dmbipy),]. The metal-metal distances of 2.858 8 (in 54) and 2.562 A (in 55) are typical of MoV-MoV single bonds. (52) a M= Mo; (53) b M=W I \ NC CN The orthorhombic form of [Cr"'(SSPMe,),] crystallized from ethanol has' 82 the same trigonal prismatic structure found in the monoclinic form obtained by sublimation. Disodium 4,5-dimercapto-1 ,3-dithiole-2-thionate7 Na,C,S, reacted' 83 with MoCl to give the distorted trigonal prismatic complex [NBu,][Mo(C,S,),]. The ligand 4-(4-hydroxyphenyl)pyridine has been used' 84 to bridge the 16-electron 0-coordinated molybdenum centre and the 17-electron N-coordinated molybdenum centre of [(MoCl(NO)Tp'}(OC,H,C,H,N)(MoCl(NO)Tp')].There is considerable interaction between the two molybdenum centres across the bridging ligand as shown by electrochemistry and ESR spectroscopy. Labile dinuclear Mo"' complexes are formed'85 by sulfur extraction from SPMe as in Scheme 9. Crystal structural analyses for all three compounds (56) (57) and (58) were made and the coordinatively unsaturated nature of (57) confirmed. E. Skrzypczak-Jankun and A.A. Pinkerton Acra Crystallogr. Sect. C 1991 47 2211. le3 G. Matsubayashi K. Douki and H. Tamura Chem. Leu. 1992 1251. 184 A. Das J. C. Jeffery J. P. Maher J. A. McCleverty E. Schatz M. D. Ward and G. Wollermann Angew. Chem. Int. Ed. Engl. 1992. 31. 1515. '" K.A. Hall S.C. Critchlow and J. M. Mayer. Inorg. Chrm. 1991 30. 3593. Cr Mo and W c1 PMe c1 I I Me3P Mo PMe3 + SPMe3 -80" MO-/CI,M6PMe, Me3P' I PMe3 Me3P'I \s'I PMe3 c1 PMe C1 (56) +PMe3 -PMq 11 PMe3 C1 PMe C1 +MeCN MO-Mo-PMe3 N PMe3 PMe C1 C Me (57) (58) Scheme 9 The reaction of [Mo,S,Br,] with PBu in thf gave'86 the anion [Br,OMo(p- S),MoOBr,12-which has a bent MS,M bridge with terminal syn M=O groups; an unusual reaction of thf to give [Bu,P(CH,),PBu,12 +,provides the counter-ion.The reaction of [M20,S2I2- (M = Mo W) with sulfur and hydrazine hydrochloride gave'87 complexes [(MO(S2)2}2(S,)(p2-NH2NH2)]2with long polysulfide chains -forming one of the bridging ligands. The other bridge has a zig-zag M-N-N-M chain where hydrazine bridges the two metal centres in an end-on mode.Each half of the molybdenum-containing anion is pentagonal bipyramidal with the five sulfur atoms in the equatorial plane. There is some statistical disorder in the S chain. The in situ reaction of CS and PR (R = Et Bu Cy) with (59) gave'" complexes (60)which have q3-S,C,S' coordination to Mo and q2-S,S' coordination to Sn. There is no direct molybdenum-tin bond but a weak Sn-C1 bond provides further bridging between the metal atoms. Treatment of a suspension of [W(CO),] in refluxing CH,Cl with S,Cl,. while irradiating with tungsten light gave'89 the adduct WCl,S.S where the WC1,S unit F.A. Cotton R. L. Luck and C.S. Miertschin Inorg. Chem. 1991 30 1155. I*' N. Zhu S. Du X. Wu and J. Lu. Angew'.Chem. Int. Ed. Engl. 1992,31. 87; S. Du N. Zhu X. Wu and J.Lu Inorg. Chem. 1992 31 2847. IH8 D. Miguel J. A. Perez-Martinez V. Riera. and S. Garcia-Granda. Anyew. Chrm. Inr. Ed. Enyl.. 1992.31. 76. D. L. Hughes J. D. Lane and R. L. Richards. J. Chcm. Soc. Dulron Truns..1991. 1627. 156 H. Sloan forms a square pyramid with apical S. The S ring occupies a position below the base of the pyramid with the distances of the chlorine atoms to three of the sulfur atoms of the S ring being significantly shorter than the van der Waals distances. The shortest W-SFi, distance is close to the sum of the van der Waals radii. 18 Selenium- and Tellurium-donor Ligands Gas-phase electron diffraction of WSBr and WSeBr has shown'" a regular square pyramidal structure with the chalcogen at the apex and the tungsten atom above the plane of the bromine atoms.A mass spectral study of [Mo3(p3-X)(YZ),(dtc),] (X Y Z = S;X Y = S Z = Se; X = S Y Z = Se) showed'" similar fragmentation patterns with easier loss of chalcogen in the equatorial position compared with the bridging X atom. Coordinatively unsaturated metal centres occur in the symmetric [W,Se2(PPh2Me),(SePh),].2thf which was prepared" by the reaction of SiMe,(SePh) with [WCl,(PPh,Me),] in thf at room temperature. The centro- symmetric complex has asymmetric W-Se-W bridges (2.380 2.473 A) a distortion which is similar to that found in [W,Se,]'- and [W,Se,,l2-. The coordination sphere of each tungsten is made up by one phosphine and two selenolate ligands to give distorted trigonal-bipyramidal geometry. The [Wv'Se,12 -anion underwent 193 an induced internal electron-transfer in its reaction with R,NC(S)SSC(S)NR (R = Et Bu') to form the eight-coordinate [WVSe,(S,CNR,),].There is a correlation of the lowest energy CT band with the reactivity of [ME,]"- for M/E combinations Mo/S W/S W/Se V,'S. Re/S; [WSe,]'~ has similar reactivity to [MoS,I2-. The isostructural selenides [PPh,],[M,(WSe,),] (M = Pb Sn) contain'94 four tetrahedral WSe moieties but two of these share one edge with an MSe octahedron; the other two share two edges with a Se vertex common to both MSe octahedra (61 ). Oxidative decarbonylation of molybdenum and tungsten hexacarbonyls by the anion [As,Se,]'- gave"' (62) while use of [As2Se,I3- gave (63). The former can be converted to the latter by the addition of red selenium.There is an unusual asymmetric unit cell with three discrete chemically-similar anions in (62b) with mixed As/Se coordination in a trigonal prismatic arrangement around tungsten and the two carbonyl ligands capping two of the square faces. In contrast (63) is six-coordinate through selenium only with some interaction between one selenium atom on each of the two ligands to support bonding. Complex (63 M = Mo) also resulted'96 from the reaction of [PPh,][MoSe,] with excess As,Se although [NBu,][WSe,] with excess As,Se gave the dianion (64). The first terminal transition-metal-tellurium double bond is reported' 97 in tvans-[W(PMe,),(Te),] (65) where the W-Te bond length (2.596A) is shorter than known W-Te single bonds (typically 2.68-2.88 A).Evidence suggests that Me,PTe is a catalytically active species in the formation of 190 E. M. Page. D.A. Rice K. Hagen L. Hedberg and K. Hedberg. Inory. Chern.. 1991 30. 4758. I91 K. Hegetschweiler. P. Caravatti V. P. Fedin a;id M. N. Sokolov. Heir.. Chim. Acro 1992 75 1659. 19* P. M. Boorman. H.-B. Kraatz. and M. Parvcz. J. Chem. Soc.. Dalton Truns. 1992. 3281. Y. Gea. M.A. Greaney. C. L. Coyle and E. I. Stiefel. J. Chem. Soc.. Chern. Comrnun.. 1992. 160. Y.-J. Lu and J.A. Ihers 4crn Cry,\tulloyr.. Sect. C. 1991 47 1600. 19' S.C. O'Neal. W.T. Pennington and J. W. Kolis. Inorq. Chern. 1992. 31. 888. S.C. O'Neal. W.T. Pennington and J. W. Kolis J. Am. Chern. Soc. 19Y I. 113 710. I')' D. Rabinovich and G. Parkin. J. Am. Ckern. Soc. 1991.113. 9421. Cr Mo and W Se\W/Se Se-M-I Se-W-Se \ Se-M-/\ se\ /Se /\ Se \ L (62) a M = Mo b,M=W \/““-rSe Se 2-/e-Se,-,Se -As\\se7MyseAjAs Se/w\se Se-Se Se-Se (61) M=Pb,Sn (63) M =Mo W r Se /Se-Se I 12- (65)from [WH(PMe3),(q2-CH2PMez)] and elemental tellurium. A similar reaction of (65) with HIS gave the sulfur analogue by elimination of hydrogen. The central M,Te rhomboid cores in [M,(CO),,(p,-Te)z] (M = Cr W) have 198 long metal-metal distances though distortion from tetrahedral form around Te for both compounds and magnetic data for the tungsten compound support the presence of a metal-metal bond. ~ In [Cr,(CO)20(q2,p,-Te,)]2 and in [Cr,(CO)zo(t~2.p3-Te3)]2four Cr(CO) -fragments are attached to the end tellurium atoms of the two and three atom chains respectively with no other bridging to the Cr atoms; there is disorder of the middle tellurium atom in the bent Te chain of the latter anion.19 Halide Ligands The structure of [CrF,] has attracted attention with theoretical studies pre- dicting trigonal prismatic’99 and octahedral”’ structures. Experimental data are 14” L.C. Roof. W.T. Pennington. and J.W. Kolis. Inorq. Chcw. 1992. 31. 2056. I” C.J. Marsden and P. P. Wolynec. Inorg. Chem.. 1991. 30 1681. K. Pierloot and B.O. Roos. Inorg. C/~WI..1992. 31. 5353; A. Neuhaus. G. Frenking C. Huber and J. Gauss. Inorq. Ch~m.,1992. 31. 5355. 158 H. Sloan held201 to indicate an octahedral structure though some analysis suggested'" that its existence is doubtful.In the [WSF,] -anion the tungsten atom is displacedzo3 above the plane of the equatorial fluorine atoms of the octahedral structure towards the sulfide ligand. There is disorder between the sulfide and axial fluoride ligands in the crystal. NMR spectroscopy shows no exchange between the axial and equatorial fluoride ligands in solution. A reversible colour change dependent upon pH was found'' with (66) where hydroxide addition occurs on the fluorinated acac ligand. The equilibrium constant is four orders of magnitude larger than for the corresponding hydroxylation of the cobalt analogue. ,CFJ 2+ Triple fluoro bridges were foundzo5 in binuclear [{ W(CO)2(PMe2Ph)2}2(pF)3] [BF,] prepared from [WH,(PMe,Ph),] and HBF,.OEt,.The crystal structure shows each tungsten atom between parallel planes of the fluorine atoms and of the other ligands. In the latter plane the carbonyl and phosphine ligand pairs are in trans dispositions. Near-IR emission and absorption spectral studies of the strongly exchange-coupled dinuclear anion of Cs,[Mo,Cl,] showed"' significant weakening of the Mo-Mo bond in the excited state corresponding to a lengthening of about 0.1 A. The chloro bridges in [Mo(~-C~),O,C~,]~ -arezo7 asymmetric. The anion of [htmmp][W,CI,] has208 a W-W distance of 2.409 A emphasizing the tendency for third row elements to give more rigid metal-metal bonds; the related [Mo,CI,]~ compounds show greater variability of the metal-metal bond length. Reaction of [Mo,(OAc),] with SiCIMe and dppe in thfkoluene followed by layering the pink solid in a solution of CH,Cl,/py with hexane gave2'' [Mo,Cl,(OAc),(py),] as one of the products.The acetate ligands bridge the Mo-Mo bond in a cis configuration and the molecules are linked into infinite chains by asymmetric chloride bridges (Mo-Cl = 2.440 3.082 A). From this and similar compounds the trans effect on the Mo-O,,,,,, bond is in the order PEt > Bu'CO 3 C1 > py. The Mo-I bond in [MoOI(dmpe),] + was found' lo to be very long at 2.964 A most likely because of the trans influence of the 0x0 ligand. ''I E.G. Hope W. Levason. and J. S. Ogden Inory. Chem. 1991 30,4873. 202 J. Jacobs H.S. P. Muller H. Willner. E. Jacob. and H. Burger Inory. Chem.. 1992 31. 5357. 2n3 M.Hilbers M. Liige and R. Mattes Inory. Chim. Acfn 1992 201 I. 2"4 T. Katou Y. Yamamoto K. Kuroda. K. Watanabe and Y. Kitamura Inory. Chim. Acta. 1991 180,13. 205 D. M. Dawson R.A. Henderson A. Hills and D.L. Hughes J. Chem. Soc.. Dalton 7i.ans.. 1992 973. 'Oh R. Stranger. G. Moran E. Kransz. L. Dubicki H. Gudel and N. Furer Inory. Chem.. 1992 31. 2860. 207 R. Herbst-Irmer and E. Egert Actu Crystallogr..Sect. C. 1992. 48 1843. 208 K.R. Dunbar and L. E. Pence. Acta Crpstalloyr.. Sect. C. 1991. 47. 23. 2"y J.-D. Chen. F.A. Cotton and S.-J. Kang. Inorg. Chim. Acta. 1991. 190. 103. 'In B. E. Owens and R. Poli. Ac~aCrystallogr.. Sect. c'. 1992. 48. 2137.

ISSN:0260-1818    

DOI:10.1039/IC9928900127

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

12 Mn Tc Re By J. D.CRANE School of Chemistry and Molecular Sciences University of Sussex Falmer Brighton East Sussex BN1 9QJ UK 1 Manganese The octahedral complexes [Mn"'L,]O and [Mn"L,] -of 4-chloro-o-benzoquinone oxime (HL) have been reported and the magnetic moments of both compounds indicate low-spin configurations.'*2 In solution the Mn"' complex has a strong preference for the mer-geometry whereas for Mn" the mu-and fuc-isomers are observed both in solution and in the solid state. Furthermore the interconversion of these isomers in solution is sufficiently slow at low temperature (260K) for electrochemical studies to show that the mer-isomer is 180 mV easier to oxidize than the fuc-isomer. Oxidation of Mn" acetate with [NBui][MnO,] in the presence of HN(C(NH)NH,) (HL) yields the red water-sensitive acetate salt of [MnL,] +,a rare example of an octahedral Mn'" complex with N c~ordination.~ Octahedral Mn" complexes of periodate and iodate anions have been prepared; in the structurally characterized complex [Mn(HI0,)2(H210,)]7 -the periodate ligands are bidentate whereas spectroscopic studies indicate4 that the iodate ligands are monodentate in [Mn(103),]2-.Attempts to prepare analogous complexes of Mn"' or Mn" were unsuccessful. Octahedral 0 Mn" coordination is also found5* in the hetero- polymolybdate anion [MnMo90,,l6-. The reaction of 3,5-di-tert-butylcatechol (H,L) with [Mn(N(SiMe,),},] in py yields the phenolate-bridged dimer [MnyL,(py),]; recrystallization of this compound from toluene results in the loss of py and dimerization to [MnyL,(py),] .' Aerial oxidation of this tetranuclear compound yields the mixed-valence complex [Mn"Mn',"L,(py),] in which the central Mn" is octahedral whereas the two Mn"' centres are five-coordinate one being trigonal bipyramidal and the other square-based pyramidal.The tetraol derived from Hfacac F,CC(OH)2CH,C(OH),CF (H,L) has been prepared and structurally characterized as a tetraalkoxide bridging ligand in [(fa~ac)~Mn"~(p-L)Mn"'(facac)~]~ -(1 ).8 P. Basu and A. Chakravorty J. Chem. Soc. Chem. Commun. 1992 809. P. Basu and A. Chakravorty Inorg. Chem. 1992 31 4980. R. 0.C. Hart S.G. Bott J. L. Atwood and S. R. Cooper J. Chem. Soc. Chem. Commun.. 1992 894. W. Levason M. D. Spicer and M. Webster Inorg.Chem. 1992 31 2515. H. Stratemeier M. A. Hitchman D. L. Kepert B. W. Skelton K. E. Sugars and A. H. White,J. Chem. Soc.. Dulton Trans. 1992 3035. ' S.J. Dunne R.C. Burns T. W. Hambley and G. A. Lawrance Aust. J. Chem. 1992 45 685. ' S.C. Shoner and P. P. Power Inorg. Chem. 1992. 31 1001. * E. Bouwman J.C. Huffman E. B. Lobkovsky G. Christou H-L. Tsai and D. N. Hendrickson Inorg. Chem. 1992 31,4436. 159 160 J. D.Crane CF (1 1 The high spin Mn" complex [Mn(N(CH,CH,PPh,),}I] has been structurally + characterized and the P31 metal coordination geometry is approximately tetrahedral with an additional long Mn-N interaction of 2.634(9) A." A series of Mn" complexes of triarylphosphines has been investigated by cyclic voltammetry but no correlation between the one-electron oxidation potentials of these compounds and their ability to bind 0 reversibly is apparent." Mn powder reacts with PMe31 to yield the chain -polymer [Mn11(PMe3)2(p-I)2Mn1'(p Reaction of this compound with an excess of 0 yields [Mn"'(PMe,),I,] whereas controlled addition of 0 allows the isolation of the intermediate mixed-valence product [Mn'"( PMe3)12(p- I)Mn"(PMe,),I,].With PMe,Ph and MnT the trinuclear complex [{ M~"(PM~,P~)I(~-I),),M~I~~(PM~,P~)~] is formed which under controlled condi- tions reacts with 0 to yield [Mn~(p,-O)(p,-I),(PMe,Ph)4].'2 Several Mn" com- plexes with phosphine oxide and phosphinate ligands have been prepared and their ability to bind SO reversibly has been investigated.' l6 Reaction of anhydrous Mn" halides with [PPh,],[WS,] in MeOH/Et,O yields the heterometallic anion [S2W(p2-S)2Mn(p2-S)2WS2]2in which the Mn" centre is high ~ spin with distorted tetrahedral coordination.' In [Mn,L,]'- (H,L = propane-1,2-dithiol) the equivalent metal geometries are distorted trigonal bipyramidal and the Mn,(p-SR) core is planar with alternate short and long Mn-S distances of 2.359(1) and 2.665(1)A.18 Mononuclear Mn"' complexes of salen-type ligands act as mild catalysts for both the %-oxidation of silyl enol ethers and mono-epoxidation of 1,3-dienes with PhIO or NaOC1.19.20 The Mn"' Schiff base complex [MnL'(OAc)J has been structurally ' F.Cecconi C. A. Ghilardi. S. Midollini and A. Orlandini J. Chem. So(,..Dulron Truns. 1992. 33. I 0 G.Q. Li. C. A. McAuliffe A.G. Mackie P. P. MacRory and P.T. Ndifon J. Chrm. Soc. Dalron Truns. 1992 1297. I' C. A. McAuliffe S. M. Godfrey A.G. Mackie. and R. G. Pritchard. J. Chrm. Soc.. Chem. Comniun. 1992 483. B. Beagley A. G.Mackie P. P. Matear. C. A. McAuliffe P.T. Ndifon and R. G. Pritchard. J. Chem.Soc. Dalton Trans.. 1992 1301. l3 S. M. Godfrey D. G. Kelly. and C. A. McAuliffe .I. C'hern. Soc,.. Dalton Truns.. 1992 1305. l4 S. Abbas B. Beagley. S. M. Godfrey D.G. Kelly C.A. McAuliffe and R.G. Pritchard J. Chem. Soc.. Dalton Truns.. 1992 1915. S. F. Banda. C. A. McAuliffe and P. P. Matear Inory. Chim. A(,ru. 1992 193 197. 16 S. F. Banda. 0.El-Sayrafi. C.A. McAuliffe and P. P. Matear Inory. Chim. Acra. 1992 194 227. l7 A. Bencini F. Cecconi C.A. Ghilardi S. Midollini. F. Nu77i. and A. Orlandini Inory. Chem. 1992 31 5339. l8 X. Chen B. Kang L. Weng. L. Huang. H. Liu. D. Wu. X. Lei. M. Hong. and J. Lu. Transirion Met.Chem.. 1992 17 509. '' D. R. Reddy and E. R. Thornton J. Chem. Soi,.,Chrm. Cornmun.. 1992. 1072. D.S. Thomsen. 9. Schbtt and K.A. Jorgensen J. Chem. Soc. Chem. Cornmun. 1992 172. Mn Tc Re 161 N (HzL') R = H X = -CH2CHzCH2-I (H2L2) R = NO2 X = -CHZCH~CH~N(CH~)CH,CH~CH~-X I (H3L3) R = H X = -CH2CH(OH)CH2-(H3L4) R = H X = -CH2CH2CH(OH)CH2CH2-R&OH characterized and exists as a linear chain polymer with bridging acetates.,' Octahedral [MnLZ(OH)] is a remarkably stable example of a complex with a terminal hydroxide ligand bound to Mn"' (Mn-OH = 1.827(3)A).' Schiff base ligands based on L3 and L4 have been used to prepare di- and tetranuclear complexes of Mn11',23-25 as well as a dinuclear mixed valence Mn"'"' complex.26 These systems are all of interest as potential models for the 0 evolving centre of photosystem 11 as are the dinuclear Mn"""' M~III/IV and Mn'V/lV complexes containing the [Mn,(p-O),]"' (n = 2 3 4) core.27 The protonation of a single bridging 0x0 group in [LSMn111(p,-O),Mn"'L5]2 has + been studied.28 The pK,(MeCN) of the resulting acid is 16.2 [corresponding to pK,(H20) -8.71 but the rate of proton exchange is a factor of lo6 slower than for a typical organic OH group of comparable acidity.Protonation of an 0x0 group in [L'Mn'V(p2-O),Mn1VL'] has been shown by EXAFS to result in a 0.1 A increase in the inter-metal distance and is accompanied by loss of the catalase activity of the starting compound.29A range of Schiff base (H,L) complexes [LMn'V(p,-O),Mn'VL] has been shown to undergo two facile 0,-transfer reactions with [Fe"L] to produce [Mn"L] and [LFe111(p2-0)Fe"'L].30 The centrosymmetric mixed-valence complex [(bpy),Mn"1(p-O),Mn1v(bpy)2]3 has been studied by single-crystal synchrotron resonance scattering and the two Mn centres could be di~tinguished.~~ The electron transfer reactivities of this and similar complexes have been studied and in particular it was shown that [(phen),Mn'1'(p-O),Mn1V(phen),]3+ can be reversibly reduced and protonated in solution to yield [(phen),Mn"(p-OH),Mn"'(phen)J3 + .32.33 In addi- 21 N.Aurangzeb C.E.Hulme.C.A. McAuliffe. R.G. Pritchard M. Watkinson. A. Garcia-Deihe. M. R. Bermejo. and A. Sousa. J. Chrm. Soc.. Chrm. Commun.. 1992. 1534. 22 D.M. Eichhorn and W. H. Armstrong. J. Chem. Soc.. Chem. Commun.. 1992. 85. 23 M. Mikuriya Y. Yamato. and T. Tokii. Chem. Lutr.. 1992 1571. 24 M. Mikuriya Y. Yamato and T. Tokii Bull. Chem. Soc. Jpn. 1992. 65. 1466. 25 M. Mikuriya Y. Yamato and T. Tokii Bull. Chrm. Soc. Jpn.. 1992 65. 3624. 26 E. Larson A. Haddy M. L. Kirk. R. H. Sands. W. E. Hatfield.and V. L. Pecoraro,J. Am. Chem.Soc. 1992. 114 6263. 27 E. Larson. M. S. Lah. X. Li J.A. Bonadies. and V. L. Pecoraro Inory. Chrm.. 1992 31 373. 28 J. M. Carroll and J. R. Norton. J. Am. Chem. Soc.. 1992 114. 8744. 29 E. J. Larson P. J. Riggs J.E. Penner-Hahn and V. L. Pecoraro J. Chem. Soc. Chern. Commun.. 1992. 102. 30 G.C. Dailey and C. P. Horwitz. Inorq. Chem.. 1992. 31. 3693. 71 Y. Gao. A. Frost-Jensen M. R. Pressprich P. Coppens. A. Marquez and M. Dupuis. J. .4m. Chrm. Soc.. 1992 114 9214. 32 M. M. Monzyk and R. A. Holwerda Inorg. Chem.. 1992. 31. 1969. 33 R. Manchanda H. H. Throp. G. W. Brudwig. and R. H. Crabtree. Inorg. Chum. 1992. 31. 4040. 162 J. D.Crane tion the tetranuclear 0x0-bridged complex [Mn',V(p2-O)6(bpy)6]4 has been charac- + terized. Many new multinuclear Mn complexes incorporating carboxylate ligands have been prepared.35p46 With the bidentate amine ligands dmbipy and tmeda air-sensitive + core are form-dinuclear complexes containing the [Mn11(~,-OH2)(p2-OAc),Mn'1]2 ed.37 The triply bridged [Mn"'(p2-O)2(p2-OAc)Mn'v]2 + core has been structurally characterized in the complex [Mn2(L6),0,(0Ac)12 + .38 In aqueous acid this com- pound is aerially oxidized to [Mn~(L6)),O2(0Ac)l3+ whereas in distilled water the product is [Mn6(L6)308(OH)2]6+(Z) which contains two discrete [Mny(p2-+ O),(OH)] core^.^^'^^ The mixed-valence cubane complexes containing the [Mn1VMn~'(p3-O)3(p3-X)(OAc)3]3+ (X = C1 Br) cores have been prepared and their redox and magnetic properties ~tudied.~l-~~ + In addition [Mn!Mn!1(p4-O)2] lo ,44 + + [Mn~'(p2-0),(p3-O),]l3 + ,45 [Mny'MnY Fey'O 2] ' and [Mn','Mn',VO 2] ' cores have been structurally characterized as carboxylate complexes the last of which undergoes a one-electron reduction to the [Mn 20,] core.46 + (L6> core of (2) 34 C.Philouze G. Blondin S. Menage N. Auger J.-J. Girerd D. Vigner M. Lance and M. Nierlich Angew. Chem.. Int. Ed. Engl.. 1992 31. 1629. 3s R. L. Rardin P. Poganiuch A. Bino. D. P. Goldberg W. B. Tolman S. Liu. and S.J. Lippard J. Am. Chem. Soc. 1992 114. 5240. 36 D. P. Kessissoglou M. L. Kirk. M. S. Lah X. Li C. Raptopoulou. W. E. Hatfield. and V. L. Pecoraro. Inory. Chem. 1992 31 5424. 37 S.-€3.Yu S.J. Lippard. 1. Shweky and A. Bmo Inorg. Chem. 1992. 31 3502. 3n S. Pal. J. W. Gohdes W.C.A. Wilisch and W. H. Armstrong Inorg. Chem. 1992 31. 713. 39 S. Pal and W.H. Armstrong Inorg. Chrm. 1992 31 5417. 40 S. Pal M. K. Chan and W. H. Armstrong J. Am. Chem. Soc. 1992 114 6398.4' S. Wang H.-L. Tsai W. E. Streib G. Christou and D. N. Hendrickson J. Chrm. Soc.. Chem. Commun. 1992. 1427. 42 D. N. Hendrickson G. Christou E. A. Schmitt E. Libby J. S. Bashkin S. Wang. H.-L. Tsai J. B. Vincent P. D. W. Boyd J.C. Huffman K. Folting Q. Li. and W. E. Streib J. Am. Chem. Soc. 1992. 114 2455. 43 E. A. Schmitt L. Noodleman E. J. Aaerends and D. N. Hendrickson J. Am. Chem.Soc. 1992.114.6109. 44 A.G. Blackman J.C. Huffman E. B. Lobkovsky. and G. Christou Polyhedron 1992 11 251. 45 S. Wang H.-L. Tsai W. E. Streib. G. Christou and D.N. Hendrickson J. Chem. Soc. Chrm. Commun. 1992. 677. 46 A. R. Schake H.-L. Tsai N. de Vries. R. J. Webb K. Folting D.N. Hendrickson and G. Christou. J. Chem. Soc. Chem. Commun. 1992 181. Re 163 Mn Ti- 2 Technetium A series of Tc"'"' complexes of general formula [T~(SR),(diars),]~" has been prepared of which trans-[Tc"(SPh),(diars)J and tr~ns-[Tc"'(SMe),(diars),]~ have been structurally ~haracterized.~' In one case the initially formed isomer trms-[Tc"'(SPh),(diars),] ' rearranges to the more stable cis-isomer upon standing in solution.Due to ligand constraints a distorted octahedral metal geometry is found in + the tetradentate thioether complex cis-[Tc"'L(SPh),] [L = Bu"S(CH,CH,S),Bu"] and no tram-isomer is ob~erved.~' Cis-dithiolate coordination is also found in [T~"'(drnpe)~(tdt)] +.in which the Tc(tdt) fragment is planar and the overall metal geometry is halfway between octahedral and trigonal pri~matic."~ Tc" appears to be stabilized by the oxalate ligand in the related complex [Tc(dppe),(C204)].'" The reaction of [TcVOL4I3' (L = tetramethylthiourea) with dppe yields the two struc- turally characterized complexes [TcVOL,( Me2NCS2)]' + and [Tc"(dppe) (Me,NCS,)]+ and a mechanism for the conversion of (Me2N)2CSto [Me,NCS,] is ~ propo~ed.~' A series of complexes of general formula [Tc'HL(dppe),] [L = P(OMe),.CO CNR] has been prepared by displacement of the labile N ligaiid in [Tc'H (N,1(d ppe 1,I.'' The reaction of 2-Ph2PC,H,SH (HL) with [Tc'OCl,] -,[Tc'NBr,(PPh,),] and [Tc'"Cl,( PPh,),] yields TcVOC1L, Tc'NL, and PW-TC"'L, respectively. the last of which is isostructural with the Re"' analogue.53 The corresponding tris(1igand) Tc"' complex of 2-Ph2PC,H40H also has the same basic structure.'" Reaction of [NH,][TcO,] with 12-diamino-benzene (H,L) yields [TcV"L,] + in which the metal coordination geometry is almost ideal trigonal pri~matic.~' In the presence of a reducing agent (Na,S,O,) the product is the square-based pyramidal complex [TcOL,] - and a similar structure is found for the analogous 4-nitrocatecholate complex." The nitrosyl and thionitrosyl complexes cis-[Tc(NO)(NH,)(phen),]' + and c.is-[Tc(NS)Cl(phen),] + have been prepared arid their structures compared." The Tc-NO and Tc-NS groups are both approximately linear (172 and 170 ) with iszrx bands at 1715 and 1 173cm-' respectively.The ESR spin Hamiltonian parameters of a range of Tc(NO) Tc(NS) and Tc(N) complexes have been correlated.'* The kinetics of py exchange in truns-[MVO2(py),lf (M = Tc Re) have been investigated by 'H NMR spectro~copy.~~ The exchange for both metals is shown to proceed z:iu a dissociative mechanism with the rate for Tc being -8000 times faster " T.Konno. M. J. Heeg. J. A. Stuckey. J. R KirchhotT. W. R. Heineman. and E. Deutsch. /wr</.Ckoni. l9Y2. 31. 1173. " H.-J. Pletrsch H. Spies. P. L.eibnitz. G. Reek. J. Beger. and R. Jacobi. Po/,rhrt/rori,IYY2. 11. 1623. ") T. Konno. J. R. Kirchhoff. M.J. Heeg. W. R. Heineman and E Deutsch. J. Chi. SIC. .. L)cilro,i Truiiv.. 1992. 3069. ") S. Seifert R. Muenre. P. Leibnitr. G. Rmk. and J. Staoh. /mr$g. Cliini. Atrcr. 1902. 193. 167. 'I F. D. Rochon. R. Melanson and P.-C. Kong. Inorg. Chiin. Ac'frc. 1992. 194. 43. '' L. Kaden.M. Findeisen B. Lorenz. K. Schmidt and M. Wahren. /trorq. Chirrt. .4c,lu. 1992. 193. 213. 53 J. R. Dilworth. A. J. Hutson. S. Morton. h4.Harman. M. B. Hursthouse. J. Zubieta.C. M. '4rcher. and J. D. Kell}. Polvhrdron 1992. 11 2151. 54 C. Bolzati. F. Refosco. F. Tisato. G. Bandoli. and A. Dolmella. Inorq. C/tirn. .kr(i. 1992. 201. 7. 55 T.I. A. Gerber H. J. Kemp. J. G. H. du Preez. G. Bandoli. and A. Dolmella. Iriorq. Ckirri. .4ctri. 1992. 202. 191. " F. D. Rochon. R. Melanson. and P.4. Kong. .4crtr Crj..\fLi//og/r. SK~.C. IYY?. 48. 785. 5-J. Lu and M. J. Clarke. J. Chunr. Soc.. Dulroii Trcin.\. 1992. 1243. '' J. B. Raynor. T. J. Kemp. and A.M. Thyer. Ittorcq. Cliini. A(.r(i. 1997. 193. 191. "' L. Helm. K. Deutsch. E. A. Deuhch. and A. E. Merbaoh. Hrlr..Chini. .Ac,((i. 1992. 75.710. 164 J. D. Crane than for Re. Protonation of [TcVO2(CN),l3-yields the complexes [Tc"O(OH)(CN),]~- and [TcVO(OH,)(CN),] - the former of which could not be isolated as it rapidly dimerizes to [TcvO(CN),(p2-O)TcvO(CN)4]4-.60 The aqua complex reacts reversibly with [NCS] to form ~~U~S-[TC~O(NCS)(CN),]~ - which was structurally characterized. The phenylimido complex [TcV(NPh)Cl,(dppe)] contains a nearly linear Tc-NPh group (176 ") with a Tc-N distance of 1.687(9) A typical of sp hybridization of the [PhNI2-group.61 The nitrido complex cis-[TcVNCl(phen),][PF6] crystallizes with a pseudo two-fold axis resulting in a reproducible apparent lengthening of the Tc-N distance by 0.15 A relative to the ordered complex cis-[T~~NCl(phen),]Cl.H,0.~~ Correct treatment of this disorder however eliminates the possibility of bond-stretch isomerism.The reaction of [TcVNBr,]-with bipy yields the related complex cis-[TcVNBr(bipy),][TcBr4] which contains the previously unknown tetrahedral [Tc"Br,]'-anion.63 With [TcVNCl,] and chelating diphosphines R,PCH,CH,PR (L) the products are usually trans-[TcVNCIL,]+ (R = Me Ph) whereas with the bulky ligand (R = Pr') the product is believed to be the dimer [LTcVNCl(p2-C1),TcVLNCI]. The bis-oxo bridged complex [(Et,NCS,)TcV'N(p,-O),TcV'N(Et,NCS2)] (3) and mononuclear mixed ligand nitrido complex [TcVN(S2C20,)(S2CNEt2)]have also been reported.64 Several new Tc complexes with N/S donor sets have been evaluated as potential 99mT~ based imaging agents in diagnostic nuclear medicine.65 71 N N 3 Rhenium An ab initio investigation of the relative stabilities of several classical [M(H),] and non-classical [M(q2-H2)] structures of [MH7(PH3)J (M = Re Tc) has been re- ported.72 These studies indicate that for Re the classical form would be more stable by 24 kcal mol-' whereas for Tc the non-classical structure [TcH,(q2-H,),(PH,),] would be more stable by 2-12 kcalmol-' depending upon the level of calculation.hO A. Roodt. J.G. Leipoldt E.A. Deutsch and J.C. Sullivan. Inory. Chrm. 1992 31 1080. 61 T. Nicholson. S. L. Storm. W. W. Davis A. Davison. and A.G. Jones Inorg. Chim. Actu. 1992. 196. 27. 62 M. J. Clarke and J. Lu. Inorg. Chem. 1992 31. 2476. 63 C. M. Archer. J. R. Dilworth.D. V. Griffiths M. McPartlin and J. D. Kelly J. Chern. Soc. Dulton Trans. 1992 183. 64 J. Baldas J. F. Boas S. F. Colmanet. and G. A. Williams J. Chem. Soc.. Dalton Truns. 1992 2845. 65 R. Pasqualini and A. Duatti. J. Chern. Soc,. ChKm. Commun. 1992 1354. 66 P. Koch and H.R. Mlcke Angrw. Chrm. Int. Ed. Enyl. 1992 31 1507. 67 Y.-C. J. Chen and K. D. Janda 1.Am. Chem. Soc.. 1992. 114. 1488. 68 A. Marchi. L. Marvelli. R. Rossi. L. Magon V. Bertolasi V. Ferretti and P. Gilli J. Chrm. Soc,.,Dalton Truns.. 1992 1485. 69 B. Chen M. J. Heeg and E. Deutsch Inory. Chrm.. 1992. 31 4683. 7(1 C. S. John. L. C. Francesconi. H. F. Kung. S. Wehrli G. Graczyk and P. Carroll Pol-yhrdron. 1992. 11 1145. 71 L. Hansen. R. Chi A. Taylor. Jr. and L.G.Marzilli. Inorg. Chrm.. 1992 31. 2801. 72 G. R. Haynes R. L. Martin. and P. J. Hay. J. Am. Chrm. Soc.. 1992. 114. 28. Mn Tc Re 165 Unfortunately representative Tc complexes are unknown. However the borderline nature of the Re complexes is revealed by a study of the isosteric phosphine complexes [ReH,{P(4-C6H4R),),] (R = OMe Me H F CF,).? The 'H NMR spin-lattice relaxation times (TI)decrease with the electron withdrawing ability of R and are consistent with the presence of an elongated q2-H ligand with an H-H distance varying from 1.42A (R = OMe) to 1.24A (R = CF,). The complex [ReVH,L] + [L = PhN(CH,CH,PPh,),] and its protonated form [ReVH6L] have been pre- pared; the former is a classical complex whereas T measurements indicate the presence of one or more q2-H ligands in the latter.74 The analogous complex [ReVH,(triphos)] reacts with EPh (E = P As Sb) with loss of H to yield [Re"'H,(EPh,)(triphos)] which can be pr~tonated~~ to [ReH,(EPh,)(triphos)] + .Thermal elimination of H in the absence of EPh yields [Re~H,(triphos),] which is readily oxidized by 0 to the Ke"/Re"' mixed-valence complex [(triphos)Re(p,- H),Re(triphos)] +. The Re hydrides [(dppe),Re(p-H),ReH,(dppe)] [(dppe)ReH(p-H)3(pL-dppe)ReH(dppe)] 7 + [ReH,(l-l-H)(l-lL-dmpm),ReH2]+ and [Re3(P3-H)2(p2-NMe,),(NMe,),] have also been rep~rted.~~.?~ The activation of Re-H bonds by electron transfer has been studied by cyclic voltammetry; the oxidation of [Re"'HCl(NCR)(dppe),] in aprotic solvents results in deprotonation by an overall + bimolecular process whereas reduction induces dehydr~genation.~~ The reaction of [ReH,(PPh,),] with 2,4,6-Pr;-C6H,SH (HL) under N yields the extremely air-sensitive complex [Re"'(N,)(PPh,)L,] in which the ql-N molecule [Re-N = 2.00( l) N-N = 1.01 (2) A] is readily displaced by superior donor ligands (CO MeCN Bu'NC).'~ The IR spectrum shows a strong vNN band at 21 30 cm ',the ~ highest frequency so far reported for a Re(N,) complex.Displacement of N from [Re'(N,)Cl(dppe),] with Bu'CP followed by reaction with H,O yields the P-bonded phosphinidene oxide complex [Re(POCH,Bu')Cl(dppe),] which has a short Re-P distance of 2.203( 1) A." Displacement of N with Me,SiCN gives the isocyanide complex [Re'(CNSiMe,)Cl(dppe),1 which is cleaved by HBF in MeOH to yield the aminocarbyne complex [Re(CNH,)Cl(dppe),] + which has a Re-C distance of 1.802(4)81 and a Re-C-N angle of 171.9(3)".81 The mononuclear Re" complexes [ReCl,(dme)] and [ReCl,(dppe)] have also been structurally characterized.82 A series of complexes of tetrabromo- and tetrachlorocatechol (H,L) has been prepared and the molecular structures of [ReVO(MeOH)L,] and [ReVO(OPPh,)L,] determined in which the MeOH and Ph,PO ligands are weakly bound trans to the 0x0 groups.83 Reaction of [ReVOCl,(PPh,),] with the chelating ligands Ph,ECH,CH,P(O)Ph (L E = P As) results in ligand exchange and quantitative formation of [ReVOCl,L] in which the phosphine oxide coordinates trans to the 0x0 73 D.Michos X.-L.Luo. J.A.K. Howard and R.H. Crabtree Inorg.Chem.. 1992. 31 3914. 74 D. Michos X.-L. Luo and R. H. Crablree J. Chem. Soc... Dalton Truns.. 1992 1735. '' M. T. Costello. P. E. Fanwick M. A. Green and R. A. Walton Inory. Chem.. 1992. 31 2359. 76 K. E. Meyer D. R. Root P. E. Fanuich. and R. A. Walton. Inory. Chem. 1992. 31 3067. 77 D. M. Hoffman D. Lappas and E. Putilina Inorg. Chem. 1992 31 79. 7H C. Amatore J. J. R. Frausto Da Silva M. F. C. Guedes Da Sllva A. J. L. Pombeiro and J.-N. Verpeaux. J. Chem. Soc.. Chem. Commun.. 1992 1289. 79 J. R. Dilworth J. Hi] R. M. Thompson. and D. L. Hughes J. Chem. Sac..,Chem. Commun. 1992 551. P. B. Hitchcock J. J. Johnson. M. A. N. I). A. Lemos M. F. Meidine J. F. Nixon. and A. J. L. Pombeiro J. Chem. SOL.. Chem. Commun. 1992. 645. A. J. L.Pombeiro Inorg. Chim. ktu. 1992. 198-200 179. '' D. W. von Gudenberg. 1. Sens. U. Muller. B. Neurnuller and K. Dehnicke. Z. Anory. Allg. Chem.. 1992 613. 49. *3 C.F. Edwards W. P. Griffith A. J. P. White and D. J. Williams. J. Chem. Soc.. Dulton Trans.. 1992. 957. 166 J. D.Crane atom.84 The chelating ligand [N(P(Se)Ph,},] reacts with [ReVOCl,(PPh,),] to yield [ReVOCl( N(PSePh,),},] which loses Se during recrystallization to produce [ReVO(OEt)(Ph,PNPSePh,),l (4) in which the two remaining Se donor atoms are trans to each other.85 Photolytic elimination of CO from the oxalate complex [ReVO(C,O,)(HB(pz),)] is reported to generate the highly reactive Re”’ 0x0 complex [ReO(HB(pz),)] which can be trapped by oxidizing agents such as Me,SO to yield [ReVilO,{HB(pz),)] or CDCl to give [ReVOCl,(HB(pz),)].86 The luminescence properties of the ReV 0x0 and nitrido complexes of a series of chelating phosphine and arsine ligand~,~~ and the molecular structures of the unusual seven-coordinate distorted pentagonal bipyramidal complexes [ReVO(OMe),(quat)]+ and [ReVNC1(PPh,)(quat)] have been reported.88 The structures of the nitrido com- + plexes [ReVN(OH,)(CN)J2 and [ReVN(N,)(CN),J3-have also been deter-mined,89g90and the relationship between structure and reactivity reviewed.” Reaction of [ReVOC1,(PPh,),] with PhMeNNH yields the bis(hydrazid0) complex [ReVC1,(NNMePh),(PPh3)]+ which reacts” with [Me,NCS,] -to give cis-[ReV(NNMePh),(S,CNMe,),] -.The phenylimido complex [ReV(NPh)Cl,(bipy)] reacts with excess bipy in EtOH to yield9 tr~ns-[Re~(NPh)(OEt)(bipy),]~+.This complex could not be converted to the expected cis-isomer indicating the stabilizing + effect of the multiple-bonded truns-[Re(NPh)(OEt)l2 core [Re-N = 1.740(6) Re-0 = 1.895(5)A]. Ph ,Ph ph\ ph-p’Se-.. -*-#p,~ II -Re-II NLp/l \ P-Ph ,\ OEt Se’ \Ph Pli Ph The gas-phase structure of Re,O at 230°C has been determined by electron diffraction; the molecule is bent with a Re-0-Re angle of 143.6(9)’ and Re-0 distances of 1.708(2)8 (terminal) and 1.892(5) A (bridging).94 The solid state structure of the asymmetric solvate [O,Re(p-O)ReO,(thf),] is also reported. Reaction of Re207 with Bu‘Si(OH) yields the cyclic tetramer [(Bu‘SiO( OReO,)),] in which the four ReO groups are all cis to one another.95 Reaction of Re,07 with (Ph,SbO) yields 84 K.V. Katti and C. L. Barnes Inorg. Chem. 1992 31 4231. n5 R. Rossi A. Marchi L. Marvelli M. Peruzzini U.Casellato. and R. Graziani J. Chem. Soc..Dulton Trans. 1992. 435. Yh S.N. Brown and J. M. Mayer. Inory. Chem. 1992. 31. 4091. n7 V.W.-W. Yam K.-K. Tam M.-C. Cheng. S.-M. Peng and Y. Wang J. Chem. Soc.. Dalton Truus. 1992. 1717. 88 C.-M. Che Y.-P. Wang K -S. Yeung K.-Y. Wong and S.-M. Peng. J. Chem. Soc. Dalton 7’run.v.. 1992 2675. 89 W. Purcell I. M. Potgieter. L.J. Damoense and J. G. Leipoldt Trunsition Met. Chem.. 1992 17. 387. YO W. Purcell. L. J. Damoense and J. G. Leipoldt Inory. Chirn.Actu 1992 195 217. 9 I J.G. Leipoldt S.S. Basson. A. Roodt and W. Purcell Polyhedron 1992 11.2277. 92 1. R. Dilworth P. Jobanputra. S.J. Parrott. R. M.Thompson. D.C. Povey and J. A. Zubieta. IWyhedron. 1992 11 147. Y3 M. Bakir S. Paulson. P. Goodson and B. P. Sullivan Itwry. Chem. 1992 31 1127. 94 P. Kiprof. W. A. Herrmann F. E. Kuhn. W. Scherer. M. Kleine M. Elison. K. Rypdal. H. V. Volden S. Gundersen. and A. Haarland Bull. Sx. Chirn.Fr. 1992 129 655. 95 N. Winkhofer. H. W. Roesky M. Noltemeyer. and W.T. Robinson. Ange~. Chem.. Inr. Ed. Enyl.. 1992.31 599. Mn Tc Re 167 either [(0,ReO)SbPh,(p-O)SbPh3(ORe03)] or [(O,ReO)SbPh,(OReO,)] depend-~ ing upon the ratio of the reactants.' The tetrahedral [ReV"0,S2] and [ReV"OS,] -cores have been structurally characterized9' as their Cu' halide complexes [ICu(p2- S),ReO,] -and [(C~CU),(~~-CI)(~,-S),R~O]~ -.The electrochemically generated d' [ReV1S,I2-anion has been spectroscopically ~haracterized'~ as both the free ion and in the complex [(bipy),R~"(p-ReS,)Ru"(bipy),]~ +. A series of cyclic phosphazene Rev'' arylimides has been reported of which [(ArN),Re(p-NPPh,NPPh,N),-Re(NAr),] (Ar = 2,6-Pr>C,H3) has been structurally ~haracterized.~~ Reaction of [Re,Cl,]'-with HBF in MeCN yields the cationic dimer [Re2(NCMe),,l2+ with an Re-Re triple bond of length 2.259(4)A.'Oo The axial MeCN ligands are weakly bound with Re-N distances of 2.51(3)A and the two Re(NCMe) fragments are staggered by 45 ' with an average Re-N distance of 2.08A. A series of di-4-tolylformamidine complexes of the Re;' core (n = 4 5 6) has been structurally characterized.The 6-chloro-2-hydroxypyridine (HL) complex of the + Re core [(q2-L)ClRe(p-L),ReCl,] is the first example of q2-2-hydroxypyridine coordination in these dimetallic complexe~.'~~ PHPh has been shown to add oxidatively to the electron rich Re-Re triple bond in [Cl,Re11(p-dppm)2Re11C12] to yield [C12Re1"(p-dppm)2(p-Cl)(p-PPh2)Re1"HCI]. lo3 Reaction of the bromide ana- logue of this product with [NO][PF,] yields the Re""' complex [Br(NO)Re(!i- dppm),(p-H)(p-Br)ReBr(POPh,):I,with the p-PPh group being oxidized to a terminal POPh ligand. The preparation of the unsymmetrical re"^" complex [(dmpm),Cl,ReReO,] [Re-Re = 2.4705(5)A],'' and an ah initio theoretical investi- gation of its electronic structure have both been rep~rted."~ The dinuclear Re" complex [Re2(dppm),(02CMe),C12] reacts with H,S in the presence of HBF in THF or CHCl to yield [ClRe(p-dppm I,(~-SH),R~C~] whereas in acetone the product is the gem-dithiolato complex [ClRe(p-dppm),(p-S,CMe,)ReCl] (5).106,107 Me.Me " U. Wirringa H. W. Roesky H.-G. Schmidt and M. Noltemeyer Chem. Ber. 1992 125. 2359. Y? A. Miiller A. Hildebrand E. Krickemeyer. D. Siilter. H. Biigge and A. Armatage. Z. Anory. Ally. Chem.. 1992 614. 115. YX R. Schafer W. Kaim. M. Moscherosch and M. KrejCik. J. Chrm. Soc.. Chem. Commun.. 1992. 834. yy R. Hasselbring H. W. Roesky. and M. Noltemeyer ,4nge\r. Chum.. Int. Ed. Enyl.. 1992. 31 601. '''' S. N. Bernstein and K. R. Dunbar. Anqtw. Chem.. Int. Ed. EnyI. 1992. 31. 1360. F.A.Cotton and T. Ren J. Am. Chem. So(,. 1992 114. 2495. F.A. Cotton and T. Ren Polyhedron 1992 11 81 I. I. Ara P.E. Fanwick. and R.A. Walton. Polyhedron. 1992. 11 1277. I04 I. Ara. P. E. Fanwick. and R.A. Walton Inory. Chem.. 1992. 31. 321 I. lo' M. Costas T. Leininger G.-H. Jeung. and M. Benard. Inory. Chrm. 1992. 31 3317. IUh K.-Y. Shih P.E. Fanwick and R. A. Walton. J. Chem. Soc,. Chem. Commun. 1992. 375. K.-Y. Shih P. E. Fanwick and R. A. Walton Inory. Chun.. 1992 31 3663.

ISSN:0260-1818    

DOI:10.1039/IC9928900159

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

13 Fe Co and Ni By S.A. COTTON Felixstowe College Felixstowe Suffolk IP11 7NQ UK 1 Introduction Organometallic compounds are dealt with elsewhere in this volume and receive only a passing glance here. Similarly coverage of complexes of macrocyclic ligands has been limited. Particular trends discernible this year include continued interest in binuclear iron 0x0-species and in nickel complexes with sulfur ligands. 2 Simple Binary and Coordination Compounds of Oxygen Nitrogen and Halogen Donors An important new book' covers the synthesis and structures of the various iron oxides hydroxides and basic iron salts. The synthesis has been described of a y-Fe,O,/polymer nanocomposite as a magnetic material with appreciable transmission in the visible region of the spectrum.Barium surface doped iron(Ir1) oxide particles for high-density magnetic recording have been studied. Photo-oxidation of matrix-isolated iron pentacarbonyl at 20 K leads to the identification of two binary iron oxides one believed to be the peroxide Fe(q2-0,) and the other the planar (or neatly so) trioxide FeO, rather than O=Fe=O as previously ~uggested.~ The hydride CaMgNiH, synthesized by sintering ternary metal alloy powders under dihydrogen has tetrahedral [NiH4I4- anions present (Ni-D distances in the corresponding deuteride are 1S97-1.602 A).' The electron affinity of FeCl has been reported' to be 4.3 & 0.2eV. 0-donors.-A report7 concerning higher oxidation states involves iron(v1) with the observation of sharp-line near-IR luminescence in FeOi-.A ferryl(v) intermediate has been invoked' in a study of DNA cleavage with a system involving an iron(r1) complex and dioxygen or H20,. [For some other iron(1v) complexes see pages 180 and 183.1 Among the aqua-complexes of metal halides both cis and trans-stereuchemistries U. Schwertmann and R. M. Cornell 'Iron Oxides in the Laboratory. Preparation and Characterization'. VCH Weinheim New York 1991. R.F. Ziolo E. P. Giannelis B. A. Weinstein. M. P. O'Horo. B. N. Gangulq. V. Mehrotra. M. W. Russell. and D. R. Huffmann Science 1992. 257. 219. ' C. Sarda C. Bonino P. Mollard and A. Rousset. 1.Moyn. Muyn. Murer.. 1992 109 127. M. Fanfarillo A. J. Downs. T. M. Greene and M. J. Almond Inory. Chem.. 1992. 31. 2973. ' B. Huang. K. Yvon and P.Fischer 1.Allo~.~ Compd.. 1992. 178. 173. ' M. M. Koborov. Y. V. Pervova and L. N. Sidorov Mendelerr Commun. 1992 41. M. Herren and H. U. Gudel. Itiory. Chcm. IY92. 31 3683. " R.E. Shepherd. T.J. Lomis. and R. R. Koepsel J. Cheni. Soc.. Chem. Conimun.. 1992. 222. 169 170 S. A. Cotton are known for MX2.4H20 units (Table 1 lists those whose structures have been determined). The structures of FeBr2-4H,O CoBr;4H20 and NiCI,-4H20 all involve' octahedral coordination of the metal; the first two are truns but the nickel complex is cis. Steric repulsions between bromines may favour the adoption of the trans-isomer though hydrogen-bonding and the effects of electron configuration may also be important. Table 1 Stereochemistry in MX2.nH20(n = 2 4 6) Fe co Ni n CI Br C1 Br c1 Br 2 t ~ t t t ~ 4 t t C t c - 6 ~ t t t t (c = cis; t = trans) The two crystalline forms of FeF,.3H20 have been reinvestigated lo and it is suggested that a previously reported structure of FeF2.4H,0 was in fact that of a-FeF,.3H,0.Reports on halogenoferrates include the syntheses' ' from iron bromine and the appropriate bromide of several AFeBr (A = alkali metal NH, Ag). Detailed magnetic studies have been made on two tetrach1oroferrates.l2.' The novel [Fe,C1,I2~ ion has a structure based on edge-sharing tetrahedra.I4 Like the corresponding chloride FeBr,.2Ph,PO has been shown" to be rrans-[FeBr,(OPPh,),][FeBrJ and [COI,(ONM~,)~] is pseudotetrahedral whilst [CoCI (ONMe,),] is similar." FeCl reacts with CIOTeF to form [Fe(OTeF,),] which readily reacts with bases and is believed to have a three-coordinate trigonal planar structure; it forms a distorted octahedral trjs(adduct) with S0,ClF.' ' Iron(m) is well known to form complexes with polyols and sugars; magnetic susceptibility and ESR studies suggest that the iron exists in mononuclear (presumably aqua) species with normal magnetic moments at pH 1-2 polynuclear species with lowered moments at pH 3-10 and mononuclear complexes where the iron is probably coordinated to the alcoholic OH groups at higher pH." Further investigations have been reported' 9,20 in the complex area of iron(1rr)-nitrilotriacetate complexes; it is K.Waizumi H. Masuda and H. Ohtaki. Inory. Chirn. Actu. 1992 192. 173. D.G. Karraker and P. K. Smith. fnorg. Chem. 1992. 31 11 19. I' G. Thiele. D. Honert and H. Rotter. Z. Anorg. Allgem. Chrm.. 1992. 616. 195. R. Shaviv C. B. Lowe. J. A. Zors. C. B. Aakeroy. P. B. Hitchcock. K. R. Seddon. and R. L. Carlin Inory. Chirn. Acta 1992 198-200. 613. l3 R. Shaviv K. E. Merabet. D. P. Shum C. 9. Lowe. I). Gonzalez. R. Burriel. and R. L. Carlin. Inorg. Chem.. 1992 31 1724. 14 K. Ruhlandt-Senge and U. Muller. 2.Narurforsch Teil B. 1992. 47. 1075. l5 E. Durcanska T. Glowiak E. Gyepes I. Ondrejkovicova. and G. Ondrejovic. Actci Fnc. Rerum Nut. Unit.. Comeniunae Chim.. 1991. 39. 3 (Chem. Ahsrr. 1992. 117. 80521). S. Jin M. Nieuwenhuyien W. T. Robinson and C.J. Wilkins. Actci Crystcilloyr. Sect. C. 1992. 48. 274. " T. Drews and K. Seppelt.Z. Anorg. Allgem. Chem. 1991 606 201. H. Yokoi. Y. Mori T. Mitani. and S. Kawata Bull. Chem. Sot. Jpn.. 1992. 65 1x98. 19 S. L. Heath. A. K. Powell H. L. Utting. and M. Helliwell. J. Chrm. Sot,.. Dcilfori 7rans.. 1992. 305. 2" Y. Nishida. K. Yoshirawa and T. Akamatsu. Chem. Lett. 1991. 1521. FP Co and Ni concluded that a mononuclear species is obtained at low pH which dimerizes to [(Fe(nta)(H20))20]2- at higher pI3. The structure of the barium salt of the latter (1) has been reported.’ 0 \\ 0 Octahedral six-coordinate iron has been confirmed for a bis(dipico1inato) ferrate iron(iii) complex;21 such iron(m) complexes catalyze the oxidation of saturated hydrocarbons by H202 in pyridine-acetic acid and the high-spin ion cis-[FeCl,(picolinate),] -has been characterized as a model for one-iron non-haem enzymatic oxidations.22 The reactive intermediates for this and a number of other intermediates for the metal-induced activation of H202 have been investigated kineti~ally.~~ Iron carboxylates investigated include24 [Fe(la~tate)~(H,O),] and the iron(iI1) oxydiacetate species [Fe{O(CH2C02)2}(H20)2X] (X = C1 Br) in which the car- boxylate occupies meridional positions with the two water molecules trans.25Two different kinds of trinuclear carboxylates have attracted attention.Inelastic neutron scattering shows 11 transitions in the region between 2-25 cm-’ in a ‘traditional’ p,-0x0-centred mixed-valence carboxylate,26 [Fe30(02CCD3),(C,D,N)3]* (C,D,N). These transitions disappear on dilution in a host lattice indicating that they originate in intermolecular electronic transitions.Iron(i1) acetate reacts with a bidentate N-donor BIPhMe [2,2’-bis( 1-methylimidazolyl)phenylmethoxymethane]to give an unusual trinuclear complex [Fe,(OAc),(BIPhMe),] (2) in which the three irons have a linear rather than triangular arrangement featuring one monodentate and two bidentate bridging acetates. Magnetic susceptibility studies indicate ferromag- netic exchange co~pling.~’ Several iron carboxylate complexes featuring bridging ligands have been postulated as models for iron sites in proteins. These are discussed together with a number of p-0x0 complexes in Section 7. I A. Cousson F. Nectoux and E. N. Rizkalla Acru Crj,stul[ogr.,Sec,r.C. 1992 48.1354. 22 J. Chem., D. H. R. Barton. S.D. Beviere W. Chavasiri. D. Doller W.-D. Liu and J. H. Reibenspies N~N 1992 16. 1019. 23 H.-C. Tung. C. Kang. and D.T. Sawyer J. Am. Chem. Sot,.. 1992 114. 3445. 24 P. Liu and M. Hong Jiegou Huuxue 1992. 11. 44 (Chem.Ahstr.. 1992. 117 101 459). 2s A. K. Powell J. M. Charnock A. C. Flood C. D. Garner. M. J. Ware and W. Clegg J. Chem. Soc. Dulton Trans.. 1992. 203. 2h U. A. Jayasooriya R. D. Cannon C. E. Anson. S. K. arapKoske. R. P. White and G.J. Kearley. J. Chem. So(..,Chem. Commun. 1992 379. 21 R. L. Rardin. P. Poganiuch. A. Bino. D. P Goldberg W. B. Tolman S. Liu and S.J. Lippard J. Am. Chem. Soc.. 1992. 114. 5240. 172 S. A. Cotton (2) R=CH3 The iron(1rI) complex of N,N'-bis(2-hydroxyphenyl)ethylenediamine-N,N'-diacetic acid28 (H,edda) has a very high stability constant (log K = 40.l) though not as high as a new hexadentate ligand which has an affinity for iron exceeding that of enterobac- tin29 at phyological pH.Iron catecholate complexes with cubane-like Fe,O cores3' (others are dimeric) have been synthesized whilst monomeric bis(catecho1ate) complexes have likewise been characterized3' and the redox properties of the iron(II)/(III) redox couples investigated. Metal complex ferrimagnets [NBu,] [M"Fe"'(ox),] with three-dimensional network structures of alternating Fe"' and MI' ions have been prepared.32 Several papers have appeared concerning the effect of high pressure on kinetics. The reaction of the iron(II1) aqua ion with azide has been studied by stopped-flow methods33 and shown to involve predominantly the reactions of [Fe(H2O),(OH)I2 + with N; and HN,; the corresponding reaction with thiocyanate has been reinves- tigated.The [Fe(CN),] -/[Fe(CN),I4 self-exchange reaction involves a very high positive volume of activation.34 The redox exchange of [Co(edta)] -and [Co(hedta)(H,O)] -has been described in terms of a non-adiabatic outer-sphere mechanism in which ring-closure and elimination of water precede electron transfer.35 The pressure dependencies of the electrode potentials of [Fe(H20),l2+I3+ [Fe(phen)3]2fi3+ [Fe(CN),]3-/4p and [Co(~epulchrate)]~+'~+ have been re-ported .3 Several alkali metal tetra-alkoxo and aryloxo cobaltates of the general type M,[Co(OR),]-xTHF have been synthesized; from spectroscopic data they seem generally to have tetrahedrally coordinated cobalt.37 Six-coordination is general for solvated species including those of cobalt(II) in most 0-donor solvents such as water dmso and dmf but an EXAFS of cobalt(1r) 28 J.F. Gibson and 0.J. Vaughan. J. Chem. Soc. Dulton Truns. 1992 1375. 29 R. J. Motekaitis Y. Sun and A. E. Martell Inorg. Chim. Actu 1992 198-200 421. 30 S.C. Shoner and P.P. Power Inory. Chem. 1992 31 1001. 31 D. Zirong S. Bhattacharaya J. K. McCusker P. M. Hagen D. N. Hendrickson and C. G. Pierpoint Inorg. Chem. 1992 31 870. 32 H. Tarnaki M. Mitsumi K. Nakarnura N. Matsumoto S. Kida H. Okawa. and S. Iijima. Chem. Lett. 1992 1975. 33 M. R. Grace and T. W. Swaddle. Inory.Chem.. 1992 31 4674. 34 H. Takagi and T.W. Swaddle Inory. Chrm. 1992 31 4669. 35 W. H. Jolly D. R. Stranks and T.W. Swaddle Inory. Chem. 1992. 31. 507. 36 H. Doine T.W. Whitcornbe and T.W. Swaddle Can. J. Chem.. 1992 70 81. 37 A.I. Ibrahim W. Gaube W. Kalies. and B. Witt J. Prakt. Chem. 1992 333 397. Fe Co. and Ni 173 and its chloro complexes in hmpa indicates that four-coordination is general in species [C~(hmpa),-~Cl,](~-”)+. Co-0 and Co-Cl bond lengths are shorter in the four- coordinate species than in corresponding ions like [CO(H,O),]~’. Among other complexes of simple 0-donors several cobalt complexes of pyridine N-oxide (PyO) and trimethylamine oxide have been studied39 with structures determined for [co(opy161[cocl4] 7 [cO(opy)& [Co(ONMe )4]12 and [Co(ONMe )2x2] (X = C1 I); as indicated by the formulae six-coordination is general for pyridine N-oxide and tetrahedral four-coordination for trimethylamine oxide.Six-coordination also occurs4o in [Co(hfac),(OPPh,),]. A modified electrolytic process for the synthesis of cobalt(I1r) acetate has been de~cribed.~’ N-donors.-Coordination numbers between 3 and 8 are known for iron(m) complexes. What appears to be a new geometry for four-coordination is the trigonal mono- pyramid rather than the usual tetrahedron for the brown high-spin pentane-soluble triamide complex (3),where the bulky trialkysilyl groups inhibit access to the vacant axial position.42 ,NSiMe2Bu‘ Bu‘Me$iN.-Fe’ ) ciaiMe2But (3) The crystal structure of [Fe(4-F-bipy),][PF63 shows four of the eight possible isomers;43 electronic spectra of iron(r1) complexes of phen bipy terpy and other ligands and their reduction products have been examined.44 FeN coordination has been crystallographically characterized for an iron(I1) tris(diimine) complex and its dissociation in the presence of hydroxide examined in a number of different solvents;45 the kinetics of reactions of diimine-cyanide complexes with various oxidizing agents have been analyzed.46 A convenient synthesis47 has been reported for the high-spin iron(I1r) poly(pyrazoly1)borate complex [NEt,][FeCl,{ HB(pz),)].The syntheses have been rep~rted~**~~ of a large number of [Co(N,),L,] complexes = pyridine or substituted pyridines) as well as the structures of two examples (L = py 4-Mepy); all appear to have rner geometry.Cobalt(II1) ammines are a hardy 3X K. Omtsumi. K. Tohji. Y. Abe. and S. Ishiguro. Inorq. Chim. Actu 1982. 191. 183. 34 (a) S. Jin M. Nieuwenhuyzen. and C.J. Wilkins J. Chem. Soc. Dalton Truns.. 1992 2071 ; (h) S.Jin M. Niewenhuyzen W. T. Robinson and C. J. Wilkins Actu Crj~.stulloyr.Sect. C. 1992 48 274. 40 J. R. Polam and L. C. Porter. Acra Crj~srulloqr.. Sect. C 1992 48 1761. 41 U. B. Ogutveren R. E. Plirnley. and 1. Nieve J. Appl. Electrochem. 1992 22 351 42 C.C. Curnmins J. Lee R. R. Schrock and W. D. Davis. Anqew. Chem.. Int. Ed. Enql.. 1992 31 1501. 43 C. K. Cho and A. S. Secco Actu Crystalloqr. Sect. C. 1992 48. 165. 44 P.S. Braterman J.-I. Song and R.D. Peacock. Inorg. Chem. 1992 31. 555. 45 M.J. Blandarner. J. Burgess J. Fawcett P. Guardado C. D. Hubbard. S. Nuttali L.J.S. Prouse S. Radulovic. and D. R. Russell Inory. Cheni. 1992 31 1383. 4h J. Burgess and B. Shraydeh Polyhedron. 1992. 11. 2015. 4-S. Cho D. Whang K. Han and K. Kim. Inorq. Chem. 1992. 31 519. 4H M. A. S.Goher. R. J. Wang and T. C. W. Mak. Polyhedron. 1991. 11 829. 44 F.A. Mautner Cryst. Res. Tc.chnol. 1991 26. 883. 174 S.A. Cotton perennial. The structure of [CO(NH,),][cUCI,] has been determined5’ above and below the transition temperature of 281 K. Thermal analyses have been carried oUt51-53 on a number of hexaammine salts with and without the presence of added potassium halides. A classic photoisomerization in [Co(NH,),(NO,)] C1 (nitro to nitrito) has been rein~estigated,~ together with the reverse thermal isomerization by single crystal diffraction.Kinetic studies have been carried out5 on the spontaneous isomerization of [Co(NH,),(SCN)I2 + ; the synthesis and hydrolysis (showing first order dependence on OH-) of the [Co(NH,),(SMe,)13+ ion has been reported.s6 [Co(NH,),(CO,)]CI reacts in the solid state with NH,SCN to give trans-[Co(NH,),(NCS),]Cl whilst in the analogous reaction with [Co(en),(CO,)]Cl cis-[Co(en),(NCS),]CI is formed first subsequently isomerizing into the tr~ns-isomer.~~ The structure of [Co(NH,),{ (S)-alaninate}]SO has been reported.58 The structure of [Co(CO,)(phen),] shows59 that Co-N bonds trans to 0are slightly longer than the cis-Co-N bonds; cis-[Co(glycine)(phen),] C1 has also been syn- thesized and crystallographically characterized.“ A series of paper~~l-~, reports syntheses structures and configurations of [CoX(dien)(dapo)] (X = halide pseudohalide NO, ONO) complexes and their + base hydrolysis.Other amine complexes reported include [Co(medien)(dien)] 3+ (medien = 3-methyl-1,5-diamin0-3-azapentane), where both the fuc and mer-isomers have been isolated and subjected to molecular mechanics analysis,, and isomers65 of + . [C~(trien)(salicylate)]~ Quinquepyridine ligands form mono-helical 1 1 and double-helical 2 2 cobalt(r1) c~mplexes;~~,~~ the crystal structure (4)of the complex [Co(cp,qpy)(MeoH)(H,o)][PF,] [cp,qpy = 4’,4”’-bis(4-~hlorophenyl)-2,2’ 6‘,2“ 6f’,2fff shows pentagonal bipyramidal seven-coordination.6”’,2””-quinquepyridine] The structure of tetragonal [NiCl,(Py),] has been redetermined,68 whilst the structures of planar trans-[NiCl,L,] (L = 2,6-Me2Py 2,3,6-Me3py) have also been T. Aoyama S. Ohba Y. Saito. and I. Bernal Acra Crystullogr. Sect. C. 1992 48 246. L. Zheng L. Dai and X. Xin Thermochim. Acta 1992. 196 437. 52 M.D. Patil G.N. Natu and S.B. Kulkarni Buli. Chem. Soc. Jpn. 1992 65 1026. 53 L. H. Khalil N.A. Moussa and S. Mikhail J. Muter. Sci.. 1992. 27 557. 54 M. Kubota and S. Ohba Actu Crystullogr. Sect. C. 1992 48 627. 55 A. Ellis A. Fultz R. Hicks,T. Morgan L. Parsons M. J. Saderholm L.A. Smith M. Stabb J. K. Starnes L. J. Sun and L. Roecker Aust. J. Chem. 1992 45 2049. 56 D.A. Buckingham C. R. Clark and G. F. Liddell Inorg. C‘hem. 1992 31 2909. ” J. Zhuang Q. Cheng. X. Xin and L. Zheng Yingyong Huaxue 1992. 9. 33 (Chem. Ahstr.. 1992. 117 102997). 58 B. Prelesnik K. Andjelkovic and N. Juraanic Acta Crystullogr. Sect. C. 1992 48 427. 59 C. A. McAuliffe R. G. Pritchard M. R. Bermejo A. Garcia-Vazquez A. Macias J. Sanmartin J. Romero. and A. Sousa Acfa Crystullogr. Sect. C 1992 48 1841. 60 B. Ye T. Zheng L. Ji and H. Zhuang Chin. Cheni. Lett. 1991,2 529 (Chem. Abstr. 1992,116.206613). 61 P. Comba D. A. House W.G. Jackson W. Marty. H. Stoeckli-Evans and L. Zipper. Helc. Chim. Actu 1992 75 1130. 62 P. Comba W.G. Jackson W. Marty and L. Zipper Helc. Chim. Actu 1992 75 1147. 63 P. Comba W. G. Jackson W. Marty and L.Zipper Htdc. Chim. Acta. 1992 75 1172. 64 I. M. Atkinson F. R. Keene J. M. Gu1bis.G. H. Searle,and E. R. T.Tiekink,J. Mol. Struct. 1992,265.189. 65 Y. Yamomoto E. Toyota T. Kumon and H. Sekizaki Bull. Chem. Soc. Jpn 1992 65 283. 66 E. C. Constable J. V. Walker D. A. Tocher and M. A. M. Daniels. J. Chem. Soc,..Chem. Commun.. 1992 768. ” E.C. Constable and J.V. Walker. J. Chem. Soc. Chem. Commun. 1992 884. “ R. E. Bachman. K. H. Whitmire. S. Mandal. and P. K. Bharadwaj. Acta Crvstalloyr.. Sect. C 1992. 48. 1836. Fe Co and Ni in~estigated.~~ Tetragonal pyramidal five-coordination occurs7o in [Ni(3,5-dimethyl- piperidine),(NCS),] and the structures of five dimeric adducts of substituted pyridines with nickel(I1) carboxylates likewise display five coordinate sp geometries with Ni-Ni distances of 2.708-2.765 (Reproduced with permission from J.(‘hem. Soc. Chem. Commun. 1992 768) The structure of tr~ns-[Ni(en)~(NCS),] has been redetermined.72 EXAFS has been used to provide comparative structural data on nickel(I1) and (HI) bis(diamine) complexes; both Ni-N and Ni-halogen distances shorten on increasing the oxidation state the former proving perhaps surprisingly the more sensitive.’ Ethanol solutions of the nickel(r1) diamine complex [Ni(N,N-Me,en),][C1O4] absorb and fix CO in air to give a trinuclear carbonato complex [Ni3(H20)4(C0,)(Me,en),lCCI0,1 (5). The transformation can be reversed by passing N through the solution whilst the presence of perchlorate seems to be important as only slight fixation is observed with other counter-ions (e.y.halide nitrate ~ulfate).’~ (Reproduced with permission from Inoty. Chem. 1992 31 1060) 69 W. L. Darby R. J. Butcher and L. M. Vallarino Inorq. Chim. Acta. 1992. 194 113. ’() M. Koman E. Jona and E. Durcanska Acta Crys~alloqr.,Sect. C 1992. 48 1652. M. Morooka S.Ohba M. Nakashima.T. Tokii. Y. Muto M. Kato and 0.M. Steward Acru Cry.sralloqr.. Sect. C 1992 48 1888. 12 N. V. Podberezskaya T. P. Shakhtshneider. A. V. Virovets and P. A. Stabnikov Zh. Srruct. Khim. 1991 32. 96 (Chem.Ahstr.. 1992. 116 140593). 73 J. Evans W. Levason. and R. J. Perry J. Chrm. SOC.,Dalton 7ratis.. 1992. 1497. 74 T. Tanase. S. Nitta. S. Yoshikawa. K. Kobayashi T. Sakurai and S. Yano Itiary. Chem. 1992,31 1058. 176 s.A.Cotton A double helical complex [Ni,(spy),][PF,] of the hexadentate ligand 2,2‘ 6’,2”:6“,2“‘:6’1’,21‘’’ :6””,2””’-sexipyridine (spy) has been synthesizedT5 (6). (Reproduced with permission from J. Chem. Soc. Chem. Commun. 1992 65) Both tetrahedral monomeric and binuclear five-coordinate nickel(I1) tris(pyra- zo1yl)borate complexes have been characterized .?‘ Using a tripodal ligand nickel(I1) complexes with NiN,S,O and NiN,S chromophores have been obtained;77 for five-coordinate complexes with NiN,S2 chromophores related to hydrogenase see Section 9. 3 Complexes of Tertiary Phosphines Two groups have ah initio calculations on c~s-[F~H(H,)(PR,)~] + . The properties of [FeXY(dmpp),] [X,Y = H C1; dmpp = Me,P(CH,),PMe,] and the structure of the dichloro compound (trans-,unlike the others) have been reported,*’ as has that of trans-[FeBr,(depe),] which is a catalyst for the Kharasch reaction between MgEtBr and alkyl halides to give alkanes and alkenes.The two proposed mechanisms involve iron(1) and iron(m) species. The structure of trans-[FeBrH(depe),][BPh4] has also been determined.8 The preparation of the symmetrically bridged alkynide [C1Fe(dmpe),(C~CC,H4C~C)(dmpe),FeCl] and the redox properties of this and other dmpe complexes [Fe(dmpe),(X)(Y)] (X Y = C1 or CCPh) have been reported.82 The cation in [Fe(NCMe),(dppe),][BF,1 is Iron(r1) complexes of a new bulky chelating phosphine 1,2-bis(di-n-butylphosphino)ethane (dbpe) have been reported [FeCl,(dbpe),] a precursor for a series of alkyne complexes is paramagnetic in solution but diamagnetic in the solid state.*“ 75 E.C. Constable and R. Chotalia. J. Chem. Soc,..Chern. Commun. 1992 64. 76 S. Trofimenko J. C. Calabrese. J. K. Kochi. S. Wolowiec. F B. Hulsbergen. and J. Reedijk. Inor6q. Chern.. 1992 31 3943. 7 K.G. Ragunathan and P.K. Bharadwaj. J. Chrm. Sor... Dulfon 7runh.. 1992. 2417. 78 J.-F. Riehl. M. Pelissier. and 0. Eisenstein. Inory. Chem. 1992 31. 3344. 79 F. Maseras M. Duran. A. Lledos. and J. Bertran. J. Am Chem. Soc,.. 1992. 114. 1922. 80 N. Bampos L. D. Field. and T. W. Harnbley Polyhedron. 1992. 11 1213. 81 D. J. Evans R. A. Henderson. A. Hills. D. L. Hughes and K. E. Ogilvie. J. Chern.SOC,.. Dulfon 7’run.s..1992 125Y. 82 L.D. Field A. V. Goerge F. Laschi. E. Y. Malouf. and P. Zanello J. Oryunorner. Chern. 1992,435 347. H\ A. J. Blake. A. J. Atkins R.O. Gould and M. Schroder Z.Krisrulloyr.. 1992. 199 287. x4 J. Lewis M. S. Khan A. K. Kakkar. P. R. Raithby. K. Fuhrmann. and R. H. Friend. J. Oryunomef. Chmi. 1992,433 135. Fe Co and Ni The non-classical hydride [FeH(H,)(pp,)] is8’ rigid in solution at low tem- + peratures with the hydride and dihydrogen ligands cis. The related cation [FeH(pp,) (N,)] + reacts with 4-pentynoic acid to give the octahedral pentynoate + [Fe(pp,)(O,C(CH,),C-CH}] in which the carboxylate acts as a chelate.8h Comparison of the analogous iron and ruthenium compounds indicates that the barrier to rotation of the dihydrogen ligand is higher in the former indicating rather surprisingly that Fe is a better back-donor than RU.~’ An extension of earlier synthetic work on reactions between metal powders and halophosphoranes has led to the synthesis of tbp [CoI,(PMe,),] from cobalt and Me,PI,.The corresponding reaction using Bu,PI gives an unusual metal phosphane complex88 (7). (Reproduced with permission from Angew. Chem. In?. Ed. Engl. 1992 31 919) The solid cobalt(r) dinitrogen complex of the tripodal ligand pp3 [Co(pp3)(N2)] [BPh,] is transformed by gaseous H into a white dihydride (the addition can be reversed under a dinitrogen atmosphere) which has a classical dihydride structure. In contrast if the reaction is carried out with the hexafluorophosphate salt of the N complex the resulting red dihydrogen complex has a non-classical structure (Scheme 1).The white tetraphenylborate salt dissolves in various solvents to give red solutions containing the q2-complex; on adding ethanol the white classical dihydride precipi- tates. Similar ethanol precipitation with solutions of the hexafluorophosphate gives the x5 C. Bianchini M. Peruzzini. A. Pola. A. Vacca. and F. Zanobini. Gnzz. Chirn. Irul.. 1991. 121. 543. Hh K. Linn D. Masi C. Mealli C. Bianchini and M. Peruuini Acru Cry.sta/loyr..Sucr. C. 1992 48. 2220. J. Eckert. A. Albinati R. P. White C. Bianchini and M. Peruzzmi Inory. Chmm. 1992 31. 4241. HX C. A. McAuliffe S. M. Godfrey A.G. Mackie. and R. G. Pritchard. Anyuw. Churn. Inr. Ed. Engl. 1992.31. 919. 178 S.A.Cotton q2-dihydride. This is therefore an example of a solid-state/solution tautomerization as well as a counter-ion influenced isomeri~ation.~’ Scheme 1 (Reproduced with permission from J. Am. Chem. Soc. 1992 114 5906) Several new nickel(0) complexes of bulky diphosphines have been reported.9o [NiBr,(PEtPh,),] has pseudotetrahedral coordination” whilst [Ni(N,),( PEt ,),I has a trans-planar geometry;’ charge-transfer photolysis of the latter gives dimeric [(Ni(N,),(PEt,)),]. Several mono- bi- and tri-nuclear Ni(PMePh,) fluoroalkyl complexes have been reported.93 Square planar NiCl and NiBr complexes of 3,4-dimethyl-3’,4’-bis(diphenylphosphino)tetrathiafulvalene have been synthesized and structurally ~haracterized.’~The results of force-constant calculations for [Ni(PX,),] (X = F C1 Br Me) have been ~ornpared.’~ Elemental S reacts with [NiX,(PPh,),] (X =halide NO, NCS) to afford NIX and Ph,PS whilst the corresponding reaction with [NiX(S,CNR,)(PPh,),] gives NIX and [Ni(S,CNR,),] by disprop~rtionation.’~ The new ylid complex [Ni(CH,PPh,CH,PPh,),]Br fea-tures square-planar coordination of nickel.97 .The influence of coligands on sulfur dioxide binding in Ni(PR3),(S02) complexes has been investigated by MO calcula- tion~;~~ small phosphines which are strong donors are expected to favour the q1 pyramidal mode of bonding.Various nickel(o) diphosphine complexes bind CO .99 89 C. Bianchini C. Mealli M. Peruzzini and F. Zanobini. J. Am. Chem. Soc.. 1992 114 5905. 90 P. Mastrorilli G.Moro C.F. Nobile and M. Latronico Inorq. Chim. Actu 1992 192 183. 9’ J.0. Malm V. Alfredsson G. Svensson and J. Albertsson Actu Crystallogr. Sect. C. 1992 48 406. 92 A. Becalska R. J. Batchelor F. W. B. Einstein R. H. Hill and B. J. Palmer. Inorg. Chrm. 1992 31 31 18. 93 R. McDonald K. C. Sturge A. D. Hunter and L. Shilliday Orgunometallics. 1992 11 893. 94 M. Fourmigue and P. Batail Bull. Soc. Chim. Fr. 1992. 129. 29. 9s H.G. M. Edwards and V. Fawcett. Inorg. Chim. Acra . 1992 197. 89. 96 J. Darkwa W. A. A. Ddamba. and L. M. Koczon. Bull. Chem. Sots. Erhiop.. 1991.5.73 (Chem. Ahsrr. 1992 116 222 285). 97 J. K. Gong. T. B. Peters P. E. Fanwick and C. P. Kubiak Orgunornr~rullics.1992. 11. 1392. J. Reinhold M. Schuler T. Hoffmann and E. Wenschuh Inorq.Chrm. 1992 31 559. O9 P. Mastrorelli G. Moro C.F. Nobile and M. Latronico Inorq. Chim. Actu 1992. 192 189. Fe Co and Ni 179 Some five-coordinate bis(triarsine) complexes of nickel show 'O0 an extensive nickel- centred redox chemistry with all oxidation states from 0 to +4 observed by cyclic voltammetry. 4 Complexes with S and Se Donors The bulky thiol2,4,6-triphenylthiophenol(HSTriph) has been synthesized; its reaction with [Fe(N(SiMe,),),] involves reduction to the iron(I1) compound [Fe(STriph),] a dimer (8) like the analogous silylamide with three-coordinate iron. O' R I S RS-Fe' 'Fe-SR 'S' I R Several investigations have concerned simple complexes of monomeric mercapto ligands. A general synthesis has been reported for stable [Fe"'(SR),]- models for oxidized rubredoxin with crystallographically characterized examples for R = Me Et and Ph.'" The structure of [NMe,],[Fe(SePh),] has been determined;" the Fe-Se bond is reported to be more ionic than that between Fe and S.Several iron(i1) thiolates are reversible CO carrier~.''~ Syntheses have been reported for [Fe,(SMe),(NO),] a known tumorigenic promoter and related systems.' OS Electronic spectra and crystal-field calculations have been carried out for [Ni- (SR),I2- and some solvolysis has been shown to occur;'06 mass spectra have been reported for several Ni and Ni thiolates along with the crystal structure of [Ni6(SPr)l,].'07 Use of the bulky thiolate S-2,4,6-Pr\C6H (SR) gives a binuclear species [Ni,(SR),] which is based on face-sharing bitetrahedra with three bridging thiolates."' Mixed-valence nickel thiolates [Ni,(SPr),X] (X = Br,I) have chain structures (related to those of [Ni,(SR),]) with individual [NI,(SR),X]' molecules joined by halogen bridges.The halogen bridges are symmetrical in the iodide but not in the bromide.'" Single-crystal ESR electronic spectra and magnetic susceptibility data have been reported' lo for [PPh,],[Co(SPh),:] whilst [Co,(SPr'),] -is the first complex to have face-sharing MS tetrahedra.' '' 100 J. Downard L. R. Hanton. and R. L. Paul. J. Chem. Soc. Chem. Commun. 1992 235. I"' K.-Ruhlandt-Senge and P. P. Power Bull. Soc. Chim. Fr. 1992 129 594. L. E. Maelia M. Millar and S.A. Koch. Inorq. Chem. 1992 31 4594. N. Ueyama H.Oku W. Y. Sun. A. Nakiimura. and K. Fukuyama Phosph.. Sulph. Silicon Relar. Elrm.. 1992 67 151. '04 A. Szakacs J. Kresz L. Marko Z. Nagy-Magos and J. Takacs Inorg. Chim. Acto 1992 198-200 401. A. R. Butler C. Glidewell and S. M. Glidewell J. Chem. Soc. Chem. Commun. 1992 141 Polyhedron 1992 11. 591. 'Oh T. Yamamura and H. Arai Bull. Chem. Soc. Jpn. 1992 65 1799. 107 H. Feld A. Leute. D. Rading A. Benninghoven. G. Henkel T. Krueger. and B. Krebs,Z. Narurforsch. Teil B 1992 47 929. ion A. Silver and M. Millrear. J. Chem. Soc. Chem. Commun. 1992. 948. 10') T. Kruger B. Krebs and G. Henkel. Angew. Chrm. Int. Ed. Engl.. 1992. 31 54. K. Fukui N. Kojima H. Ohya-Nishiguchi and N. Hirota. Inorg. Chrm.. 1992 31. 1338. 180 S. A. Cotton The reaction of NiCl, PPh, and Na,(edt) (edt = ethane-1,2-dithiolate) in meth- anol causes cleavage of a C-S bond and the isolation of square-planar [Ni(PPh,),{ S(CH2)2S(CH,),S)].1 ' The octahedral anion [Ni(thioxanthate),] is ~ oxidized electrochemically to the Ni"' analogue; it does however decompose at room temperature to the dimer [Ni2(SEt),(CS3),l2- which has thiolato bridges and one CS group chelated to each nickel.' ' Among dithiocarbamates [Fe(S,CN(CH,CH,OH),),] and solvates have been reinvestigated' l4 and previous studies re-evaluated.Tris(dially1dit hiocarbamato)co bal t is isomorphous with the iron analogue with trigonally distorted octahedral coordination. ' ' 5 Complexes of Porphyrins and other Macrocycles Porphyrins.-There has again been intense activity in this field.Of interest are 0x0-iron(1v) chlorin and porphyrin n-cation radical complexes prepared by rn-chloroperoxybenzoic acid oxidation of iron(r1r) species.' l6 ' l9 In contrast NMR evidence has been adduced to support the assignment of n-anion radical character in two-electron reduced iron(1tr) meso(P)-substituted porphyrins. ' 2o Resonance Raman and magnetic resonance' ,' have been used to compare iron porphyrin complexes in the oxidation states (I) through (iv); electronic and Resonance Raman spectra have been used to characterize bis(imidazo1e) model complexes of iron(protoporphyrin).' 22 Other applications of Resonance Raman spectroscopy to the study of iron porphyrins include' 23 examination of Fe-OH bond strengths in high- and low-spin bis(hydrox- ides) of co-condensation products' 24 of [Fe(tpp)] with ethene and oxygen in matrices at 25 K and of iron hydroporphyrins.' 25 A structurally characterized five-coordinate iron(Ir1) 'picket-fence' porphyrin com- plex affords on reduction a five-coordinate iron(ir ) complex with unusually large quadrupole splitting in the Mossbauer spectra.' 26 Other structures reported' 27 include those of two salts of [Fe(tpp)(EtOH),] + of an iron(oep) cation radical,' 28 and of a five-coordinate high-spin iron(rrr) oxophlorin complex.' 29 The structure of [FeLCl] (L = dioxobacteriochlorin) a model for heme d, I" G. Henkel and S. Weissgraber Angw Chrm.. Irir. Ed. Etiyl. 1992 31. 1368. R. Cao X. Lei Z. Huang M. Hong. and H. Liu J. Coord. Chrm. 1992 25.165. S.B. Choudhury and A. Chakravorty Inorg. Chun.. 1992. 31. 1055. I I4 D. L. Boyd N. V. Duffy A. Felczan E. Gelinterer. D. L. Uhrich. G.A. Katsoulos and J. B. Zimmerrnan Inory. Chim. Acta 1992 191. 39. E. Kello J. Lokaj and V. Vrabel Coll. Cxch. Chern. Cornmuti.. 1992. 57 332. IJh A. L. Balch. C. R. Corman. L. Latos-Grazynski. and M. W. Renner. J. Am. Chrm. Soc,.. 1992. 114 2230. S.Ozawa Y. Watanabe and I. Morishima Inorg. Chrm.. 1992 31. 4042. 'In H. Fujii and K. Ichikawa. Inorg. Chem.. 1992. 31 I1 10. 'I9 K. Yamaguchi. Y. Watanabe and I. Morishirna Inory. Chrm.. 1992 31. 156. I2O K. Yamaguchi and I. Morishima. Inorg. Chrm.. 1992 31. 3216. K. R. Rodgers. R.A. Reed. Y.O. Su and T.G. Spiro Inorg. Chrm. 1992. 31. 2688. 122 A. Desbois and M.Lutz Eur. Biophys. J.. 1992. 20 321. K. H. Rogers R. A. Reed T.G. Spiro. and Y. 0.Su Nrw J. C'hrm.. 1992. 16 533. A. Weselucha-Birczynska I. R. Paeng A. A. Shabana. and K. Nakamoto Nrw J. Chrm.. 1992. 16. 563. L. A. Anderson M. My1rajan.T. M. Loehr E. P. Sullivan. and S. H. Straws Nw J. Chrni.,1992,16,569. E. L. Bominaar X.-D. Ding A. Gimelseed. E. Rill. H. Winkler A. X. Trautwein H. Nasri J. Fischer. and R. Weiss Itiory. Chrm.. 1992 31 1845. 12' W. R. Scheidt D. K. Geiger. Y. J. Lee. P. Gans and J. C. Marchon. Inory. Chrm.. 1992 31 2660. IZR W. R. Scheidt H. Song. K. J. Hailer M. K. Safo. R. D. Orosz. c'.A. Reed. P.G. Debrunnerand. and C. E. Schulz. Inorgq. Chrm.. 1992 31. 939. 12V A. L.Ralch. L. Latos-Grazynski. B. c'. Noll. M. M. Olrnstead. and E.P. Zovinka /nor$/.Chrm. 1992.31 2248. Fe Co and Ni shows'30 significantly longer Fe-N bonds to the saturated pyrroline rings (2.1 1 A) compared with those to the unsaturated pyrrole rings (2.04A); binuclear [(Fe(tpp)},O] has been suggested as a model for cytochrome P-450 mono-oxygenase.' 31 [(Fe(oep)},O] can be protonated to give a p-hydroxo complex ion [(Fe(oep)},OH]+ whose crystal structure (9) shows a large Fe-0-Fe angle (146.2.) owing to ring-ring interactions.' 3' (Reproduced with permission from J. Am. Chern. Soc. 1992 114 4420) A modified picket fence iron(iir) porphyrin has been suggested as a model for haemoglobin mutants.' 33 Reaction of the picket-fence species [Fe(NO,),(TpivPP)] -( HzTpivPP = r,r,r,~-mt.so-tetrakis-o-pivalamidophenyl)porphyrin) with mercaptans gives iron(t1) NO complexes but on reaction with KSR anionic iron(ir1) complexes [Fe(NO,)(SR)(TpivPP)]-are obtained; structures are reported for both types.' 34 Several low-spin bis-ligated (porphinato)iron(tir ) complexes of the type [Fe( tmp)L,] + (tmp = tetramesitylporphinato; L = 2-MeHim substituted pyridine) have been syn- thesized.Structures of several examples have been determined' 35;the axial ligands are perpendicularly aligned leading to the 'large y max' type of ESR spectra characteristic of cytochromes b. The effect of substitutent size on free rotation of the axial bases of cytochrome b models has been studied.'36 and 'H COSY has been used to determine ' "I K. M. Barkigia. C. K. Chang. J. Fager. and M.W.Renner. J. Am. Chrni. Soc... 1992 114. 1701. I.'' C. Guo. S. Zhu. and M. Gui. HMU.YUK Xuehuo. 1992. 50. 129 (Chrm. Ahsrr.. 116. 206669). 13' W. R. Scheidt. B. Cheng. M. K. Safo. F. Cukiernik. J.-C. Marchon. and P.G. Debrunner. J. Am. Chmi. Soc.. 1992. 114. 4420 H. Imai S. Nakagawa. and E. Kyuno. Inory. C'hini. Ac,ru 1992. 193. 105. H. Nasri. K. J. Haller. Y. Wang. B. H. ltuynh. and W. R. Scheidt. fnory. Chrni. 1992. 31. 3459. M. K. Safo. Ci.P. Gupta. C. T. Watson. U. Simonis. F. A. Walker. and W. R. Scheidt. J. .4m. Cliem. SOC,.. ' 1492. 114. 7066. F A. Walker. L. Simonis. H. Zhang. J. M. Walker. T. McDonald Ruscitti. C. Kipp. M. S.A. Arnputch. B.V. Castilio. S. H. Cody. D. L. Wilson. R. E. Graul. G.J. Yong. K. Tobin. J.T. West. and R.A. 182 S.A. Cotton spin densities at the pyrrole fi-positions of unsubstituted low-spin iron(r1r) tpp complexes.' EXAFS studies on iron(I1) and (111) 'basket-handle' porphyrins include' 38 the assignment of an Fe"(0,) rather than an Fe"'(0;) formulation to a dioxygen adduct; '7ONMR and FTIR studies of oxygenated 'hybrid' haemoprotein models with axial hindered bases indicate considerable polarizability of the Fe-0 moiety; there is however no hydrogen bonding between the dioxygen and the NH groups of the picket fence in contrast to the results with unhindered bases.' 39 Syntheses have been reported' 40 for several octaethyltetraazaporphyrin complexes of iron; the ligand is a stronger a-donor and n-acceptor than porphyrins and therefore stabilizes the unusual 'intermediate' spin state of 3/2 for iron(r1r) in FeLCl.Pyr~lysis'~' of [Fe(tpp)Cl] has been studied by FTIR and Mossbauer spectroscopy; Fe(tpp) complexes have been investigated as surface-polymer coupling reagents and as corrosion inhibitors. 142 Iodine oxidation of (tetrabenzoporphyrinato)cobalt(Ir) Co(tbp) affords Co(tbp)I a macrocycle-oxidized molecular conductor. '43 One-electron reduction of methyl- cobalamin adds an electron to an antibonding orbital considerably weakening the Co-C bond resulting in a > 1015 enhancement of bond hom~lysis.'~~ The structure of a dicobalt cofacial porphyrin 145 and the characterization of a p-superoxo complex have been reported whilst the ground states of [Co(tpp)] and [Co(oep)] cation radicals have been probed by ESR.'46 A simple synthesis of aquacobalamin has been de~cribed,'~~ as has a new B, model system using a ligand with a pendant pyridyl group.14' The structures of several nickel(i1) b-halogenated pyrrole porphyrins have been determined,149 as well as a nickel ~hlorin,'~' whilst the first chlorophin has been obtained from oxidative ring-opening of an (octadehydrocorrinato)nickel(II)salt.' ' The nickel(1) octaethylisobacteriochlorin anion is being investigated as an F 430 m0de1.l~~ Other Macrocyc1es.-This area is reviewed elsewhere in this volume; a selection of Barichivich New J.Chem.1992 16 609. 13' Q. Lin U. Simonis A. R. Tipton C. J. Norvell. and F.A. Walker Inorg. Chem. 1992 31 4216. 13' C. Cartier M. Momenteau E. Dartyge. A. Fontaine G.Tourillon. A. Michalowicz and M. Verdaguer J. Chem. SOC.,Dalton Trans. 1992 609. 139 I. P. Gerpothanassis B. Loock and M. Momenteau J. Chem. SOC.,Chem. Commun. 1992. 598. I4O J. P. Fitzgerald B.S. Hafferty A. L. Rheingold L. May and G.A. Brewer Inorg. Chem. 1992,31 2006. (a) T. Sheng B. Rebenstorf A. Widoloev and R. Larsson J.Chem.Soc. Faraday Trans.. 1992,88,477,;(h) J. Blomquist H. Laang R. Larsson and A. Wideloev J. Chem. SOC.,Faraday Trans. 1992 88 2007. 14' B. Meyer-Roscher T. Siemens and H. Brockmann Ado. Muter. 1992 4 496. 143 K. Liou T. P. Newcomb M. D. Heagy J. A. Thompson W. B. Heuer R. L. Musselman C. S. Jacobsen B. M. Hoffmann and J. A. Ibers Inorg. Chem. 1992 31 4517. 144 B. D. Martin and R.G. Finke J. Am. Chem. SOC.. 1992 114 585.145 J. P. Collman J. E. Hutchison M. A. Lopez,A. Tabard R. Guilard W. K. Seok J. A. Ibers and M. L'Her J. Am. Chem. SOC. 1992 114 9869. 146 M. Satoh Y. Ohba S. Yamaguchi. and M. Iwaizumi Inorg. Chem. 1992 31 298. 14' R. Bieganowski and G. Klar J. Chem. Res. (S) 1992 116. I48 A. Gerli M. Sabat and L.G. Marzilli. J. Am. Chem. Soc. 1992 114 671 I. D. Mandon P. Ochenbein J. Fischer R.Weiss. K. Jayaraj R. N. Austin A. Gold P.S. White.0. Brigaud P. Battioni and D. Mansuy Inorg. Chem. 1992. 31 2044. 150 K. M. Barkigia M. A. Thompson J. Fajer R. K. Pandey K. M. Smith and M.G. H. Vicente New J. Chem. 1992 16 599. 15' C. K. Chang W. Wu. S. Chern and S. Peng Angew. Chem. Inf. Edn. EnqI. 1992. 31 70. 15' G. K. Lahiri L,. J. Schussel and A. M. Stoltzenberg Itiorg.Chem. 1992 31 4991 Fe Co and Ni 183 papers is discussed here where the interest lies principally in the metal centre. A macrocyclic tetraanionic ligand has been used to stabilize iron(Iv) as a six-coordinate bis(buty1isocyanide) adduct (lo).'53 The five-coordinate(SP) iron(1rr) complex of a tetraimidazole ligand [FeLCl] loses the chloride in methanol solution to become a six-coordinate bis(Me0H) solvate whose properties model the lipoxygenase binding site.' 54 Non-octahedral cobalt(II1) complexes are still relatively rare as are paramagnetic cobalt(u1) compounds; several five-coordinate tropocoronands (1 1) with both square pyramidal and the more unusual trigonal bipyramidal geometries have been syn- thesized with the larger macrocycle ring favouring the latter geometry.' 55 Complexation of CoCI with the pentadentate crown ether 15-crown-5 has led to the isolation' 56*157 of several complexes which are generally pentagonal bipyramidal + [Co(15-crown-5)L2l2 (L = MeCN H,O).Polymer-supported cobalt(i1) complexes of tetraazamacrocycles form dioxygen adducts with considerably greater lifetimes than the same complexes in solution.' 58 The effect of ring size upon ligand field strength and redox potential has been studied for cobalt(m) complexes of some N macrocycles.' 59 The crystal structure and electron density distribution are reportedt6' for trigonally compressed meso-[Co(hexaen)]Cl at 106K (hexaen = 1,4,7,10,13,16-hexaazacyc-looctadecane). The effects of the donor atoms and their position and spacing and of the ring size have been examined for a number of cobalt and nickel(I1) complexes of mixed-donor macrocycles.' Nickel(]) and (III) complexes continue to attract interest. The N donor hexaclen (1,4,7,10,13,16-hexaazacyclooctadecane) forms'62 stable [Ni(hexaclen)][AsF,] on reduction of the Ni" analogue. The structure of the tetragonal nickel(II1) complex [Ni([13]aneN4)Br2]Br ([13]aneN4 = 1,4,7,10-tetraazacyclotridecane) has been de- terrnined.l6 Oxidation of [Ni((9)aneS,)J2 + affords the isolable Ni"'analogue which has significantly shorter Ni-S distances than the Ni" c~mpound.'"~ Complexes of cyclam-type ligands continue to be popular. Kinetic studies show'65 that the formation of such complexes consists of a fast second-order reaction [first order in both nickel(1I) and ligand] followed by a slower first-order rearrangement of the intermedi- ate.Studies of nickel(I1) complexes of sterically congested substituted cyclams indicate the substituents affect the magnetic behaviour with less congested complexes more Is3 T. J. Collins B. G. Fox,Z.G. Hu K. L. Kostka,E. Munck,C. E. F. Rickard,and L.J. Wright,J. Am. Chem. Soc.. 1992 114 8725. IS4 E. Mulliez G. Guillot-Edelheit P. Leduc. J. C.Ch0ttard.C. Bois A. Bousseksou. and W. Nitschke. New 1. Chem. 1992 16 435. lS5 B.S. Jaynes. T. Ren S. Liu. and S.J. Lippard. J. Am. Chem. Soc,.. 1992. 114. 9670. 156 0.K. Kireeva B. M. Bulychev N. R. Streltsova V. K. Balsky and A. G. Duniun. Polyhedron 1992 14 1801. IS7 B. M. Bulychev 0.K.Kireeva. V. K. Bzlsky and N. R. Streltsova Polyhedron 1992. 11. 1809. J. H. Cameron and S. Graham J. Cheni. Soc. Dalton Trans.. 1992 385. Is9 M. Tsuchimoto and J. Fujita Bull. Chem. Soc. Jpn. 1992 65 191. I ti0 M. Morooka S. Ohba and K. Toriumi. Acta Crystallogr.. Sect. 8,1992 48 459. Ih' K. R. Adam M. Antolovich D. S. Balduin L. G. Brigden P.A. Duckworth. L. F. Lindoy A. Bashall M. McPartlin and P. A. Tasker J. Chem. Soc. Dalton Trans.. 1992 1869. lb2 G. Gencheva M. Miteva E. Zhecheva and P. R. Bonchev 7eor. Eksp. Khim 1991.27.339 (Chrm.Ahstr.. 116 50 267). H. Miyamae K. Yamauchi and M. Yamashita. J. Chem. Soc. Dalton Trans. 1992 2921. lh4A. J. Blake. R. 0.Gould M. A. Halcrow. A. J. Holder T. I. Hyde and M. Schroder,J. Chem. Soc. Dalton Trans..1992 3427. 165 J. R. Roeper and H. Elias Inorg. Cheni. 1992. 31. 1202. 184 S.A. Cotton But N N But (1 1) (Reproduced with permission from J. Am. Chem. Soc. 1992 114 9670) Fe. Co urid Ni 185 likely to be high-spin.' h6 cis-[Ni(isocyclam)(H2O),]C1,~2H,O(isocyclam = 1,4,7,11-tetraazacyclotetradecane) has six-coordinate geometry with cis-water molecules more distorted than that in the corresponding cyclam complex. On heating it undergoes deaquation-anation to give c~is-[NiCl,(isocyclam)] and on further heating isomerizes irreversibly to the trans-isomer with concomitant configurational change in the ligand. In contrast ci.~-[Ni(cyc1am)(H20),]C1,~2H,0 does not isomerize on heating.lh7 Some new asymmetric tetraaza macrocyclic complexes of nickel have been preparedlh8 and their binding to synthetic polymer supports examined.The study of nickel complexes of ligands with pendant arms added to the cyclic 1,5-diazacyclooc- tane has shown that metal-ligand bonding can influence the adoption of the unfavourable chair/chair configuration of the fused metallacycle rings.' 69 6 Schiff Base and Related Complexes Trends in the UV/visible and EPR spectra and in the redox potentials of mononuclear iron(w) complexes of Schiff bases derived from salicylaldehyde have been examined resulting in a correlation between the frequency of a ligand-metal CT band and the FellI/I1 redox potentia1.17' The p-0x0 complex [(Fe(salophen)},O] forms a dmso adduct that has a square-pyramidal structure linked by a bent Fe-0-Fe bridge,' 71 whilst octahedrally coordinated iron is found in low-spin K[Fe(acacen)(CN),].2H20.Structures have also been for [Fe(acacen)X] (X = CI NO,) and [{Fe(acacen)),O]. [acacen = N,N'-ethylenebis(acetylacetonylideneiminate)]. Another binuclear com-plex features a terephthalate bridge.' 73 Electrochemical oxidation of the oxygen carrier [Co(salen)] has been in a range of solvents. Solid-state 15NNMR studies on NO adducts ofcobalt N-substituted salicylideneiminate complexes suggest that the shift tensor may be used as a criterion of bond angle; the structure of the bent [Co(NO)(esal),](Co-N-0 129' ) (esal = o-OC,H,CH=NEt) was determined.' 7s In the field of reduced Schiff base complexes acetone solutions of the nickel tetrahydrosalen complex (12a) add 0 at low temperatures changing in colour from cherry-red to yellow-orange with dehydrogenation only as far as a dihydrosalen complex (12b); the reaction has been shown in one case to be first order in both 0 and the nickel complex.[No such dehydrogenation reaction is observed with correspond- ing Felrr and Cu" complexes]. The reaction is inhibited by adduct formation (e.y. with 166 K. Kaobiro. A. Nakyama. T. Hiro. and Y. Tobe. Inory. Chem.. 1992. 31 676. 1 h7 Y. Satake Y. Ihara H. Senda. M. Suruki. and A. Uehara. Inory. Chem.. 1992. 31. 3248. 1 hH J. H. Cameron. H. B. Harvey. and I. Sourar. Inory. Chim. ktu. 1992. 192,253:J. Chrm. Soc.. Dulfori 7i.un.s.. 1992. 597. lhy M. Y. Darensbourg. I. Font. D. K. Mills.M. Pala. and J. H. Reibenspies. Itwry. Ch~m..1992. 31. 4965. I" K. Ramesh and R. Mukherjee. J. Chem. Soc.. Dultori Truns.. 1992 83. 1'1 F. M. Ashmawy A. R. Ujaimi C.A. Mc4ulitTe. R. V. Parish. and R.G. Pritchard. Inory. Chirn. .4ctu. 1991. 187. 155. I'' X. Wang W.T. Pennington. D. L. Anhers. and J.C. Fanning. Polyhrdron 1992. 11. 2253. M. Dusek. V. Petricek. J. Kamenicek. and Z. Sindelar. Actu Cr>stulloyr.. Sec,r. C. 1992. 48. 1579. E. Eichhorn A. Rieker and B. Spciser. Anyc9c.. Chem.. fnr Ed. Enyl.. 1992. 31. 1214. C.J. Groombridge. L. F. Larkworthy. A. Marecaux. D. C. Povey G. W. Smith. and J. Mason. J. Chum. Soc.. Dulton Truns.. 1992. 3125. 186 S.A. Cotton py); nickel complexes of either the corresponding salen or dihydrosalen ligands do not form such adducts.' 76 Me Schiff base complexes of Ni" are of course noted for their interesting magnetic properties.It is generally assumed that diamagnetic tetracoordinate complexes are square planar and paramagnetic complexes are tetrahedral; equilibria between the two are often observed in solution depending upon solvent and temperature. Some complexes with NiN,S2 chromophores exhibit similar behaviour. The characteriz- ation of a square-planar paramagnetic complex (13) of a related ligand but with N202 Pi Pi coordination of nickel rather shatters this comfortable illusion.' 78 Nickel complexes of unsymmetrical quadridentate Schiff bases with a pendant N-acetyl or trifluoroacetyl substituent have been synthesized; the crystal structure of one of the latter shows'79 that a 'non-bonding' Ni-F interaction may be responsible for inhibited enantiomer interconversion.Crystal structures have been reported for two nickel complexes.'8o [Fe(acac),(NO,)] has been synthesized from [Fe(acac),] and used to make the binuclear heterometallic [Cu(saIen)Fe(acac) (NO,)]. "'A. Bottcher H. Elias L. Muller and H. Paulus. Anyew'. Chem. Int. Ed. Engl. 1992 31 623. D. Laroque I. Morgenstern-Badarau H. Winkler E. Bill A. X. Trautwein and M. Julve Inorg. Chim. Acta 1992 192 107. ''' T. Frommel W. Peters H. Wunderlich and W. Kuchern Angew. Chem. Inr. Ed. Engl. 1992 31. 612. 179 M. Kwiatkowski and G. Bandoli J. Chem. Soc. Dalton Trans. 1992. 379. Y. Elerman. H. Paulus I. Svoboda and H. Fuess Z. Krist..1992. 198. (a)129; (h) 132. Fe Co and Ni 7 Oxo-bridged Species and Models for Oxygen-containing Proteins There have been two reviews relevant to this area which includes such important iron-containing biological systems as haemerythrin and ferritin. One' discusses synthetic models for iron-oxygen aggregation and biomineralization the other' 82 binuclear iron centres in proteins. Dicobalt substitution of iron in haemerythrin has been carried out; EXAFS measurements indicate a dicobalt site (Co-Co 3.54 A) with histidine 1igati0n.l~~ Ah initio Hartree-Fock calculations reported'84 on the well-known binuclear ion [Fe,0CI,12-indicate the coupling between the irons to be sensitive to the Fe-0 distance but less so to the Fe-O-Fe angle; the bromide analogue [Fe20Br,12 has a ~ similar structure.lS5 Many structurally characterized iron complexes have been reported.A di-iron(I1) complex [Fe,(p,-OAc),(tpa),][BPh,l [tpa = tris(2-pyridylmethy1)aminel has been suggested as a model for the core of ribonucleotide reductase. The iron atoms are some 4.29 8 apart consonant with the very weak observed antiferromagnetic interaction. On oxidation it converts to a p-0x0 species [Fe2(p-O)(OAc)2(tpa)2][BPh,l (14)with (Reproduced with permission from J. .4m. Chem. SOC.,1992 114 7788) the advent of the p-0x0 bridge accompanied by a switch to monodentate terminal behaviour by the acetates.'' Diferrous complexes with two OH bridges [Fe,L,(OH),] [L = HB(3,5-Pri),] or alternatively with one OH and one carboxylate bridge.181 K.S. Hagen. Angew. Chem. Int. Ed. Engl. 1992. 31 1010. R.G. Wilkins Chem. SOC.Re[:.,1992 21 171. J. Zhang D. M. Kurtz M. J. Maroney md J. P. Whitehead Inorg. Chem. 1992 31 1359. I 84 J. R. Hart A. K. Rappe S. M. Gorun and T. H. Upton Inorg. Chem. 1992 31. 5254. Ins P. J. M. Evans B. W. Fitzsimmons W. G. Marshall A. J. Golder L. F. Larkworthy D. C. Povey and G. W. Smith. J. Chem. SOC.,Dalton Trans. 1992 1065. I 86 S. Menage Y. Zang M. P. Hendrich and L. Que J. Am. Chem. Soc.. 1992. 114. 7786. 188 S. A. Cotton (Reproduced with permission from Inorg. Chem.. 1992 31 3342.) [Fe,L,(OH)(O,CPh)] (15) have been characterized and suggested as haemerythrin A m0de1s.l~~ different type of bridging system in a di-iron(1r) complex (16) is provided"' by two benzoates and a water molecule in [Fe,(H,O)(O,CPh),(tmen),].Bridging by two carboxylates and a p-0x0 group has been reported this year in models for the di-iron 0x0 centres in haemerythrin and the B2 subunit of ribonucleotide (16) (Reproduced with permission from J. Am. Chrm. Soc. 1992 114 8741) "' N. Kitajima N. Tamura. M. Tanaka and Y. Moro-oka Inorg. Chem.. 1992. 31. 3342. K.S. Hagen and R. Lachicotte J. Am. Chem. Soc. 1992 114. 8741. Fe Co and IVi + reductase (RRB2). For [Fe20(bmima)2(02CR)2]2 [bmima = bis(( l-methyl- imidazole-2-y1)methyl)amine;R := Me Ph] (17) magnetic data are fitted with temperature-dependent J values and interpreted in terms of a weakening of the hydrogen bond between a solvate water molecule and the 0x0 bridge.'89 Complexes such as [Fe20(H,0)2(02CCH,Cl)2(bipy)2][N03]2 have been made by a new route from the parent iron carboxyiate ferric nitrate and bipy.''' Mixed-metal p-oxobis(acetato) dimers where one metal may be iron have been the subject of detailed magnetic study."' (Reproduced with permission from Inclrg.Chenz.. 1992 31 1126) Among spectroscopic measurements. the first detailed 2D NMR study of paramag- netic di-iron complexes both ferrous and mixed valence has been made.'92 Electron transfer in Fe"Fe"' complexes with both phenoxo and carboxylate bridges and high-spin FeN,O chromophores has been studied by NMR and ESR.'93 The first iron(i1r) complex e~hibiting'~ a nematic mesophase believed to involve an oxo- bridge is reported (1 8).A hexanuclear cluster [Fe,(p,-C)) (p2-OMe) (OMe ),( tren )2] ' has been sugges- ted'95 as a soluble model for the core of ferritin. Possibly the most interesting report of the year concerns the trapping of quite large iron hydroxide units containing hydroxo(oxo) iron clusters with 17 and 19 iron atoms. K. J. Oberhausen J. F. Richardson R. J. O'Brien. R. M. Ruchanan. J. K. McCusker R. J. Webb and D. N. Hendrickson Inorg. Chmn.. 1992 31 1123. K. L. Tdft. A. Masschelein. S. Liu. S.J. Lippard. D. Garfinkel-Shweky. and A. Bino. Inory. C'hitn. ,.lc,to. 1992 198-200. 627. R. Hotzelmann. K. Wieghatdt J. Ensling. H. Romstedt P. Gutlich E. Bill IJ. Florke. and H.-J. Haupt. J. Am. Chem. Soc.. 1992 114 9470. L.-J. Ming H.G.Jang and I-. Que Inorg. Chrm. 1992. 31 359. M. S. Mashuta R. J. Webb. J. K. McCusker. E.A. Schmitt K. J. Oberhausen. J. F. Richardson R. M. Buchanan and D. N. Hendrickson J. Atn. Chern. Soc.. 1992 114. 3815. Y. Galyametdinov. G. Ivanova. K. Griesar. A. Prosvirin. I. Ovchinnikov. and W. Haase. Adr. Marer.. 1992. 4. 739. V. S. Nair and K. S. Hagen Inory. Chrm.. 1992 31. 4048. 190 S. A. Cotton Their structures have a common core (19) confirmed by X-ray diffraction and have important implications for biomineralization processes. 96 (Reproduced with permission from Angew. Chem. Int. Ed. Engl. 1992 31 192) 8 Cluster Complexes Including Iron-Sulfur Proteins An extensive volume'97 containing 10 reviews devoted to iron-sulfur proteins has appeared.Articles discuss trinuclear cuboidal and heterometallic cubane-type clus- the replacement of S by Se,198b the EPR spectra,'98c and the structural and ter~;~~~' functional diversity198d of iron-sulfur proteins; and Fe-S clusters in enzymes. 98e An iron(I1) complex with a tetradentate peptide has been proposed199 as a model for the reduced form of rubredoxin. Iron-sulfur dimers have been synthesized as models for Rieske-type proteins; the ESR spectra of the reduced forms indicate oxygen coordination.200 S.L. Heath and A.K. Powell Angew. Chem. Int. Ed. Engl. 1992 31 191. ly7 'Adv. Inorg. Cheni.' Vol. 38. ed. R. Cammack Academic Press 1991. lY8 (a)R. H. Holm in ref. 197 p. 1; (h)J. Meyer J.-M. Moulis J. Gaillard and M. Lutz in ref. 197 p. 74; (c) W.R. Hagen in ref. 197 p. 165; (d)H. Matsubara and K. Saeki in ref. 197 p. 223; (e) R. Cammack. in ref. 197 p. 281. '9y W. Sun A. Kajiwara N. Ueyama. and A. Nakamura J. Chrm. Soc. Dulton Truns. 1992 3255. P. Beardwood and J. F. Gibson J. Chem. SOC..Dulton Trans. 1992 2457. Fe Co and Ni 191 FAB MS has been applied to four-iron clusters.201 Crystal structures reported include [AsPh,],[Fe,S,(SAd),] (SAd = l-adamantanethiolate),20zand Fe,S clus-ters where both thiolates and thiourea are the terminal ligand~.~' An oxidative conver~ion~'~ of an Fe,S core into an Fe,S centre has been reported whilst clusters [MFe,S,] (M = Mo W) that are structurally and electronically analogous to the reduced three-iron centres in ferredoxins have been ~haracterized,~' as have cubane clusters with NiFe,E (E = S Se) cores.2o6 The characterization of high nuclearity clusters [P-Na,Fe 8S30]8- and [Na,Fe20Se,,]9 -has been reported.207 Notable selenium and tellurium-containing clusters are [Fe,Te,(PEt,),][PF,] (cubane) [Fe,Se,(PEt,)][PF,] (stellated octahedron)208 and [Fe,Te,(PEt,),] (c~bane).''~ Single-crystal ESR spectra" have been obtained at 4.2 K of [Co6(p3- S),(PEt,),][BPh,] whilst CoBr, Na,S and dppm give a cluster2' with a distorted Co core [CO,(,U,-S)~{ Ph,PCH P(O)Ph,),].On the other hand [CoCl(PPh,),] reacts with excess Li,S to give [C~,(,U,-S),(,U~-S),(PP~,),B~~,,C~~~,] which has a capped prismane core. l2 A range of clusters with between 4 and 21 nickels results from the reactions of Se(SiMe,) with [NiC12L2] (L = R,P) e.g.[Ni7Se,(PPr\)6].2l3 9 Other Metalloproteins Reviews have appeared on the electronic structures of the active sites in non-haem iron enzymes,2 and of multiple weak forces in ion-binding molecules such as enterobac-tins.2'' Two families of synthetic chiral enterobactin analogues have been made one catechoylamide being the most efficient iron(II1) binder yet synthesized with a stability constant for the Fe3+ complex within three orders of magnitude of enterobactin itself;" two structures have been determined of simple iron(Ir1) complexes that relate to that of enterobactin.2' A comparison of the X-ray absorption spectra of nickel complexes with NiN,S2 chromophores,e.g. [Ni(terpy)(2,6-Me,C6H,S),I with those of a [FeNi] hydrogenase indicate the latter to have a distorted tbp nickel centre with a mixed N/O and S donor ESR spectroscopy has been used to probe the redox behaviour of '"' W.L. Lee D.A. Gage Z. H. Huang C. K. Chang M. G. Kanatzidis and J. Allison J. Am. Chem. So(,. 1992. 114 7132. '02 H. Kambayashi M. Nakamoto S. M. F'eng H. Nagao and K. Tanaka Chem. Lett. 1992. 919. '03 U. Bierbach W. Saak D. Haase and S. Pohl Z. Naturforsch. Teil B. 1991 46,1629. '04 E. K. H. Roth and J. Jordanov Jnorg. C'hem.. 1992 31 240. 'OS D. Coucouvanis S.A. Al-Ahmad A. Salifoglou V. Papaefthymiou A. Kostikas and A. Simopoulos J. Am. Chem. Soc. 1992 114 2472. '06 S. Ciurli P. K. Ross M. J. Scott. B.-B. Yu and R. H. Holm J. Am. Chem. Soc. 1992 114 5415. 207 J. F. You G.C. Papaefthymiou and R.H. Holm J. Am. Chem. Soc. 1992 114 2697. 208 F. Cecconi C. A. Ghilardi S. Midollini and A. Orlandini J. Chem. Soc.. Chem. Comrnun. 1992 910. 'OY M. L. Steigerwald T. Siegrist S. M. Stuczynski and Y. U. Kwon J. Am. Chem. Soc. 1992 114 3155. A. Bencini S. Midollini and C. Zanchini Inory. Chem. 1992 31 2132. M. Hong Z. Huang X. Lei B. Kang. F. Jiang and H. Liu Chin. J. Chem. 1992 9 425. 212 F. Jiang L. Huang X. Lei H. Liu B. Kang. Z. Huang and M. Hong Polyhedron 1992 11 361. 'I3 D. Fenske H. Krautscheid and M. Mueller Angew. Chem. Int. Ed. Engl. 1992 31 321. '14 E. 1. Solomon and Y. Zhang Ace. Chem. Rus. 1992 25 343. 215 A. Shanzer J. Libman and S. Lifson Pure Appl. Chum. 1992,64 1421. 'I6 Y.Tor. J. Libman A. Shanzer C. Felder and S. Lifson J. Am.Chem. Soc. 1992 114 6661. T. D. P. Stack T. B. Karpishin and K. N. Raymond. J. Am. Chem. Soc. 1992 114. 1512. 'I" M. M. Olmstead J. P. Whitehead C. Bagyinka M.J. Maroney and P. K. Mascharak Inorg. Chem. 1992. 31. 3612. 192 S. A. Cotton related species with both Nil and Ni"' compounds identifiable.,l Compounds with [NiN,Se,] chromophores have also been explored.220 A nickel macrocyclic complex catalyses the reduction of protons to H under electrochemical conditions.22' The electronic and NMR spectra of nickel(]])-substituted carboxypeptidase have been measured and its reactivity with D-and L-phenylalanine investigated.,,' 10 Complexes with Unusual Magnetic Properties including Spin-equilibrium Compounds Reviews in this area have covered intersystem crossing in iron(i1) complexes,223 spin-fr~stration~~~ complexes .,' in iron(1ir) complexes and electronic spin crossovers in cobalt(1r) Among iron(1r) complexes the effect of substituents on the spin state of iron(]]) tris-complexes of substituted bipyridyls has been examined.226 Magnetism of the crossover compound227 [Fe(NCS),(5,6-dmp),] (dmp = dimethylphenanthroline) has been examined including LIESST studies below 70 K.The crystal structure ofthe 'non- spin-crossover' 2,9-dmp analogue has been determined ; comparison with the parent [Fe(NCS),(phen),] suggests that steric hindrance is responsible for high-spin behaviour down to 6 K. Specific heat anomalies in spin-transition systems [Fe(NCS),(bts),] and [Fe(2-pic),]C12 [bts = 2,2'-bis(4,S-dihydro-S-methyl-l,3-thiazole; 2-pic = 2-picolylamine] have been studied by microcalorimetry and thermal conductivity.228 A structural comparison of the spin-crossover compounds [Fe(NCS),L,] (L = 2,2'-4,5-dihydrothiazine or phen) which exhibit rather different crossover behaviour has been made the former showing a gradual singlet-quintet transition the latter an abrupt transition.Whilst the overall molecular changes are broadly similar in terms of bond-shortening and a trend towards a more regular FeN octahedron the rapidity of changes in the lattice parameters differs mirroring the susceptibility changes. while there are also differences in structural anisotropy.229 The first two-step spin crossover (at 164 and 197K) to be observed in a polynuclear complex has been detected in dinuclear [(Fe(bt)(NCS) 1 ,bipym] (bt = 2,2'-bithiazoline) by magnetic susceptibility and Mossbauer rneas~rernents.~~~ Sub-picosecond AS = 2 intersystem crossing has been observed in the low-spin state of a spin-crossover compound.231 A kinetic study of the high-spin -+ low-spin relaxation in [Fe(ptz),][BF,] 'Iy N.Baidya M. M. Olmstead. and P. K. Mascharak. J. An7. Chrm. Soc.. 1992 114 9666. 220 N. Baidya B.C. Noll M. M. Olmstead. and P. K. Mascharak. It70ry. Chrm.. 1992 31. 2999. 12' L. L. Efros. H. H. Thorp. G. W. Brudvig. and K. H. Crabtree. Itzorgq. C'hem.. 1992. 31 1722. 222 I. Bertini A. Donaire. R. Monnanni. J.-M. Moratal. and J. Salgado. J. Chrm. Soc,..Dolron ?'r~itn.,1992. 1443. 223 A. Hauser. C'oord. Chcw. Rtw..1992 111. 275. 224 J. K. McCusker. E.A. Schmitt and D.N. :lendrickson. NATO AS/ Su.. Srr. E. 1991. 198. 297 (Chem. Ahsrr.. 1992. 116 226 404). lZ5 J. A. Zarembowitch. New. J. C'hmi.. I%)?, 16. 255. 22h D. Onggo and H. A. Goodwin. Ausr. J. Chern. 1991. 44. 1539. 22 7 D. C. Figg. R. H. Herber. and J. A. Potenm. Inory. Chrv77.. 1992 31 21 I I. R. Jakobi H. Romstedt. H. Spiering and P. Gutlich Anyrw. Chrm.. It7f. Ed. Enyl.. 1992. 31. 178. J.-A. Real. 9. Gallois. T. Granicr. F. Suez-Panama. and J. Zarembowitch fiiorq. Chmi.. 1992. 31. 4972. 230 J.-A. Real. H.Rolvin A. Bousseksou. A. Dworkin. 0.Kahn F. Varret. and J. Zarembowitch J. .4m. Chem. Soc. 1992. 114. 4650. "' J. K. McCusker. K. K,Walda. R. C. Dunn. J D. Simon. D. Magde. and I>. N. Hendrickson.J Am Chrm. Soc.. 1992 114. 6919. Fe Co and Ni (ptz = propyltetrazole) has shown the kinetics to deviate from first order because of cooperative effects of elastic origin.232 Iron(rrr) complexes.-The ability of the octaethyltetraazaporphyrin ligand to stabilize the S = 3/2 state for iron(i1i) has already been mentioned (p. 182). The complex [Fe(sal,trien)][BPh,] acetone (sa1,trien is a hexadentate ligand derived from salicylaldehyde and triethylenetetraamine) has been isolated in two crystalline forms; the monoclinic form is a spin-crossover system whilst twin crystals are high-~pin.,~~ The crystal structure of the monoclinic form at 290 K reveals bond lengths intermediate between those expected for pure high and low-spin systems.Another Schiff-base type complex with a pentadentate ligand (mbpN) forms a six-coordinate lutidine adduct [Fe(mbpN)(lut)][BPh4] (20)that undergoes spin-state interconversion faster than the lifetime of the 57Fe excited state.234 (Reproduced with permission from Bull. Chem. Soc. .lap. 1992 65 1825) Two studies examining equilibria between 312 and 1/2 states may be noted. One paper23 examined nitrosyl-iron complexes of a Jager-type ligand whilst the complex [Fe(bipy),{ONC(CN),j ,][ONC(CN),] has magnetic moments of 3.63 pB at 378 K and 2.56 pB at 80 K.236 Several paramagnetic cobalt(ii1) tropocoronands have already been mentioned in Section 5. The complex [C~(tripyam),][ClO,]~ (tripyam = tri-2-pyridylamine) when freshly prepared contains some low-spin isomer with the ’E ground state frozen into the solid; this reverts to the high-spin 4T form over some months.On ion-exchange 232 A. Hauser Chem. Phjs. Lett. 1992. 192 65. 2x Y. Maeda H. Oshio Y. Tanigawa T. Oniki. and Y. Takashima. Hxperfine Interucr. 1991. 68. 157. ’j4 Y. Maeda Y. Noda H. Oshio and Y. Takashima Bull. Chem. Soc. Jpn. 1992 65 1825. ’-”E. Konig G. Ritter. J. Dengler. and L. F. Larkworth). Inorcq. Cherii. 1992. 31 1196. ”’ K. N. Gerasimchuk. N. Laslo and V.V. Skopenko. Dokl. .4kud. Xuuk. Ckr. SSR. 1991. 7. I IX (Chrm. Ahstr. 1992. 116. 142 644). 194 S. A. Cotton onto laponite it is absorbed as a pink aqua complex [C~(tripyam)~(H~O),]’+ with bidentate ligands but if microwave-accelerated the orange [C~(tripyam)~]~ + species is absorbed.Iron(I1) complexes of this ligand have likewise been The first paramagnetic planar Ni” complex to be characterized has already been mentioned in Section 6 and the effect of ring substituents on nickel cyclam complexes in section 5. Some binuclear nickel(r1) complexes with thiolate bridges (21) have been synthesized and studied; these are unusual in that one nickel site has square planar N2S2coordination of low-spin Ni” and the other has a square pyramidal N3S2 donor set yielding high-spin nicke1(11).’~* C14 C13 (21) (Reproduced with permission from Bull. Chem. SOC.Jup. 1992 65 512) ’”S. P. Bond C. E. Hall C.J. McNerlin W. R. McWhinnie and D.J. Walton J. Muter. Chem. 1992,2 37. 238 M. Mikuriya M. Handa S. Shigematsu S. Funaki F.Adachi,and H. Okawa Bull. Chem.Soc.Jpn. 1992 65 512.

ISSN:0260-1818    

DOI:10.1039/IC9928900169

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

14 Copper By D.W. SMITH Department of Chemistry University of Waikato Hamilton New Zealand 1 Copper(1) Chemistry Mononuclear Species.-The elusive linear molecule Cu(C0)CI has been trapped in an Ar matrix.' The environmentally-important reaction between Cu(g) and NO gives the matrix species CuNO and Cu(NO,),; the former is apparently Cu+NO while the latter is probably' Cu+(NO;) (NO,). The first mononuclear Cu' NO complex is rep~rted.~ The reaction of TI[HB(Bu'pz),] with CuCl gives a dimer which on treatment with NO yields [Cu(NO){HB(Bu'pz) I]. Most monomeric [CuL,X] have trigonal planar Cu' but [CuL,]I [L = 1-aza-2-(1-pyrrolidiny1)-propenyl]has linear CuN coordination with non-coordinated iodide. Other linear two-coordinate monomeric species are [L~(OPP~,),][CUB~,]~ and [Cu(OAc),] in [Cu(phen),] [C~(OAC),]~(O,CCH,),H.~ Most monomeric species have trigonal planar three- or tetrahedral four-coordinate Cu'; their relative stabilities have been discussed by means of extended Hiickel calculation^.^ The products of reactions between copper(1) species and [MS,]' -(M = Mo W) continue to attract attention.In [NEt,][(PPh,),(AgSOWS,Cu)(CN)] 8a and its AgS,WS,Cu analogue the Cu has trigonal three-coordination CuS,C with short Cu-W distances of 2.65A. The Mo analogues are similar.8h The 33S NMR spectra of these systems have been reported.8c Trigonal planar monocopper(1) species include [CuL,Br] (L = 2-thioxohexamethyleneimine) (CuS,Br co~rdination),~" [Cu(dike)( PMe,)] (dike = H. S. Plitt M. R. Bar R. Ahlrichs.and H. Schniickel Inory. Cheni.. 1992. 31. 463. D. Worden and D. W. Ball J Phys. Chem.. 1992. 96. 7167. S. M. Carrier. C. E. Ruggiero W. B. Tolman. and G. B. Jameson. J. Am. Chem. Soc. 1992 114 4407. B. Xiaohua and E. M. Holt. Actu Crystulioyr.. Sect. C 1992 48 1655. ' J. P. Fackler. C. A. Lopez and R. E. Winpenny. Actu Crystulloyr.. Sect. C 1992 48. 2218. ' D. J. Darensbourg E. M. Longridge E.V. Atnip and J. H. Reibenspies. Inorcq. Chem.. 1992 31. 3951. ' J. K. Burdett and 0. Eisenstein Inorg. Chem. 1992 31 1758. * (a)N.Y. Zhu. S.W. Du. P. C. Chen X. T. Wu and J. X. Lu,J. Coord. Chem.. 1992,26,35;(h)S. W. Du. N. Y. Zhu P. C. Chen X.T. Wu and J. X. Lu Polyhedron 1992,ll. 109; J. Chem. Soc. Dalton Truns. 1992,339; [c) M. Kony. R.T.C. Brownlee and A.G.Wedd. Inory. Chem. 1992 31. 2281. (n)P. Karagiannidis P. Akrivos. B. Kojic-Prodic. and M. Luic. J. Coord. Chrm.. 1992. 26. 215; (h)H. K. Shin K. M. Chi J. Farkas M. J. Hampden-Smith. T. T. Kodas and E. N. Duesler. Inorg. Chem. 1992.31. 424; (c) P.S. Coan. J.C. Huffmann and K.G. Caulton Inory. Chem. 1992 13,4207; (d) M. J. McGeary R. C. Wedlich P. S. Coan K. Folting. and K. G. Caulton Polyhedron. 199?,11,2459; (e)S. K. Hadjikakou P. Aslanidis P. Karagiannidis. A. Aubry and S. Skoulika Inorg. Chim. rlctu 1992. 193. 129 (/) P. D. Akrivos. G. Kapsomenos. P. Karagiannidis S. Skoulika and A. Aubry Inory. Chitn..4cru. 1992,202,73;(0) G. A. Bowmakcr W. Jirong. R. D. Hart A H. White. and P. C. Healy J. Chem. Soc. Dulton Truns.. 1992 787; (h)A. Habiyakare E. A. C. Lucken and G.Bernardinelli J. Chrm. Soc.. Dalton Truns. 1992 2591 195 196 D.W. Smith acac and fluorinated derivatives)," YCU(OS~P~,),(PM~,P~)~' and [CU(OS~P~,>(PM~,P~)]"~ (both CuO,P) [CuXL(PR,)] (X = ClJ; L = pyrimidine-X 2-thione; R = o-t~lyl:~' = I; L = 2-thioxohexamethyleneimine; R = cyc1ohexyl:"f (both CuPSX) [CuX2(PPh,)]- (X = CI,Br,I),"Y [CuL,]X (L = alkylpyridine),9b and [Cu(PR,),I] (R = cycl~hexyl).~' EXAFS studies of Cu' in aqueous pyridine indicate the presence of [Cu(py),]+ with no coordinated water."' The first monomeric copper(1) thiolate is [Cu(SSi(OBu'),)(phen)] a planar CuN,S system; the bulky thiolate prevents bridging.9k Tetrahedral four-coordinate monomeric Cu(1) species include [CuCl( PPh,)L2] (L = 2-thioxohexamethyleneimine),' Oa [CuX( PPh,),L] (L = thiones/thioureas),'Ob [Cu{S,POCH,C(CH,),CH,O)( PPh,),],' OC [CuL(PPh,),] (L = bidiazine),' Od + [Cu(cis-Ph,PCH=CHPPh,),] +,lor and [CuL] + (L = N,N1-bis([2-(phenylrnethyl-thio)phenyl]methylene)ethane-I ,2-diamine).Bi- Oligo- and Polynuclear Species.--The most interesting of these are the topological products of supramolecular engineering. This is a field which displays coordination chemistry in its full maturity. Perhaps the highlight is a Cu complex with a trefoil knot (86-membered knotted ring) using bridged phen derivatives.' la.' The self-assembly of [Cu,L,]" (L = 2,2' 6',2" :6",2"'-quaterpyridine) as a double helix does not require four methyl substituents as previously suggested; the methyl groups control the pitch of the helix not its assembly.' '' The choice of spacer groups is crucial to the self-assembly of helical versus non-helical species; [Cu,L,]'+ [L = 1,3-bis(benzimin-dazol-2-yl)benzene] has a non-helical structure with linear CuN coordination but with py substituted for benzene additional weak Cu -Nbonds lead to a double helix.' Id The same group has further investigated the control by central ion stereochemical preferences of the self-assembly of double and triple helices.[Cu,L,]'+ [L = bis(benzimidazolyl)methane] has a double-helix structure but with L' = (ben-+ zimidazol-2-y1)methane non-helical [CuL'] is obtained in both cases Cu has tetrahedral coordination.' '' Another double helix is [Cu,L,][ClO,] (L = 1,2-' ' bis(9-methyl-l,lO-phenanthrolin-2-yl)ethane).Tris-carotenoid macrobicyclic ligands obtained from the condensation of N(CH,CH,NH,) with polyolefinic aldehydes yield Cu complexes which might be prototypes of 'molecular cables' conducting wires polarized at each end by a cation; these too have tetrahedral CuN (I) G. L. Soloveichik 0.Eisenstein. J. T. Poulton. W. E. Streib. J. C. Huffmann. and K. G. Caulton fnorg. Chern.. 1992,31. 3306; (j)K. Ozutsumi and T. Kawashima Polyhedron 1992 11 169; (k) B. Becker W. Wojnowski. K. Peters. E.-M. Peters and H.G. von Schnering. Polyhedron. 1992. 11. 613. lo (a)B. Kojic-Prodic M. Luic. P. Karagiannidis. P. Akrivos and S. Stoyanov J. Coord. Chem. 1992.25,21; (b)R. Singh and S. K. Dikshit. Polyhedron 1992 11 2099; (c)U. N. Tripathi. R. Bohra G.Srivastava. and R.C. Mehrotra Polyhedron 1992. 11 1187; (d)C. Vogler and W. Kaim Z. Naturfimch. 7eil B,1992.47. 1057; (e)S.J. Berners-Price L. A. Colquhoun P.C. Healy K. A. Byriel and J. V. Hanna J. Chem. Soc. Dalton Trans.. 1992 3357; (f ) D. A. Nation. M. R. Taylor and K. P. Wainwright. J. Chrm. Soc.. flakon Trans. 1992 1557. 2411. (u)C. 0.Dietrich-Buchecker and J.-P. Sauvage N~N J. Chrm.. 1992. 16,277; (h)C.0. Dietrich-Buchecker. J.-P. Sauvage J. P. Kintzinger. P. Maltese. C. Pascard and J. Guilhem. New J. Chem. 1992. 16 931; (c) E.C. Constable. M. J. Hannon A. Martin. P. R. Raithby and D. A. Tocher. Polyhedron 19q2 11.2967; (d) S. Ruttimann. C. Piguet G. Bernardinelli B. Bocquet and A. F. Williams. J. Am. Chem. Soc.. 1992. 114. 4230; (e)C.Piguet G. Berdardinelli. B. Bocquet. A. Quattropani and A. F. Williams .J. Am. Chem. Soc. 1992,114,7440:(1')Y. Yao M. W. Perkovic D. P. Rillema and C. Woods. Inory. Chrm. 1992,31.3956;(q) J.-M. Lehn J.-P. Vigneron. I. Bkouche-Waksman J. Guilhem. and C. Pascard Helc. Chim. Actu 1992,75 1069; (11) G. Bida. B. Divisia-Blohorn. M. Lapkowski. J.-M. Kern and J.-P. Sauvage J. Am. Chem. Soc. 1992 114 5986; (i) M.-T. Youinou. N. Rachrnaouni. J. Fischer. and J.A. Osborn. Angrrz. Chem.. Inr. Ed. Engl.. 1992. 31. 733. Copper 197 coordination.' lg Copper(1) may be useful for its template effect to entwine end- functionalized chelating ligands before polymerization by formation of functionalized polypyrrole films.' lh A self-assembling Cu system [Cu,L,][CF,SO,] (L = 3,6-bis(2'-pyridyl)pyridazine),with a square Cu core (tetrahedral CuN,) may have a role as a relay in multi-electronic reduction processes.''I Bridged binuclear Cu' complexes are of interest as models for proteins and enzymes such as haemocyanin and tyrosinase. A popular ligand is a 1,3-disubstituted benzene with a tridendate N-donor dangling from each substituent. Reversible binding of 0 and CO has been studied.'," In the former case one bridging oxygen atom is also bound to the benzene ring between the aliphatic substituents suggesting a model for hydroxylating enzymes such as tyrosinase as well as for haemocyanin. These studies have been extended to peroxo- 0x0- and dihydroxo-bridged species. lZhThe structures of [Cu,L(NCMe)12 + and [CU~LICO),]~ + (L = 1,3-bis[bis(2-pyridyl)methylarnine] benzene) show no bridging however and reaction with 0 does not lead to aromatic hydroxylation.lZc Other structurally-characterized di- oligo- and polycopper(1) complexes include [CuCl(NCMe)] (polymeric chains connected in pairs tetrahedral CuC1,N)' and [CuXL] (X = C1 Br I; L = Me$ tht polymer tetrahedral CUX,S,).'~' [Cu(pz)l ,,(NCMe)]l' and [Cu,(Me,pz),]~"' have polymeric pz-bridged struc-ture~;~~~ the former contains chair-like Cu units with an unusually short bent Cu-NCMe coordination. Polymeric [CuL] (HL = 3,5-dicarbomethoxypyrazole) reacts with C,H NC to give [CuL(NCC,H ')I2 which on treatment with CO/py gives [Cu,L,py,(CO)] where one Cu is three-coordinate and the other four- coordinate the latter including a terminal CO.' 3d The phosphonates Cu(O,PR).H,O (R = CH, C,H,) have layer structures with five-coordinate square pyramidal CLI'.'~~ [CuI (PR,)] (R = cyclohexyl) has the usual p-I,-bridged structure and extended Huckel calculations help to explain the Cu-Cu distances in planar LCu(,u-X),CuL systems." A neat electrochemical synthesis (from copper metal Se,Ph, and PPh in CH,CN) yields [(Ph,P)Cu(p-SePh),Cu(PPh3),], containing both three- and four- coordinate Cu'.' 3f Se-donors also feature in [(PMe,Ph),Cu(p-WSe,)Cu(PMe,Ph)] ((1) K.D. Karlin Z. Tyeklar. A. Farooq M.S. Haka. P. Ghosh R. W. Cruse. Y. Gultneh J. C. Hayes. P. J. Toscano and J. Zubieta. lnorcq. Chern.. 1992. 31. 1436; (h)I. Sanyal. M. Mahroof-Tahir M.S. Nasir. P. Ghosh. R.I. Cohen. Y. Gultneh R. W. Cruse. A. Farooq. K. D. Karlin. S. Liu. and J. Zubieta. Inory. Chern.. 1992 31 4322; (c)S. Schindler D. J. Smlda and C. Creutz. Inory. Chrm.. 1992 31. 2255. '' (a)P. G.Jones. Actu Crystulloyr.,Sect. C. 1992.48 1307 (h)H. Maelger. F. Olbrich J. Kopf D. Abeln and E. Weiss Z. Noturfbrsch. TrIl B. 1992. 47 1276 (c)S. Kitagawa. M. Munakata and T. Tanimura Inorg. Chem.. 1992 31. 1714; (d)G.A. Ardizzoia. E. M. Beccalli. G. La Monica. N.Masciocchi. and M. Moret Inorg. Chrm.. 1992,31.2706; (r)Y. Zhang and A. Clearfield. Itiory. Chrm. 1992.31. 2821 ;(I)J. Kampf R. Kumar and J. P. Oliver Inory. Chern.. 1992 31 3626; (y) C.C. Christuk M.A. Ansari. and J. A. Ibers Inory. Chrm. 1992,31,4365; (h)S. Bernes F. Skcheresse and Y. Jeannin. Inory. Chim. Acru.1992. 191. 11 (I) Y. Jeannin F. Secheresse S. Bernes. arid F. Robert Inorq. Chim. ACIU,1992. 198-200.493 (j) H. Chen. M. 0.Olmstead. S. C. Shoner. and P. P. Power J. Clirm.Soc..Dalton Truns.. 1992.451:(k)D. Li. H. K. Yip C. M. Che Z.Y. Zhon. T. C. W. Mak. and S. T. Liu J. Chrm. Soc,..Dulton Trut7.s.. 1992.2445 (I) R. Castro M. L. Duran J. A. Garcia-Vazquez J. Romero A. Sousa. E. E. Castellano. and J. Zukerman-Schpector. J. Chum. Soc.. Dulton Trms.. 1992 2559; (m)M. Hoyer and H. Hartl. Z. Anory. A/ly. Chrm. 1992.612.45 (n) A. Wilk. W. Massa,C. Friebel. and D. Keinen. Z. Anory. '4lly. Chrn7.. 1992,608,88;(o)G.A. Bowmaker D. Camp. R.D. Hart. P.C. Healy B. W. Skelton and A. H. White. .Ausr. J.Chrm. 1992. 45. 1155; (p) C. L. Baker F.J. Lincoln. and A. W. S. Johnson. Aust. J.Chrm.. 1992.45. 1441; (4) A. Abu-Raqabah. G. Davies M. A. El-Sayed A. El-Toukhy S. N. Shaih h and J. Zubieta. lnory. Chim. Actu. 1992 193.43; (r)T.Konno. K. Okamoto,and J. Hidaka. lnory. Chcrn.. 1092.31,3875 (s) L. F. Rhodes. R. L. Ransemer K. Folting J. C. Huffmann. and K.G. Caulton. lnory. Chim. .4ctu 1992. 191 31; (t) M. Machida. T. Shigematsu. N.. Nakanishi S. Tsuchida and T. Minarni J. Chrm. Soc... Furciduy Truns. 1992. 88. 3059. 198 D.CY. Smith (tetrahedral CuP,Se,) and [(p3-CI)(p,-WSe4)(Cu(PPh,)),] (tetrahedral CuPCISe with a Cu,WSe,CI cubane core).'3g The 'ultimate step' in the addition of CuCl to [MoS,]'-is asserted to be [NMe,],[MoS,(CuCl),CI,] a Cu octahedron with Mo at its centre each Cu bridging an edge of the MoS tetrahedr~n.'~" A short review of such includes the structures of [NPr,],[MS,Cu,C1,] (M = Mo W) where the cluster is chair-like ('cubane with an extra face') with one three-coordinate Cu in the 'back of the chair'.The amides [Cu(N(SiMePh,),)] and [Cu{N(SiMe,Ph) >I4 contain respectively a planar Cu,N core and butterfly Cu,N,.' 3j [CU,(PP~,),I,]~-is described as a centrosymmetric I-bridged tetrahed- The r~n.~~ coordination geometries in [Cu,L,(NCMe),Cl,][CIO,] [L = bis(diphenylphosphinomethyl)phenylphosphine] are best described as P,NCu(p-Cl)CuP,(p-Cl)CuP,N. '" The reaction of CuI with 4,6-dimethyl-pyrimidine-2-thione (HL) gives [Cu,L,] where each Cu in the octahedron is three-coordinate (NS, three different ligands).'31 Iodocuprates(r) with solvated cations (e.y. [Li(NCMe),] +) may contain discrete anions such as [CU,~,]~ with ~ three-coordinate Cu or have polymeric structures e.g. [Cu,I,]~-with Cul tetrahedra.' 3m An NCS-bridged dimer is found in [PPh,],[Cu,(NCS),].' ,"Halogen-bridging leads to trigonal three-coordination in [CuX(PPh,Mes)] and [CuX(PPhMes,)] (Mes = me~itylene).'~" Linear CuS is found in polymeric Ag3CuS,.' 3p Transmetallation of [CuClL] (L = N,N-diethylnicotinamide) with Sn '" complexes gives the air-stable [Cu,SnX,CI,L,] (X = S-methylisopropylidenehyd-razinecarbodithioate monoanion).13q [CU,(MA,),(M,A,L)]~+ [M = Rh"' It-'*'; L = cystamine; A = 2-aminoethanethiolate] has ,u2-and p,-bridging thiolato and disulfide S atoms with planar CuS coordination.' 3r [CU,R~,H,,(PP~,),]~+,an octahedral Cu cluster prepared by the reaction of [Cu(CH,CN),]+ with [ReH,(PPh,),],' 3s may with creative accounting be classed as a Cu' compound.The CuC1-Cu,MoO4-Cu,PO system has been studied as an ion-conducting glass.' 3t A number of theoretical papers have explored the structures of Cu' complexes; reference 7 has been cited. Extended Hiickel calculations on [Cu,Br,13 -have focused on the unusual square planar geometry about Br bridging 4Cu.14" Phosphine steric effects on the catalytic activity of [CuCI(PR,)] oligomers have been studied; a large cone angle hinders a~tivity.'~" A general method for the conversion of [CuX(PR,),] to [CuX(PR,),] using BH,-THF has been propo~ed.'~" Photochemistry and Electronic Spectra of Copper(]) Complexes.-The relevant excited states are mostly charge transfer (Cu +ligand) states.The luminescence of [C~,(dpprn),(NCMe),]~+has been studied in relation to its catalysis of photoinduced C-C bond formation. ' Another phosphine-bridged luminescent compound [Cu,(dpmp),(NCMe),(p-Cl),][C104] has been subjected to photoredox scrutiny.' 3k The cluster [Cu,(mtc),] (mtc = di-n-propylmonothiocarbamate) has a rich emission spectrum,'5h as do the arenethiolates [CuA] [A = SC,H,(CH,NMe,)-2 etc.].'5c Another interesting cluster [Cu,I,(py),] exhibits a double emission; the higher- energy band is attributed to charge-transfer (I +py) while the lower-energy emission l4 (a)L. Subramanian and R. Hoffmann. Inorg. ('hem. 1992. 31 1021; (h)M. Onishi and K.Hiraki Inorg. Chim. Acta 1992 202. 27; (c)D.K. Srivastava N.P. Rath and L. Barton Polyhedron 1992 11. 1251. Is (a)D. Li C. M. Che H. L. Kwong. and V. W. W. Yam. J. Chrm. Soc.,Dalton Trans.. 1992.3325 (h)F. Sabin. C. K. Ryu P. C. Ford.and A. Vogler Inorg. Chcm..1992,31. 1941; (c)D.M. Knotter,G. Blase J. P. M. van Vliet and G. van Koten Inorg. Chrm.. 1992. 31,2196; (d)M. Vitale. W. E. Palke and P. C. Ford. J. Phys. Chrm. 1992 96. 8329. Copper I99 involves a cluster-centred transition with both I -+ Cu charge-transfer and Cu 3d -+4s.' 5d A polarized single crystal reflectance study on partially oxidized Cu' phthalocyanins16" is a highlight among electronic spectra. An ah initio calculation on the excited states of [CuL(PH,),]+ (L = HN=CHCH=NH) sheds light on charge- transfer spectra.'@' The coordination of NH on the (111) surface of CuCl has been studied using UV and X-ray photoelectron spectroscopy with SCF-Xr calcula- tions.'6c 2 Copper-containing hlixed Oxides and Precursors Here we cover work of general interest on the synthesis and structures of mixed oxides containing Cu regardless of its putative oxidation state (which is usually best determined from the coordination geometry). Included are synthetic precursors to oxide systems of interest to inorganic chemists. In CuYMo,O Cu has 2 + 1 coordination i.e. linear CuO with a weaker third bond.17" Cu,La,Mo,O, contains two types of Cu one with 2 + 1 coordination and the other 2 + 2.17' CuMW,O (M = Ho Yb) has tetrahedral CuO, but in CuYW,O the copper is 2 + 4.'?' The coordination geometries and bond lengths leave no doubt that these are Cu'M'' rather than Cu"M' (M = Mo W).CuZr,(PO,) is an insulating phosphate with catalytic properties. This like CuYW,O, has 2 + 4coordination.'7d The first alkali/alkaline earth oxocuprate NaBa,Cu',lCu'''O contains square planar Cu"0 and Cu"'0 units.''" Sr2Cu0 is unremarkable (square CuO,) but in Sr,CuO,- (x -0.1)the copper has a mean oxidation number of -3.8;"' each Cu is square pyramidal five-coordinate with two oxygen atoms at 1.75 8 and three at 1.90A. Cu,NbTaO contains two types of Cu" one 4+ 2 and the other square pyramidal five-coordinate.' 8c Sr,IrCuO is evidently Sr~Ir'"Cu''O, although the Cu-0 distances (square CuO,) (1.98-2.02 A) seem distinctly long for CU(II).' 8d Chemical phase diagrams for the YBa,Cu,O -x family have been reviewed.'"' Highly resolved ESR spectra of Cu2+ pairs bridged by single 0 atoms have been obtained with Cu-doped Ce0,.'8f Thermochemical studies of BaCuO +Iand La,Ni,Cu -x are rep~rted,''~.~ and the effect of Sr substitution on the structure and superconductivity of YBa Cu,O has been studied.'" Also reported have been X-ray structures of BaCuSi,O, (square CUO,)'~".' and Ba,Cu,[Si,O ,] (square CuO, cyclic anion).'" I' (u) D.E.Rende M.D. Heagy. W.B. Heuer. K. Liou. J.A. Thompson. B.M. Hoffman. and R.L. Musselman Inorg. Chem.. 1992 31 352; (b) S. Sakaki. H. Mizutani. and Y. Kase Inory. Chem. 1992 31. 4575; (c) J. Lin P. M. Jones. M. D. Lowery R. R. Gay and E.I. Solomon Inory. Chrm. 1992 31 686. I' (a)T. F. Kriiger and H. Muller-Buschbaum. Z. Anory. Allg. Cheni.. 1992.609 55; (h)T. F. Kriiger and H. Miiller-Buschbaum. Z. .Anorj. Allg. Chrm.. 1992,614 35; (c) H. Muller-Buschbaum and T. F. Kruger. Z. Anory. Ally. Chem. 1992. 607. 52; (d) I. Bussereau. M.S. Belkhiria P. Gravereau. A. Boireau. J. L. Soubeyroux R. Olazcuaga. and G. Le Flcm Acra Crystallo~jr..Srcr. C.. 1992 48. 1741. (a) G. Tams and H. Miiller-Buschbaum 2. Anorg. Allg. Cheni.. 1992. 617. 19; (h)F.J. Berry. C. Greaves. R. C. Lobo,and R. Strange Polyhedron 1992,ll. 2331; (c,)O.Harneit and H. Muller-Buschbaum,Z. Anory. Allg. Chem. 1992,613,60; (d)M. Neubachzr and H. Muller-Buschbaum. Z. Anorg. Ally. Chem. 1992.607. 124 (e)P. Karen 0.Braaten and A.Kjrkshus. Actu Clrem. Scund. 1992 46 805; (j) A. Aboukais. A. Bennani C. F. Aissi G. Wrobel M. Guelton and J. C. Vedrine J. Chem. Soc.. Furuday Trans. 1992. 88 615; (9)A. F. Maiorova S.N. Mudretsova S. F. Pasin and M. A. Bykov. 7'hermochim.Acta 1992.197.219; (h)T.C. Vaimakis Thermochim. 4ctu 1992. 206. 219; (i) P. Karen A. Kjekhus. and A. F. Andersen Acra Chem. Scund.. 1992 46 1059. (a)H. C. Lin. F. L. Liao. and S. L. Wang Acfu Crysfalloyr.Sect. C. 1992 48 1297 (h)J. Janczak and R. Kubiak Actu Crystullogr.,Sect. C.. 1992,48. 1299 (c)J. Janczak and R. Kubiak Actu Crj,.stalloyr. Srcr. C. 1992 48 8. 200 D. W. Smith Precursors to the superconducting mixed oxides are of great importance. Alkox- ides,204 formateq20d alkoxoalkyl-substituted fl-diketonates,20e nitrates,'8h iod- ates,'Of and acetates2O4 have been evaluated.Some of these have interesting structures. [Cu,(p-OCMe,),][OC(CF,),] has three Cu202 rings two outer Cu atoms have the unusual trigonal planar three-co~rdination.~~~ The new formates CaCu(HCOO) and Ca,Cu(HCOO) have formate-bridged chain structures and behave as one-dimen-sional ferromagnets;20h these undergo thermal decomposition to give respectively CaCuO and C~,CUO,.~~" Work on the alkoxides BaCu,[OC(R)C(H)C(R )O] (OR'),(HOR') led to a new series of cubane-type complexes [C~(dike)(OR)],.~~'*' 3 Copper(r1) Complexes + MononuclearSystems.-The electronic structure of the humble [CU(H,O),]~ ion has been the subject of elaborate experimental and theoretical studies. Spin-polarized neutron diffraction measurements2 lo,' on [ND,]2[Cu(D,0),][S0,]z lead to an electron density distribution and orbital populations consistent with water behaving as a 7r-acceptor! These findings are somewhat at variance with ah initio-SCF calcula- tions,' which suggest little covalency; the highest occupied orbitals are essentially lcqd pure 3d with a total population of 9.02.The potential-energy surface is very flat and the stabilization afforded by the so-called Jahn-Teller distortion is only 7 kJ mol- '. Density functional calculations on [M(H,O),]' + lead to regular octahedra for M = Mn Ni and Zn; for Cu the observed rhombic structure is found to be most stable.,' Halogenocuprates(lr).Na,CuMF (M = Ga In) have [CUF,]~"~ chains with 4 + 2 coordination about Cu and a relatively small tetragonal elongation.22" Flattened- tetrahedral (DZd) [CUC~,]' -is present in [SM~,],[CUCI,],~~~ [l-methylpiperazin-i~rn],[CuC1,]Cl~,~~' In and [NHM~,],[CUCI,].~~~ (BEDT-TTF),CuCI,.H,O 20 (a)C.P. Love C.C.Torardi and C. J. Page Inorg. Chem. 1992.31.1784; (h)A. P. Purdy C. F. George and G.A. Brewer Inorg. Chem. 1992.31.2633;(c)W. Bidell. V. Shklover.and H. Berke Inorg. Chem.. 1992.31. 5561 ;(d)M. J. Sanchis. P. Gomez-Romero. J.-V. Folgado F. Sapifia. R. Ibafiez. A. Beltran J. Garcia. and D. Beltran Inorg. Chern. 1992,31,2915; (e)W. S. Rees. C. R. Caballero and W. Hesse. Angew. Chem. Inr. Ed. Engl.. 1992,31,735;(f)M. Karppinen. I-. Niinisto and M. Veber Acta Chem. Swnd. 1992.46,255;(H) S. Wang. K. D.L. Smith Z. Pang. and M. J. Wagner. J. Chem. Sot.. Chem. Commun. 1992. 1594; (h)M. J. Sanchis. F. Sapifia R. Ibafiez. A. Beltran and D. Beltran Muter. Left. 1992 12. 409; (i) C. Sirio. 0. Poncelet. C. G. Hubert-Pfalzgraf. J. C. Daran. and J. Vaissermann Polyhedron 1992. 11. 177. 2' (a)B. N. Figgis L. Khor E.S.Kucharski and P. A. Reynolds. ktu Cry.srulloyr.,Sect. R 1992.18 144; (h) B. N. Figgis. C. J. Kepert E. S. Kucharski. and P. A. Reynolds. Acta Crystallogr.. Sect. B.1992.48. 753; (c) R. Aakesson L.G. M. Pettersson M. Sandstrom. and U. Wahlgren J. Phy.s. Chem. 1992.96 150; (d)R. Aakesson. L.G. M. Pettersson. M. Sandstrom. P. E. M. Siegbahn and U. Wahlgren. J. Phys. Chem. 1992 96. 10773; (e)K. Waizumi H. Ohtaki. H. Masuda N. Fukushima and Y. Watanabe. Chem.Letr.. 1992. 1489. 22 (a)N. Ruchand J. Grannee P. Gravereau. P. Nufiez A. Tressaud W. Massa G. Frenzen and D. Babel. Z. Anorg. Allg. Chem. 1992 610. 67; (h)M. R. Bond and R. D. Willett. Actu Crystullogr. Secr. C. 1992 48 1189; (c) A. Bonamartini-Corradi. L. P. Battaglia J. Rubenacker. R. D. Willett. T. E. Grigereit. P. Zhou and J. E. Drumheller. Inorg. Chem.. 1992.31. 3859; (d)I. D. Williams P. W. Brown and N. J. Taylor. Actu Crystullogr.. Sect. C. 1992.48 759 (y) P. Day. M. Kurmoo T. Mallah I. R. Marsden R. H. Friend. F. L. Pratt W. Hayes D. Chasseau J. Gaultier G. Bravic and L. Ducasse. J. Am. Chcvn. Soc.. 1992. 114 10722; (.f')T.Aoyama S. Ohba. Y.Saito. and I. Bernal. Acru Crjwdlo~qr.. Sect. C. 1992.48.246; (g)R. Shaviv. M.E. Redmond. and R. L. Carlin Inory.Cheni.,1992.31. 1762 (/i)G.Valleand R. Ettorre. Acru Cri,.sru/logr.,Src,t. C.. 1992. 48 919 (i) M. Sano S. Komorita and H. Yamatera Inor(/. Chrm.. 1992. 31. 459; (j) B.M. Bulychev.0. K. Kireeva V. K. Belsky,and N. R. Streltsova Polyhcdron 1992.11. 1809; (k)A. C. Massabni 0.R. Nascimento. K. Halvorson. and R. D. Willett. Inorg. Ckem. 1992. 31. 1779. Copper 201 [BEDT-TTF = bis(ethy1enedithio )tetrathiafulvalenium] D2d [CuCl,]' -ions are link- ed by bridging-H,O into dimers; this metallic charge transfer salt has remarkable electrical properties arising from the coexistence of localized and conduction electrons. 2e The saga of [Co(NH,),][CuCl,] continues. The X-ray structure of the low- temperature ( < 280.8 K) tetragonal phase221 shows that the [CuC1,I3- ions are somewhat distorted from the D,,symmetry found in the high-temperature cubic phase; one equatorial bond is elongated by 0.19 8 and two are shortened by 0.06 A.Specific heat measurements on [Co(NH,),][CuCI,] in the range 1.6-40 K have illuminated the magnetic ordering but more work needs to be done.22g Square pyramidal [CuC1J3 - previously postulated in the tetragonal phase of [Co(NH,),][CuCl,] has been established in [piperazinium] [CuCl ,]Cl.MeOH.2 "Planar [CuCl (H ,O)] -is found in the 2-chloroimidazolium salt.22h XANES spectra for a number of chlorocuprates(r1) show structural correlations with the intensity of the 1s +3d transition.,,' D, [CuC1,I2-occurs in [Co(15-crown-5)(H,0),][CuC14],22J while [CuBr,]'- is present in [AS(OH)P~,],[CUB~,].~~~ Mixed-valence copper halide complexes are discussed below (Section 4).Complexes with Bipy Phen and Refuted Ligunds. The IR spectra of [M(bipy)J2' [M(phen),I2+ and [M(bipy-N-oxide),12' (M = 3d element) show few band split- tings attributable to the Jahn-Teller effect for M = Cu; accidental degeneracies are blamed.,," Two different Cu" complexes with bipy and oxalate have been found in the same [Cu(C,0,)(bipy)][~Cu,(C,0,),(bipy),(H,0),]X2 (X = NO; BF ClO,). A rare example of monodentate OH-has been found23c in [Cu(OH)(pyridoxinato)( bipy)].H,O; the coordination geometry is square pyramidal with an apical OH- (2.22 A). In [Cu(C,O,)(bipy)(H,O)] the croconate is bidentate and the coordination is square pyramidal CUN,~,.~~~ Two distinct neutral croconato- complexes are found in lhe same crystal in [Cu(C,O,)(terpy)] [Cu(C,O,)(terpy)(H,O)]; the former is square pyramidal CuN,O, the latter elongated octahedral CUN,~,.~~' The first topa-containing Cu" complex (a possible model for amine oxidase) is [Cu(~~-topa)(bipy)(H,O)]BF~.3H,O, another square pyramidal complex with a long axial Cu-0 bond.,,' Refinement of the X-ray structure of [Cu(NCS),(phen),] shows the usual axially-elongated CuN coordination with equatorial NCS In [CuC'12(phen),].2H,0 the CuN,O,CI chromophore has long Cu-Cl bonds.23h[Cu(acac)(phen)(H,O)](NO,)~H,Ohas square pyramidal coordination (apical H,0).23' [Cu(bipym),(H,0)](C104)2~2H,0 has trigonal bi- pyramidal CuN,O coordination,23J while [Cu(diphen)(H,0)I2+ [diphen = 1,2-bis(9-methyl-1,lO-phenanthrolin-2-yl)ethane] is square pyramidal CuN40.' Is Square (u)D.A.Thornton and G. M. Watkins. J. Cod. Chrm. 1992. 25. 299 317; (h)A. Gleizes. M. Julve. M. Verdaguer J. A. Real J. Faus and X. Solans. J. Chem. Soc. Dulton Truns. 1992. 3209; (c)I. I. Mathews. S. P. S. Rao and M. Nethaji Polyhedron 1992 11. 1397; (d)I. Castro J. Sletten. J. Faus and M. Julve. J. Chrm. Sol,. Dalton Truns. 1992 2271 (e)M. Aguilo X. Solans. I. Castro J. Faus. and M. Julve Acru Crystulloyr..Sec~. C. 1992,48 802; (f)N. hakamura. T. Kohzuma H. Kuma and S. Suzuki J. Am. Chem. Soc. 1992,114,6550 (9)M. Kabesova and 1.Koziskova Coll. Czech. Chem. Commuri. 1992.57 1269; (h)J. Kozisek P. Baran and D. Valigura Acru Crystdlogr. Swr. C 1992. 48 31 (i) S.I. Troyanov A. N. Grigor'ev A. A. Drozdov and L. I. Martynenko Russ. J. Inory. Chum.. 1992. 37. 57; (i)L. W. Morgan W. T. Pennington J. D. Petersen R. R. Ruminski D. W. Bennett and J. S. Kommel Ai,tu Crysrulloyr.. Srct. C 1992 48. 163; (k)X. Solans L. Ruiz-Ramirez. A. Martinez. L. Gasque and R. Moreno-Esparza. Actu Crj5stu//oyr.,Sect. C. 1992.48 1785 (0M.C Munoz. R. Ruiz. M. Mollar. F. Lloret M. Julve.and X. Solans Acta Crystallogr. Sect. C 1992. 48. 21 1 I. 202 D. W. Smith pyramid a1 C u N ,0(0H ) is fo u nd in [Cu (L-ty rosi n a t o)(bipy )(H 0)] C 1 wh i1e [Cu(NO,)(terpy)(MeOH)]+ is elongated-octahedral CuN,O (bidentate NO ).231 Miscellaneous Mononuclear Copper(11) Complexes. Coverage under this subheading follows the ligand sequence N-donors (N + 0)-donors S-donors and P-donors.The first structurally-characterized linkage isomerism of thiocyanate with Cu" is reported,," in [Cu(NCS),L,] (L = 3-acetylamino-l,2,4-triazole).Among Cu" phthalocyanins/porphyrins spectroscopic and electrochemical studies dominate. ESR/ENDOR spectra24h of a number of such complexes have been examined while packing interactions in Cu(oep) have been studied by means of resonance Raman spectroscopy.24' ESR has been applied to the aggregation of meso-substituted Cu" p~rphyrins*~~ and the overtone/combination bands in the Raman spectrum of [Cu(pc)] have been analy~ed.~,' Pulse radiolysis has been applied to the study of one-electron reduction and demetallation of water-soluble Cu porphyrin~.~~~ Particu-larly interesting is the reaction of 0; with [CuL] [LH = tetrakis(3,Sdi-t-butyl-4-hydroxypheny1)porphyrinl.The Soret (UV) band disappears as does the super- hyperfine ESR structure due to pyrrole N; the 0; ESR signal disappears at 77 K. The formation of a quinone complex is Square pyramidal five-coordination is found in [CuL(NCS),] [L = N-(2'-(6-methyl)pyridyl)methylene-2-(2'-pyridy1)ethylaminel and a general discussion of stereochemistry in five-coordinate [CuLX,] is pre~ented.~," [Cu(NCS)L]NO (L = dipropylenetriamine) is a planar CuN complex; molecular mechanics have been applied to its stru~ture.~~' D, [Cu(NCS),I2- and C, [Cu(NCS),-j3 -have at last been characterized.' 3" [CuC12L2] (L = 4,5-diazafluoren-9-one) has CuN,C12 coordination with two long and two short Cu-N bonds and two short Cu-Cl bonds.24J [CuX2L,] (X = salicylate; L = 3-pyridylmethanol) has 4 + 2 coordination with two long Cu-0 bonds.2s" The anodic oxidation of copper in acetone solutions of the 4-aminoantipyrene-salicylaldehyde Schiff base has been studied.2s" 2-[bis(2-pyridyl- methyl)aminomethyl]-4-nitrophenolate(L) is an interesting tripod ligand ;2''mono-meric [CuLCl] has square pyramidal five-coordination [cJ the dimeric Cu' complexes in references 12(ak(c).[Cu(acac),] reacts with C2N2 to give [j-iminodiketonato complexes (square CUN,~,).~~~ [CuXL,] (X = terephthalate; L = 3-picoline) is square pyramidal CuN20 with weak intermolecular ferromagnetic coupling2" 24 (a)S. Ferrer J. G. Haasnoot. J. Reedijk E. Muller M. Biagini-Cingi.A. M. Manotti-Lanfredi F. Ugozzoli and C. Foglia J. Chem. Soc. Dalton Truns.. 1992 3029; (h) S. P. Greiner I). L. Rowlands. and R. W. Kreilick J. Phjs. Chem. 1992.96 9132; (c)L. D. Sparks W. R. Scheidt. and J.A. Shelnutt Inory. Chem. 1992,31,2191;(d)G.Doughertyand R. F. Pasternack,lnorg. Chim. Actu 1992,195,95;(e)A. J. Bovil1,A.A. McConnell B. N. Rospendowski and W. E. Smith J. Chrm. Sol,. Faraday Trans. 1992 88 455; (f) M. Kumar P. Neta. T. P.G. Sutter. and P. Hambright J. Pkvs. Chem.. 1992,96 9571; (y) T. Ozawa and A. Hanaki Pdjhedron 1992 11 1437; (h)J. I. R. Larrarnendi J. L. Mesa R. Cortes. T. Rojo. M. K. Urtiaga. and M.I. Arriortura Po/yhedron. 1992 11 623; (i) G. Gliemann U. Klement A.C. Stuckl C. Bolos. G. Manoussakis and G. St. Nikolov. Inorg.Chim.Actu. 1992. 195 227; (j)C. Balagopalakrishna M.V. Rajasekharan. S. Bott J. L. Atwood and B. L. Ramakrishna. Inorg. C-hem.. 1992 31 2843. 25 (a)N.N. Hoang R. Ruiz M. Mollar F. Lloret M. Julve. and X. Solans. Actu Crystulloyr.. Sect. C. 1992.48 1933; (h)M. Gaber. H. E. Mabrouk A. A. Ba-lssa and M. M. Ayad. Monutsch. Chem.,1992 123 1089; (c) U. Rajendran R. Viswanathan. M. Palaniandavar. and M. Lakshrninarayanan. J. Chrm. Soc.. Dalton Truns.. 1992. 3563; (d)M. Basato. B. Corain and G.Zanotti. J. Chem.Soc,.,Dulton Trans.. 1992.3003; (6,) E. Aakalbassis P. Bergerat. 0.Khan. S. Jeannin Y. Jeannin. Y. Drornzee and M. Ciuillot Inory. Chrm. 1992. 31,625;(f) A. L. Abuhijleh and C. Woods. J. Chem.Soc. Dalton 7rans. 1992 1249; (y) M. R. Sundberg and R. Sillanpaa Actu Chem.Scand. 1992 46. 34; (11) D. F. Mullica D. €3. Tippin ad E. L. Sappenfield J. Coord. Chem.. 1992,25 175; (i)T.-H. Lu. C.-C. Wang Y.-L. Liou. and C.-S.Chung Actu Crj.stulloyr. Srcr. C. 1992,48. 269; 0)M. McCann. E. Murphy C' Cardin and M. Convery. Polylicdron. 1992. II 3101; (k) X.-M. Chen and T.C.W. Mak. Polyhedron. 1992. II. 2567. Copper 203 (Cu-Cu = 4.14 A). Rare examples of mononuclear Cu" carboxylate complexes are found in [CuX,L,] (L = substituted imidazole; X = ferrocene~arboxylate);~~' both cis and trans isomers are square CuN,O with weak axial Cu-0 bonds. Monodentate 3-iodobenzoate (L) is found in [CuL,( 1,3-~n),].~~~ Cu[Fe(CN),NO].2H20 has an elongated CuN,O octahedron with long axial bonds to cyanide N and water.25h [CUL(NCS),]~~' (L = 4,7-diazadecanediamide) is square pyramidal with terdentate N,O and axial NCS- .The reaction between [Cu(OAc),(H,O)] and phenylphos- phinic acid PhP(O)(H)(OH) in the presence of py gives the phenylphosphonate complexes [Cu(PhPO,H),(py),] and [Cu( PhP0,H),(py)4].H20.25j Square antipris- matic CuO coordination is found in [CuL,][ClO,] (L = pyridiniopropionate) with four long and four short Cu-0 bonds.25k [CuL,][dmf] (L = 3-hydroxy-6-methylpyridine-2-thione) has the same planar CuO,S coordination as the Ni anal~gue.,~" The first example of a Cu" thiolate with a reversible cyclic voltammogram (oxidation to Cu"') is claimed.26hA new mimic for blue proteins is [Cu(SPh){HB(3,5-Pr\pz),)] with similar spectra and CuN,S coordination.26' SCF-Xct-SW calculations suggest that the long Cu-S bond (2.9A) in these proteins has a strength about 30% of a 'normal' Cu-S bond.2hd Cytotoxic properties of Cu" semi- and thioseniicarbazones are discussed.26' Most other Cu"-S work involves thiaethers (thianes).[CuCl,L] (L = 1,4,7-trithiacyclononane)has square pyramidal CuS,Cl coordination; smaller cyclic trithianes give polymeric species with bridging S atoms.26f Another blue protein model [CuLI2+ [L = 1,8-bis(3,S-dimethyl-l-pyrazoyl)-3,6-dithiaoctane]is CuN,S with an unusually high redox potential.26g The related ligand 1-(3,S-dimethyl-l-pyrazoyl)-3-thiapentanegives [CuL(NO,),] (square CuN0,S coordination with weak axial Cu-0 interaction).2hh Branched amino-polythiaethers are more selective for Cu" among the 3d elements than EDTA-type ligands.26' Cu" analogues of the Cu'N,S systems described previously have been prepared.There are few reports of Cu" complexes with P-donors. 1-Hydroxypyridine-2-thione (LH)forms [CuClL] and [CuBrL(LH)] which with PR give [CuXL(PR,),] (square pyramidal CuXNSP Binuclear Copper(i1) Complexes.-Carboxylates. A study of the structures of 16 binuclear complexes [CuX,L] (X = C1,CCOO; L = pyridine base) shows a correla-tion between the coupling constant 2J and the Cu-Cu distance.27Q The analogous 26 J.A. Boyko W. F. Furey. and R. A. Lalancette Actu Crysrcilloyr.. Sect. C. 1992.48 1606; (h)S. Mandal R. Shukla,and P. K. Bharadwaj Polyhedron 1992 11 1855; (c)N. Kitajima. K. Fujisawa. M. Tanaka. and Y. Moro-oka .I. Am. Chem. Soc. 1992.114 9232; (d)M. D. Lowery and E. I. Solomon Inory. Chirn. Ac,tci 1992.198- 200.233 (e)R. Cao. A. Garcia. and E. Castell. Monutsc~h.Chern. 1992. 123,487; (f')J. Shen and J. Pickardt. Z. Nurui-forsch.. Teil B. 1992.47 1736; (y)W.G. Haanstra. M. F. Cabral J. de 0.Cabral W. L. Driessen. and J. Reedijk Inory. Chem.. 1992.,31.3150; (h)W. G. Haanstra. W. L. Driessen and J. Reedijk 4ctu Crr'.srcrIloyr.,Sect. C 1992.48. 14; (i) T H. Cooper M. J. Mayer. K.-H. Leung L. A. Ochrymowycz. and D. B. Rorabacher. Inorg. Cheni.. 1992.31.3796; 0)T. S. Lobana and P. K. Bhatia. J. Chem. Soc..Ddron Trans. 1992 1407. 27 (u)H. Uekusa S. Ohba T. Tokii Y. Muto M. Kato S. Husebye. 0. W. Steward S.C. Chang J. P. Rose. J. F. Fletcher. and I. Suzuki Actci Crystu//o!~r.. Sect. B 1992.48 650; (h)J. Kawata S. Ohba T. Tokii. Y. Muto and M. Kato. Ac,ru Crystulloyr. Sec'i. C. 1992.48 1590 (c,) S. Cueto P. Rys. H.-P. Straumann. V. Gramlich and F. R. Rys. Acru Cry.srullogr..Sect. C. 1992,48 2122; (rl) S.-X. Liu Actu Crj~stulloyr., Sec,r.C 1992.48.22;(e)S.-X.Liu and Y.-P. Yu. Acfu Crystulloyr.. Sec,r.C. 1992,48.652 (1)D. Jin R. Yang. B. Xue K. Kozawa. and T. Uchida. J. Coord. Chem.,1992.26,321 (y)B. M. Holligan J. C.Jeffery. and M. D. Ward J. Chem. Soc,.,Dulfon Trum. 1992 3337 (h) J. P. Maher P. H. Rieger. P. Thornton and M. D. Ward J. Chern.Soc.. Dulton Truns.. 1992.3353; (i)S.F'. Perlepes. E. Libby W. E. Streib K. Folting and G. Christou Polyhedron. 1992. 11,923; (i)S. P. Pcrlepes. .I.C. Huffman and G. Christou. Polyhrdron 1992. 11. 1471 (k) J.C. JeRery E. Schatz. and M. D. Ward. J Cheni. Soc.. Dulron Trans.. 1992. 1921; (I) C. George and A. 204 D. W. Smith compounds with X = 2-chlorobenzoate and 3-cyanobenzoate have the usual struc- ture~;~~’.~ in the latter cyano N atoms complete square pyramidal five-coordination. A new type of dimeric structure occurs in [C~(X)(bipy)],.dmf.H,O~~~ and [C~(X)(phen)],,2H,O~~“= 9-hydroxy-9H-fluorene-9-carboxylate); (X these have a CU,~, core and square pyramidal CuN,O coordination. A new (and bold) synthesis is the preparation of [Cu(OOCPh),(OPPh,)] by the treatment of copper metal with dibenzoyl peroxide.27f Species [Cu,L,(CH,COO)] + containing the cores Cu,(O),(OAc) where L is a terdentate (hydroxypheny1)bipy derivative have interest- ing ESR and magnetic proper tie^.^^^,^ The reaction between [Cu(OAc),(H,O)] and bipy produces a variety of products with the [Cu2(OAc)J2+ c~re.~”.j Another acetato-bridge occurs in [Cu,(OAc)L,] [LH = 6-(2-hydroxyphenyl)-2,2’-bi-pyridyl] ,2 7k with square pyramidal CuN,O coordination.[Cu (p-C204) (tmen){ OC(CF,),},] is also square pyramidal CuN,O with five short (2.00-2.06 A) Cu-ligand distances27’ [see also reference 23(h)]. The EDTA-related ligand toluene- 2,6-diarnine-N,N7N’,N’-tetraacetate acts as a binucleating agent towards CU’~.”’’ Other Binuclear Copper(zr) Complexes. Halide bridges occur in [SMe,],[Cu,Cl,] 22b and in [(MeCN),Mg(l5-~rown-5)][Cu,Cl,];~~“ in the former the planar anions are stacked to give square pyramidal five-coordination while in the latter the non-planar ions are discrete (D2dabout cu); see also reference 22(k).[CuX,L] (L = cycloheptane-1,2-diol; X = C1,Br) has square pyramidal CuX,O coordination with two bridging halides.28b 0,-bridged systems are of biological interest. Side-on peroxo-bridging is found in [Cu(HB(3,5-R2pz) )],O, a model for haemocyanin and tyrosinase.28c.d Thermally-stable peroxide/hydroperoxide Cu complexes have been obtained with the binucleating ligands discussed in references 12(a)-(c); mixed-valence Cu”” species may be formulated as superoxo systems.28e.f [Cu(OH)(CF,SO,)(bipy)] contains both centro- and non-centrosymmetric (OH),-bridged ferromagnetically-coupled dimers with square pyramidal CuN,O coordination; CF,SO; ions form long apical Cu-0 bonds.’ 8g [Cu( OH)( bipym)(H ,O),] [ClO,] 2.H ,O is cent rosymmetric and ferromag- Purdy Actu Crysrallogr.Sect. C. 1992. 48 155; (m)S. Dominguez A. Rancel J. V. Herrera A. Mederos and F. Brito J. Coord. Chem.. 1992 25 271. 28 (u)T.B. Rubstsova O.K. Kireeva. D. M. Bulychev N. P. Streltsova V.K. Belsky. and B. P. Tarasov Polyhedron 1992 11 1929; (h)A. Lehtonen and R. Sillanpaa Acru Chem. Scund. 1992 46 249; (c) N. Kitajima K. Fujisawa C. Fujimoto. Y. Moro-oka. S. Hashimoto T. Kitagawa. K. Toriumi. and A. Nakamura J. Am. Chem. Soc. 1992 114 1277; (d)M. J. Baldwin D. E. Root J. E. Pate K. Fujisawa N. Kitajima and E. I. Solomon J. Am. Chum. Soc. 1992 144. 10421 ; (e)M. Mahroof-Tahir N. N. Murthy. K. D. Karlin N.J. Blackburn. S.N. Shaikh and J. Zubieta. Inory. Chem.1992 31. 3001; (f) M. Mahroof-Tahir and K. D. Karlin J. Am. Chem. Soc.. 1992 114 7599; (y) I. Castro J. Faus M. Julve C. Bois J. A. Real and F. Lloret J. Chem. Soc.. Dalton Trans. 1992,47;(h)I. Castro. M. Julve. G. De Munno G. Bruno J. A. Real F. Lloret. and J. Faus. J. Chem. Soc. Dullon 7’run.s..1992. 1739; (i) L. P. Wu M. E. Keniry and B. J. Hathaway Actu Crjstullogr.. Sect. C 1992.48.35;(j)S. Yan. C. Peng. D. Liao Z. Jiang. G. Wang H. Wang and X. Yao. Polyhidron. 1992 11 879; (k) C.E. Xanthopoulos M. P. Sigalas G.A. Katsoulos C. A. Tsipis and A. Terzis Polyhedron. 1992 1 I. 2819; (I)1. Castro J. Sletten J. Faus M. Julve. Y.Journaux. F. Lloret and S. Alvarez Inory. Chem. 1992.31 1889; (m)J.-P. Costes F. Dahan and J.-P. Laurent Inory. Chem. 1992.31.284; (n)W.L. Driessen W.G. Haanstra and J. Reedijk. Actu Crystulloyr. Sect. C 1992,48 1585; (0)J.-M. Dorr,inguez-Vera. E. Colacio. J. Ruiz J. M. Moreno and M. R. Sundberg Actu Chem. Scud. 1992 46. 1055; (p) P. J. van Koningsbruggen J. G. Haasnoot R. A.G. de Graaff J. Reedijk and S. Slingerland Acru Crystulloyr. Secr. c‘ 1992. 48. 1923; (4) Z. Shonrong L. Qinhui S. Mengchang D. Aubang and H. Liangren Polyhedron 1992 1 I 941 :(r)J.-C. Zheng R. J. Rousseau and S. Wang Inory. Chem. 1992.31 106;(s)S. S. Tandon L. K. Thompson and R. C. Hynes Inory. Chem. 1992 31,2210; (t)M. G. B. Drew D. Marrs. J. Hunter and J. Nelson J. Chem. So(,.,Dulron Trans. 1992. 1 I; (u) C.J. McCarthy. L. K. Thompson M. J. Newlands. and R. C. Hynes. Ai,ru Crysrulloyr. Sect. C.. 1992. 48 430;(0)J.Ling A. Farooq K. D. Karlin T. M. Loehr. and J. Sanders-Lochr. ltiory. Chem.. 1992.31 2552; (w)P. V. Bernhardt P. Comba T. W. Hambley S. S. Massoud and S. Stebler Inory. Chrm.. 1992,31.2644; (.u) D. Lelitvre. L. Bosio J. Simon. J.-J. Andre and F. Bensebaa. .I. ,4m. Ckern. Soc.. 1992. 114 4475. Copper 205 netic with a singlet state 147cm-' above the triplet ground state.28h Two more p-(OH) complexes are of interest [Cu,(OH),(FBF,),L,] and [Cu,(OH),(H,O)L,] C1,.2H20 (L = di-2-pyridylamine).2S' The former is square pyramidal CuN,O,F with a very long (2.7581) apical Cu-F bond. Both are ESR-silent although their room-temperature magnetic moments are normal. Bridging ethoxide occurs in [Cu,(OEt)(L)(MeOH)][ClO,] ,[LH =2,6-diformyl-4-t-butylphenol [di(benzoylhyd-ra~one].~'j[Cu,(C,O,)(Et,salen)(H,O)]~H,Ois the first example of binuclear Cu" with p-l,2-squarate; the short Cu-Cu distance is matched by strong antiferromagnetic coupling.28k Bridging bis-bidentate croconate appears in antiferromagnetic [Cu,(C,O ,)L2].3H ,O [L = bis(2-pyridylcarbony1)amidel.28z [cu2x(c104)2-(Me,en),(H,O)] [X = tetraacetylethanato(2 -)] exhibits both intra-and inter-molecular antiferromagnetism the latter is larger consistent with the relative Cu-Cu distances.28m Tetrakis[2-(3,5-dimet hyl-l-pyrazoyl)ethyl]-l,2-ethylenediamine (L) forms [Cu,(N0,),(L)(H,0),][N03]2 with square pyramidal CuN,(pz)-N(amine)O(N0,)O(H,0).28" A novel example of two Cu" bridged by one pz is [Cu,L,(pz)]-(LH = uracil derivative);280 the lack of X-ray data is compensated by extensive spectroscopic magnetic and MMX force field calculations.A doubly N-1 ,N-2 triazole-bridged dimer [CuL(H2O),],(SO,),~4H,O is unique in that the anion is not coordinated.28P The binucleating ligand N,N',N",N"'-tetra-(2-aminoethy1)-1,1,2,2-ethanetetraamide(4-) gives [Cu,L].lOH,O (square pyramidal CuN,O); cyclic voltammetry shows oxidation to CU"'.~~~ A Cu zwitterion complex has been characterized as [Cu,Cl,L,] [L = 1,3-bis(dimethylamino)propan-2-ol] (square pyramidal CuNO,Cl with bridging O).,'' [Cu(ClO,)L(H,O)] (L = 1,4-dihydrazinophthalazine) is quite antiferromagnetic (-25 = 489 cm- '); square CuN coordination is supplemented by long Cu-OH and Cu- OC10 interactions.28s A new Schiff base cryptand from the condensation of tris(2-aminomethy1)amine with terephthaldehyde gives [Cu L(NCS),] having terminal N-bonded NCS and no magnetic coupling2'' NCS also appears in [Cu(NCS)L],(NCS) [L = tet-rakis(dihydroimidazolyl)benzene] with square pyramidal CuN coordination and a fairly long Cu-Cu distance (7.47A).28uThe vibrational bands associated with the bridging ligands in Cu,(p-OH)(p-phenolate) complexes have been studied.2'" The use of ESR measurements in conjunction with molecular mechanical modelling for the characterization of binuclear Cu complexes has been discussed.28"' Liquid crystals containing dimeric substituted laterally-bridged CU" phthalocyanins exhibit intra- molecular antiferromagnetism and intermolecular ferromagnetism.28" Oligo-und Polynuclear Copper(rr) Complexes.Multidentate aminoalcohol ligands form complexes such as [Cu,Cl,L,] [L = 1,3-bis(dimethylamino)-2-propanolate],with square pyramidal CuNO,Cl coordination and bridging alk~xide.,~" [Cu,L,] (LH = 3,5-dimethoxycarbonylpyrazole)has collinear Cu atoms all planar four- coordinate.29h One product of the reaction between [Cu(OAc),(H,O)] and bipy is 29 lo)J.-C.Zheng R.J. Rousseau. and S. Wang Inor(q. Chem.. 1992.31 106 (h)M. Angaroni G.A. Ardizzoia. G. La Monica E. M. Beccalli N. Masciocchi. and M. M0ret.J. Chem. Soc.. Dulron Truns.. 1992.2715 (c)S. hfeenakumari and A. R. Chakravarty. J. Chrm. Soc. Dalton Trans.. 1992. 2749; (d)V. G. Albano C. Castellari A. C. Fabretti and A. Guisti. Inor$. Chim. Acta 1992,191,213 (e)P. E. Kruger. G. D. Fallon B. Moubaraki. and K.S. Murray. J. Chrm. Soc.,Chem. Commun. 1992. 1726; (1)J. Pons X. Lopez J. Casabo A. Caubet. J. Ruis and C. Miravitlles. Inorg. Chim. Actu 1992. 195. 61 (q)G. Davies X. Liu. and M. A. El-Sayed. Inorg. Chim. Acta. 1992. 195. 35; (h) M.A. El-Sayed. Polyhedron 1992. 11. 1261; (i) S. Meenakumari and A. R. Chakravarty. J. Chiw. Soc,..Dulron Trans.. 1992. 2305 (i)F. Sapina. E. Escriva J.V. Folgado A. Beltran D. Beltran. A. Fuertes. and M. Drillon. Inorg. Chem.. 1992. 31 3851. 206 D. U'. Smith [Cu,(OAc),(H,O)(bipy),][PF,I, which has ferromagnetic coupling and a remark- ably small Cu-0-Cu bridging angle of 93".29cCu and Cu oximidates have been ~haracterized,,~~ while a tetranuclear species formed from two Cu Schiff base complexes with bridging pyrazolate behaves magnetically as a 'pair of dimer~'.,~' Another such 'pair' is found in [Cu,L,(H,0),]~(N03),~4H,0 [L = 3,5-bis(pyridin-2-yl)pyrazolate] which contains square pyramidal CuN,O and has strong intradimer antiferrornagneti~rn.~~~ The protonation of compounds containing the edge-bridged Cu tetrahedron (e.y.[C~,Cl,(p,-O)(py)~]) has been examined.29g Oxidation of [Cu(X)(L)] (X = C1,Br; L = N,N-diethylnicotinamide) gives [Cu,X,L,] .29h Reac-tion between [Cu(OAc),(H,O)] and Him gives [Cu,(OH),(OAc),(H,0)(Him)4]2 + which contains four- five- and six-coordinate CU.,~' The Cu units are further linked into chains by aqua bridges. Another Cu system is Cu,[CuL],(NO,),~l 5H,O (L = cyclohexenediaminetetraacetate) with bridging carboxylate Turning now to polynuclear systems the product of the reaction between Cu(s) and TCNE is now formulated as [Cu2 'TCNE' Dicyanamide complexes [Cu{ N(CN),),L,] (L = 2-,3- or 4-aminopyridine) are polymeric with bridging CN nitrogen atoms.30h Linkage isomers of [Cu{N(CN),),(Him),] are proposed for two products apparently CuN polymers.30c The lilac deposit that befouls Australian swimming pools is Na,Cu(C,H,N,03),~6H,0 a polymeric isocyanurate complex [square CUN,(OH,),].~~~ Of related interest is [CuL(H,O)] [LH = 1,3-dimethyl-5-((2-carboxypheny1)azo)barbituric acid] a helical chain polymer with ferromagnetic interchain coupling.30' [Cu,(NCO),L,] [LH = N,N'-bis(3-aminopropyl)oxamide] is a one-dimensional chain (square pyramidal Cu) with alternate bridges of oxamide and cyanate.,Of [C~(bipyrn)(H,O),],[ClO~]~, has 4 + 2 elongated octahedral coor- dination but if bipym is replaced by 2,3-bis(2-pyridyl) pyrazine the octahedron is axially-compressed."g One-dimensional Heisenberg chains are identified in [Cu(en ),I [Cu(C,O,),] and [Cu(C,O4)(bipy)]*2H,0; the former is antiferromagnetic and the latter ferromagnetic with (Cu-p-0,C-p-0,-Cu) ~xalate.~~" The zwitterion complex [CU,(N~)~(NO,),(M~~NCH,COO)~],, is a linear polymer in which all three ligands are involved in bridging3" [CuBrL],[PF,] [L = N-(2-pyridylethyl)pyridine-2-carbaldimine] has unusual cationic mono-p-bromo ~hains.~'J [CuL],Br,(MeOH) [L = N,N-bis(2-pyridylmethyl)-y-aminobutyrate]has square pyramidal CuN,02 c~ordination.~'~ Copper(I1) chloranilate trihydrate is a linear coplanar Cu chain bridged by chloranilate diani~ns.~" [CuCl,L] (L = 1,3,5-trithiacyclohexane)is a polymer with square CuCl,S coordination and bridging thianes.,,] Hetero-bi- -ohgo- and -polynuclear Copper(@ Complexes.These are of interest for their structures and magnetic properties and as models for biological systems. [CuLM(Me,bipy)] [L = N,N'-ethylenedisalicylamidate(4-);M = Mn" Co"] have (a)A. Rockenbauer G. Speier and L. Szabo Inorg. Chim. Actu 1992,201.5; (h)M. Hvastijova. J. Kohout. and H. Kohler Monatsch. Chem. 1992 123 493 (c) J. Mrozinski. M. Hvastijova and J. Kohout. Polyhedron 1992 11,2867; (d)R. D. Hart B. W. Skelton and A. H. White. Aust. J. Chrm. 1992.45 1927 (e)E. Colacio. J.-M. Dominguez-Vera J. P. Costes. R. Kivekas.J.-P. Laurent J. Ruiz and M. Sundberg. Inorg. Chrm.. 1992 31 774; (1')F. Lloret. M. Julve. J. Faus R. Ruiz I. Castro M. Mollar and M. Philoche-Levisalles. Inorg. Chrm.. 1992.31.784; (g)L. W. Morgan K. V. Goodwin W. T. Pennington. and J D. Petersen. Inorg. Chem.,1992.31 1103; (h)H. Oshio and U. Nagashirna. Inorg. Chem.. 1992.31.3295; (I) M.-Y. Chow Z.-Y. Zhou. and T.C. W.Mak. Inorg. Chem.. 1992,31,4900;(j)T. Rojo R. Cortes. J. I. R. de Larramendi,and G. Madariaga. J.Chem. Soc..Dalton Truns. 1992,2125; (k)D. M. Steams L. R. Hoffman and W. H. Armstrong. Actu Crystulloyr.. Sect. C. 1992,48. 253; (I) S. Cueto. H.-P. Straumann P. Rys W. Petter. V. Grarnlich and F. R. Rys Ac,fu Crysfallogr..Sect. C. 1992. 48. 458. Copper 207 interesting magnetic properties." [LCu( im)ZnL] [ClO,] (LH = 4-diethylene-triamine acetic acid) is proposed as a model for superoxide di~mutase.~" A binucleating N,O ligand obtained by the condensation of 2,6-diformyl-4-methyl- phenol and 1,3-pn gives antiferromqyetic Cuy and Cu"Ni" c~mplexes;~ a further example of the latter type is reported,31d and a CuyNiy derivative of a Cu system previously described29-' has been prepared. Bridged Cu"Fe"' systems where the Fe atom is bound to a porphyrin may serve as models for cytochrome-c oxidase; S-bridged3 and peroxo-bridged3If complexes have been studied. [Cu{ Cr(A),(OH),),]"+ where (A)4 represents one quadridentate or two bidentate or four monodentate ligands has an S = 7/2 ground Cu"MoV' Schiff base complexes have chain structures with cubane-like Cu,Mo,O cores; ESR shows that the Cu pairs are ferromagnetically-coupled to give an S = 1 ground state.31h Copper-lanthanide systems are becoming a large and fascinating field.In [Gd2Cu(C,0,),(H,0),,]~2H,0 Cu is bonded to two oxygen atoms (from different squarate ions) and 4H,O; there is no magnetic coupling between Cu" and Gd111.32a But [L in Gd,(C,0,)[CuL]3[Cu(H20)5]~20H20 = 1,3-propylenebis(oxamate)(4-)] which has a polymeric layer structure there is ferromagnetic Cu-Gd coupling ria the oxamate bridge; the Cu-Gd distance is c'u. 5.7A.32h In addition to such two-dimensional materials one-dimensional systems Ln [CuL] have a remarkable tube-like structural motif and complex magnetic properties. For Ln = La Ce Pr and Sm antiferromagnetic Cu-Cu coupling cia Ln dominates.For Ln = Nd there appears to be an S = 0 ground state!32c 4 Mixed-valence Systems [LH],[CuBr3][CuBr4]~H,0~MeOH(L = uracil derivative) contains trigonal-planar [CuBr,] -and flattened-tetrahedra133a[CuBr,]'-. [NMe,Et,-,][Cu,X4] (X = Cl,Br) a more complex Cu"" system. exhibits 'pinned charge density wave^'.^^'' [Cu'Cu~(CN),L,]NCS (L = l-thia-4,7-diazacyclononane) is polymeric with edge- sharing Cu'(Cu") tetrahedra and CN- bridging Cu' and Cu11.33c S-donors featuring among CuI'" systems include a triazole thi~ne,~~" [18]ane N2S4,33e and [14]ane S4.33f I' (u)D.-Z. Liao S.Juan Z.-H. Jiang S.-P.Yan. P. Cheng. and G.-L. Wang. Polyhedron 1992.11.2621 ; (h)Z. Mao D. Chen W. Tang K. Yu and L. Liu. Polyhedron. 1992 11.191; (c)B. Srinivas N. Arulsamy and P. S. Zacharias. Polyhedron 1992,Il. 21 1:(d)A. Escuer R. Vicente J. Ribas. R. Costa and X. Solans. Inory. Chem. 1992.31 2627; (e)B. R. Serr C. E. L.. Headford 0.P. Anderson C. M. Elliott K. Spartalian V. E. Fainzilberg. W. E. Hatfield. B. R. Rohrs. S. S. Eaton and G. R. Eaton Inory. Chem. 1992.31. 5450 (f')A. Nanthakumar M.S. Nasir. and K.D. Karlin J. iim. Chern. Soc. 1992. 114 6564; (y) J. Glerup. P.A. Goodson D.J. Hodgson M. H. Lynn and K. Michelsen. Inorq. Chem. 1992 31 4785; (h) D. P. Kessissoglou C. P. Raptopoulou. E.G. Bakalbassis. A. Terzis. and J. Mrozinski Inorcg. Chem.. 1992. 31 4339. 32 ((I) A. Buuayad C. Brouca-Cabarrecq,and .I.-C. Trombe. Inorg. Chin].Actu 1992.195 193; (h)O.Guillou. P. Bergerat.0. Khan.E. Bakalbassis K. Boubekeur. P. Batail. and M. Guillot. Inorg. Chem. 1992,31. 110; (c) 0.Guillou. R. L. Oushoorn. 0.Khan. K. Boubekeur. and P. Batail. Angrw. Chem.,lnr. Ed. Enql.. 1992. 31 626; Inory. Chim. Actu 1992. I9S200. 119. 33 (u)M. R. Sundberg. R. Kivekas J. Ruiz J. M.Moreno. and E. Colacio. Inory. Chern. 1992.31. 1062; (h)B. Scott R. D. Willett. L. Porter and J. Williams Inorg. Chem.. 1992. 31. 2483; ((,) K. Wasielewski and R. Mattes. Z. NarurJimch. Teil B. 1992 47 1795; (d)N. Atkinson A. J. Blake. M. G. B. Drew G. Forsyth R. 0.Could. A. J. Lavery. G. Reid and M. Schroder J. Chem. Soc. Dultori Truns.. 1992 2993; (e)M. B. Cingi F. Bigoli. M. Lanfranchi M. A. Pellinghelli A. Vera. and E. Buluggiu J. Chem. Soc. Dalton Trans. 1992,3145; (f)N. E. Meagher.K. L. Juntunen C.A. Salhi. L. A. Ochrymowycz. and D. B. Rorabacher J. Am. Chem. SOL. 1992 114. 1041I; (u)R. Sillanpaa and J. Valkonen. Acru Chem. Scund. 1992,46 1072; (/I) M. Tabata and M. Babasaki Inory. Chm . 1992. 31 5268 (i) J. Takeda T. Ohya and M. Sato Inorcg. Chem. 1992. 31 2877 G) K. K. M. Yusuff and E. J. Mathew J. Coord. Chrm. 1992 26 133. 208 D.W.Smith [Cu,L,(dmf)],[Cu,I (HL = 3-aminopropanol) contains alkoxy-bridged Cu" atoms in the cation while the anion consists of one eight-membered and two six-membered rings.33g The incorporation of Cu" into porphyrins is accelerated in the presence of reducing agents possibly because of deformation of the ring by the larger Cu' atom;33h this is supported by the fact that in the absence of reducing agents the incorporation of Cu" into the non-planar dodecaphenylporphyrin is faster than with planar p~rphyrins.~~' Reports of Cu"' have been sparse.Reaction of CuBr with benzoic dithiocarbamic anhydride (LH,) gives [Cu3L6][Cu,Br6]; the cation appears33' to contain 2Cu"' and 1Cu". CU"~''~ mixed-valence systems have been reported among the Ln-Cu-oxamate species mentioned above.32c

ISSN:0260-1818    

DOI:10.1039/IC9928900195

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

15 The Noble Metals By D.T. THOMPSON 'Newlands' The Village Whitchurch Hill Reading RG8 7PN UK 1 General Overview.-In this chapter new coordination chemistry of the noble metals Ru Os Rh Ir Pd Pt Ag and Au is reviewed. 'The volume of literature on the chemistry of these elements is very large and only the most significant papers and reviews can be included. The chemistry described has many applications both in the laboratory and for products and processes in industry. These include use in medicine (e.9. cancer chemotherapy) and catalysis (e.9. hydrogenation hydroformylation hydrosilation). Interesting work on the preparation and characterization of coordination compounds on catalyst support materials has been reported and promises to be relevant to forward thinking in both homogeneous and heterogeneous catalysis.Some of the latest developments in the use of platinum metals as catalysts to meet increasingly stringent auto-exhaust emissions requirements has been reviewed.' The concept of utilizing favourable overall exothermic heats of reaction to produce chemicals while at the same time producing electrical energy from an electrochemical cell is appealing from an aesthetic viewpoint and also responds to present day concerns about conservation and the environment. The use of platinum catalysts in these systems has been reviewed.' The method for pure hydrogen production from gas mixtures (e.g. methanoljwater cracking gas) based on the use of palladium alloy membranes especially Pd/Ag has been reviewed.Key factors are the choice of membrane materisl minimization of membrane thickness design of the membrane holder design of the membrane equipment and start-up/shut-down procedure^.^ The continuing interest in pallad- ium-hydrogen/deuterium systems and their potential use in developing the so-called hydrogen economy and new energy sources have been reviewed. The beta-phase hydride composition in Pd-alloys is rationali~ed.~ The coordination of dinitrogen to ruthenium and other platinum metals complexes is studied as a possible atmospheric pressure route to the fixation of nitrogen although the Pt/Rh gauzes employed for ammonia oxidation continue to be used successfully and their chemistry investigated. Coordination of gaseous molecules such as CO to ' H.Windawi Platinum Met. Rev.. 1992 36. 185. ' S H. Langer. Plurinuni Met. Rrr.. 1992. 36. 202. V. Z. Mordkovich. Y. K. Baichtock and M. H. Sosna. Platinum Met. Rw.. 1992 36 90. ' F. A. Lewis. Platinum Me?. Rev.. 1992. 36. 196; M. Fleischrnann and S. Pons. J. Eler~rroantrl.Chem. 1992. 332 33. 209 210 D.T. Thompson platinum group metal species is investigated as a basis for sensor technology. Developments in the chemistry of the platinum group metals have been fully reviewed in a recent book edited by Hartley.' The versatility of soluble palladium complexes in the direct synthesis of organic carbonyl compounds has been the subject of recent Synthesis of heterocyclic systems by activation of isocyanide carbonyl trifluoromethyl and nitrile ligands in Pt" and Pd" complexes has been reviewed -coordinated isocyanide carbonyl and trifluoromethyl ligands are converted to heterocyclic carbenes while nitrile ligands are converted to oxazolines by using different synthetic strategies; mechanistic and structural aspects some significant reactions and the electrochemical behaviour of the metal coordinated heterocycles are reported.8 Silver compounds find a wide range of applications based on their bactericidal photochemical and hydrogen diffusion (when alloyed with Pd etc.) properties.Both silver and platinum have been used as effective electrical connections for the high T superconductors as have oxide substrates such as Sr,RuO,. There are outlets for gold technology in decorative and electronic printed circuit board applications and gold has also been used as a conducting layer on silicon in electronic circuitry involving super- conductors.The silver-sheathing of high- T,superconductor wires has been reviewed.9 New methods for winning the precious metals continue to be sought. It has been shown that 2-ethylhexylaminomethylpyridinecan extract Pd" Rh"' and Pt'" from aqueous hydrochloric acid solution with excellent selectivity over Cu". Ni" Co" Cd". Zn" and Ir'". It forms 1 1 complexes with Pd" Rh"' and Pt" ions accompanied by chloride ions.' Review Articles.-Reviews have been published on cancer chemotherapy include clinical trials of cisplatin and carboplatin and the use of new cisplatin analogues,' the relevance of hydrogen bonding in the mechanism of action of platinum antitumour compounds,12 and agents which may be used to circumvent cisplatin resistance.I3 The past five years work has also been summarized.'4 A book containing articles on the role of noble metals in biological systems and their significance in medicine mineral exploration and the environment has been published.' ' A review of the activation of carbon-hydrogen bonds in alkanes and other organic molecules using organo transition metal complexes indicates the scope selectivity and mechanism of reactions in which low-valent iridium and rhodium complexes undergo intermolecular C-H oxidative additions.I6 D.T. Thompson Platinuni Mrr. RPL..,1992. 36. 34. ' H. M. Calquhoun D.J. Thompson and M. V. Twigg 'Carbonylation Direct Synthesis of Carbonyl Compounds' Plenum Press.New York. 1991 see also M. J. H. Russell. Platinum Met. Rrt.. 1992.36 39. ' F. J. McQuillin D. G. Parker and G. R. Stephenson. 'Transition Metal Organornetallics for Organic Synthesis' Cambridge University Press Cambridge 1992. U. Belluco. R. A. Michelin R. Ros R. Bertani. G. Facchin M. Mozzon. and L. Zanottu [norg. Chim. Actu. 1992. 19tL200. 883. C.T. Wu. M. J. McGuire. G.A. Risch. R. B. Poeppel. K. C. Goretta H. M. Herro and S. Danyluk Proy. High Temp. Supercond.. 1992 28. 370. I" Y. Baba and T. Fukumoto C'hem. Lett.. 1992. 727 I' L. R. Kelland S.J. Clarke and M.J. McKeage Pluriwm Mer. Re;>.,1992. 36. 178. J. Reedijk Inory. Chim. Actci 1992. 198200. 873. l3 H. Timmer-Bosscha N. H. Mulder and E.G. E. deVries Br.J. Cancer. 1992 66 227. Is M. Green M. Garner. and D. M. Orton. 7ransition Met. Chrm. (London). 1992 17 164. l5 'Noble Metals and Biological Systems; their Role in Medicine. Mineral Exploration and the Environ- ment' ed. R. R. Brooks CRC Press. Boca Raton Florida 1992 p. II. 16 R.G. Bergman Adr. Cheni. Siv.. 1992. 230 21 I. The Noble Metals 21 1 A theoretical study of the activation of carbon-carbon bonds by transition metal atoms using quantum chemical models for the C-C bonds in ethane cyclopropane and cyclobutane indicates that palladium has the smallest barriers for the C-C bond breaking reaction and the C-C bond in cyclopropane is the easiest to break in line with general experimental evidence for transition metal complexes. ’’ Design concepts for developing highly efficient chiral bisphosphine ligands in rhodium-catalysed asymmetric hydrogenations have been reviewed.The work of Shi and Anson on multiple intramolecular electron transfer reactions in the catalysis of the reduction of dioxygen by cobalt rneso-tetrakis(4-pyridyl)porphyrin to which four pentaammineruthenium groups are coordinated has been reviewed. ’ Precursors to colloids films and catalysts i.e. solvated atoms of Pt Pd and Au have been described,20 and platinum group organometallics have recently been the subject of intensive investigation designed to establish the characteristics of their decomposition which results in metal or metal-containing coatings; the applications that are or could be of commercial significance have been reviewed.2’ Recent developments in the chemistry of olefin complexes of Pd and Pt have been reviewed,22 as have the coordination and cluster chemistries of silver.’ The chemical nature of C, as revealed by its chemical reactivity towards ruthenium and platinum reagents has been reviewed and it has been concluded that the double bonds in C, react like those in electron-poor alkenes and arenes rather than those in benzene.24 The work published on a multiply-substituted buckminsterfullerene (C,,) with an octahedral array of platinum atoms has been re~iewed.’~ A review of recent research in the area of coordination and organometallic chemistry of monoazadienes (mad) emphasizes both the coordination of mad to and its activation by low-valent ruthenium carbonyl complexes and the reactivity and interconversions of the oligonuclear azametallacycles.26 A survey was published in 1992 covering platinum palladium and nickel chemistry published in the years 1984 and 1985.27 General Aspects.-EXAFS data have been collected at 10 K for metal fluorides including OsF,,IrF, and PtF, and refined to give M-F bond lengths which lie in the range 1.81-1.83 A.Similar data were obtained for the related hexafluoroanion-containing K2[MF,] and K[MF,:] (M = Os Ir Pt) as powdered solids at room temperature giving bond lengths of 1.88-1.91 A.28 The fluorination of Pt metals under anhydrous conditions in a flow system yields volatile MF (M = Ru Rh Os Ir Pt) in high yield. The flow fluorination of Ru also P. E.M.Siegbahn and M.R.A. Blombery. J. Am. Chem. Soc.. 1992 114. 10548. 18 K. Inoguchi. S. Sakuraba and K. Achiwa. Synletr 1992 169. A. B.P. Lever Chemrracts Inorg. Chem.. 1992. 4 58. 20 K. J. Klabunde Platinum Met. Rec. 1992 36,80. ’’ A.Z. Rubezhov Platinum Met. Rec. 1992 36.26. 77 -H. Kurosawa and I. Ikeda J. Orqanomei. Chem. 1992 428 289. 23 C E. Housecroft Coord. Chem. Rec.. 1992 115 141. 24 P.J. Fagan J.C. Calabrese and B. Malone. ACS Symp. Ser. 1992. 481. 177. 25 A.H. Cowley Chemtracts Inory. Chem. 1992 4 99. 2h C.J. Elsevier. W. P. Mul and K. Vrieze. Inory. Chem. Acta. 1992 198-200 689. 27 P. A. Chaloner J. Oryanomet. Chem.. 1992. 432 387. 2n A. K. Brisdon J. H. Holloway E.G. Hope W. Levason J. S.0gden.and A. K. Saad J. Chem. Soc,..Dalton Trans.1992 139. 212 D.T. Thompson affords green [(RuF,),] and bright red [(RuF,),]. In the case of Pd no volatile products were observed the only product29 of the reaction being Pdll[Pd'VF,]. K[MF,] (M = Os Ir) were prepared in high purity by reduction of MF with KBr in anhydrous HF. Further reduction with one equivalent of KI in anhydrous HF afforded pure K,[MF,]. Reduction of K[RuF,] with KBr has produced3' K,[RuF,]. Platinum metal hydrido and trifluoroacetato complexes react with PhN=C(R)NHPh (R = H Me Et Ph) to give [Ru(CO)(PhNC(R)NPh),(PPh,)l [MX(C0){PhNC(R)NPh)(PPh3),], and [IrX,(PhNC(R)NPh)(PPh,),](M = Ru 0s; X = H C1; X = H, Cl, or HCl). The reactions of [RuH,(PPh,),] and [OsH,(PPh,),] with amidines are accompanied by an avid alcohol carbonyl extraction thus giving [M (C0)H( PhNC(R)NPh} (PPh,),] .The chemistry of bi- and polynuclear metal cluster compounds continues to be an area of activity particularly in the UK and other European countries. Strong o-donating bridging ligands control the metal-metal interaction and photophysical and electrochemical properties of dinuclear ruthenium and osmium complexes with N-donor ligands -this topic has been reviewed.32 The syntheses and structure determinations of novel types of heterodinuclear Pt-M (M = Ag Sn or Pb) neutral or anionic complexes where Pt -+Ag bonds are formed by the reaction between anionic platinum complexes and silver salts or complexes have been reported., The occurrence of the icosahedron in inorganic chemistry has been discussed.Examples include the carbonyl cluster [Rh ,Sb(C0),,I3- and gold clusters such as [Au ,(Au)C~,(PM~,P~),,]~+. Delocalized bonding gives these structures relatively high chemical ~tabilities.~ Electrochemical activation of transition metal complexes including osmocene [RhCl2(3-methylpyridine),]C1 [RhCl,(3-~hloropyridine)~]Cl, [RhCl,(py),]Cl and [IrCl,(py),]Cl has been reviewed.35 2 Ruthenium Electron transfer reactions between encapsulated [Ru(NH~)~L]' (L = pyrazine, + bipy) and cyclodextrin give equilibrium constants ranging between ca. 20 and 100. The effect of encapsulation on electron transfer rates to [Co(edta)] -was also determined and a specific orientation of reactants within the precursor complex ~onsidered.~ + + [Ru(dp~z)(bipy),]~and [Ru(dppz)(phen),12 (dppz = dipyrido[3,2 :a-2',3' :c]-phenazine) serve as molecular light switches for DNA displaying no photolumines- cence in aqueous solution but luminescing intensely in the presence of DNA.The luminescence enhancement observed upon binding is attributed to the sensitivity of the excited state to quenching by water; in DNA the metal complex upon intercalation into the helix is protected from the aqueous solvent thereby preserving the 29 J. H. Holloway E.G. Hope G. Stanger. and D. A. Boyd J. Fluorine Chem.. 1992. 56 77. 30 W. Casteel and T. Horwitz Eur. J. Solid Stutr Inorg. Chem. 1992 29 649. 31 T. Clark and S. D. Robinson Polyhedron 1992. 11. 993. 32 R. Hage J. G. Haasnoot J. Reedijk and J. G. Vos. Chemtructs Inorg.Chem. 1992. 4. 75. " R. Uson and J. Fornies Inorg. Chim. Actu. 1992 198-200 165. 34 R. B. King Inorg. Chim. Actu 1992 198-200 841. 35 J. E. Anderson T. P. Gregory E.T. Maher and C. P. Murphy Prep.-Am. Chum. Soc. Dic. Pet. Chrm. 1992 37 565. 3h M. D. Johnson V.C. Reinsborough and S. Ward Inorg. Chem. 1992. 31 1085. The Noble Metals 213 luminescence. These ruthenium complexes are shown to be unique reporters of nucleic acid structures and may become valuable in the design of new diagnostics for DNA.,' For some complexes of this type luminescence enhancements of a factor of 20-300 are observed on binding to DNA; two binding modes have been proposed to account for these emission characteristic^.^^ The synthesis and photophysical characterization of highly luminescent complexes of Ru" containing the 4,4'-di-(pcarboxyphenyl)-2,2'-bipyridineligand have been described and the implications of the results on the design of photosensitizers disc~ssed.,~ The photocatalytic reduction of molecular nitrogen to ammonia has been reported to be catalysed by complexes of aminopolycarboxylates in the presence of Pt-CdS-RuO,.The best results here obtained with [Ru(edta)(N,)I2-. The photo- catalysed reaction mixture also contained traces of hydrazine. Isotopic studies with I5N gas confirm that molecular nitrogen is the source of ammonia.40 Oxidation of [Ru,L,(NH,),(dpb)] (H,dpb = diporphyrindiphenylene; L = l-t-butyl-5-phenylimidazole) leads to N-N bond formation and ultimately yields [Ru,L,(p-N,)(dpb)] uia the corresponding (p-N2H,) and (p-N2H2) complexes.The prospects for six-electron NH oxidation and electrocatalytic four-electron reduction of N to N2H4 are disc~ssed.~~ .4n unusually stable bridged N complex of the biphenylene bridged diporphyrin [Ru,L,(p-N,)(dpb)] is proposed as a model for a nitrogen reduction catalyst based on cofacial metall~diporphyrins.~~ The catalytic reduction of nitrous oxide to dinitrogen in the presence of [RU~(CO)~,] and K0,CMe in DMSO has been reported.43 The quantitative activation of dihydrogen by the phosphinidene-stabilized ruthe-nium cluster [Ru,(CO),,(p(,-PPh)] to give [Ru,(CO)~~(~-H),(~,-PP~)] under photolytic ambient conditions has been described. The reverse reaction took place under CO in the presence of cyclohexene which was hydrogenated., [RuL(NO)] (H,L = edta) is an excellent oxygen atom transfer agent towards both hex-1-ene to form hexan-2-one an3 cyclohexene to form the corresponding epoxide in catalytic cycles which need no co-catalyst.The catalyst retains its activity over many turnovers. In the neutral complex the free carboxylic acid moiety is deprotonated4' to balance the charge on the [NO]'. Ci~-[Ru'"O(bipy),(py)]~+and c~i~-[Ru"'(OH)(bipy),(py)]~+ promote the oxida- tions of hydroquinone 2-chlorohydroquinone and 2,6-dichlorohydroquinone to the corresponding quinones in distinct one-electron steps following pH-dependant rate Y. Jenkins A. E. Friedman N. J. Turro and J.K. Barton. Biochemistry 1992 31 10809. R. M. Hartshorn and J.K. Barton.J. Am. Chem. Soc. 1992. 114. 5919. 39 K. Kalyanasundaram M. K. Nazeeruddin M. Graetzel G. Viscardi P. Savarino and E. Barni. fnory. Chim.Acra 1992. 19S200 831. 4" M. M. T. Khan R. C. Bhardwaj C. Bhardwaj and N. N. Rao. J. Phorochem. Photohiol.. 1992 68. 137. 41 J. P. Collman. J.E. Hutchison M.S. Ennis M. A. Lopez and R. Guilard. J. Am. Chem. Soc. 1992. 114 8074. 42 J. P. Collman J.E. Hutchison. M.A.Lopez and R. Guilard J. Am. Chem. Soc.. 1992. 114. 8066. 43 C.S. Li. K. S. Sun and C. H. Cheng. J. Chem. Soc. Dulton Trans. 1992. 1025. 44 F. Van Gastel J. F. Corrigan. S. Doheriy. N. J. Taylor and A.J. Carty. Inorg. Chem. 1992. 31 4492. 45 M. M.T. Khan K. Venkatasubramanian Z. Shirin and M.Bhadbhade J. Chem. Soc. Dalton 7iun.s.. 1992. 1031. Jh R.A.Binstead. M. E.McGuire. A.Dovletoglou L. E.Roecker and T. J. Meyer J. Ant. Cheni. Soc. 1992 114. 173. 214 D. T. Thompson The reaction at room temperature of [Ru(CO)H(OAc)(PPh,),] with fl-nitrostyrene promotes C-N bond cleavage and yields [Ru(CO)(NO,)(OAc)(PPh,),l styrene and traces of nitr~ethylbenzene.,~ [RuCl(NO)(salen)] prepared from Na,salen and [RuCl,(NO)] was aquated in the presence of AgSbF to give trans-[Ru(H,0)(NO)(salen)][SbF6]. At 1 mol% loadings this catalyst accelerates Diels -Alder reactions by many orders of magnitude over the corresponding thermal reaction. In many cases accelerations of > lo5are observed. Its mild Lewis acid characteristics serve to suppress polymerization even with sensitive substrates. Reactions of aldehyde and ketone dienophiles are promoted but not those of a,,!l-unsaturated Reaction of [R~(bipy)~(C0),][PF~], with two equivalents of [NBu,]OH in aqueous ethanol affords an q-CO complex [Ru(bipy),(C0)(CO,)].3H2O,which is a key intermediate in the catalytic reduction of CO to CO.Addition of an HCl solution to a methanol solution of this product regenerates the starting material,49 i.e. CRu(biPY),(CO),I2+. Insertion reactions of CO and CO with ruthenium benzyl arylamido and aryloxide complexes have been studied in order to compare the reactivity of Ru-C Ru-N and Ru-0 bonds.50 A methyl to CO transformation has been reported when the commonly employed radical trap tempo (2,2,6,6-tetramethylpiperidine-l-oxyl) reacts with [RuMe(oep)] (H,oep = octaethylporphyrin) in benzene ultimately leading to [Ru(CO)(oep)] in 60% yield.Isotopic labelling and IR spectroscopy verify that the methyl ligand is the source of the C0.5 Reaction of [RuCl,(bipy)(CO),][PF,] with NaNO in refluxing methanol/water for 24 h gave [Ru(bipy),(Co)(No,)][PF,] in which the NO and CO groups are in cis-positions on the Ru".~ The synthesis characterization and molecular structure of the first metal complex containing thallium chloride as a ligand is reported. [RuH(q'-ClTl)(pp,)][PF,] was obtained by extraction of T1' in an aqueous phase5 by [RuHCl(pp,)] bP3 = P(CH2CH,PPh,),l. The first example of an arachno-3-metallapentaborane i.e. arachno-3-(q5-C,Me,)Ru(PMe,)B,H was prepared by reaction of ([RuH,(PMe),Cp*] with pentaborane(9).The molecular structure of the product shows a pentaborane( 11) framework in which an [Ru(PMe,)Cp*] fragment is substituted in the 3-po~ition.~~ A spectroscopic assessment has been made of the degree of n-stabilization of unsaturation in the ruthenium complexes [RuHX(CO)(PBu\Me),] (X = I C1 OPh NHPh OCHCF, OH OSiPh, OSiPhMe, and OSiMe,). The trend of CO frequencies for these compounds as well as for the analogous pyridine adducts [RuHX(CO)(py)(PBu\Me),] establishes the relative electron donor power of the potential n-donor ligands X. It is argued that a 'push (from X)-pull (by CO)' interaction 4' A. Yousfi and R. Mathieu J. Oryunomet. Chem. 1992 426. C33. 48 W. Odenkirk A. L. Rheingold and B. Bosnich J. Am. Chrm. Soc. 1992 114 6392. 49 H.Tanaka. H. Nagao S.M. Peng and K. Tanaka Orqunomrtdlics 1992 11 1450. SO J. F. Hartwig R.G. Bergman and R. A. Anderson J. Am. Churn. Soc. 1992 114. 5907. 51 J. W. Seyler P.E. Fanwick. and C. R. Leidner. Inory. Chem. 1992 31. 3699. 52 H. Tanaka H. Nagao and K. Tanaka. Inory Chrm.. 1992 31 1971. 53 C. Bianchini D. Masi K. Linn C. Mealli M. Peruzzini and F. Zanobini. Inory. Chem. 1992.31 4036. s4 P. D. Grebenik M. L. H. Green M. A. Kelland. P. Mountford,and J. B. Leach NewJ Chem. 1992,16.19. The Noble Metals 215 permits retention of significant 7c-donation even in the six-coordinate pyridine adducts where the 18-electron rule would predict pure o-donor behaviour by X., The matrix isolation and transient photochemistry of the ruthenium complex [RuH,(dmpe),] has been studied.The steady state photolysis of this compound yields [Ru(CO)(dmpe),] with CO cis-[Ru(dmpe),(SiEt,)H] with Et,SiH cis-[Ru(C,H,)H(dmpe),] and [Ru(C,H,)(dmpe),] with C,H, and cis-[R u (CN) (dmpe),] with Me ,CNC .,' The complexes [RuSR(PPh,),Cp] where R = 4-C6H,Me l-C3H7 and CHMe, react with SO to give two types of product; one type [Ru(PPh,),(S(SO,)R)Cp] possesses a labile S-bonded SO group and the other type [Ru(PPh,)(SO,)- { S(SO,)R)Cp] possesses both S-bonded and Ru-bonded SO groups neither of which are labile.57 The nature of Ru(I1)-S(thioether) bonding has been probed by a combination of structural computational and spectroscopic methods. The structure of [Ru(NH~)~(SM~E~)][PF~] contains approximately octahedral ruthenium cations separated by disordered [PF,] -anions.,* Seven water soluble complexes of Ru and tppts were prepared and characterized [tppts is the trisodium salt of tri(m-sulfophenyl)phosphine] e.g.[RuCl,(tppts),], [RuHCl(tppts),l [RuH(OAc)(tppts),l [RuH (tppts ),I 7 and [RuCI (CO )2 (tppts),l. Spectroscopic investigation^^^ showed that in solution they have the same structures as their organosoluble analogues containing PPh,. A new synthetic approach has provided RuF as a deep pink polycrystalline solid from the interaction of AsF with [RuF,]'- in anhydrous HF solution; its structure has been compared with those of KuF and RuF,.~' The effects of both pre- and continuous sonication on the kinetics of oxidative dissolution of RuO,.H,O by BrO ions under acidic conditions are such that the rate of dissolution is increased due to reduction in particle size and increase in specific surface area.,' The conversion of [Ru,(CO),(~-O,CE~),(PP~~H)~] into [Ru,(CO),(p-PPh,),] under a pressure of CO and into [Ru2(C0),(p-0,CEt),(PPh2Et),] in the presence of ethylene and water were studied and the implications in the catalytic hydroformylation of ethylene discussed.62 The reaction of [Ru,(p-H),CpT] with two equivalents of diphenylacetylene gives a dinuclear ruthenium dihydride complex which has a perpendicularly bridging diphenylacetylene ligand.' Mixed-valence [( P-P)CIRu(p-CI),RuCl( P-P)] and the [RuCl(p-CI)(P-P)] complex [P-P = Ph,P(CH2),PPh (n = 3-6) or related chiral analogues] were prepared via reduction with hydrogen and structural investigations ~ompleted.'~ The reaction of [(Ru(p,-Cl)Cp*),] with NaNHPh in THF affords a blue '' J.T.Poulton K. Folting W. E. Strieb and K.G. Caulton. Inory. Clirm. 1992. 31. 3190. " C. Hall W. D. Jones R. J. Mawby. R. Osman R. J. Perutz and M. K. Whittlesey J. .4m. Chem. Soc.. 1992 114 7425. " A. Shaver and R.Y. Plouffe Inory. Chrm. 1992 31 1823. '' K. Krogh-Jespersen X. Zhang Y. Ding J. G. Westbrook J.A. Potenza and H. J. Schugar. J. '4m.Chem. Soc,. 1992 114 4345. '')E. Fache C. Santini F. Senocq and J. hl. Basset J. Mol. Catul. 1992 72. 331. '"W. Casteel. A. P. Wilkinson H. Borrrnann R. E. Serfass and N. Bartlett. Inory. Chern. 1992 31 3124. 61 D. Worsley and A. Mills. U/trasonrc.s 1992 30. 333. h2 A. Beguin H.C.Bottcher and G. Suss-Fink. J. Chem. Sot.. Dulton Truns.. 1992. 2133. 6.1 H. Ornori T. Kakigano and Y. Marooka Oryunomeru//ics.1992. 11. 989. 64 A.M. Joshi. I.S. Thorburn. S. J. Rettig and B. R. James Inory. Chim. ilcru 1992 198-200. 283. 216 D. T. Thompson anilide complex [(Ru(p-NHPh)Cp*),]. X-Ray crystallographic structure analysis reveals a folded dimeric structure with bridging anilide ligand~.~~ A new diamagnetic linear chain complex [(cymene)Ru(p-Cl),Ru(p-Cl),Ru-(cymene)] was prepared by irradiation of [(Ru(cymene)Cl,),]. A single reversible oxidation wave in the cyclic voltammogram was assigned to a Ru"~"' oxidation of the central Ru atom in the novel trinuclear Ru"-Ru"-Ru" halide and there was evidence for stabilization of the central Ru" in an octahedral environment of chlorine ligands.66 The paramagnetic Ru"' complex [{ RuCl,Cp*),] reacts with atmospheric oxygen to give the 0x0-bridged Ru" complex [{ RuCl,Cp*),O] containing a linear Ru-0-Ru unit with significant n-bonding which also accounts for the diamagnetism of the product.67 The tetranuclear ruthenium clusters [Ru~(CO),(~-CO),(~,-S),{C(NHR)~) ,] (R = CHMe, Et) (1) and [RU~(CO),(~-CO),(~,-S)~{C(NHR),)]CHMe, Et) (R = were obtained from the thermal reaction of [RU~(CO)~ ,]with thioureas SC(NHR),.Single crystal X-ray structure analyses reveal a pseudo-octahedral Ru,S skeleton with three bridging carbonyls in the Ru plane.68 The linear tetranuclear 66-electron monoazadienyl clusters [RU,(CO)~,(R'C=CHCH=NR~),] (R',R2 = Me CHMe,; Me cyclohexyl; Ph CHMe,) which consist of mixtures of diastereoisomers react in heptane solution at 90'C with hydrogen to give a single diastereoisomer of the tetranuclear 64-electron butterfly clusters [Ru,(CO),(p-H),(R'C=CHCH=NR2),] via the intermediacy of [Ru H(CO),(R 'C=CHCH=NR2)] .69 R R H / H N :N, R! R 0 (1 1 The hydrothermal synthesis of a novel Ru2 +/Te; cluster [Ru,(CO) ,(Te,),] from the reaction of [Ru,(CO),,] with Na2Te in the presence of [PPhJCl at 1 lO"C has been reported.Its molecular structure shows a strong resemblance to the fundamental building block of the pyrite-type RuTe, i.e. the central Te;- unit is surrounded by six octahedrally disposed Ru atoms in the formal +2 oxidation A heptaruthenium carbonyl cluster [PPN][Ru,H(CO),,] was prepared and characterized crystallographically.The metal core is a monocapped octahedron and the 98 valence electron count implies the presence of one H -ligand; it is proposed that this is interstitial within the octahedral portion of the Ru cage.'l h5 R. E. Blake R. H. Heyn. and T. D. Tilley. Po~~~hrdrori. 1992 11. 709. 66 R. Goerissen U. Koelle. and T. P. Spaniol Polyhedron. 1992. 11. 2317. 67 K. M. Rao C. L. Day. R. A. Jacobson and R. J. Angelici. Orqunometu/lic.s. 1992. 1 I. 2303. bH U. Bodensieck J. Santiago. H. Stoeckli-Evans. and G. Suss-Fink. J.Chum. Soc. Dulfon7iun.s.. 1992.255. '' W. P. Mul C. J. Elsevier. M. van Leijen. K. Vrieze. W. J. J. Smccts. and A. L. Spek. 0rqunomc)ttdlic.s. 1992. 11 1877. 7" S.P. Huang and M.G. Kanatzidis. J. Am. Chmm. Soc.. 1992. 114. 5477. C. E. Housecroft A. L. Rheingold. and X. Song Inor!/. Chem.. 1992. 31 4023. The Noble Metals 217 [Ru,(CO),,] reacts with a thiourea-functionalized silica xerogel derived from (EtO),Si(CH,),NHC(=S)NHPh to give a tethered metal carbonyl cluster. This surface organometallic species has the same CO stretching pattern as that of the model compound [Ru3(p-H)(p,-SC(NHPr)NPh)(CO),], obtained from the reaction of [Ru (CO) ,] with N-phenyl-N'-propyl thiourea. 72 The photoelectrocatalytic reduction of oxygen at chemically modified electrodes using Ru" and Co"' can be achieved using [Ru(bipy),>l2 as sensitizer and the cobalt + species as an electron relay.73 3 Osmium Hydride transfer and dihydride elimination from osmium and ruthenium metallopor- phyrin hydrides K[MHL(por)] [M = Ru 0s; H,(por) = octaethylporphyrin rneso-tetramesitylporphyrin; L = thf l-t-butyl-5-phenylimidazole,PPh, py] have been examined as model processes for hydrogenase enzymes and the hydrogen electrode reaction.74 A new recognition probe for biomolecules [Os(en),(v*-H,)]" has been shown to bind readily to a number of biomolecules including nucleotides RNA amino acids peptides and phospholipids.In each case binding leads to a characteristic 'H NMR signal for the dihydrogen which appears in a spectral window in the range 6 = 0 to -20 ppm as well as to characteristic values of the coupling J, and of the relaxation time T,. This enables small structural differences in molecules to be distinguished.Upon one-electron oxidation the diamagnetic [O~(en),(v~-H,)]~ + is converted to a paramagnetic probe. 75 The use of pharmaceutical compositions containing osmium compounds has been patented for the treatment of bacterial and fungal infection^.'^ The preparation of the first transition metal trihydroxysilyl complex [OsCI(CO)- (Si(OH),} (PPh,),] was achieved via hydrolysis of [OsCl(CO)(SiCl,)(PPh,),] with aqueous NaOH s~lution.'~ X-Ray crystallography has shown that [Os(C,H,)(CO),] is an osmacyclopropane with a trigonal bipyramidal structure. The ethylene carbons are twisted out of the equatorial plane by 4.0 ' .The axial carbonyls tilt towards the ethylene carbons7* such that the C-0s-C bond angle is 171.3(5)".The five regioisomers of [C,,{OsO,(py) ),I prepared via the bisosmylation of fullerene were separated by preparative HPLC and converted to their 4-t-butyl- pyridine analogues.79 [NH,],[OsBr6] reacts smoothly with 2,3-diamino-2,3-dimethylbutane (HL) in water to give [Os(HL)L,]'+. The same brown complex is also obtained when OsC1,-3H2O reacts with an excess of HL in ethanol. The chemical shifts 12 E. Boroni G. Predieri A. Tiripicchio and C. M. Tiripicchio. Orgunomefullics 1992. 11 3456. '' K. V. Gobi and R. Ramaraj J. Chem. Soc.. Chem. Commun. 1992. 1031. 14 J. P. Collman P.S. Wagenknecht and N. S. Lewis J. Am. Chem. Soc. 1992 114 5665. '' Z. W. Li and H. Taube. Science 1992 256 210. '' B. A. Murrer PCT fnt. uppl. WO 10117 1992. 77 C.E. F. Rickard W. R. Roper D. M. Saiter and L. J. Wright J. Am. Chem. Soc. 1992 114 9682. in B. R. Bender J. R. Norton M. M. Miller. 0.P. Anderson and A. K. Rappe Orqanometullics 1992 11. 3427. 79 J. M. Hawkins A. Meyer T.A. Lewis U. Bunz. R. Nunlist G. E. Ball. T. W. Ebbesen and K. Tanigaki. J. Am. Chem. Soc. 1992 114 7954. 218 D. T. Thompson of the NH protons and the NH-0s distances are both indicative of strong 0s-N z-bonding8' Octahedral [OS(N,)(NH,),(NH,P~)][O~SCF~]~ was oxidized with loss of N to give [OS(NH,),(NH,P~)(O,SCF~)][O~SCF~]~, and reduction of this product with Zn/Hg in methanol generated ~~~-[OS(M~OH)(NH,),(NH,P~)]~ + which isomerized with reversible P-hydride elimination to cis-[OsH(NH3),(q2-NH2=CHEt)] [O,SCF,] .The first report of a cis-iminium hydride in equilibrium with its amine precursor is also reported in this paper:81 [Os(NH,),(q2-NH,CH(CH,0Me)-(CHMe,))l2+ isomerized with reversible [&elimination to [OsH(NH,),(q2-NH2=C (CH,0Me)(CHMe,)}]21. Osmium(v) (IV) and (111) complexes with tetradentate dianionic chelating ligands such as salen have been synthesized by reducing the corresponding trans-dioxoos- mium(vr) complexes with PPh,. Electrochemical studies of trans-dia!koxyosmium(Iv) complexes in acetonitrile showed a reversible wave assignable to the oxidation of 0s" to osv.82 Tris(1,2-ethanediamine) complexes of Os" Os"' and 0s" were prepared and oxidative dehydrogenation in air was found to give ethanediimine complexes.83 by The oxidation of [OSC~(NH,),]~~ Ce" in water gave [OSN(NH,),]~+ quantitatively.Excitation of [OsN(NH,),I3' in the solid state or in solution at 30G400 nm resulted in room temperature photolumine~cence.~~ In contrast to the reaction of [OsH(q-BH,)(CO)(PR;),] [PR; = P(CHMe,), PMe(CMe,),] with methanol under reflux which gives the dihydrides cis,cis,trans-[OsH,(CO),(PR;),] the reaction with ethanol or 2-methoxyethanol under the same conditions forms the corresponding hydridoosmium(I1) complexes [OsHR(CO),- (PR;),] (R = Me MeOCH,) in good yields. The structure of this product [R = Me PR; = P(CHMe,),] reveals an octahedral coordination sphere around the osmium centre with the CO ligands in cis and the phosphines in trans positions. On reacting the product (R = MeO) with electrophiles e.q.HX where X = C1 CH,CO, CF,CO, the monohydrides [OsHX(CO),( PR;),] are formed uia preferential cleavage of the 0s-CH bond. Treatment of cis-[OsBr,(CO),] with the ether-phosphine (P-0) ligands R,PCH,CH,OMe (R = Ph cyclohexyl) and Ph,PCH,R' (R' = 2-tetrahydrofuryl 1,3-dioxolan-2-y1 1,3-dioxan-2-yl 1,4-dioxanyI) results in the formation86 of the cis,cis,trans-complexes [OsBr,(CO),(P-O),]. New mononitrosyl derivatives of iron ruthenium and osmium have been reported e.y. [MHL,(NO)][PF,] [M = Ru 0s; L = P(OEt),Ph] were prepared by allowing [MH(q2-H,)L,][BF,] to react with [NO][PF,] at -80 "C in dichloromethane. Deprotonation of the cation with NEt or OH-gaves7 the five-coordinate CM(NO)L,ICPF,I. no A. Patel A. Ludi H. B. Buergi A.Raselli and P. Bigler Inorq. Chem.. 1992 31 3405. J. Barrera S.D. Orth and W. D. Harman. .I. Am. Chem. Soc. 1992 114 7316. n2 W.-K. Cheng. K. Y. Wong. W.-F. Tong T.-F. Lai and C.-M.Che J. Chem. Soc,..Dalton Trans. 1992.91. '' P. A. Lay and A.M. Sargeson. Inorg. Chim.Acta 1992 198-200. 449. R4 H. W. Lam. C. M. Che and K.Y. Wong J. Chem Soc. Dalton Trans. 1992 141 1. '' M.A. Esteruelas F.J. Lahoz J.A. Lopez L.A. Oro. C. Schleunken C. Valero. and 11. Werner Orgunomrtallics 1992. 11. 2034. H6 E. Lindner H. Rothfuss. R. Fawzi. and W. Hiller. Chem. Ber.. 1992. 125. 541. 87 G. Albertin S. Antoniutti and E. Bordignon. J. Chem. Soc.. Dalton Trans. 1992. 11 11. The Noble Metals [OsCl,(PPh,),] reacts with P(C,H,SH-2)3 to give [OsL] (2) as shown by X-ray crystallography (Ph groups omitted for clarity) formed by the oxidative coupling of two P(C,H,S-2) ligands via two disulfide bonds.88 New thiosulfato complexes of osmium have been prepared by reacting [OsO,-(S,0,),]2-with a variety of inorganic and organic ligands.The products include [Os0,(S,0,),L,]2-(L = pyridine 4-t-butylpyridine etc.) and [Os02(py),(S,0,)]. The X-ray crystal structure of [NBu,][Os(H ,O)(PMe,Ph),(S,O,),] reveals an octahedral geometry around the 0s atom with the two trans S-bonded S,OS-ligands adopting a syn geometry with respect to each other each forming a strong hydrogen bond to the axial H,O ligand.89 Well-resolved ESR spectra of [OsOF,] have been obtained in WF, CF,CH,Cl and SO at 77 K. Hyperfine coupling to 1890s and to four equivalent fluorine atoms was measured but no coupling to the axial fluorine was observed.From analysis of spin Hamiltonian parameters it was concluded that cn. 1 1.5% of the unpaired electron was delocalized from the osmium d-orbital on to each equatorial fluorine atom." Reaction of [Os,( CO) (NCMe),] with trans-diphenyl thietane resulted in the formation of cis-and trans-[Os,(CO),,(p-SC(H)PhCH,C(H)Ph)]; the isomers are formed in approximately equal amounts in the early stages of the reaction but the trans-isomer slowly isomerizes to the cis-isomer. The observed loss of stereochemistry at the carbon centre is attributed to a stepwise ring-opening mechanism." The reaction of pentafluoronitrosobenzene with [Os,(CO) 2] at 125 "C in octane gave [0s3(C0)9(p3-NC6F5 121.92 Reaction of the complex [Os,(CO),,(p-H)(NCMe)( SSi(OMe),j] with alkynes HCECR (R = Me,C p-tolyl) yield complexes that on treatment with CO produce the silyl alkenes trans-RHC=C(H)Si(OMe),.The characterization of this intermediate demonstrates that the hydrosilation by the cluster complex is initiated by a hydride insertion rnechani~m.~ A cluster of three osmium atoms has been reported to stabilize cyclobutyne a molecule which is very unlikely to exist in the free state. Thus reaction of 1-(pheny1thio)cyclobutene with a three osmium atom cluster and subsequent reaction with trimethylamine oxide gave the cyclobutyne deri~ative.~~ Some reactions of [Os,(p-H),(CO),(p,-CX)] (X = OMe or Cl) involving C-N and C-P bond formation have been described.95 [OS,~C(CO),,]~-has been studied as a RH J.R. Dilworth. Y. Zheng and J. R. Miller J. Chrm. Soc. Dalton Trans. 1992 1757. '' C.F. Edwards W. P. Griffith and D. J Williams J. Chem. Soc. Dulton Truns. 1992 145. J. H. Holloway E. G. Hope J. B. Raynor. and P. T. Townson J. Chem. Soc.. Dalron 7iuris. 1992. I 13 I. " R. D. Adams and M.P. Pompeo. Orgurtomefallics 1992. 11 103. " H.G. Ang W. L. Kwik and K. K. Ong J. Fluorine Chem. 1992 56. 45. y3 R. D. Adams. J.E. Cortopassi. E. Jeffrey and M.P. Pompeo Inorg. Chem.. 1991 11. 1. 94 R.D. Adams. G. Chen X. Qu. W. Wu. and J.H. Yamomoto J. Am. Chem. SOL'.. 1992 114. 10977. '5 B. F. G.Johnson. F.J. Lahoz. J. Lewis N. D. Prior P. R. Raithby. and W. W. Tak. J. Chrm. Soc,.. Dalton Truns. 1992 1701.D.T. Thompson substrate for redox condensations with mercury(i1) electrophiles. Its reaction with HgX (X = C1 Br or I) initially generates the halomercury-capped clusters [Os,,C(CO),,(HgX)] -,which undergo redistribution reactions in solution. This can be prevented by blocking one coordination site of the Hg atom with a CF group thus producing96 stable [Os,oC(CO),,(HgCF,)] -. 4 Rhodium Soluble rhodium complexes have been used for a variety of catalytic reactions. including hydrogenation hydrosilation hydroformylation and hydroboration often with achievement of significant stereoselectivity when required. Investigations concerning the optical induction in asymmetric hydrogenation reactions of for example (Z)-acetamidocinnamic acid using [{ RhCl(cod)}2] and chiral diphosphine catalysts confirm the stereochemical control function of mono- and disubstituents in seven-membered chelate ring diphosphines whereby the bulkiness of substituents in the backbone of the ligands is reflected in higher enantiosele~tivities.~' Rhodium(i1) perfluorobutyrate catalyses the hydrosilation of 1-alkenes under mild conditions and the mode ofaddition determines the products which are formed.When the alkene is added to triethylsilane normal hydrosilation occurs; reversed addition causes the formation of allyl- or vinyl~ilanes.~~ Rhodium(1) chiral diphosphine complexes efficiently and rapidly catalyse the intramolecular hydrosilation of silyl ethers derived from allylic alcohols. The reaction proceeds uia silyl-olefin insertion and both the turnover-limiting and enantioselective steps are believed to be the silyl-olefin insertion.It was concluded that the major diastereoisomeric intermediate the silyl metal olefin hydride produced the major enantiomer of the product.99 In the presence of [(RhCl(CO),),] the reaction of enamines e.g. BuCH=CHR (R = mor-pholino) with a hydrosilane e.g. HSiEt,Me resulted in regioselective incorporation of CO into the x-carbon to give x-(siloxymethylene)amines e.g. Me(CH,),CR=C (H)OSiEt,Me which can easily be converted into a-siloxyketones by hydrolysis. loo Excellent regiocontrol was achieved in the rhodium-catalysed hydroformylation of some alkenyl phosphites and good stereocontrol was obtained in the hydroformyla- tion of some cyclohexenyl phosphites.Thus hydroformylation of CH,=CHCHCHROP(OEt) (R = H Me Ph) with H,/CO and [Rh,(CO),,] catalyst for 22 h at 50 "C in benzene gave MeCH(CHO)CH,CHROP(OEt) which were reduced with LiAlH to the corresponding alcohols in good yields.'"' The reaction of catecholborane (HBO,C,H,) with Wilkinson's catalyst [RhCl(PPh,),] yields a variety of products depending on the B/Rh ratio solvent and temperature. Of particular relevance to alkene hydroboration is the degradation of catecholborane to B,(O,C,H,),/BH and production of the dihydride [R h C1 H ,(P Ph ,)J. 'O2 Rhodium catalyses the decomposition of x-diazo-P-ketophosphonamidates, e.y. Vh L. H. Gade B. F. G. Johnson J. Lewis. M. McPartlin. and H. R. Powel1.J. Chern. Soc.,Dulton Trans.1992 921. 9' H. Krause and C. Sailer J. Orgunomet. Chem.. 1992 423 271. VX M. P. Doyle G.A. Devora A. 0.Nefedov 0.Andrei and K. G. High Orqanometullic~s. 1992. 11 549. " S. H. Bergens. P. Noheda J. Whelan. and B. Bosnich. J. Am. Chern. Sot.. 1992. 114 2121; 2128. I00 S. Ikeda N. Chatani Y. Kajikawa K. Ohe and S. Murai J. Org. Chem.. 1992 57. 20. '"I W. R. Jackson. M.R. Moffat P. Perlmutter. and E. E. Tasdelen Aust. J. Chem.. 1992 45 823. '(I2 K. Burgess. W. A. Van der Donk S.A. Westcott and T. B. Marder. J. Am. Chem. Soc. 1992 114 9350. The Noble Metals 22 1 (Me,CH),NP(O)(OEt)CH( :N,)Bz and intramolecular C-H insertion of the result- ing carbene intermediates is the key step in the synthesis of mono and bicyclic 1,2-azapho~phetidines,'~~ such as (3).Me (3) In continuing studies on carbon-hydrogen bond activation the reaction of [RhCl(P(CHMe,),),] with methyl vinyl ketone has been shown to lead to the formation of the olefin complex trans-[Rh(CH,=CHCOMe)Cl{P(CHMe,),),] which rearranges at ambient temperatures to give the hydrido vinyl Rh"' isomer [RhClH(CH=CHCO Me)( P(CHMe ),),I. 'O4 The first example of a cycloocta-1,3-diene ligands bound to rhodium has been obtained by reacting [{RhBr,(q5-C,Ph,)),] with cycloocta-l,3- or 1,5-diene under reducing conditions. The unsaturated bonds of both ligands are extremely short. '05 The remarkably stable paramagnetic Rh" complex [Rh(CNBu'),(tmpp),][BF4] [tmpp = tris(2,4,6-trimethoxyphenyl)phosphine],containing phosphine and isocyan- ide ligands was obtained by reacting [Rh(q3-tmpp),][BF,] with two equivalents of t-butylisocyanide.The isocyanide ligands in the equivalent [BPh,] -salt occupy rrans positions in the unit cell. This latter salt represents the first stable well-characterized mononuclear organometallic Rh" complex. 'O6 Reduction of carbon disulfide by [RhH,( PMe,)Cp*] gives the bridging dimethyl- thiolate complex [Rh(PMe3)(SCH,S)Cp*]. Reaction with COS gave the known compound^'^^ [Rh(CO)(PMe,)Cp*] and [Rh(CO),Cp*]. Photochemical and spectral properties of the sulfito Rh"' complexes rrans-[Rh(CN)(NH,),(SO,)] and Na[truns-Rh(NH,),(SO,)J have been described.'08 The '03Rh NMR signals of all ten monomeric aquabromorhodium(ri1) complexes [RhBr,l(0H),),_,l6-" with n = 0-6 including the geometric isomers for n = 24 have been assigned.Evidence was obtained for the existence of oligomeric aqua- bromorhodate(ir1) species and structural characteristics were proposed consistent with the observed chemical shifts.' O9 Nearly all the substances generated in water said to involve Rh'" Rh' and Rh" species such as 'Claus' blue are in fact superoxides of Rh"'. The 0; ligand in 'Claus' blue results from oxidation' 'O of OH-by Cl,. Based on a combination of X-ray crystallographic and ,'P NMR studies the interconversions of [RhX,L,] [Rh,X,L,] and [Rh,X,L3] (X = C1 Br; L = PEt, PMe, POMe,Ph) take place with complete stereo- and regiospecificity. Whenever Rh-X-Rh bridges are broken it is the Rh-X bond most weakened by a [runs-phosphine I('' K.Afarinkia J. I.G. Cadogan and C.W Rees. J. Chem. Soc.. Chem. Commun. 1992 285. '(I4 T. Dirnberger and H. Werner. Chem. Bcr. 1992 125. 2007. "I5 J. Baghdadi N. A. Bailey. A. S. Dowding. and C. White. J. Chem. Sot...Chem. Cornmuti.. 1992. 170. 'Oh K. R. Dunbar and S.C. Haefner Orgarromrtallicc. 1991. 11. 1431. W. D. Jones and A. D. Selrnecry OrguriomL.fullic..s 1992 11. 889. C. R. Maria. M. E. Frink E. Tfouni. and P.C. Ford. Inorg. Cliim. .A(,rri. 1992. 193 159. '04 M.C. Read. J. Glaser and M. Sandstrosm. J. Cheni. Soc,. Dultoti Trtrt7.s.. 1992. 233. "" 1. J. Ellison and R. D. Gillard J.Chem. Soc... Chrm. Commun.. 1992 851. 222 D.T. Thompson ligand that is opened followed by attachment of an additional phosphine to the Rh atom. For example attack by L' on anti-[Rh,X,L,] gives exclusively the ax,ax,eq,eq product with L' in an axial position.Attack of P on ax,ax,eq,eq-[Rh,X,L,] gives exclusively' '' mer-[RhX,L,]. Electronic infrared Raman and resonance Raman spectra of the dirhodium tetrakis(thiocarboxy1ate) complexes [Rh,(CH,COS),L,] (L = PPh, AsPh, SbPh, CH,COSH) were recorded at temperatures down to 15 K and compared with results for the analogous tetraacetate complexes. Longer Rh-Rh bond lengths are indicated for the first of these.' l2 The unusual divalent dinuclear rhodium complex bridged by a bis(dimethy1phos- phinomethane) ligand [Rh,(CO),(p-dmpm),] has been prepared by the reaction of trans-[(RhCl(CO)(dmpm)),] with aqueous sodium hydroxide and CO; in solution under CO the product is in equilibrium with [(Rh(CO)(p-CO)(dmprn)),].The structure of the first product is believed to be unsymmetrical having a trans arrangement of diphosphine ligands at one metal a cis arrangement at the other and a mixed valence Rh+/Rh- formulation while the second product is symmetrical having the bridging diphosphines cis at both metals and a corresponding Rho/Rho formula- tion.' ' Protonation of [CoRh(CO),(,u-dppm),] gives [CoRh(,u-H)(CO),(p-dppm)J in which the Co-Rh bond is shorter in the product than in the starting material. The product exhibits fluxionality in solution and this possibly occurs via inversion of the CoRh(p-H) unit.' l4 Reaction of [(RhCl(C,H,),),] with E(CH,CH,CH=CH,) (E = S,Se) affords the trimeric complexes [(RhCI(E(CH2CH2CHCH,),)),].The structure of the Se com- pound suggests that the coordination sphere at each Rh atom consists of a distorted trigonal bipyramid with two alkene groups from the same selenoether in equatorial positions one bridging Se is in an equatorial position and the other in an axial site with a terminal chloride in the other axial site.' ' The reactions of [Rh(q3-allyl),] with surfaces of silica alumina titania and magnesia have been followed by IR spectroscopy isotopic labelling experiments quantitative analysis of gaseous products and elemental analysis. On silica it is suggested that two 18-electron species are possible on the surface one for which the rhodium is coordinated both to an oxygen and a hydroxyl group linked to the same Si atom and another for which the oxygen atom and the OH group are linked to two different Si atoms.' ' The results obtained by EXAFS and temperature programmed desorption (TPD) techniques clearly showed' l7 that [Rh,(CO),,] is formed by the exposure of partially reduced Rh/active carbon to CO at 353 "C and further converted into metallic Rh particles at 473 "C.The reductive carbonylation of silica-supported MC1;3H20 (M = Rh Ir) was 'I1 F. A. Cotton J. L. Elgin. and S.J. Kang. J. Am. Chem. Soc. 1992 114. 4015. 'I2 R. J. H. Clark W. J. West and R. Withnall Inorg. Chem. 1992 31. 456. 'I3 J.A. Jenkins and M. Cowie. Organometullics 1992. 11 2767. 'I4 D. J. Elliot J. J. Vittal R. J. Puddephatt D.G. Holah and A. N. Hughes Inorg. Chem. 1992 31 1247. lS E. W. Abel D.G.Evans J. R. Koe V. Sik M. B. Hursthouse. and M. Mazid. Polyhedron. 1992. 11 401. 116 P. Dufour C. Houtman C.C.Santini C. Nedez J. M. Basset L.Y. Hsu S.G. Shore and S.C. Shore J. Am. Chem. Soc. 1992 114 4248. 117 K. N. Takahashi T. Takeyama. T. Fujimorto. A. Fukuoka. and M. Ichikawa Chrm. Lett.. 1992. 1441. The Noble Metals studied at atmospheric pressure under both CO and a mixture of CO and H,O. These salts may be converted into [{Ir(CO)3Cl)n] and [(RhCl(CO)),] respectively. Under CO and H,O at 70 "C [Ir4(CO)12] is exclusively formed. [Rh,(CO),,] was obtained using CO and H20 at 25 "C using [{Rh(CO),Cl),] as the starting material instead of RhCI,. The reaction mechanisms were discussed.' '* The study of surface organometallic chemistry has included the definition of a new class of highly chemoselective hydrogenation catalysts Rh,Sn(Bu"),/SiO,.The catalyst was extremely active and selective in the hydrogenation of citral (geranial and neral) to the corresponding unsaturated alcohols (geraniol and nerol) with 96% selectivity at 100% conversion. The catalyst can be prepared by partial hydrogenation of tetrabutyltin on surface rhodium (Rh,) atoms of Rh(0) particles supported on silica. ' + The complex [Rh(CO)(tmppI,] [tmpp = tris-(2,4,6,-trimethoxyphenyl)phos-phine] reversibly binds CO within a glassy polymer matrix to form the dicarbonyl species [Rh(CO),(tmpp),] and the reversibility of this reaction raises the possibility for use as a CO sensor.12o 5 Iridium Iridium complexes of dehydroamino acids and the resolution of racemic diphosphines have been discussed with reference to their use in catalytic asymmetric hydrogena- tion.' ' IR spectra measured at room temperature in n-heptane solution provide strong evidence' 22 for intermolecular hydrogen bonding between [Ir(CO),Cp*] and steri- cally crowded perfluoroalcohols e.9.(CF,),CHOH. A novel molecular solid in which a C, moiety is bound intramolecularly to Ir and enveloped intermolecularly by two benzyloxybenzyl side chains has been prepared and characterized crystallographically. [IrCl(CO)(AsPh,),] reacts with PhCH,OC,H,- CH,PPh (bobPPh,) to give [IrCI(CO)(bobPPh,),]. Addition of C, to [IrCI(CO)- (bobPPh,),] in benzene yielded black crystals of [Ir(CO)Cl(bobPPh,),(qz-C,,)l.The C, unit is bonded to a six-coordinate Ir with a trans-(0C)IrCl unit and cis phosphine ligands. The benzyloxybenzyl side-chains of one complex form a nest into which the free side of the C, moiety of an adjacent molecule fits. This arrangement creates infinite chains of the complex molecules in the s01id.l~~ The effect of transition metal coordination on the photophysical properties of C, has been studied in [Ir(CO)(q5-C,H,)(q2-C,,)]. Under identical conditions this complex generated 60% as much ally1 peroxide compared to when either C, or tetraphenyl porphyrin are used as sensitizers.' 24 Water-ligand exchange in iridium ammine complexes has been studied in acidic 1 M perchlorate media leading to the conclusion that there is a kinetic trans-effect order for pentaammineaquairidium(m),for a fixed set of cis-ligands i.e.OH, NH < Cl~, for 1IH R. Psaro. D. Roberto R. Ugo C. Dossi and A. Fusi. J. Mol. Catal. 1992. 74 391. B. Didillon J. P. Candy A. El Mansour. C. Houtmann. and J. M. Basset J. Mol. Cut.. 1992. 74. 43. 12" J. 1. Dulebohn S.C. Haefner. K. A. Berglund. and K. R. Dunbar Chem. Maler. 1992 4 506. J. M. Brown and P. J. Maddox. Chirulit! 1992 4 71. S.G. Kazarian P.A. Hamley and M. PoliakoK J. Chem. Soc.. Chem. Commun. 1992. 994. 123 A. L. Balch V.J. Catalano. J. W. Lee and M. M. Olmstead J. Am. Chem. Soc. 1992 114 5455. Y. Zhu R. S. Koefod. C. Devadoss J. R Shapley. and G. B. Schuster Inory. Chem. 1992. 31 3505. 224 D. T. Thompson substitution reactions at 25 "C at an iridium(rI1) centre.The variation in the kinetic trans-effect for iridium(rrr) compared with rhodium(m) and chromium(n1) for the same trans-ligand was rationalized in terms of differences in ligand field stabilization energies.' New complexes of the Vaska-type e.g. trans-[IrCI(CO)L,] [L = P(OEt)Ph,] have been prepared and characterized. The oxidative addition of hydrogen occurred stereospecifically with cis-addition of H parallel rather than perpendicular to the X-Ir-CO axis leading to cis,trans-[IrClH,(CO)LJ with a trans disposition of the two L ligands.'26 The non-classical hydride complexes [IrCIH,(H,)(PR,),] (R = CHMe, cyclo- hexyl) were generated from [IrCIH,(PR,),] and hydrogen in either solution or the solid state. The reversible uptake of hydrogen by the P(CHMe,) derivative in the solid state was monitored via FTJR spectroscopy (M-H absorptions).' 27 Unusual paramagnetic behaviour of 1rtv and Rh" dihydrido complexes in both the solid state and in solution has been reported for [Ir'VH,Cl,L2] (L = PPr; and PCy,) whose magnetic moment values were in agreement with a spin-paired (I5 electron configuration; however after recrystallization a significant reduction in their peffwas observed.Despite different petfvalues however samples of the same complex exhibit identical IR spectra and XRD powder patterns in the solid state as well as identical NMR and ESR spectra in The use of p-deuterium isotope effects to study the rate and equilibrium of an organometallic transformation has been reported.The oxidative addition of silane SiHR (R = Et) and the corresponding deuteride SiDR, to the iridium centre in the heterodinuclear c~mplex[Cp,Ta(~c-CH~)~Ir(CO)~] and to its deuterated analogue have been examined. The Si-H(D) bond contributes only a small normal primary isotope effect to the forward rate constant; the tendency of deuterium to act as an inductive electron donor relative to hydrogen is suggested to account for its ability to enhance the rate of oxidative addition reactions which convert Ir' to Ir"' centres.' 30 Li[RuH,(PPh,),] reacts with [[IrCl(cod)~,]to form a kinetic product [(cod)Ir(p- H),Ru(PPh,),] which then isomerizes to [(cod)Ir(p-H),RuH( PPh,),] (I) as the thermodynamic product. In solution at room temperature (I)is in equilibrium with free hydrogen and a dehydrogenated species.Upon removal of hydrogen a new species [(cod)IrH,Ru{PPh,(C,H,))(PPh,),] (11) is formed. When (11) is placed under hydrogen it reverts to (I) demonstrating the reversibility of this transformation. Spectroscopic data as well as labelling studies suggest that (TI) contains a phosphine ortho-metallated to ruthenium. The n-cloud of the ortho-metallated phenyl ring may play a role in donation to iridium.',' The synthesis and comparative chemistry of the early-late transition metal heterobimetallacycles [Cp,Ta(CH,),Ir(CO)( L)] (e.,y. L = PPh,) and their main- group late transition metal analogues [{R,P(CH,),jIr(CO)(L)] (4) have been 125 F. Galsboel. L. Moensted. and 0. Moensted. Acttr Chew. Scud. 1992 46. 43. '" X.L. Luo. M. Ikmetrius. R. H. Crabtree and M. B. Hall Inorg. Chim. Acru 1992 198-200. 429. 127 M. Mediati. G. N. Tachiban. and C. M. Jensen Inory. Clirm.. 1992. 31 1827. 12" D Ajo. D. Attanasio. S. Lucente. P. Mura. A. Segre. and F. De Zuane. J. Mu(qn. Mugn. Murrriuls. 1992. 102 107 1997. 129 D. Attanasio P. Mura. A. Maldotti. S. Sostero and 0.Traverso. New J. Chrm.. 1992. 16. 347. 13" M. J. Hostetler and R.G. Bergman J. Am. Chem. Soc. 1992. 114. 787. 13' J. T. Poulton K. Folting and K. G. Caulton. Orricitiometci/lic\. 1992. II. 1364. The Noble Metals described. X-Ray diffraction studies show that the Ir(CH,),P metallacycle in contrast to that of the Ta-Ir compound is non-planar. Solution studies suggest that the early metal fragment can act as both an electron sink and source for the late transition metal fragment through a direct Ta-Ir bond interaction.' 32 A new group of bimetallic sulfur-bridged complexes having the general structure [Cp*M(PR,)S,IrCp*] (R = Me,M = 1r;R = Me,M = Rh;R = p-tolyl M = 1r)has been prepared.Heating these syslems leads to the metalla-sulfur cubane complexes [{CptMIrS,),] (M = Ir Rh). A mechanistic study of the cubane assembly reaction was undertaken using the p-tolyl complex.' 33 The fluxional behaviour of [Ir,H(CO) '1 was investigated using 13C NMR spectroscopy. Unlike all other Ir carbonyl clusters studied to date. whose fluxionali- ties are due only to CO site exchanges the non-CO ligand participates in the lowest energy intramolecular process.' 34 'The synthesis and mechanisms-of-fluxionality of the iridium clusters [IT,(CO)~ (PH -,!Phn)] (n = I or 2) are reported.The complexes exist in solution as the all-terminal isomers but there are small concentrations of the CO-bridged isomers [Ir,(CO),(p-CO),(PH,Ph)] and [Ir(CO),(p-CO),(PHPh2)] with the P ligand axial and equatorial to the bridged face.'35 Samples prepared by adsorption of [Ir(acac)(CO),] on either partially dehyd- roxylated or hydrated MgO were treated under CO at room temperature to form supported [Ir,H(CO) -and [Ir,(CO),J2 ~,respectively. A sample prepared by adsorption of [Ir4(C0)1,] on partially dehydroxylated MgO was treated with water-saturated He at room temperature to form [Ir,(CO)l,]2- on the MgO surface. Each of these anions was extracted in high yield by cation metathesis with [PPNICI.Consecutive formation of [Ir,H(COj '1 -,[Ir8(CO)22]2-.and [Ir,(CO) s]2 -on the MgO surface was observed as the temperature of the carbonylation reaction was increased from 25 to 200°C. The organometallic chemistry occurring on the basic MgO surface is similar to that occurring in basic s~lution.'~~ A sample prepared by adsorption of [Ir,(CO) on MgO powder was treated in CO at 100 "C and 1 atm whereupon the surface species was converted to [Ir,(C0),2]2- in high yield. The product could be extracted into solution uia cation metathesis. and this represents an alternative method'"' for the preparation of [Ir,(C0),,I2-. Gaseous [M(C,H,),Cp] (M = Ir Rh) has been used as the organometallic precursor for laser-assisted organometallic chemical vapour deposition of films of rhodium and iridium.Depositions were carried out in an atmosphere of helium and hydrogen at room temperature and pressure to give high purity ( < 1'/o C) thin films of metal. Wavelength dependence studies of the Rh precursor show that only irradiation 132 M. J. Hostetler M. D. Butts and R.G. Bergman. Inory. Chim. Acra 1992 198-200 377. 133 D.A. Dobbs and R.G. Bergman J. Am. Chem. Soc. 1992. 114 6908. '34 M.J. Davis and R. Roulet Inory. Chim Actu. 1992. 197 15. B. E. Mann M. D. Vargas. and R. Khadar J. Chrm. Soc.. Dalton Trans.. 1992. 1725. 136 S. Kawi and B.C. Gates Inorg. Chrm.. 1992 31. 2939. 13' S.D. Maloney M. J. Kellep. and B. C. Gates .I. 0ryanomr.rullic~Chrm.. 1992. 435. 377.226 D. T. Thompson into the charge transfer band of the compound causes decomposition; deposits can also be obtained thermally.'38 6 Palladium The solvent extraction behaviour of the palladium dimethylglyoxime complex was studied in acidic media under conditions applicable for radiochemical studies of short-lived activities. Distribution coefficients were determined in HCl HNO, and HCIO as a function of acid concentration for the extraction of carrier-free palladium by dimethylglyoxime in chloroform.' 39 The extraction of Pd" and Pt" from a chloride medium by some diamine and monoamine extractants such as N,N,N',N'-tetraoc- tylethylenediamine and N,N-dioctyl-2-(aminomethyl)pyridinedissolved in 5% isodecanol-benzene has also been investigated.'4o The partial molar volumes of dilute aqueous solutions of K,[PtX,] K,[PtX,] K,[PdX,] and K2[PdX,] complexes (X = C1 Br or SCN) have been determined from density data measured at 298.15 K. 14' Palladium complexes continue to be used as catalysts for the synthesis of a wide range of organic compounds. A catalyst produced from [Pd,(dba),]CHCl and triphenylphosphine facilitates the syntheses of g-calcidiol and calcitriol thus providing part of a new strategy for the synthesis of Vitamin D.', Palladation of the oxime of 2-benzyl-2-methylcyclohexanone occurs exclusively in the methyl group and attempted reactions of benzyl groups with enforced equatorial orientations fail. These observations together with the value of the primary deuterium isotope effect (4.0 5 0.5) for CH and CH,D groups indicate a transition state for palladation characterized by advanced C-H bond cleavage a tendency to sp2 hybridization at the carbon centre and substantial Pd-C bond formation.143 A new synthesis of a 1-phosphaalkyne Arc-P has been reported in quantitative yield'44 by reaction of a phosphaalkene ArP=CCI (Ar = 2,4,6-BuiC,H2) with [Pd(PPh,),l-Palladium and platinum-promoted desulfurization of N-sulfinylarylamines (ArNSO) was obtained by treatment with PdC1 or K,[PtCl,] in MeCN to give [MCl,(NH,Ar)] (M = Pd Pt). The presence of Pd or Pt greatly accelerated desulfurization. The reaction produced a truns-diamino complex with Pd whereas Pt favoured a cis-produ~t.'~~ The electronic structure of catalytically important palladium complexes has been studied by photoelectron spectroscopy.The Pd 3d5, level binding energies have been measured by ESCA for a series of Pdo and Pd" compounds. Pdo complexes showed a considerable variation in these energies depending on the ligands. In Pd(n-allyl) complexes the energies were almost constant. This is explained by the donor/acceptor characteristics of the ligands. Differences in the reactivity of these complexes result I38 J.S. Cohan H. Juan R.S. Williams and J. I. Zink Appl. Phys. Lett. 1992. 60. 1402. I39 H. L. Hall J. Radiounulyt. Nucl. C'hem. 1992 158 21 I. I40 B. K. Tait and D. P. Shillington S. Afr. J. Chem.. 1992. 45 17. 141 F. Kawaizumi. J. Chem. Soc.. Faraduy Trans. 1992. 88. 2351. I42 B. M. Trost J.Dumas and M. Villa J. Am. Chem. Soc,. 1992 114 9836. 143 A. P. Wells and W. Kitching Oryanomeru/lic.s 1992 11 2750. I44 V. D. Romanenko M. Sanchez. T.V. Sarina M. R. Mazieres. and R. Wolf 7ctrahedron Lett. 1992 33 298 1. I45 J. R. S.Maia and C. A. L. Filgueiras. Transiriori Met. Chem. (London).1992. 17. 228. The Noble Metals 227 from electron exchange between ligands viu the metal atom the electron density of which is ~nchanged.'~~ The new acyl palladium(I1) complex [PdI(COMe)(bipy )] has been prepared using two routes (i) by insertion of CO into the Pd-C bond of [PdIMe(bipy)]; (ii) by ligand exchange from [PdI(COMe)(tmeda)]. The cationic species obtained by reaction of both these acyl complexes with AgOSO,CF undergo alkene insertions into the Pd-C acyl bond that lead to remarkably stable products.147 The reaction of 2-(2'-thienyl)pyridine (Hthpy ) with Pd(OAc) results in a clean conversion to cyclometallated [(thpy)Pd(pOAc)Pd(thpy)]in which a new Pd-C bond is formed at the 3' position of the thienyl ring.'48 Bow-step and twist conformations and stacking interactions have been found viu X-ray structure determinations of [Pd(bipy),][BF,], [Pd(phen),][BF,], and [Pd( 3.4,7,8-tetramethyl- 1,lO-phenan throline] [BF,] ,.( bipy ) -a variety of ligand distortions and stacking interactions were found.149 There is evidence for the formation of zero valent Pd from mixtures of Pd(OAc), PPh, and [Pd(OAc),(PPh,),] -in the presence of excess triphenylphosphine the zero valent Pd complex generated in situ had the same 31 P NMR and cyclic voltammetric properties as those of [Pd(PPh,),].'50 The synthesis of the water-soluble phosphine P(CH,OH) (L)on a reasonable scale ( >50 g) has led to the preparation of water-soluble phosphine complexes of Pd and Pt.e.g. treatment of [MX,(cod)] (M := Pd Pt; X = CI Br I) gives [MX,L,] which are soluble in water methanol and DMSO but insoluble in most common organic solvents. The best method for synthesizing [PdL,] is the addition of an aqueous solution of L to a CH,C12 solution of [Pd(PPh,),]. followed by isolation of the product from the aqueous layer. The crystal structure of [PdL,]CH30H shows the Pd' centre to be tetrahedrally coordinated by L. The hydroxyl groups are all involved in either intra- or intermolecular hydrogen bonding.' I Synthesis of new water-soluble tertiary phosphines Ph PCH ,CH,SO,Na and Ph PCH,CH ,P(O)(OEt,) (L) hav- ing terminally substituted alkylene sulfonate or alkylene phosphonate chains is reported; the phosphonate reacts with [PdC1,I2- and Br- to give truns-[PdBr,L,] with L coordinated tlia the P atoms of the tertiary phosphines.'52 One-electron oxidation of the d8 dialkyls [PdMe,(dmpe)] [Pd(CH,SiMe,),-(dmpe)] and the phosphine derivative (5)by chemical and electrochemical methods results in homolytic cleavage of the Pd-alkyl bond to produce an alkyl radical and the corresponding cationic palladium (r1)monoalkyl complex.The oxidative cleavage reactions also exhibit selectivity. Oxidation of (5) results in exclusive loss of the CH groups and oxidation of [PdMe(OPh)(dmpe)] results in preferential cleavage of the Pd-0 bond.These results suggest that the oxidative cleavage chemistry developed for do metal alkyls can be extended to late transition metals.'53 I46 F. Boekrnan A. Gogoll L. G. M. Petterson. 0.Bohrnan. and H. 0.G. Siegbahn. Orgunonirtullic s 1992.1 I. 1784. 14' B. A. Markies. M. H. P. Rietveld J. Boersma A. L. Spek and G. Van Koten. J. Oryuriornrt. Them.. 1992 424 C12. 14' E. C. Constable and L. R. Sousa J. Orgmomrt. Chern.. 1992 427. 125. 14') S. Geremia. L. Randaccio M. Giovanni. and B. Milani J. Chrm. Soc.. Dulton Trans. 1992. 21 17. Is(' C. Arnatore A. Jutland. and M.A. M'Barki. OryunomPrullics 1992. 11. 3009. 15' J. W. Ellis K. N. Harrison. P. A.T. Hoye A.G. Orpen P. G. Pringle and M. B. Smith Inory. Cheni..1997 31. 3026. 152 S. Ganguly. J.T. Maguc. and D.M. Roundhill. Inorg. Chern. 1992. 31. 3500. Is' A. I-. Seligson and W.C. Trogler J. Am. Chem. Soc,. 1992. 114. 7085. D. T. Thompson The reaction of dichloroethyne with [Pd(PPh,),] or [RhCl(PPh,),] gives com- plexes with a phosphonioacetylide ligand Ph,P+C-C-. A platinum compound with the same ligand can be prepared'' by reaction of [Pt(C,H,)(PPh,),] with [Ph PC-CCl] CI. The tertiary phosphine-coordinated Pdo complexes [PdL (styrene)] (L = PMe, PMe,Ph PMePh,) react readily with allylic carbonates (methyl 2-methylallyl carbonate and ally1 ethyl carbonate) in THF to afford cationic z-ally1 palladium complexes' 55 having an alkyl carbonate anion [Pd(~~-allyl)L,][OC00R].Monometallic bis(bicarbonat0) complexes of Pd" [Pd(OC(O)OHI 2L2] and [Pd(OC(O)OH},(L-L] have been obtained' s6 cia the insertion of carbon dioxide into the Pd"-hydroxide bonds in [{ PdL2(p-OH)),][BF,12 and [{ Pd(L-L)(p-OH)),] [BF,],. The p-hydroxo complexes were prepared from [PdC1,L2] (I = PPh, PPh,Me) and [PdCl,(L-L)] [L-L = dppe bis(dicyc1ohexylphosphinojethane] by treatment with AgBF in aqueous acetone. Reaction of Na,[ PdCI,] with p-tolyl-o'-(2-chloroethylthio)azobenzene(L) pro- duces [PdClL] where the azobenzene ligand acts in a tridentate (C,N,S) manner with the fourth coordination position being occupied by the chloride ion. Reaction of [PdClL] with rn-chloroperbenzoic acid leads to insertion of 0 into the Pd-C bond to give the corresponding phenolato complex.The reaction is first order with respect to each reactant and has a large negative entropy of activation.''7 A new Pd' dinuclear complex [Pd,Cl,(p-mmpcn j,] [mmpcn = (dimethylphos-phinomethy1)dimethylaminel has been prepared and its X-ray crystal structure revealed that this Pd complex is a head-to-tail isomer in which the two coordination planes around the Pd are coplanar.'" [Pd,X,(p-L-L),( PR,),] [HL-L = pyrazole 3,5-dimethylpyrazole(Hdmpz); X = C1 Br I; PR = PBu, PMe,Ph PMePh,] were prepared and characterized by 'H and ,'P NMR spectroscopy and in the case of [Pd,C12(~c-dmpz),(PMe2Ph),]by single crystal X-ray diffraction. The structure shows two Pd atoms bridged by two dmpz ligands that form asymmetric Pd-N bond distances an observation which may be correlated with the different trans influences associated with the C1 and P atoms that complete the square-planar geometries around the Pd atoms.' s9 A simple synthesis of the dinuclear phosphido-bridged palladium(1) complex K.Suenkel J. Oryunornet. Churn.. 1992. 436 101. 15' F. Ozawa T.I. Son S. Ibina. K. Osakada. and A. Yamamato Oryurionietrrllrc~s,1992 11 171. 156 S. Ganguly J. T. Mague and D. M. Roundhill Inory. Chem.. 1992. 31 383 1. 157 C. K. Pal S. Chattopadhyay C. Sinha. and A. Chakravorty J. Oryc~nomer.Chent. 1992. 439. 91 Is' T. Suzuki and J. Futita Chetn. Le//. 1992. 1067. 159 V. K. Jain S. Kannan. and E. R.T. Tiekink. J. Chum. Soc...Dukon 7'ron.s.. 1992 2231. The Noble Metals 229 [{Pd(PBu\H)(p-PBu\)),] was reported via UV irradiation of [Pd{P(CMe,),),] in hexane or THF.The by-products are 2-methylhexane and hydrogen.' 6o Treatment of [Pd(CF,SO,)l(dppp)] [dppp = 1,3-bis(diphenylphosphino)pro-pane] reacts with hydrogen to give [{ Pd(dppp)),][SO,CF,], a palladium dimer with side-on phosphine coordination. ' Multiple and successive insertion of isocyanides into the Pd-C bonds in hetero-dinuclear p-ethynediyl complexes of Pd and Pt have been reported. For example [ClPd(PEt3),C~CPt(PEt,),C11 with ten equivalents of PhNC in THF16 gave [C1Pd(PEt,),(C=NPh),oC~CPt(PEt3)2Cl]. The first triply bridging alkyne complexes of palladium have been prepared and characterized. Reaction of alkynes RCECR (R = CO,Me C0,Et) with [M3(p3- + CO)(p-dppm),(O,CCF,)] (M = Pd Pt) gives [M,(p3-q2-RC-CR)(p-dppm,)-(O,CCF,)]+ and the structure of the Pd derivative (R = C0,Me) was determined.The trifluoroacetate ligand is easily replaced by chloride. NMR studies show that the alkyne is rigidly bonded in all the Pd and Pt complexes. For Pd but not for Pt the electronegative alkyne substituents are necessary prerequisites to the isolation of stable alkyne complexes.' 63 The synthesis structure and reactivity of anionic tripalladium clusters have been studied. [Pd,(p-X)R(p-S02)2(PPh3)3] (X = C1 Br) were prepared from the reaction between [Pd,( PPh,),(p-S0,)2(p3-S02)2]and X-.These triangulo clusters undergo a variety of reactions and for example one of the SO ligands may be replaced by NO' to give triangu/o-[Pd3(p-C1)(p-NO)(p-SO,)(PPh,),],and the triangle may be capped by the metal fragments Au(PPh,)+ and T1+ giving [Pd3AuC1(SO,),(PPh,),1 and [Pd,TlCl(S0,),(PPh,)3] respectively.' 64 The pentapalladium cluster [Pd,(p-CN~yl),(CNxyl)~(p-SO,)~] (xyl = C,H,Me,-2,6) was obtained in high yield'65 from the reaction between [Pd,(dba),]CHCl and xylNC under an atmosphere of SO,.Substitution and fragmentation reactions of pentapalladium clusters have been reported. For example in the reaction with CO the structure of the reaction product is [L dependent on the nature of the phosphine in [Pd5(p-S0,)2(p3-S02)2L5] = PPh, P(C,H,OMe-p), P(Me2Ph),].' 66 The synthesis of other tetra- and pentapalladium clusters with sulfur dioxide as ligand have been reported.[Pd,(SO,),L,] (L = PPh, PMePh, AsPh, etc.) have been synthesized from the reaction of [Pd,(dba),]CHCl with L under an atmosphere of SO, or by the reduction of palladium(I1) acetate by NaBH in the presence of L and SO,. The reaction of [Pd,(dba),]CHCl with PMe under an SO atmosphere,'67 however surprisingly gives [Pd,( PMe,),(SO,),]. [Pd(PMe,),] under 1 bar CO at 50 "C spontaneously transformed to [Pd6(p3- CO),( PMe,),] which has the first octahedral hexapalladium cluster core. 16' [Pd(PPh,)(edt)] (edt = ethanedithiolate) reacts with zirconocene dihydride with- 16" P. Leoni. M. Sommovigo M. Pasquali P. Sabatino and D. Braga. J. Oryunomet. Chrm. 1992,423,263. Ihl P. H. M. Budzelaar. P. W. N. M. Leeuwen. C. F. Roobeck and A. G. Orpen Orgunometa/lics 1992.11.23.IhZ K. Onitsuka T. Joh and S. Takahashi Anyew. Chrm. Inr. Ed. Engl. 1992. 31 851. Ih3 M. Rashidi G. Schoettel. J. J. Vittal. and R. J. Puddephatt. Oryunometul1ic.s. 1992. 11 2224. 164 A. D. Burrows J.C. Machell and D. M. P. Mingos J. Chrm. Soc. Dalton Truns. 1992 1939. '65 A. D. Burrows H. Fleischer and D. M P. Mingos J. Oryunomet. Chem.. 1992. 433. 31 I. Ih6 A. D. Burrows J. C. Machell. D. M. P. Mingos. and H. R. Powell J. Chem.Sot,.. Dulton Truns.. 1992. 1521. 1 h7 A. D. Burrows. D. M. P. Mingos. and H. R. Powell J. Chem. Soc.. D~ltoriTruns.. 1992. 261. IhH K. H. Friedrich. M. Mager U. Floerke and H. J. Haupt Oryunomrrullics. 1992. 11. 3915. D. T. Thompsori out any evidence of C-S bond cleavage to give [Cp,Zr(edt)Pd (edt)ZrCpJC,H,.The stereochemistry around Pd is distorted tetrahedral and the Pd-Zr separations are 2.886(1)A suggesting bonding interactions between the metals,’69 as shown in (6). Treatment of the incomplete cubane-type cluster [Mo,(H,O),S,]~+ with Pd metal in aqueous HCI solution afforded a mixed metal sulfido cluster tentatively formulated as [Mo,PdCI(H,O),S,]Cl, which upon further reaction with tacn gave a simple cubane-type cluster [Mo,PdC1S,(tacn),]C1,~4H20 the structure of which has been unambiguously determined by X-ray analysis. This is a novel example of a cuboidal mixed-metal sulfido cluster having the noble metal site embedded in the Mo,S core.’ ’O The hydrothermal reaction of PdCI with K,Se in the presence of KOH and H,O in a 1 5 :5 :40 ratio produced K,[PdSe,,] a metal polychalcogenide compound containing two interpenetrating three-dimensional diamond-like frameworks of [Pd(Se,),12-and [Pd(Se,),]* -.Each framework contains large tunnels running parallel to the a and h crystallographic axes. The coordination geometry around Pd is square planar.’” The use of Pd and its alloys in hydrogen purification is well known. The solubility of hydrogen in Pd-Y-Ag alloys has been studied and compared with previous data on Pd-Ag and Pd-Y alloys. The hydrogen solubility behaviour at low concentrations of hydrogen in the Pd-Y-Ag alloys under a ‘constant volume’ condition can be mainly attributed to the strong H-Y attractive pair interaction in the Pd host lattice. Both the stability of the P-hydride and the hydrogen concentration at the E,, phase boundary increase following alloying with Y from that of 5 at% Ag/Pd alloy and the changes in properties with Y content are similar to those in Pd-Y binary alloys (hydrogen diffuses 2.53 times faster through Pd-Y than through Pd-Ag).’ 72 The synthesis and structure of rubidium palladium hydrides [Rb,PdH,] and [Rb,PdH,] prepared by the reaction of RbH with Pd sponge in a pure hydrogen atmosphere have been studied.Both crystal structures can be described as framework arrangements of corner sharing octahedra made of Rb ions. There are isolated H -ions and also linear [PdH,]’- dumbbells in Rb,PdH or planar [PdH,]’- groups in [Rb,PdH J. ’73 7 Platinum Indepth studies on the mechanism of action of the cancer treatment drugs related to cisplatin have continued this year and significant progress has been made in the level of 16’ M.P. Boorman. G. K. W. Freeman. and M. Parvez Polyhedron. 1992 11. 765. I 70 T. Murata H. Gao Y. Mizobe. F. Naksno S.M0tomura.T. Tanase. S.Yano. and M. H1dai.J. Am. Chem. Soc.. 1992 114 8287. K.W. Kim and M. G. Kanatzidis. J. Am. Chem. Sw.. 1992 114. 4878. 172 Y. Sakamoto N. Ishimaru and Y. Inoue. Bur. Bunsen-Grs. Phjs. Chem. 1992 96. 128. I73 S. I. Prokop’ev. Yu. I. Aristov V. N. Parmon. and N. Giordano. Int. J. Hjdrogen Energy. 1992. 17. 275. The Noble Metals 23 1 understanding of the chemical and biological mechanisms involved. Only a very small selection of the most significant chemical work is given here. Reactions between ’’N-labelled cisplatin (cis-[PtCl,(NH,),]) and guanosine 5‘-monophosphate (GMP) were studied in aqueous solutions using NMR techniques.+ The reactive species [PtCl(H,O)(NH,),] was detected’ 74 as well as hydrogen bonding in the product [Pt(GMP-N7)2(NH3)2]2+. The primary mode of action of both cisplatin and carboplatin involves production of crosslinks in DNA. These compounds induce mutations in bacterial as well as in mammalian cells. From experiments using the Chinese hamster it was shown from the aminoacid sequences obtained that the less toxic carboplatin produced a very similar if not identical mutagenic outcome.’ Reactions of L-methionine with [PtX,]’- (X = C1 Br I) (1 1 and 2 1 ) have been studied in aqueous solutions at pH 1-9 using ‘H 13C 15N and 195PtNMR spectroscopy.The 2 1 complexes are thought to be metabolites of cisplatin.’ 76 The presence of isomeric complexes of [PtCl,(HMet)] (HMet = L-methionine) ’ [PtCl,(Met)] [PtC1,(HMet),12+ [PtCl(HMet)( Met)] and [Pt(Met),]’+ in aqueous platinum(i1)-methionine systems has been demonstrated and the quantitative distribu- tions of the different isomers estimated by NMR. Formation of [PtCI(Met),]’ was detected and the importance of this cation in the isomerization of rruns to cis geometry is postulated. A method of obtaining dimethionineplatinum(I1)complexes enriched in cis-isomers was developed and the products of this reaction were characterized.’ ” [PtCl,(dansen)] (dansen = 2-[(3-dansylpropyl)amino]ethylamine),an analogue of cisplatin has been synthesized and has been shown to bind covalently to DNA to form bi-functional 1,2-intrastrand cross -links adducts that display analogous structures to those formed on binding cisplatin to duplex DNA.The luminescence cellular uptake and DNA-binding properties of this Pt complex which contains a tethered dansyl group should ensure several applications such as its intracellular distribution and processing by DNA repair enzymes.’78 The DNA-binding properties of [PtCl,(NH,)(NH,C,H ‘)I,which has been identified as a metabolite of the orally ingested drug cis,trans,cis-[PtCl (NH,)(NH *C,H )(OCOC,H7)’] indicate that the major adduct formed is an intrastrand cross-link (54%)involving adjacent guanosine residues followed by interstrand or long range intrastrand cross-links also involving guanosine nucleoside residues (18%).Unlike cisplatin this metabolite system forms d(ApG) intrastrand cross-links to only a minor extent (8%).179 The cytotoxicity of platinum complexes of structural formula trans-[PtCl,LL’] (L = L’ = pyridine or thiazole or L = quinoline and L’ = R’R”S0) has been studied in murine L1210 and human tumour cell lines. The results indicate that use of a sterically hindered planar ligand greatly enhances cytotoxicity compared with truns-[PtCl,(NH,),] such that in some cases cytotoxicity equivalent to that of the clinically used cis-isomer i.e. cisplatin is obtained. The new trans-platinum complexes are also non-cross-resistant with cisplatin in both murine and human tumour cell lines. S. J.Berners-Price A. T. Frenkiel. J. D.Ranford. and P. J. Sadler. J. Chern.Soc.. Dulron Truiis.. 1992.2137. ”’ J.G. DeBoer and B. W. Glickman Curcinogenesis. 1992. 13. 15. I” R. E. Norman. J. D. Ranford and P. J. Sadler Iiiorg. Chem.. 1992. 31 877. I” ‘T.Grochowski and K. Samochocka. J. Chem. Soc. Dulron Truns. 1992 1145. 1’8 J. F. Hartwig P. M. Pil. and S.J. Lippard J. Am. Chem. Soc.. 1992. 114 8292. ”’J. F. Hartwig and S.J. Lippard J. Am. Chem. Soc. 1992. 114. 5646. 232 D. T. Thompson The results point to the possibility of a new line in anti-tumour agents acting via a new mechanism and with activity complementary to agents such as cisplatin.' In the search for new drugs to improve further on the performance of cisplatin carboplatin and iproplatin a novel class of ammine/alkylamine platinum(1v) car- ),] boxylates of formulae cis,trans,cis-[PtCl,(NH,)(NH,R)(OCOR' (R and R' = aliphatic aromatic or alicyclic) has been found to exhibit selective cytotoxicity to intrinsically cisplatin resistant human ovarian carcinoma cell lines.This novel class of platinum compound represents a valuable lead in the development of a 'third generation' agent capable of exhibiting activity against clinical disease currently resistant to cisplatin.' As far as homogeneous catalysis is concerned platinum catalysts are used much less often than their palladium analogues. However carbon-carbon and carbon-oxygen bond formation has been reported from the reaction of Pt" with bicyclo[4.1 .O]- hept-2-ene and related derivatives.The bicyclo[4.1 .O]hept-2-ene is readily transformed stereospecifically and regiospecifically via Pt" to trans-disubstituted cyclohexane and cyclohexene derivatives. A Pt" intermediate has been isolated.' 83 The use of heterogeneous catalysts based on Pt continues to expand in both atmospheric pollution control (page 209) and chemical processing. The Pt/Rh catalyst and Pd catchment gauzes used in medium- and low-pressure ammonia oxidation plants have been examined by SEM-EDAX and XPS. The noble metals were mainly in the metallic state and catalyst deactivation was governed by rhodium enrichment in the alloy surface.la4 A catalyst pack for the manufacture of hydrogen cyanide from mixtures of ammonia oxygen and hydrocarbon gas in a single pass has been described.The catalyst pack consists of two superimposed layers comprising at least one platinum group metal. The catalyst is 10% Rh/Pt and this process gives a higher conversion of ammonia to HCN than those previously described.' 85 Square planar anions of the type [Pt(CN),RI2- have been subjected to aqueous exchange with 13CN- and the exchange kinetics followed by 13C NMR. The coordinated alkyl group produces two distinct environments for the coordinated cyanide ligands which consequently exchange with exogenous cyanide ion at two different rates. With R = CH, the exchange of cis CN- is lo- and trans CN- is 10 ' times slower than for the same process for the reference compound [Pt(CN),I2 -. In all these cases the rate laws are strictly second order first order in CN -and first in metal complex with no evidence for solvent involvement.' 86 A convenient method for small scale preparations of trans-[PtCl,(NH,),] (e.g.for preparing 15N-labelled compounds) is to heat [Pt(NH3)JC12 at 190-195 'C under vacuum.15N and '95Pt NMR spectra have been used to characterize trans-diammineplatinum(l1) complexes in solution with aquo chloro nitrato sulphato acetato and phosphato ligands. A solution of trans-[Pt(H,O)(NH,),(OH)]+ if allowed to stand gives a precipitate of trcrns-[(Pt(NH,),(,~-OH)),][N0~]~. I5N NMR N. Farrell L. R. Kelland. J.D. Roberts and N. Van Beausichem. Cancer Res.. 1992. 52. 5065. N. Van Beausichem and N. J. Farrell. Inorg. Chem.. 1992 31 634. 1 RZ L. R. Kelland B. A. Murrer G. Abel C.M. Giandomenico. M. Christen P. Mistry. and K. R. Harrap Cancer Rrs. 1992 52 822. I ti3 J. 0. Hoberg and P. W. Jennings Oryunometu/lic~.s,1992. 11 3452. J. I.G. Fierro J. M. Palacios and F. Tomas. J. Mater. Sci.. 1992. 27. 68. lnSJ. P. Agrawal US Patent 5096687 1992. '*' A. Y.C. Hung J.C. Woolcock. M. F. Rettig. and R. M. Wing Inory. Chem. 1992 31. 810. The Noble Metals 233 spectra have been used to determine acid dissociation constants' 87 for trans-[Pt(H20),('5NH3),]2+ and for trrtn~-[PtCl(H,O)('~NH,),]+.15Nsolid-state NMR spectra have been recorded for a series of platinum complexes with two different amine ligands; 'N-enriched en and natural abundance 3,7-diazanonane- 1,9-diamine. The results show that the 5Nchemical shift and J coupling to '"Pt are very sensitive to the effective oxidation state of the metal atom and that in both discrete Pt" and Pt" complexes as well as in mixed valence complexes which can be formed therefrom the platinum atom environments become more similar on changing from chloro to bromo to iodo species.This trend is attributable to the fall in the effective positive charge on the metal atom as the halogen atom is changed in this order and not to increased valence delocalization upon formation of a linear chain.'" The first arylplatinum(1v) hydrides have been isolated from such reactions as the oxidative addition reaction of CF,C02H with cis-[Pt( l-CloH,NMe2-8-C,N)2]. A mechanistic study of the formation of the hydride versus the zwitterionic hydrogen- bridge complexes shows that the Lewis basicity of the anion is an important factor in product formation.' 89 A new paramagnetic platinum(1Ikxeatinine complex [AsPh,][PtCl,L] (L = cre-atinine) has been synthesized and shown to crystallize to give a columnar honeycomb motif of Ph,As+ cations with the channels occupied by creatinine-complex anions.A remarkable feature of the structure is the formation of short'" Pt-H intermolecular bonds of 2.73(2)A. The coordination of RC(CO)NH (R = H Me) to Pt"(dien) (dien = diethylene-triamine) gives both 0-and N-bonded amide complexes either of which are stable and can be isolated. As 0-donor ligands for Pt"(dien) the binding affinity of amides lies between H20 and the weakly coordinating Me,CO. The 0-bonded amide complexes [Pt(dien)OC(R)NH,]'+ are the kinetically preferred isomers in acetone but they rearrange very slowly and intramolecularly to the thermodynamically more stable N-bonded amide complexes.This is the reverse of relative amide affinities for harder metal ions such as [M(NH,)J3' (M = Co Cr Ru) despite the comparable polarizing power for Pt(II)(dien).' 91 The diastereoisomers of [PtCl [(S)-Hp-Mepn)] [(S)-Hp-Mepn = (S)-l-(2-amino-2-methylpropyl)amino-2-propanol] have been prepared and studied in both solution and the solid state.'92 The complexes [PtPh,(bipy)] [PtPh,(bipym)] [{ Pt(p-tolyl) )2(p-bipym)] and [(PtAd,),(p-bipyrn)] (Ad = 1-adamantylmethyl) were subjected to two successive one-electron reductions and the one-electron reduction products were studied in situ t:ia UV-visible/near-IR and EPR spectroscopies.The first reduction is at the heterocyclic ligand in contrast to the metal-centred reductions in such closely similar species as [Ptpy2(bipy)12 + The difyerence is attributed to the greater ligand-field strength of carbanionic as opposed to neutral N-bound ligand~.'~~ In' T.G. Appleton A. J. Bailey. K. J. Barnharn and J. R. Hall Inory. Chrni.. 1992 31. 3077. I Xn E. J. W. Austin P. J. Barrie. and R. J. H. Clark. Inorg. Chern. 1992. 31. 4281. i ny I. C. M. Wehman-Ooyevaar. D. M. Grove P. De Vaal A. Dedieu. and G. Van Koten Inorq. Chern.. 1992 31 5484. 1'40 G. Gencheva. M. Miteva. P. R. Rontchev G. Gochev. J. Macicek. E. Zhecheva. and N. D. Yordanov. Polyhedron 1992 1I 365. T. C. Woon and D.P. Fairlie Inorg. Chtw. 1992 31 4069. ")'R. Saito M. Goto. J. Hirose. and Y. Kidmi. Bull. Chrm. Sol,. Jpn. 1992 65 2118. 1Y3 P. S. Braterman J. I. Song C. Vogler and W. Kah? Inory. Chrm. 1992. 31. 222. D. T. Thompson Cationic five-coordinate Pt" complexes of general formula [PtClL(N-N)(olefin)] + were synthesized and relevant chemical and spectral properties of the new complexes discussed in comparison with related five-coordinate species. The X-ray structure of [PtCl(ethylene)(2,9-dimethyl-l,10-phenanthroline)(py)][CF,SO3] showed it to be bipyramidal with the chloride and pyridine ligands in apical positions and the olefin double bond in the equatorial plane.' 94 The five-coordinate Pt" complexes exemplified by [PtCl(ethylene)(2,9-dimethyl-l ,lo-phenanthroline)(SnPh,Cl)] have been prepared by oxidative addition of SnCl,Ph to the three coordinate Pto complex [Pt(ethylene)(2,9-dimethyl-l,lo-phenanthroline)] (7).The geometry of the five-coordinate Pt complex is bipyramidal with anionic ligands in apical positions and the olefinic double bond in the equatorial plane.195 Me (7) Novel platinum complexes with 4,4'-dipyrazolylmethane (dpzm) ligands include196 conformational isomers of the square-planar dinuclear Pt" species a-[Cl,Pt(p- dpzm ) PtCl,].idmf [I-[Cl Pt(p-dpzm) PtCl ,I and y-[Cl Pt(dpzm ) PtC12].2dmf and the corresponding octahedral Pt'" complexes a-[Cl,Pt(p-dpzm),PtCl,] .iH,O and fi-[Cl,Pt (p-dpzm) PtCl,].idmf-iH 0. l-Lithioundecafluorobicyclo[2.2.l]heptane C,F ,Li reacts with cis-[PtC12(PPh,),] and trans-[PdCl,(PPh,),] to give cis-[Pt(C,F ,)Cl(PPh,),] and trans-[Pd(C,F 1)2(PPh3),] respectively.The reactions of these complexes with dilute HC1 NaOH gaseous hydrogen oxygen and air were examined to assess the stability of the M-C bond. The X-ray crystal structure of the platinum complex shows that there are significant distortions from the ideal square planar geometry.' 97 Atropisomerism in asymmetric cis-diphosphine arylplatinum complexes has been reported. Slow rotation about the M-aryl bond has been observed in several cis-PtArP,X (P = chiral diphosphine ligand) complexes; the X-ray crystal structure of a single rotamer of (R)-[PtAr,(binap)] (Ar = o-C,H,OMe) is reported. The bite angle P-M-P of the diphosphine ligand is critical in determining the ease of metal-aryl bond r0tati0n.I~~ Comparative mechanistic studies of the thermolytic and photolytic rearrangement of [Pt(neophyl),(dppe)] (neophyl = 2-methyl-2-phenylpropyl) gave rise to the platinaindane product (8)tlia intramolecular C-H activation and hydrogen transfer to eliminated t-butylbenzene.' 99 194 V.G. Albano C. Castellari M. Monari V. De Felici A. Panunzi and F. Ruffo Oryunornerullics. 1992. 11. 3665. 195 V. G. Albano. C. Castellari. V. De Feleci. A. Panunzi. and F. Ruffo J. Orgunornet. Chem.. 1992.425 177. 196 J.A. Broomhead. L. M. Rending. and M. Sterns fnorg. Chcw.. 1992. 31. 1880. 197 P. P. K. Claire C. J. Jones J. A. McCleverty. P. L. Coe. and M. G. B. Drew. J. Orgunornet. Chem. 1992. 424.105. 198 N. W. Alcock J. M. Brown. and J. J. Perez-Torrente. 72trahedron Lett. 1992 33 389. 199 B.C. Anianiec D.T. Hardy S. K. Thomson W.N. Watkins and G. B. Young 0ryrrnomercillic.s. 1992. 11. 2591. The Noble Metals 235 Reductive elimination of Me,C from [PtH(Np)(dtbpm)] [dtbpm = bis(di-t-butyl-phosphino)methane] generates the 14-electron fragment [Pt(O)(dtbpm)] at ambient temperature. This highly reactive intermediate is capable of activating the C-F bonds of C,F, thus yielding exclusively the C-F insertion product [PtF(C,F,)(dtbpm)] .,O0 Treatment of [PtCl,L,] (L = phosphine) with the N-acetyl derivatives of the amino acids glycine DL-alanine Dr.-methionine or L-phenylalanine in the presence of an excess of Ag,O in refluxing CH,CI affords [Pt(N(COMe)CHRC(O)O-N,OjL,] (R = H Me CH,CH,SMe CH,Ph) respectively) and with L-proline [Pt(R'C(O)O- N,O',L,] (R' = pyrrolidinyl) is produced.20' Upon standing cis-[Pt(OH),(PMe,),].nH,O (n = 2-3) in air cis-[Pt(CO,) ( PMe3),].2H,O forms in which the carbonate anion forms a four-membered chelate with the Pt atom.,' Rapid addition of H,SiSiH to solutions of cis-[PtH,(dcpe)] [dcpe = 1,2-bis(dicyclohexylphosphino)ethane] in toluene produces the novel complexes [Pt(dcpe)(SiH,SiH,),] and [ (Pt(dcpe)(p-H,SiSiH,)j ,] in a 4 1 ratio with terminal disilanyl (Si,H,) and bridging disilene (Si2H4) re~pectively.~'~ Reactions of primary silanes with [Pt(PEt,),] provide high yield routes to platinum silyl complexes.If the SiH,Ar to [Pt(PEt,),] ratio is 1 2 there is quantitative formation of the dimers [(Et,P),Pt{ Y,J~,Y,J~-A~(H)S~S~(H)A~)~'~(PE~,),] (when Ar = Ph these compounds are isolated as crystalline products from pentane).If the ratio is increased to 3 1 cis-[Pt(SiH,Ar),(PEt,),] is isolated. These compounds slowly isomerize to cis,rrarzs mixtures in solution. Reaction of dinpe with this second product gives the binuclear complexes [( Pt(dmpe)(SiH,Ar) ,(p-dmpe)]. which possess five-coordinate square pyramidal Pt centres.,' The reaction of MePhSO with K,[ PtCl,] gives the expected cis-[PtCl,(SOMePh),] whereas the product with the more sterically demanding Ph,SO is K[PtCl,(SOPh,)]. An analogous monosulfide anion is also formed with Me(Bu')SO. The structures were resolved by X-ray diffraction.20s Treatment of cis-[PtCI,L,] (L = donor ligand) with either N,N'-diphenylsulfamide (H,A) or N,N',P-triphenylphosphonicdiamide (H,Q) in the presence of an excess of Ag,O in refluxing CH,Cl gave 17 new metallocycles of the types [PtAL,] and [PtQL,] respectively.The X-ray crystal structure of [PtA(cod)] showed the presence *"(I F. P. Hofmann and G. Unfried. Chrni. Rzr. 1992. 125 659. I"' R. D. W. Kemrnitt S. Mason. J. Fawcett and D. R. Russell. J. Clzum. Soc.. Dultori Trctns. 1992. 1165. '02 T. K. Miyamoto Y. Suzuki and H. Ichida Chum. Lrtr.. 1992. 839. M. J. Michalczyk. J.C. Calabrese. C. A. Kecatto. and M. J. Fink. J. Am. Chrm. Sor. 1992. 114. 7955. "I4 R. H. Heyn and T. D. Tilley. J. Am. Chrrn. Soc.. 1992. 114. 1917. '(I' S.G. de Almeida J. L.Hubbard. and N. Farrell. Inory. Chim. A(,r(r. 1992 193 149. 236 D. T. Thompson of an entirely flat four-membered ring whereas that of [PtQ(PPh,),] exhibits a small puckering angle but with no substantial Pt-P transannular interaction.,' A dinuclear platinum complex with bridging hydrazine [NPr,],[PtCl,(p-N,H,)PtCl,] has been prepared and the dinuclear dianion is stabilized by intra- molecular NH . . . C1 hydrogen bonding. Comparison of the crystallographic and spectroscopic data with those of [PtCl,(NH,)]- has shown that the Pt-N bonds have very similar characteristics in the two cases.'o7 [NBu4][Pt2X9] (X = C1 Br) is formed when [NBu,][PtX,] reacts with CF,CO,H. The X-ray structure of [N(PPh3)2][Pt2Br9] shows that the anion contains pairs of face-sharing octahedra with nearly D, symmetry.The electrostatic interaction between the Pt atoms results"' in a Pt-Pt distance of 3.23A. The reaction of [NBu~],[P~,(P,O~H,)~] with Et,S in methanol in the presence of H202 gives [NBu,]~[P~,(P~O~H~),(SE~~),] in which the Pt-Pt bond length is 2.766(1) A which suggests that o-electronic delocalization of the Pt"'-Pt"' bond with the Pt-SEt bond is even more pronounced than that with Pt-SCN and Pt-I.,09 Reaction between [PPh,]X (X = C1 Br) and K2[PtX,] in water leads to either [PPh,],[PtCl,] or a mixture of [PPh,],[PtBr,] and [PPh,],[Pt,Br,] depending on the halogen present. Reaction of PtI with KI and [PPh,]I gives [PPh,],[Pt,I,] as the sole product. All of these compounds react with S,N in dichloromethane to give [PPh,][Pt'"X,(S,N,)] which contain [S,N,]'-.Evidence from '5N NMR spectros- copy indicates that in all cases the S,N ligand adopts a facial coordination mode bound by two sulfur atoms and one nitrogen.'" Ph'PSOH reacts with [PtCl,(dppe)] to give" ' the bipyramidal Pt,S,-containing cluster [Pt ,(dppe),S,] [(Ph PSO),H][OH]. [Pt2(p-acetate),(H20)2][C104] was prepared by heating K,[Pt(NO,),] in a 2 1 mixture (by volume) of HOAc and 1M HClO,. Its X-ray crystal structure indicates the shortest Pt-Pt bond distance yet measured 2.3905( 14) A. The Pt-Pt bond is compressed due to the restraints imposed by the four bridging acetate groups. When the compound was dissolved in water one of the acetate bridges was broken." ' Reaction of [Pt2C12(p-Cl)2( PR,),] with NaTeAr gave [Pt2X,( PR3),(p-X)(p- TeAr)] (e.g.Ar = Ph p-tolyl; PR = PBu, PMe,Ph; X = C1) which on metathesis with KBr or KI afford the corresponding bromides and iodides.'13 Amongst mixed metal complexes which continue to be prepared in great variety one interesting example is the Pt"/Ni" complex with a lantern type structure [PtNi(NCMe)(p-L),] prepared' l4 from [Pt(HL),]Cl (HL = 4-methylpyridine-2-thiol) with Ni(OAc) in naphthalene at 120°C in the presence of KHCO,. The reactions of the n-ethylene complexes [Pt(H,C=CH,)(PR,),] [PR = PPh,; (PR3)' = (Ph,P(CH,),PPh,}] with Ir(1) triflate complexes rrans-[Ir(CO)(OTf)- 'Oh R. D. W. Kemmitt S. Mason M. R. Moore and D. R. Russell J. Chem. Soc. Dalton Trans. 1992 409. 207 L. L. Nguyen. J. Kozelka.and C. Bois Inorq. Chim. Acra. 1992. 190 217. 2 on P. Hollman. W. Preetz H. Hillebrecht. and G. Thiele. Z. Anorg. Allg. Chem. 1992 611. 28. 209 C. M. Che M.C. Cheng Y. Wang and H. B. Gray Inorg. Chim. Acru. 1992 191. 7. 2io P. S. Belton V. C. Ginn P. F. Kelley and D. J. Woollins J. Chem. Soc.. Dalton Trans.. 1992 1135. 'I1 M. J. Pilkington. A.M. Z. Slawin D. J. Williams and D.J. Woollins J. Chem. Soc. Dalton Trans. 1992 2425. 'I2 T.G. Appleton K.A. Byriel J. R. Hall and C. H. L. Kennard J. Am. Chem. SOC.., 1992 114. 7305. 2i3 V. K. Jain S. Kannan and R. Bohra Polyhedron. 1992. 11 1551. 'I4 T. Nishioka I. Kinoshita K. Kitano and S. Oii Chem. Lett. 1992 883. The Noble Metals 23 7 (PR;),] (PR; = PPh, PMePh,) result in C-H bond activation and the ready formation of the novel heterobimetallic Ir-Pt complexes (9).,' OTf-(91 The coordinatively unsaturated [Pt3(p3-H)(p-dppm),] adds phosphine or phos-+ phite ligands L to give [Pt3(p3-H)L(p-dppm),] + .Combined information from the X-ray structure determination and low temperature NMR studies shows that L is terminally bonded that the Pt,(p,-€1) group is distorted such that the H- binds most strongly to the Pt atom having the higher coordination number and that L can migrate easily around the Pt triangle.," Displacement of ligands in [PtBr,(en)] by /3-and ;I-mercaptoamines 2-(dimethy1amino)ethanethiol (HL) 3-(dimethy1amino)propane-1 -thiol and 4-mer- capto- 1-methylpiperidine in alkaline aqueous solution gave different kinds of com-plexes depending on the nature of the mercaptoamine; e.y.with HL [Pt(,u-L-N-p-S)Br] was formed consisting of discrete trimeric molecules with a central Pt,S ring. Each Pt atom is square planar and coordinated by an S,NBr donor set; the aminothiolate ligands are simultaneously chelating through S and N. and bridging through S while Br is terminally bonded. l7 The Longoni/Chini cluster [Ptl,(CO),o]'- was prepared on MgO powder by surface mediated synthesis from Na,[PtCl,] in the presence of CO. Both the formation of [Pt ,(C0),,J2 -and its decarbonylation at 120 'C under vacuum were character- ized by TR and X-ray spectra. The decarbonylated cluster had an average Pt-Pt bond distance of 2.76A and an average Pt-Pt first shell coordination number of 3.7 indicating that the trigonal prismal.ic framework structure of [Ptl ,(C0),J2 was ~ retained after decarbonylation.When this product was recarbonylated the dianion was not re-formed however.218 The bimetallic cluster [Pt,Ru,(CO), (p-H),(p,-H)] has been prepared and its derivative [Pt,Ru,(CO),,(p3-H)(,u-H)(p3-PhC2Ph)] exhibits 100% selectivity for the hydrogenation of diphenylacetylene to (Z)-stilbene. l9 The mixed-valent compound [Pt( NH,),],[(NC),Fe(CN)Pt(NH,),(NC)Fe(CN),] was used as the starting point for the synthesis and characterization of Na,[L(NC),Fe(CN)Pt(NH,),(NC)Fe(CN),L](where the sixth coordination site on the terminal iron units has been varied using six different substituted pyridine and pyrazine ligands L) and [Pt(NH,),],[(NC),M (CN)Pt(NH 3)4(NC)M (CN),] (M = Fe.Ru 0s). All of the compounds had an intervalent charge-transfer band in their visible absorption spectrum. Both series of complexes were modelled using Mar- cus-Hush theory to estimate the reorganization energies for the optical electron- "' P. J. Stang Y. H. Huang and A. M. Arif. Urganornetcl//ic~s.1992 11. 845. 216 R. Ramachandran D.S. Yang N.C. Payne. and R. J. Puddephatt fnory. Chrm.. 1992. 31 4236. 'I7 M. Capdevila W. Clegg P. Gonzalez Duarte. and I. Mira. J. Chrm. Soc.. Dalton Trans. 1992 173. 'IH J. R. Chang. D.C. Koningsberger. and B.C. Gates J. Am. Chem. Soc,.. 1992. 114 6460. 'IL) R.D. Adams. 2.Li. P. Swepston W. Wu. and J. Yamamoto. J. Am. Chrm. Soc.. 1992. 114. 10657. 238 D. T. Thompson transfer processes electron-transfer rate constants thermal activation barriers.and the degrees of localization of these species. In addition the kinetics of formation photochemistry and a novel solvent-gated charge-transfer process are discussed.220 3-Ferrocenylpyridine (3-Fcpy ) reacts with [PtCl,] -to give square planar cis-[PtCI2(3-Fcpy)]. In acetone acetonitrile or dimethylsulfoxide solution this product undergoes a two-electron oxidation process which involves the two appended ferrocenyl fragments uia two one-electron reversible steps whose potentials are separated by only 36 mV. The cis-[PtI'py,] core is a convenient bridging unit to build up novel bis-ferrocene systems in which the two relatively close Fc fragments display independent redox activity.22 The preparation of [AsF,][PtF,] containing the tetrafluoroarsenic(v) cation (the last missing member of the series of tetrahaloarsenic(v) cations) was achieved cia the reaction of Pt AsF, and F under electrical-resistance heating of the Pt wire.,, 8 Silver [AgMSO,] (M = alkali metal) have been prepared from MHSO and Ag,O or Ag,CO, and used optionally with H,O, as microbicides and virucides.This is especially useful in the disinfection of drinking water swimming pools and food and ice for beverages.223 The first examples of a new type of silver complex the cyanoargentates MeAg(CN)Li Me,Ag(CN)Li, MeAg(CN)MgBr and Me,Ag(CN)(MgBr), were prepared in solution or suspension by transmetallation of MeLi or MeMgBr with AgCN. Compared with AgBr-derived reagents such as MeAg.MgBr and Me,Ag.MgBr the cyanomethylargentates are significantly less sensitive to iight.These silver complexes are used as methylating reagents e.y. the ketoaldehyde (10)reacts with high selectivity224 at the aldehyde group [best yield with Me,Ag(CN)(MgBr),]. CH3CO CH2CHO (10) The significance of the preparation of the first isolable silver carbonyl complex [Ag(CO)B(OTeF,),I has been reviewed . The reaction of silver nitrate with the ligands (L) imidazolidine-2-thione (imt) 1,3-diazinane-2-thione (diaz) and their derivatives yields [AgL(NO,)]. The NMR C-2 resonances of the diaz complexes were shifted more from the free ligand positions compared with those for the imt complexes suggesting that the former bind more strongly to Ag' than the latter.226 The reaction of 4-nitroimidazole (N0,imH) with AgNO and AgBF in neutral or weakly acidic aqueous media yielded insoluble 220 B.W. Pfennig and A. B. Bocarsley. J. Phys. Churn. 1992 96. 226. "' 0.Carugo G. De Santi L. Fabbrizzi M. Licchelli. A. Monichino. and P. Pallavicini. Inorg. Chem.. 1992. 31 765. 222 M. Broschag. T.M. Klapoetke. and I. C. Tornieporth-Oetting. J. Chum. Soc.. Chm. Commun. 1992.446. 223 A. Massarotti Sw~issPatent CH 679 997 1992. 224 T. Kauffmann C. Neiteler. and S. Robe Chem. Bur.. 1992 125. 2409. 225 T. G. Richmond Chemtructs Inorg. Chum. 1992 4 171 226 A. A. Isab Trunsitron Mc~tul Cheni. (London). 1992. 17 374. The Noble Metuls 239 [Ag(NO,im)] whose IR and 13C NMR spectra are consistent with a polymeric chain of deprotonated ligands bridging Ag atoms via the endocyclic N atoms.In strongly acidic solution [Ag(NO,ImH),]X (X = NO, BF,) were obtained in which the anions are H-bonded to the ligand N-H groups and do not interact directly with the metal.',' The reaction of highly basic sterically hindered PR [R = C,H,(OMe),-2,4,6] with AgX (X = C1 Br) yields [AgX(PR,)]. The 31PNMR spectra of these complexes in chloroform show a superposition of two doublets due to the coupling of the P nucleus with the two magnetic isotopes of Ag ("'Ag "'Ag). Reaction of [AgX(PR,)] with PR in a 1 1 mole ratio gives [Ag(PR,),]X in solution.228 Structural studies on the Ag' salts of cyclo- 1,3- and cyclo- 1,4-perfluoropropyl- bis(sulfony1)imide have shown that Ag[(CF,),(SO,),N].H,O and Ag[(CF,),-(SO,),N].H,O have lamellar structures consisting of stacked two-dimensional polymeric layers of ions.The layers consist of a hydrophilic inner region containing the metal ions which interact strongly with the sulfonyl and imide groups and the hydrophobic outer surfaces formed by the perfluoro groups.229 The preparation and characterization of acyclic mononuclear and macrocyclic dinuclear Ag' complexes of ligands derived from the Schiff base condensation of N,N-bis(2-aminoethyl)-2-phenylethylamine or N,N-bis(3-aminopropy1)-2-phenylethyl-amine with 2,6-diacetylpyridine have been reported. Changing the aminoalkyl groups of the alkylamines from ethyl to propyl provides a change from an acyclic mononuclear Ag' compound to a macrocyclic dinuclear Ag' compound.'30 Mono- and bimetallic Ag' complexes of new bis(2,2'-bipyridine) ligands have beep reported.The new ligand systems contain 2,2,2'-bipyridin-6-ylmethyl moieties linked ~)iu1,4,10,13-tetraoxa-7,16-diazacyclooctadecane,1,4,10,13-tetrathia-7,16-diazacy-clooctadecane 4,4'-bipyridinediium N,N',N"-tritosyldiethylenetriamine,and tol-uene-p-sulfonamide spacer units.* l Reaction of [Ag(Hdipic)(H2dipic)].H20(H2dipic = 2,6-pyridinedicarboxylic acid) with Gd(NO,) in aqueous methanol gave Ag[Gd(dipic),(H,0),].3H20 the first structurally characterized silver/lanthanide heterometallic complex. X-ray diffraction showed that each Gd atom is nine-coordinate and has two tridentate [dipic]'- ions and three water molecules bonded in a tricapped trigonal prismatic geometry.The Ag atoms bind to the carboxylic acid groups of both [dipicll- ligands forming polymeric Gd-carbox yl-Ag-carboxyl-Gd chains. The crystal structures of [AgHgL,( NO ,)I (LH = oxazolidone and [j-propiolactam) have been determined and shown to be significantly different despite the similar nature of the ligands the propiolactam ~ complex has helical chains and new 12-membered silver-mercury metallomacrocyclic rings.,, The preparation of silver salts of [Nb(OTeF,),] -and [Ti(OTeF5)J2 -,by treating NbCl or TiCI with six equivalents of [AgOTeF,] in Cl,FCCClF, and a study of their coordinating ability stability in the presence of electrophiles and solubilizing 211 I. Segalas and A. L. Beauchamp Cun. J. Chem.. 1992. 70. 943. ''' L.J.Baker G.A. Bowmaker. D. Camp. A. Effendy P.C. Healy. H. Schmidbaur. 0.Steigelmann. and W. H. White Inory. Chrm.. 1992 31 3656. "') D. D. Desmarteau S. S. Zuberi. W. T. Pennington. and B. B. Randolph. Eur. J. Solid Srure Imry. Chrni.. 1992. 29 777. 230 D. E. Fenton and P. C. Hellier Inory. Chm. Acru 1992. 198 200 577. 2.3' P.D. Beer J. W. Wheeler and C. P. Moore. J. Chmi. Soc.. DNlron Trms.. 1992. 2667. "' D. M. I>. Goodgame T. E. Muller and D.J. Williams. Polyhedron. 1992. 1I 1513. 2.13 D. M . L . oodgarne S. P. W. Hilland. and D. J. Williams Poljhedrori 1992. I I. 1841. D. T. Thompsoii ability have been reported. The titanium compound was recrystallized from CH,Cl to give [Ag(CH,Cl,),],[Ti(OTeF,),]. in which three bidentate CH,Cl ligands coordi- nate to Ag in the cation; the Ag ion is prevented by steric hindrance from bonding to the 0 atoms of the [Ti(OTeF,),I2- antion and is only very weakly bonded to two F atoms [Ag-F = 3.029(8) 3.033(6)81].Both products are freely soluble in weakly coordinating solvents such as chlorinated hydrocarbons and chlorofluorocarbons.234 Spectroscopic and potentiometric studies of Ag' binding by tris-pyridine strands (1 1 ) (L = I; X = H CH,CH,CO,CMe,) indicate that the formation of [Ag,L,][CF,SO,] ,is a process displaying positive co~perativity.~~~ Reaction of silver nitrate with [15]aneS,O (1,4,7-trioxa-l0,13-dithiacyclopen-tadecane) followed by addition of NH,PF, affords [Ag,([ 1S]aneS,O,),][PF,], an S-bridged linear chain polymer of [Ag([ 151 aneS,O,)] units with formal S,O Sbridge + coordination at A& and [Ag,([ 1S]aneS,O,),][ PF,], which shows distorted trigonal planar S coordination at Ag' with long range interactions to three 0-donors at each Ag'.,, A novel Ag-Mo-S cubane-type complex [(Ag,MoCIS,)(PPh,),S] was prepared from AgCl PPh, and [MoS,]'-.The molecule consists of one cubane-like cluster core three PPh ligands attached to the three silver atoms and one terminal sulfido ligand attached to the Mo. The Mo and Ag atoms are too far apart to bond effectively.237 A cubane-like complex of the molybdenum-silver-sulfur series [(Ag,MoClS,)(PPh,),O] has been synthesized from AgCl PPh, and [Mo,O,S(S,),]~ -. The X-ray crystal structure shows that the complex comprises one cubane-like cluster core [A~,MOCIS,]~' one PPh ligand attached to each Ag and one terminal 0,-attached to the Mo.,,* A vibrationally resolved electronic spectrum has been obtained for the metal dimer-rare-gas complex Ag,Xe.An unusual cancellation of factors results in the Ag,Xe having nearly the same rare-gas stretching frequency (79.9cm-') as the corresponding krypton (72.6) and argon (73.9) complexes studied previ~usly.~~" Of the many papers being published worldwide on 'high temperature' superconduc- tors just one is selected to give the reader a reference point for this important new applications field in which silver as well as gold and platinum is finding widespread use. Thick films of the high temperature superconducting oxide YBa,Cu,O, have improved critical current performance when doped with silver.Magnetization measurements and the ILV characteristics show that the silver reduces the normal state 235 D. M. Van Seggen 0.P. Anderson. and S. H Strauss. J. Am. ('Iiwi. Soc... 1999. 114. 10995 "' T. M. Garrett. [J. Koert and J. M. Lehn. J. Phj.\. Ory. C'hern.. 1999. 5. 529. 236 J. Blake. G. Reid. and M. Schroder J. c'hc,ni. Sot,.. ('hm. Comniuri.. 1992. 1074. 737 N. Zhu J. Wu S.Du. X. Wu and J. Lu Iriorq. Chirii. Acru. 1992 191. 65. "'J. Wu. N. Zhu. S. Du X. Wu and J. Lu. Po/j,hedron. 1992. 11. 1201. 234 L. Robbins. K. F. Willcq. C.S Yeh. and M.A. Duncan. J. Phrs. Chwi.. IY91. 96. 4824. The Noble Metals 24 1 resistance of the intergranular weak links by ca. two orders of magnitude and removes the sensitivity to small magnetic fields.,,' 9 Gold Bacterial leaching has been combined with the thiourea leaching method for the extraction of gold from various ores.The gold-bearing silicate ores were treated with iron-oxidizing bacteria thiobucillusferrooxidans,in sulphuric acid. The extraction of gold from the Hishikari ore with bacteria was 10-20°/0 higher than when the ore was only chemically treated.241 Successive treatment of HAuCl with the cationic surfactant hexadecylpyridinium chloride a non-ionic surfactant of the polyoxyethylene nonylphenyl ether type and then with hydrazine produces gold sols consisting of monodispersed gold particles of sizes 1540 nrn.,, Reaction of MeCN solutions of [NPr,],[WSe,] with two equivalents of Au ',Ag+ or Cu' in the presence ofexcess PMe,Ph affords [p-WSe,][M(PMe,Ph),] (M = Au Ag Cu).Substitution of PMePh for PMe,Ph gives [p-WSe,][Au(PMePh,)] in the gold case in which the geometry around the Au atoms is distorted trigonal planar.243 Treatment of (PPh2)2C2BloH,o with [AuX(tht)] (X = C1 C,F,; tht = tetrahyd-rothiophene) gives two-coordinate [(AuX),((PPh,),C,B ,,H or three-coordinate [AuX( (PPh,),C,Bl0H,,)]. Other three-coordinate compounds were prepared by treatment of [Au(tht)L][ClO,] (L = tht PR, or ylide) with the diph~sphine.~, The reaction of [RAu(CH,PPh,CH,),AuR] (R = C,F or 2,4,6-C6F,H,) with [Au(ONO,)(PPh,)] [Au(PPh,),:l+ or [Au(PPh,)(tht)][ClO,] leads to neutral [(C,F,)Au(CH,PPh,CH,),Au(ON02)] (12) or monocationic derivatives [RAU(CH~PP~,CH,),AUL][CIO,](R = C,F, L = PPh, tht; R = 2,4,6-C6F3H2 L = PPh, tht).245 A [Au,{CH(PPh,),)Cl,] has been synthesized and obtained in two crystalline forms.The complex has an unusual all-cis arrangement of the three gold atoms with rather short Au-Au distances.246 Treatment of K[AuCl,] with HC(PPh,) in the presence of S(CHCH,OH) in methanol gave [Au,{HC(PP~,),)C~]~+. The related [Ag,{ HC(PPh2),),l3+ was 240 M.A. Angadi. S. M. Cassidy J. R. Law-ty Z. X. Shen A. D. Caplin N. M Alford. and T. W. Button Suprrcond. Sci. 7kchnol.. 1992. 5(1S) S1'72. 2J1 T. Kai K. Yamasaki and T. Takahashi. Biorrcorery 1992. 2 83. 242 K. Esumi N. Sato K. Torigoe and K. Meguro J. Colloid Incurface Sci.. 1992. 149 295. 14' C.C. Christuk M. A. Ansari and J.A. Iber:; Inory.Chrrn. 1992 31. 4365. 244 0.Crespo. M. C. Gimeno A. Laguna. and P. G. Jones J. Chm. Soc.. Dalton Trans. 1991 1601. 24' A. Laguna M. Laguna J. Jimenez. F. Lahoz. and E. Olmos. J. Ovyunornrt. Chrrn. 1992 435. 235. lJh A. Stutzer. P. Bissinger and H. Schmidbaur Chrm. Brv.. 1992. 125. 367. D. T. Thompson prepared by the reaction of HC(PPh,) with AgSO,CF in dichloromethane. The X-ray structures of the perchlorate salts indicate that both these cations consist of three metal atoms arranged in a nearly equilateral triangle with M-M-M angles ca. 60 ”. The intramolecular bond lengths for Au-Au and Ag-Ag are 2.9920 and 3.1618A respectively indicating that the Au-Au bonding interaction is much stronger than for Ag-Ag. Excitation of a degassed acetonitrile solution of the gold salt at 3WOO nm at room temperature leads to an observed luminescence centred at 537 nm with a lifetime of 11ps.247 [Au ,Ag ,C1 8{ P(p-tolyl),} ,][PF,] is described as having a bi-icosahedral rotor- like metal core and an unusual arrangement of bridging ligands.Since its metal core measures 1 x 1 x 1.Snm3 it can be visualized as a prototype nanomechanical rotary device for electronics applications requiring further degrees of miniaturization over current states of the art in ‘nanote~hnology’.~~~ The AuPPh grouping is well known to form a variety of clusters with different nuclearities e.g. Au, Au, and Au ’,and relativistic ab initio SCF calculations on Au and Au,(PH,) show that the PH ligands activate Au(5d) and Au(6p) participation in cluster Au-Au bonds.249 [Au,Ag,C1,(PMePh,)8][C,B,H,,]~H,0~~CH,Cl,has been synthesized in high yield from [Au l(PMePh,),,] and [AgCl(PMePh,)] in CH,CI, and its centred icosahedral geometry was confirmed by single crystal X-ray diffraction measure-ments.,50 An XPS study of a series of heterometallic gold-platinum phosphine compounds showed that for clusters there is a more complete electron-transfer from cation to anion than in the case of simple salts.2s1 Selective HCN synthesis from CCI,F and ammonia over metal catalysts supported on lanthanum fluoride and activated charcoal has been reported.This is a new reaction and it was found that 1YOAu or 1YOPt on LaF was effective for HCN formation and HCN selectivity reached 77-78% at 823 K:252 CCl,F + NH + HCN + HCl + HF + N (1) For a silicon substrate thin metal layers of gold (or silver) were patterned as a buffer mask which defined the BaY,Cu,O ~x superconducting thin film structures fabricated thereafter.Micron-sized (2-10 micron) superconducting structures with zero resis- tance above 77K were demonstrated. This technique was used to fabricate current- controlled HTS switches and interconnects.”’ 24’ C.M. Che H. K. Yip V. W. W. Yam. P. Y. Cheung. T. F. Lai. S.J. Shieh. and S. M. Peng J. Chem. Soc. Dalton Trans. 1992 427. 248 B. K. Teo and H. Zhang Angew. Chem.. Int. Ed. EnqI.. 1992 31 445. 249 P. Schwerdtfeger and P. D. W. Boyd Inory. Chrm. 1992 31 327. 250 R. C. B. Copley and D. M. P. Mingos J. Chem. Soc. Dalton Trans..1992. 1755. ”’ Yu. M. Shul’ga. A. V. Bulatov. R. A.T. Gould. W. V. Konze and L. H. Pignolet Inory. Chrm.. 1992. 31 4704. 252 Y. Takita. T. Imamura. Y. Mizuhara A. Yumi and T. Ishihara Appl. Cotd. B 1992. 1. 79. 2s3 Q.Y. Ma E. S. Yang. R. B. Laibowitz. and C.A. Chang J. F2rcrrotz. Mar.. 1992 21 487.

ISSN:0260-1818    

DOI:10.1039/IC9928900209

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

16 Sc Y the Lanthanides and the Actinides By S.A. COTTON Felixstowe College Felixstowe Suffolk lP11 7NQ UK 1 Introduction The primary inorganic literature for 1992 has been surveyed as well as Chemical Abstracts for 1992 so that publications arriving too late for the 1991 (Volume 88) survey have also been covered. The most important publication of the year may well be the joint IUPACiIUPAP recommendations concerning the discovery of elements 101-1 12. The group had already laid down criteria for the ‘discovery’ of an element and now proceeded to apply them (Table 1). The syntheses of elements 110-1 12 are not confirmed but obviously those of further isotopes are being actively pursued.’ The report has spawned polemics over the discovery of nobelium.’ Table 1 Most stable Element At.No. Date Discorerers Isotape/haljJ[fe Mendelevium 101 1958 Berkeley 258 S2d Nobelium 102 1966 Dubna 259 58m Lawrencium 103 1971 Berkeley/Du bna 262 216m Unnilquadium 104 1969 Berkeley iDubna 261 65s Unnilpentium 105 1970 Berkeley/Dubna 262 34s Unnilhexium 106 1974 Livermore 263 0.8 s Unnilseptium 107 1981 Darmstadt 262 102ms Unniloctium 108 1984 Darmstadt 265 1.8ms Unnillenium 109 1982 Darmstadt 266 3.4ms A most useful compilation3 of syntheses of ‘inorganic’ compounds of the fblock metals has been published. Two more volumes4 of the series Handbook on the Physics and Chemistry of the Rare Earths have appeared containing 12 reviews of which the articles on rare earth carbides metal-rich halides hydration of lanthanides and ’ Proy.Part. Nucl. Phys.. 1992 29 453. ’ G. N. Flerov 1. Zvara E. D. Donets. G. h.1. Ter-Akopian. and V. L. Mikheev Rudiochrm. Acra. 1992.56. 111; A. Ghiorso and G.T. Seaborg. Radiochim. Acta 1992 56 125. ‘Synthesis of Lanthanide and Actinide Compounds’ ed. G. Meyer and L. R. Morss. Topicsf-elem. Chem.. Vol. 2 Kluwer 1991. ‘Handbook on the Physics and Chemistry of Rare Earths’ ed. K. A. Gschneider Jr. and Le Roy Eyring. North Holland. 1991. (a)Vol. 14 (h) Vol. 15. 243 244 S.A. Cotton macrocycles of the fblock metals from template synthesis are of particular intere~t.~ Rare earth clusters are also examined in another review.6 Volume 6 of Handbook on the Physics and Chemistry of the Actinides has likewise appeared,' containing 15 reviews including such diverse topics as the characterization of actinide compounds by Raman spectroscopy actinide borides the chemistry of U"' the magnetochemistry of Uv actinide Mossbauer studies.hydrolysis of actinide ions transuranium elements in the Purex process and self-radiation effects in actinide chemistry.8 Two special issues of a journal have been devoted to actinides and their fission products in the environment,' whilst the acceleration of the elimination of transuranium elements from mammals has been reviewed. ' A most useful compilation of thermodynamic data for actinide complexes in aqueous solution has been published.' ' A recent monograph covers the biochemistry of the lanthanides," whilst an important review treats the electronic structure and bonding in the uranyl ion and its relatives.' The increasing importance of Chinese lanthanide ores is reflected in reviews;14 rare earth permanent magnets have been surveyed.I The calculation of crystal field parameters for europium(II1) complexes in trigonal symmetry has been reviewed.I6 Reviews in the area of organometallic chemistry include structural analysis of over 90 bis(cyclopentadieny1) complexes,' ' application of lanthanides to organic syn- thesis,' surface-bound hydrocarbyls and catalysis,' and advances in actinide organometallic chemistry." Developments in actinide alkoxide chemistry have been brought up to date.'' Insertion compounds of transition metal and uranium oxides have been reviewed. " 2 Scandium The welcome increase of interest in this neglected element continues.Arc-vapourization of graphite-scandium (or graphite-scandium oxide) mixtures (a)G.-y. Adachi N. Imanaka and Zhang Fuzhongbz in Ref. 4(h) 61; (h)A. Simon Hj. Mattausch G.J. Miller W. Bauhofer. and R. K. Kremer Ref. 4(h) 191; (c) E. N. Rizkalla and G.R. Choppin Ref. 4(h) 393; (d)L. M. Vallarino Ref. 4(h) 443. J.D. Corbett in Ref. 3. 159. ' 'Handbook on the Physics and Chemistry of The Actinides' Volume 6 ed. A. J. Freeman and C. Keller North Holland 1991. (a)W. R. Wilmarth and J. R. Peterson. Ref. 7 I; (h)P. E. Potter Ref. 7.39; (c)J. Drozdzynski Ref. 7,281; (d) C. Miyake Ref. 7 337; (e)A. Tabuteau. Ref. 7 367; (,f) S. Ahrland Ref. 7 471; (y) J. Fuger and Hj. Matzke Ref. 7. 641. ' Radiochim.Acra. 1992. Vols. 58/59. D. M. Taylor in Ref. 7 533. I' J. Fuger I.L. Khodakovsky V.A. Medvedev E.I. Sergeyeva and J.D. Navratil. 'The Chemical Thermodynamics of Actinide Elements and Compounds' International Atomic Energy Authority. 1992. C. H. Evans 'Biochemistry of the Elements Volume 8 Biochemistry of the Lanthanides' Plenum New York. 1990. 13 R. G. Denning Srruct. Bond.. 1992. 79. 215. I4 (u)L. Yujiu. Murer. Chem. Phys. 1992. 31. 85; (h)P. Falconnet Muter. Chem. Phys. 1997 31. 79. l5 A. Higuchi. Muter. Chem. Phys.. 1992. 31. 55. I6 M.C. F. Cunha H. F. Brito. L. B. Zinncr G. Vincentini and A. B. Nascimento. Coord. Chrm. Rev. 1992 119 I. l7 W. J. Evans and S. E. Foster J. Oryanomet. Chem. 1992 433 19. G.A. Molander Chem. Rec.. 1992.92. 29. I' T.J. Marks Aec,. Chetn. Res. 1992 25 57. 'O M. Ephritikhine NPWJ. Chrm.. 1992. 16. 451. D. L. Clark A. P. Sattelberger W. G. Van der Sluys and J.G.Watkin J. AIloys Comp. 1992 180 303. 22 A. M. Chippindale. P.G. Dickens. and A. V. Powell Proyr. Solid Sturc. Chrm 1991 21. 133. Sc Y the Lunthunidrs and the Actinides 245 gives fullerenes Sc,CS2 (n = 1-3) identified by FAB MS and EPR.23 Hydrolysis of Sc,C has been related to its crystal structure.24 The compounds Sc,TC (T = Fe Co Ni Rh Ru Os Ir) are is~structural,~~ with C-C distances intermediate between a single and double bond but they only give alkanes on hydrolysis. Scandium perchlorate has been synthesized2" as a C120 adduct. It is desolvated above 95' to afford the anhydrous salt believed to have a structure similar to that of gallium perchlorate.KScF has a layered structure in which scandium acquires six-coordina- tion by edge-~haring.~~ The alkoxide adduct [{Sc(OCHR,),(NH,),j 2] (R = CF,) has six-coordinate scandium.28 Substiluted benzoate complexes have been prepared and their thermal decomposition studied2" whilst scandium triflates of aromatic amine N-oxides seem to be six-c~ordinate.~~ The first crown ether complex to feature direct coordination to scandium has been ~haracterized~l (Figure 1 ) as [ScCl,( 18-crown- 6)][SbCl,]; the crown ligand is only pentadentate giving pentagonal bipyramidal h Figure 1 View oj' the [ScCl,( 18-crown-6)] cution + (Reproduced with permission from J. Chi. Soc.. Chem. Commun.1992 1619) coordination of scandium. Sc(NCS), however does not coordinate directly to dibenzo-24-cr0wn-6.~~ Ab initio calculations on [Sc(BH,),(PH,),] indicate 2,3,3 coordination of the b~rohydrides~~ whilst among scandium organometallics [ScCp,]' is predicted to be bent.34 In the gas phase [ScMeJ undergoes migratory + insertion with alkene~.,~ The structures are reported of a dimer36 where a permethyl- " (uj C.S. Yannoni. M. Hoinkis. M.S. de Vries D.S. Bethune J. R. Salem M. S. Crowder and R. D. Johnson. Science. 1992.256. I191 :(hj H. Shinohara H. Sato. M. Ohkochi. Y. Ando. T. Kodama. T. Shida T. Kato. and Y. Saito. Nuture. 1992 357. 53. P. Karen and H. J. Fjellvaag J. illl0y.s (~omp..1992. 178 285. 25 R. D. Hoffmann R. Poettgen and W.Jcitschko ./.Solid Srare Chem.. 1992. 99 134. 26 F. Favier and J.-L. Pascal Compr. Rend. Acad. %i.. 1991 313. 619. 27 J.C. Champarnaud-Mesjard and B. Frit. Eur. J. Solid Stute Inorg. Chem.. 1992 29. 161. 2x D. C. Bradley H. Chudzynska. M. E. Hammond. M. B. Hursthouse. M. Motevalli. and W. Ruowen. Polyhedron. 1992. 11 373. "I W. Bryska and R. Kurpiel-Gorgol J. T/ierrn.And.. 1991. 37. 258. ''' G. Vincentini J. D. Ayala. and J. R. Matos. Therloc~hirn.Actu. 1991. 191 317. '' G.R. Willey M.T. Lakin. and N. W. Alcock. J. Chem. Soc,.. Chem. Commun.. 1992 1619. '' L. Tong-Bu G. Xin-Min T. Ning. and T. Min-Yu J. Chin. Rure Eurth Soc.. 1992. 1068. A. Lledos. M. Duran Y. Jean and F.G. Volatron. Bu//.So(. Chim. Fr. 1992 129 216. M. Kaupp. 0.P. Charkin and P. v. R.Schleyer. Orgunometul/it~.~. 1992. 11 2765. 2' 246 S. A. Cotton cyclopentadienyl methyl group has been deprotonated to act as a bridge (l) of a carbollide c~mplex,~' and of the complex of a silicon-bridged dicyclopentadienyl ligand. 3 Yttrium and the Lanthanides Brief details have appeared of a process for separating rare earths from other elements using supercritical CO at 40°C and l00atm; the lanthanides are converted to their carbonates whilst quadrivalent metals (Zr Th Ce) remain as the oxides.39 Binary Compounds.-As with scandium interest has been high in lanthanide fullerenes. Several groups have reported the syntheses4' of these compounds particularly Ln@C8, though other sized cages have been found. Spectroscopic data have been interpreted in terms of the metal being inside4* or outside4 the cage.Halides continue to be of great interest. Reduction of CeBr with Ce or Li gives lustrous black Ce,Br, isostructural with the La and Pr analogues with seven- and eight-coordinate cerium.43 It is likely that cerium(rI1) is present with free electrons resulting in conductivity. Enthalpies of formation of DyI and DyI have been measured44 and the Dy3 +/Dy2 + standard potential in aqueous solution estimated at 2.6 V; high-pressure phase diagrams have been for DyT,. Reduction of the tribromides and triiodides of Tm and Yb give either the dihalide or MLnX, depending upon the alkali metal M used for the red~ction.~~ 35 Y. Huang Y. D. Hill M. S0dupe.C. W. Bauschlicher,and B. S. Freiser,J.Am. Chem. Soc. 1992.114.9106. 36 S. HajeIa W. P. Schaefer and J. E. Bercaw. Actu Crystallogr. Sect. C.. 1992 48 1771. 37 R. E. Marsh W. P. Schaefer G.C. Bazan and J. E. Bercaw Acta Crystallogr. Sect. C. 1992. 48. 1416. 38 W. P. Schaefer R.D. Kohn and J. E. Bercaw Acta Crystullogr. Sect. C.. 1992 48 251. 39 Chem.Eng. News..Nov. 30,1992,24; N. Yanagihara. K. Vemulapalli Q. Fernando and J. T. Dyke J. Less Common Met. 1991 167 223; see also P. Unfried and K. Rossmanith Monutsh. Chem. 1992 123. 1. 40 M. M. Ross H. H. Nelson. J. H. Callahan and S. W. McElvany J. Phys. Chem. 1992 96 5231; E.G. Gillan C. Yeretzian K. S. Min M. M. Alvarez. R. L. Whetten and R. B. Kana,./. Phys. Chem.. 1992,96 6869; S. Suzuki S. Kawata H. Shiromaru K. Yamauchi. K. Kikuchi T.Kato and Y. Achiba J. Phys. Chem. 1992 96 7159. 41 J.H. Weaver Y. Chai G. H. Kroll C. Jin T. R. Ohno R. E. Haufler. T. Guo J. M. Alford and J. Conceicao Chrm. Php. Lrrt. 1992 190 460. 42 L. Soderholm P. Wurz K. R. Lykke. I). H. Parker. and F. W. Lytle J. Phys. Chem. 1992 96 7153. 43 K. Kramer and G. Meyer. Eur. J. Solid Stute Inorg. Chem. 1991 28. 523. 44 L. R. Morss and T.G. Spence. Z. Anory. A//yem. Chem. 1992. 616 162. 45 H. P. Beck and M. Schuster. J. Solid Stutr Chrm.. 1992 100 301. 46 G. Schilling C. Kunert T. Schleid and G. Meyer Z. Anorg. Allgem. Chum. 1992 618 7. Sc Y the Lanthanides and the Actinides 247 Previous claims for some lower halides have been revised. YCI and YBr are now known47 to be hydride-halides YXH (n = 0.7-1 .O); CeX,H (X = Br I) and Gd12H have similarly been prepared as has hydrogen-free Gd12.48 Rare-earth halide clusters have been the subject of both synthesis and theory.Monomeric Er,C and Lu,C and dimeric clusters in ~s[Erlo(~2)2]~18 have been i~olated.~~.~~ The bonding in R7Xi2Z(R = Sc Y Pr; X = C1; Z = Co Fe N)" and Y,Cl chains52 has been investigated. Several reports have appeared on halide complexes including the synthesis of anhydrous ammonium halo metal late^.^^ A wide range of similar hexachlorometallates has been synthesi~ed~~ from the anhydrous metal chloride and the alkali metal chloride at 850" and the structure of Rb,[YCl,] has been determined. Li,[YCl,] is an ionic conductor55 and [NH,Me],[YbCI,] has six-coordinate ytterbium.' Quaternary fluorides A,MLnF (A = Na Ag; M = Ca Cd; Ln = Er-Lu) have distorted fluorite structure^.^' Crystalline LnA1,Br ,have been prepared; the neodymium compound affords the tribromide on heating.58 Pentagonal bipyramidal coordination of yttrium is found in two tetrafluorometallate~~~*~~ whilst the structure of LiKYF has also been determined.61 Divalent iodo complexes have attracted attention4,., and LiSmAlF, with unexpected trigonal prismatic coordination,63 is the first fluoroaluminate with divalent samarium.Preparations and structures have been reported for a number of the later lanthanide sesqui~ulfides;~~ successful synthesis from the elements is possible using a flux of NaCl. Forms of the terbium and dysprosium compounds with the uranium sulfide structure have been characterized as have a type of Yb,S, with the bixbyite structure and F-Tm,S, which contains six- seven- and eight-coordinate thulium.Salts and Complexes.-Anhydrous perchlorates believed to have a uranium(I1r) chloride-like structure have been prepared65 for yttrium and several lanthanides by the reaction of the chloride nitrate or hydrated perchlorate with Cl,O,. Solvation numbers continue to be of interest;5c neutron-scattering measurements on 47 Hj. Mattausch R. Eger. J. D. Corbett and A. Simon Z. Anorg. Allgem. Cliem.. 1992 616. 157. A8 C. Michaelis Hj. Mattausch. and A. Simon Z. Anorg. Allyem. C'hem.. 1992. 610 23; C. Michaelis W. Bauhofer H. Buchkremer-Hermanns A. Simon and G.J. Miller. Z. Anorg. Allyem.Chem. 1992,618.96. 49 H. M. Artelt T. Schleid and G.Meyer Z Anorg. Allgem. Chern. 1992,618. 18; H. M. Artelt and G. Meyer J. Chem. Soc. Chem. Commun.. 1992. 1320. 50 M. W. Payne. P. K. Dorhout S. J. Kim T. R. Hughbanks,and J. D. Corbett. Inorg. Chem. 1992.31 1389; P. K. Dorhout and J. D. Corbett. J. Am. Chem. Soc. 1992. 114 1697. 51 S. Gao G.-X. Xu and L.-M. Li Inorg. Chem. 1992 31 4829. 52 K.A. Yee and T. Hughbanks Inorg. Chem. 1992 31 1620. s3 H. Oppermann and D. Q. Huong Z. Anorg. Allgem. Chem. 1992.616 169. 54 H. Mattfeld and G. Meyer. Z. Anorg. Allgem. Chem.. 1992. 618 13. 55 H.-J. Steiner and H. D. Lutz. Z. Anorg. AIlgem. Chem.. 1992 613 26. 56 M. Czjzek. H. Fuess and I. Pabst. Z. .4norg. Allgem. Chem.. 1992 617 105. '' J. Koch and C.Hebecker Z. Anorg. Allgem. Chem. 1992. 607 121. 5H D. Hake and W. Urland. Z. Anorg. Allyern. Chem. 1992 613 45. 59 Y. Le Fur N. M. Khaidukov. and S. Aleonard. Actu Ctyrullogr. Secr. C. 1992 48. 978. 6" P. P. Fedorov 0.S. Bondarova. I. I. Buchinskaya L. L. Vistin and B. P. Sobolev. Zn.Neory. Khim.. 1992 37. 273 A.V. Goyunov and A. I. Popov. Zh. Neorg. Khim.. 1992. 37 276. 6' A. V. Goryunov A. I. Popov N. M. Khaidukov. and P. P. Fedorov Marer. Res. Bull. 1992. 27 213. '* B. Cao S. Wang and X. Zhao. J. Alloys Compd. 1992 181. 511. 63 J. Koehler and B.G. Mueller Z. Anorg. Allgem. Chem. 1991. 606 169. 64 T. Schleid and F. Lissner. J. Alloys Conrp.. 1992 189 69 Z. Anorg. Allgem. Churn.. 1992. 615. 19. 65 F. Favier and J.-L. Pascal J. Chem. Soc. Dulton Truns.1992 1997. 248 S.A. Cotton the aqua ions indicate6‘ a decrease in coordination number across the series as is now generally accepted. Results from studies of dmso complexes of lanthanide perchlorates are in agreement6’ although infrared measurements lead to a different conclusion.68 The synthesis of 6-valerolactam complexes of lanthanide perchlorates indicates the formation of [LnL,] ions for the early lanthanides (Nd square antiprismatic) but + seven-coordinate ions for the later metals (Er-Lu Y).69 Studies of the hydrated toluene 4-sulfonates again7’show two series trigonal prismatic non-aqua ions for La to Nd but square prismatic cations [Ln(H,O),(OTs),] + for Sm onwards. In addition to the established hexaaqua perchlorate complexes hydroxy complexes can also be obtained; [Eu(H,O),(OH)CIO,][ClO,] has a layer structure with eight-coordinate euro-pi~m.~’ The structure of ytterbium nitrate trihydrate again involves tricapped trigonal prismatic nine-c~ordination;~~ twelve-coordination is present in the anionic nitrate’ complexes Cs,[La(NO,),]NO,~HNO and M,[Ln,(NO,),] (M = Li NH,; Ln = La-Pr).A neutron diffraction study on lutetium hydroxide has appeared,’ the only lanthanide hydroxide to feature six-coordination; a cerium hydroxide complex cluster’ catalyses the hydrolysis of 3’,5’-cyclic adenosine monophosphate. Among complexes with simple 0-donors the [GdCl,(thf),] -ion is cis76 whilst [SmBr,(Pr’OH),] has a pentagonal bipyramidal structure7’ which now seems to be common for lanthanide complexes with this stoichiometry./j-ketophosphoryl ligands are potentially bidentate; studies of their lanthanide complexes in the solid state and solution included the structure of nine-coordinate [Er(NO,),{ Ph,P(O)CH,- C(O)Ph},(OH,)] where both the organic ligands are monodentate (Figure 2).78 Piperazine has been reported to form 8 1 complexes with lanthanide perchlorates;79 [M(phen),(NO,),] (M = La Gd) have the expected ten-coordinate structure8’ whilst NMR data indicate that the lanthanum complex has a similar structure in solution. New tris complexes [M(bipy),(NO,),] (M = Ce Pr Nd Yb) have been reported.81 Adducts [Ln(a~ac),(OPPh,),]~~ have been reported for most and [Ln(a~ac),py,]*~ 66 L. Helm and A.E. Merbach. Eur. J. Solid Srurr Iriory.Chiwi. 1991 28. 245. ‘-A. M. Tang and J.-C.G. Bunzli Inory. Chirii. Acra. 1992 192. 201. ” P.-A. Bergstrom and J. Lindgren. Inory. Chem. 1992. 31 1529. ‘’)L. R. F. Carvalho. L. B. Zinner. G.Vincentini G.Bombieri. and F. Benetollo Inorq. Chirn. Ac,tu 1992,191 49. ’() D. L. Faithfull J. M. Harrowfield. M. I. Ogden. B. W. Skelton K. Third. and A. H. White. Ausr. J. Ckem. 1992. 45. 583. ” E. Huskowska J. Legendziewicr T. Schleid and G. Meyer Muter. Chem. Phy.5.. 1992 31. 117. ‘2 H. Jacobsen and G. Meyer Z. ilriory. Allyem. Chem.. 1992 615. 16. 73 E. Manek and G. Meyer. Z.Anory. Allgun. Chem.. 1992,610.22 1992.616 141 A. G. Vigdorchik. Yu. A. Malinovskii. A. G. Dryuchko. and I. A. Verin Krisrullogrqfiyu. 1991 36. 1395. ’4 D. F. Mullica. Lunthunitle Actinide Rrs..1991. 3 325. ” J. Sumaoka. M. Yashiro. and M. Korniyarna. J. Chrm. Sot.. Chem. Cornmuti. 1992 1707. 76 K. Wen Z. S. Jin and W. Q. Chen Chin. Chrm. Letr. 1992. 2 697. 77 L. E. Depero M.T. Arienti M. Zocchi and M. C. Gallazzi. Srrucr. Chrm. 1991 2. 595. ’’ R. Babecki A. W. G. Platt and J. Fawcett .I. Chern. Soc.. Dulron 7ruti.s.. 1992. 675 A. Lothian and A. W.G. Platt. Polyhedron 1992 11. 2983. 7q A. K. Trikha Polyhedron 1992. 11. 2273. 80 M. Frechette I. R. Butler R. Hynes. and C. Detellier. Inory. Chem.. 1992.31. 1650; V. B. Rybakov. V. N. Rybakov. A. L. Karnyshnyi L..A. Aslanov. and A. P. Suisalu. Koord. Khini.. 1991 17. 1061. ‘I N. Dong. L.G. Zhu and J. R. Wang. Chin. Chem. Lert.. 1992 3. 745. nz A.K. Trikha and K. Dilbagi. J.Rurr Eurrhs. 1992. 10. 175. n3 S.Q. Su and S. Y. Yang Chin. Chem. Ixtr.. 1992 2. 957. Sc Y the Lanthanides and the Adnides lanthanides; the pyridine complexes are evidently not coordinatively saturated as they act as NMR shift reagents with cholesterol. Figure 2 The structure of [Er(NO,),(pdpp0)~(0H~)](phenjl groups omitted for clarify). (Reproduced with permission from J. Chem. Soc. Dalton Trans. 1992 675) The polydentate ligands quaterpyridine and sexipyridine (spy) both form I 1 complexes with yttriums4 and europiums5 nitrates respectively; the latter has ten-coordinate [Eu(spy)(NO,),] cations where the sexipyridine ligand wraps itself + helically round the metal (Figure 3). Figure 3 (Reproduced with permission from J. Chem. Soc.Chem. Cornmun. 1992 771) M4 E.C. Constable S.M. Elder and D.A. Tocher Polyhedron. 1992 11 2599. '' E.C. Constable R. Chotalia and D.A. Tocher. J. Chem. SOL..,Chem. Cornrnun.. 1992 771. 250 S.A. Cotton Among complexes of simple carboxylic acids potassium europium(1r) acetate is the first ternary europium acetate with eight- and nine-coordinate europium;86 nine- coordinate samarium(Ir1) is similarly founds7 in [Sm(OAc),(H,O),],~AcOH and the triaquatris(3-aminobenzoate)complexes of the lanthanides where the carboxylate groups are all bidentate and the amine groups do not coordinate.B8 Several papers have reported the structures of lanthanide complexes of amino acidsB9 and of dipeptides." Complexes of Polyamine Polycarboxylic Acids.-Lanthanide complexes of these ligands have continued to attract attention for their potential (or actual) use as Magnetic Resonance Imaging agents.' ' Formation constants of 308 lanthanide complexes with (po1y)aminocarboxylic acids have been ~orrelated.'~ The relaxation rates of MRI chelates are affected by the number of water molecules bound to the metal and studies have therefore reported the pH dependence of the metal ion hydration state9 and the determination of the hydration numbers for Dy carboxylates from the Dy-induced 7ONMR water shift^.'^ Potential contrast agents have been patented95 and there is increasing interest in non-ionic contrast agents that use ligands such as dtpa bis(amides) (dtpa = diethylenetriaminepentaacetic acid).The crystal structure has been reported96 of the nine-coordinate dysprosium complex of a dtpa bis(amide) (2).The synthesis and stability constants have been reported for the gadolinium complexes of macrocyclic edta and dtpa bi~(amides).~~ Factors determining the proton T relaxivity of Gd-dtpa have been ree~aluated.'~ Complexes of the lanthanides with o-phenylenediaminetetraacetatehave been ~tudied.~' Linear complexing agents have also been investigated,"' a gadolinium complex having similar relaxivity to Gd-dtpa; the crystal structure of the lutetium complex of such a ligand has been determined (3). Complexes of dota (1,4,7,t0-tetraazacyclododecane-l,4,7,10-tetracarboxylic acid) are anticipated to be more kinetically inert than those of dtpa and dissociation of Gd-dota has been found to be very slow even in acid solution.'" Development of dota-like complexes continue^;'^^-^^^ the structure (4) of the neutral gadolinium complex of a monoamide shows coordination of the carboxamide oxygen as well as the " A.Lossin and G. Meyer 2.Anorg. Allgem. Chem. 1992 614 12. R7 A. Lossin G. Meyer R. Fuchs and J. Straehle Z. Naturjimch. Tell B. 1992 47 179. A. E. Koziol B. Klimek K. Stepniak Z. Rzaczynska W. Brzyska 0.I. Bodak. L.G. Akselrud V.V. Pavlyuk and V.A. Tafeenko Z. Krist. 1992 200 25. J. Liu N. Hu C. Niu and Q. Meng J. Alloys Compd. 1992 184. L1; P. Wei. T. Jin Q. Yang and G. Xu Chin. Chem. Lett.. 1991 2. 699. 90 I. Csoeregh E. Huskowska. and J. Legendziewicz Actu Crpstallogr. Sect. C. 1992.48,1030; T. Glowiak E.Huskowska and J. Legendziewicz. Polyhedron 1992 11 2897. 91 C.A. Chang Eur. J. Solid State Inorg. Cheni. 1991 28 237. " 0.Carugo and C. Bisi Castellani. Inorg. Chim. Acfu. 1992. 191 115. 93 H.G. Brittain G. R. Choppin and P. P. Barthelemy J. Coord. Cheni. 1992 26 143. 94 M. C. Alpoirn A.M. Urbano. C. F.G.C. Geraldes and J. A. Peters J. Chem. Soc. Dalton Trans. 1992. 463. 9s r.g. Chem. Abstr. 1992 116 (a)40918; (h)210423. L. Ehnebohm and B. Fjaertoft Pedersen. Acta Chern. Scand.. 1992. 46 126. 97 J.F. Carvalho S.-H. Kim and C. A. Chang Inorg. Chem.. 1992. 31 4065. " G.E. Jackson and L. L. Du Toit Polyhedron. 1992 11. 1315. " M. Yarnamoto N. Nakasuka and M. Tanaka Bull. Chem. Soc. Jpn. 1992 65 1566. loo (a)Chem. Ahstr. 1992 117 146 345; (h)P. P.K. Claire C. J. Jones K. W. Chiu. J. R. Thornback and M. McPartlin Polyhedron. 1992 11. 499. 101 X. Wang T. Jin V. Comblin. A. Lopez-Mut. E. Merciny and J. F. Desreuz Inorg. Chem. 1992 11 1095. lo' Chem. Ahstr. 1992 117 43666 151 153. ln3 S.Airne P. L. Anelli. M. Botta. F. Fedelli. M. Grandi. P. Paoli. and F. Uggeri. Inory. Chem.. 1992,31,2422. In4 S. Aime. M. Botta. G. Ermond F. Fedeli and F. Uggeri Inorg. Chem. 1992 31 1100. Sc Y the Lanthanides and the Actinides 25 1 three carboxylate oxygens to gadolinium.' O3 The structures have also been reported of the erbium'05 and gadolinium'06 complexes of dota itself where the lanthanide is bound by four nitrogens four carboxylate oxygens and one water molecule (5). 0 . L (4) R' = -CH(CH,OH), R2= PhCI-I,OCH2-(5) 23Na MAS NMR spectra have been reported for lanthanide EDTA complexes;'" the shift anisotropy of the paramagnetic neodymium complex manifest in spinning sidebands in the spectra is accounted for by a dipolar model.Alkoxides Aryloxides Amides and Related Systems.-Interest in alkoxides has been sustained. On oxidation with benzoyl peroxide [Ce(OCBu'),] forms [Ce(OCBu\),(OCOPh)].[Ce(OCBu\), reacts with di-t-butyl peroxide forming un- stable [Ce(OCBu\),(OBu'),] or [(Ce(OBu\),(OBu')},] depending on conditions."' [Ce(OPr'),] reacts with a functional aminoalcohol to give products that includelo" [Ce,(OPr') (,u-OC,H,NM~C,H,NM~,)~]. K[Nd(OAr),] (Ar = 2,6-Pr$,H3) has a solid-state structure in which one-dimen- 105 T. Jin X. Wang G.Xu. Z. Ma and H. Ling Gaodrng Xurxicio Huusur Xuehuo lY91 12 999; Chrm. Ahstr.. 1992 116 119672. I"' J.-P.Dubost J.-M. Leger M.-H. Langlois D. Meyer and M. Schaefer. Compr. Rend. Awl. Si. Sur. 11. 1991. 312 349. "' A. R. Brough C. P. Gray and C. M. Dobson J. Chern. So(,.,Chrni. Commun. 1992 741. 108 A. Sen H.A. Stecher and A. L. Rheingold Inorg. Chrni. 1992. 31. 472. 'OY L.G. Hubert-Pfalzgraf N. El Khokh and J.C. Daran Polyhrdron. 1992. 11 59. 252 S.A. Cotton sional chains of arylate anions are joined with K-arene interactions' lo (Figure 4). Another four-coordinate arylate is [Yb(OAr),(thf)] (Ar = 2,4,6-Bu\C6H,) which has been characterized crystallographically as has a dimeric hydrolysis product (Figure ~ 5)."' Alcoholysis of [SmMe,13 with t-butanol affords sublimeable [L~,S~(OBU')~] which contains a SmLiO cluster.l1 Figure 4 (Reproduced with permission from lnorcq. Chem. 1992 31 1555) Figure 5 (Reproduced with permission from Aust. J. Chem. 1992 45 671) The synthesis of alkoxides and aryloxides by the metal vapour method has been reported,' including [Sm(OAr'),l (Ar' = 2,6-Bu\C6H,). "" D. I,. Clark J.G. Watkin. and J.C. Huffmann Inory. Chem. 1992 31 1555. 'I1 G. B. Deacon. T. Feng S. Nickel. M. I. Ogden and A. H. White. Am. J. Chem. 1992 45. 671. 'I2 H. Schumann. G. Kociok-Kohn A. Dietrich. and F. H. Gorlitz. Z. Nafurforsch.. TrilA 1991. 46 896. 'I3 J. M. Carretas and A. Pires de Matos. Muter. Chrrn. Phys. 1992. 31 123. 253 Sc. Y the Lanthanides arid the Actiriitles In recent years the existence of 0x0-centred alkoxide clusters has come to be recognized.Two papers ' 4. ' ' 'report NMR studies of [Y,O(OPr'),,]. where the "Y NMR spectrum shows separate signals for the two different sites (Figure 6) whilst ''Y and 29Si data have been reported' ' for a range of yttrium compounds including alkoxides and silyloxides. ,.>'L 220 0 215.0 210 0 Figure 6 8')Y NMR spectrum of [Y,OIO'Pr),,] in C,D lit 25 C. (Reproduced with permission from inorg. Chem.. 1992. 31. 1262) [Nd,O(OPr') ,(Pr'OH)J is another isopropoxide cluster' " (Figure 7) syn-thesized from the reaction of neodymium chips with isopropanol. Other neodymium alkoxides have been synthesized with a 'clinching alcohol' ligand.' ' Mixed praesodymium-aluminium alkoxides both with and without chloride bridges have been characterized.' '* Much of the research into lanthanide alkoxides has been stimulated by efforts to discover alternative synthetic routes to the mixed oxide superconductors.Relevant to this is the synthesis of the heterometallic [(Ph,SiO),Y(~c-SiOPh,)2Cu(PMe,Ph)] (6).' l9 Lanthanide alkoxides have been shown to act as catalysts for reactions such as C-C bond formation.'20 The first mononuclear lanthanide thiolates {Sm(SAr),] (Ar = 2,4,6-Bu'C6H,) and [Yb(SAr)2(dme)2] (Ar = 2,6-Bu\-4-Me-C6H,) (7) have been synthesized'" whilst mesitylselenolate and tellurolate complexes [Yb(QMes),( thf),] (Q = Se Te; x = 2-3) and [Sm{Te(mes)),(thf),] have been reported.'22 'I4 C.J. Page S.K.Sur. M.C. Lonergan. and G. K. Parashar. MU!]. Rrson. Chem.. 1991. 29. 1191. 'I5 P.S. Coan LG. Hubert-Pfalzgraf. and K.G. Caulton. Inory. Chrm.. 1992. 31. 1262. 'Ih G. Helgesson. S. Jagner. 0.Poncelet. and I-. G. Hubert-Pfalzgraf. Po!jhrtlrori. 1991. 10 1559. 'I' W.A. Herrmann R. Anwarder. and M. Denk. Cheni. Rrr.. 1992. 125. 2399. 'Ix LJ. M. Tripathi A. Singh R. C. Mehrotra. S. C. Goel M. Y. Chiang. and W. E. Buhr0.J. Chem. Sor,..Chn. Commun. 1992 152. 'I4P.S. Coan. J.C. Huffmann. and K.G. Ciulton. Inorq. Clirni.. 1991. 31. 4107. I"' H. Sasai T. Suzuki. S. Arai. T. Arai. and M. Shibasaki. J. 4m Chcwi. Soc.. 1991. 114. 441 8. 12' B. Cetmkaya. P. B. Hitchcock. M. F. Lappert. and R.G. Smith. J. C'hrm. Soc.. Chcm. Conitnun..1992. 932. A. R. Strxlski P.A. Timinski.€3. A. Hensel. and P. A. Hianconi. J. Am. Clirm. So(... 1997 114. 159. 254 s.A. Cotton Figure 7 Molecular structure of [Nd5(p5-O)(p,-OR)2(p2-OR),o,I (R = Pr') (Reproduced with permission from Polyhedron 1992 10 1559) (6) R = Ph,Si (7) SR = SC,H2But2-2 4,6 The diphenylphosphide derivative of an amide [La(N(SiMe,),},(PPh,)(OPPh,),] has been synthesized and characterized ;'23 six-coordinate tris(benzaminidinates) of several lanthanides have been prepared the ligands producing a crystal field comparable to cyclopentadienyl. 24 Porphyrins and Phtha1ocyanines.-Porphyrin complexes of the earlier lanthanides tend to be less stable than those of the heavier metals. The preparations and properties of several lanthanum(n1) porphyrin complexes such as [LaH(por),] (por = tpp oep etc.) the triple-deckers [La,(por),] (8) and the n-radicals [La(por),] have been reported,'25*'26 as have those of similar cerium compounds.' 26.127 Several crystal 123 H.C. Aspinall S.R. Moore and A. K. Smith J. Chon. Soc.. Dalton 7rans. 1992. 153. I24 M. Wedler F. Knosel U. Pieper D. Stalke F.T. Edelmann and H.-D. Amberger. Chem. Btv-.. 1992. 125. 2171. 125 J.W. Buchler M. Kihn-Botulinski J. Loffler and B. Scharbert New. J. Chem. 1992 16. 545. 126 M.S. Haghighi and H. Homborg Z. Naturfbrsch Teil B 1991 46. 1641. 127 D. Chabach M. Lachkar A. De Cian. J. Fischer and R. Weiss New. J. Chem.. 1992. 16. 431. Sc Y the Lanthanides and the Actinides I I I1 N N isasectionof N& ,La< ::La< / aporphyrin N/ 'N/ 'N N group I I II structures have been determined as well as those of mixed porphyrin-phthalocyanine cerium(II1) complexes.' 27 Bis(phthalocyaninato)cerium(Iv) has been synthesized and its structure determined,'** whilst synthetic and electrochemical studies have been made on [Ce(oep),] and cerium(]\) pyridylporphyrin~.'~~~~~~ At the other end of the lanthanide series synthetic magnetic and electrochemical properties of the n-radical (octabutoxy)phthalocyaninesof the trivalent metals including ytterbium and lutetium have been investigated.l3l* 132 Among other N-donor macrocycles a dysprosium complex of a texaphyrin ligand (9)with an attached crownC5lether ring binds sodium by the crown ligand;'33 cerium forms a double-decker complex with a tetraazaannulene ligand' 34 whilst samarium undergoes a complicated redox reaction in forming a dimeric complex in which samarium is q6-bound to a benzene ring (lo).'35 A ten-coordinate gadolinium complex of a hexaazamacrocycle has been characterized,' 36a and a nine-coordinate complex has been as a MRJ agent (11).M.S. Haghighi. C.L. Teske and H. Hornberg Z. Anorg. AIlgem. Chem. 1992. 608 73. 12' S. Radzki. J. Mack and M. J. Stillman 'Vew. J. Chem. 1992 16 583. 13(' J. Jiang K. Machida and G. Adachi Bull. Chem. Soc. Jpn. 1992 65 1990. 131 K. Takahashi Y. Tomita Y. Hada K. Tsubota M. Hands K. Kasuga K. Sogabe and T. Tokii. Chrm. Lett. 1992 759. 13' K. L. Trojan J.L. Kendall K. D. Kepler and W. E. Hatfield Inorg. Chim. Acta 1992 198200 795.133 J. L. Sessler T. D. Moody R. Ramasam) and A.D. Sherry New. J. Chem. 1992 16 541. J. Magull and A. Simon Z. Anorg. Ailgem. Chem. 1992 615 77. 135 J. Magull and A. Simon Z. Anorg. Allgem. Chem. 1992 615 81. (a)P. H. Smith and R.R. Ryan Acta Crystallogr.,Secr.C. 1992,48,2127; (b)S.W. A. Bligh. N. Choi E. G. Evagorou M. McPartlin W.J. Cummins and J. D. Kelly Polyhedron 1992 11 2571. 256 S. A. Cotton Complexes of Crown Ethers and Related Ligands.- Electrocrystallization has been used'" to prepare [Pr( 15-crown-S)C1,] having no water molecules in the coordina- tion sphere. The I 1 complexes of lanthanum nitrate with three different crown-5 ligands are all eleven-coordinate. '38 Complexes of divalent lanthanides with 18-crown-6l 39 and with a N-pivot azacrown ether have been ~ynthesized.'~' Among glycol complexes [La(N03 )3(triethylene glycol)(OH )] is eleven-c~ordinate,'~' nine-coordinate cations are found in [CeCl(tetraglyrne)(H,O),ICI,~H,O,'"" and nine- coordination is again found in the dimeric c~mplex'~" of praesodymium chloride with tetraethylene glycol (12).Yttrium/Barium/Copper Oxide Systems.-Though magnetic properties are dealt with elsewhere in this report synthetic interest in these systems continues. The supercon- ducting material is commonly prepared by the sol-gel process; the tmhd (2,2,6,6-tetramethyl-3,5-heptadione) complexes appear to be the most popular source ma- terial~,'~~"~~ but acetates'46 and alkoxides are also used. 147 A new precursor system using I ,3-bis(dimethylarnino)propan-2-01, gives a gel that can readily be formed into films or drawn into fibres prior to ~alcination.'~~ Organometallic Compounds.-The organometallic chemistry of these metals for the years 1987-9 and 1990 has been covered in two most useful reviews.'49 Important thermochemical data are presented on lanthanide- arene bond disruption energies,' '' 137 L.Nunez and R. D. Rogers J. C.rjxdloqr,. Spec~trosc.Re,$.,1992 22. 265. (a)R. Wang.Z.Jin,andJ.Ni,Jic,~~oi4Hunruc,. 115 103 183):(h)R.Wang.Z.Jin. 1991.1U,30(C17~~r)t.Ahslr.. J. Ni. and Y. Liu Jirqou Hutisite. 199 1. 10. I62 (Clirnr.Ahstr.. 115. 946 593). 139 N. Higashiyama K. Takemura K. Keiichi. and G. Adachi. Imwq. Chini. Acru. 1092. 194 201. IJoS.A. Kulyukhin. N. B.Mikheev I. E. Veleshko. and L. N. Auerman. Kadiok/iirniJ,n. 1992. 34. 167. IJ1L. Y. Erman I,. F. Mindrul. E. L. Gal'perin V. K. Kurochkin. and V. A. Petrunin. koord. Khirn.. 1991. 17. 1286. 14' R. D. Rogers and R. F. Henry J. Crj,srli/loqr.Spe.c,rro.\r.. Rrs. 1992. 22 361. R.D. Rogers and R.F. Henry. .4ctti Crystctlloyr. Sect. C. 1992. 48 1099. K. V. Salazar. K. C. Ott. R. C. Dye. K. M. Hubbard. E. J Peterson. J. Y. Coulter and T. T. Kodas. Plzysic.~ C. 1992 198. 303. S. H. Kim. C. H. Cho D. W. Kim. K.S. No and J.S. Chun. 71iiri Solid Films. 1992. 214 329. IJ(' S. Fujihara. H. Zhuang T. Yoko. H. Kwuka. and S. Sakka J. Murrr. Rc>.s.. 1993 7 2355. 14' US. Patent 5087609; Chcwt. Ahtr.. 117 18 725. 14' S. Wang K. D. L. Smith.Z. Pang and M. J. Wagner. J. C'hrni. So<,..C'hc~r~i. Comniuri. 1999 1594. IJ9 R. D. Rogers and L. M. Rogers. J. Orq~iriorm~t. Chmi. 1997 449.(11) 83,(h)225. W. A. King. T. J. Marks. D. M. Anderson. I). J. Duncalf and F. G.N. Cloke. J. .Avi.C/ioni.S(JC... 1992. 114. 922 I. Sc Y the Lanthanides and the Actinides 257 which in some cases are greater than for d-block reference compounds such as dibenzene chromium; further evidence is presented to support 5d involvement in lanthanide-ring bonding. Organometallics of the fiblock metals are typically very reactive and susceptible to traces of moisture; two papers'".' s2 in particular have reported the characterization and structures of hydrolysis products (I 3)-( 15). Among catalytic studies mention should be made of a chiral lanthanide catalyst for stereoselective alkene hydrogenation,' s3.' 54 whilst the unsymmetrical molecule [Ph,Yb(thf)(p-Ph),Yb(thf)J (16) has been synthesized;' 55 the synthesis of triphenylytterbium is also mentioned.Me I Me (14) BU' 13u' In the area of the divalent metals uh initio calculations' 5h for [MCp,] indicate low bending potentials which can be reconciled with the bent gas-phase structures observed 151 H. Schumann. F. H. Gotlitz F. E. Hahri J. Pickardt C. Qian and Z. Xie. Z. Anorcj. A//yern.C-kern.. 1992 609. 131. 152 W. A. Herrmann. R. Anwander. M. Kleine. K. Ofele. J. Riede and W. Scherer. Cheni. BcT.?1992. 125.2391. IS3 M. R. Gagne L. Brard V. P. ConticellQ. M. A. Giardello C.L. Stern and T. J. Marks Orqrrnomerullic~.~. 1992 11 2003. 154 V. P. Conticello L. Brard M. A. Giardcllo Y. Tsuji M. Sabat. C. L. Stern. and T. J. Marks. J. 4m. (~h0~71. So(,. 1992 114. 2761. 1 s5 M.N. Bochkarev. V. V. Khramenkov. Y. F. Rad'kov L. N. Zakharov. and Yu.T. Struchkov. J. Orqanomet. Chm. 1992. 429. 27. 156 M. Kaupp P. v. R. Schleyer M. Dolg and H. Stoll. J. Am. Chern. Soc.. 1992. 114. 8202. 258 S. A. Cotton for [MCp:]. The first $-arene complex of a divalent lanthanide'57 (Figure 8) is tetrameric [(Eu(~-C,Me,)(AlC14),),1. d Figure 8 (Reproduced with permission from J. Chem. Soc. Chem. Commun. 1992 480) The structure of [Yb(thf),Cp,] has been reported along with a new synthesis,' 58 whilst a two-dimensional multidecker involving ytterbium and vanadium has been made.' 59 Other unusual compounds have included decaborates' 6o and organotin species such as [Yb(SnPh,),(thf),] and [Yb(SnPh,),] -Another heterobimetallic whose structure has been deterrninedl6 is (17) a compound in which the cyclopen- tadienyl groups support other donor groups a theme echoed elsewhere in lanthanide chemistry.Much of the work on tris(cyc1opentadienyIs) has concerned adduct~,'~ with structures reported for [M(NCMe)Cp,] (M = Tb,163 Smlh4) [Pr(butylacetate)- Cp,] 163 and [Dy(thf)Cp,] .Ih5 Physical measurements have included single crystal absorption spectra of [M(NCMe),Cp,] (M = Pr,16 Nd'67). Other substances synthesized include the very volatile tris(t-butylcyclopentadienyl) compounds of thulium dysprosium and neodymium,' 52 possible MOCVD precursors I57 H.Liang Q. Shen. S. Jin and Y. Lin J. Chrm. Soc. Chrm. Commun. 1992 480. 158 X. Ju-Song W. Ge-Cheng J. Zhong-Sheng C. Win-Qi and X. Wan-Chuan J. Rare Earths 1992,10,88. 159 M. N.Bochkarev I. L. Fedushin V. K. Cherkasov V. 1. Nevodchikov H. Schumann and F. H. Gorlitz. Inory. Chim. Acta 1992 201 69. I60 J. P. White and S.G. Shore. Inory. Chrm. 1992 31 2756. 161 L.N. Bochkarev O.G. Grachev. S. F. Ziltsov L. N. Zakharav and Yu.T. Struchkov J. Organomet. Chem.. 1992 436 299. I62 G. B. Deacon C. M. Forsyth W. A. Ptalinghug A.H. White A. Dietrich and H. Schumann. Aust. J. Chem. 1992 45 567. I63 H. Schulz. H. Schultze. H. Reddmann M. Link and H.-D.Amberper J. Organomet.Chrm.. 1992,424,139. 164 M. Adam H. Schultze. and R. D. Fischer. J. Organomet. Chem.. 1992 429 C1. 165 R. Maier. B. Kanellakopulos C. Apostolidis and B. Nuber. J. Organornet. Chem. 1992 435 275. 166 C. Apostolidis €3. Kanellakopulos R. Klenze H. Reddmann H. Schulz and H.-D. Amberger J. Organomet. Cheni. 1992. 426. 307. 167 H. Schulz H. Reddmann and H.-D. Amberger. J. Oryanomet. Chcm.. 1992 440. 317. Sc Y the Lanthanides and the Actinides 259 [Ln(MeOCH,CH,C,H,),] (Ln = La Pr)168 (18),in which only two of the threeether oxygens bind to the lanthanide and the open pentadienyl tris(vs-2,4-dimethylpen-tadienyl)terbium obtained as an unsolvated species from thf.Ih9 The structures of the tris(indeny1)-thf adducts [Ln(thf)(ind),] (Ln = Nd Gd Er)I7' have been reported as have those of the anionic species [NdXCp,] -(X = Ph,' 71 Br' 72).The first structurally characterized anthracenyl [Lu(thf )2Cp(Cl,H ,*)Ihas been reported'73 (Figure 9); the anthracenyl dianion is bound principally by two carbons in the central C ring. Figure 9 (Reproduced with permission from J. Chrm. Soc. Mendelerr Conzmun.. 1992. 118) Several dimeric [(YbXCp,),] systems (X = triflate,' 74 propoxy,' 75 naphthoxy'76) were characterized as were [{LnCl(~-C,H,Bu')),] (Ln = Pr Gd EI-'?~) and the hydrides ' [{ LnH (q-C ,H,Bu') ],I. Two bis( pentamet hylcyclopen tadieny1)y ttrium complexes that co-crystallize have been characterized' 79 and the interaction of 1 hX C. Qian. B. Wang. D. Deng. G. Wu. and P. Zheng. J. Orgunomer.Chem. 1992.427. C29. Ihy X. Qiu and J.-Z. Zheng Chinese J. Chein. 1991 10. I-" J.-S. Xia Z.-S. Jin G.-Y. Lin. and W.-Q. Chen. J. Rare Eorrhs 1991 9 253. 17' H. Gao Q. Shen J. Hu. S. Jin. and Y. Lin J. Organomec. Chem. 1992. 427. 141. S. Song. Q. Shen and S. Jin Polj'hedrotz 1992. 11 2863. D. M. Roitershtein A.M. Ellern. M. Yu. Antipin L. F. Rybakova. Yu.T. Struchkov. and E. S. Petrov. J. Chem. Soc. Mendeleer. Commun. 1992. 118. 17' J. Stehr and R.D. Fischer. J. Oryunome:. Chem.. 1992. 430. CI. 17' Z. Wu. Z. Xu X. You X. Zhou. and Z. Jin. Polyhedron. 1992. 11. 2613. I" X.-G. Zhou 2.-2. Wu and Z.-S. Jin J. Organomet. Chmi. 1992 431. 289. L77 S. Song Q. Shen S. Jin J. Guan and J'. Lin. Poljhedroti. 1992. 11. 2857. I TX Y. K. Gun'ko B. M. Bulychev G.L. Soloveichik. and V. K. Belsky. J. Oryanomet. Chrm. 1992 424 289. 179 W. J. Evans T. J. Boyle and J. W. Ziller Inorg. Chem.. 1992 31. 1120. 260 S. A. Cotton hydrazines with [Sm(thf),CpT] has been thoroughly investigated.' A remarkable trimeric complex of the [Sb,]" ion has been characterized'" (Figure 10)whilst the versatile SmCpT moiety bound to a methylmethacrylate dimer has been isolated as an intermediate in an organo-samarium catalysed polymerization. 82 Figure 10 (Reproduced with permission from J. Ckrm. Soc.. Chem. Commun. 1992 1138) Bis(trimethylsily1)methylderivatives of lanthanum both with and without support- ing pentamethylcyclopentadienyl ligands have been studied by NMR in the solid state and in solution.183 [La{ CH(SiMe,),)Cp*][BPh,] contains coordinated tetraphenyl- borate which can be displaced by thf,lR4 and an unusual alkyl with a chelating bis(phenoxide) ligand has been made.lR5 The bis(trimethylsily1)silyl ligand acts as a bridge'86 when [Ln{SiH(SiMe,),}Cp:] dimerizes in the solid state (Figure 11). The gadolinium indenyl [GdCl,(thf),(qS-C,H7)] has a structure similar to those of the analogous cyclopentadienyls( 19).'87 Figure 11 (Reproduced with permission from J. Am. Chem. Soc. 1992 114 8293) I"" W. J. Evans G. Kociok-Kohn. V. S. Leong and J. W. Ziller Inory. Chem.. 1992. 31. 3592. ''I W. J. Evans S. L. Gonzales and J. W. Ziller J. Chem. Sot. Chem. Commun.. 1992. 1138. I '2 H. Yasuda H. Yamamoto. K. Yokota S. Miyake and A. Nakamura J. Am. Chem.Soc.. 1992,114,4908.C. J. Schaverien and G. J. Nesbitt J. Chem. So(,.. Dalton 7ran.s.. 1992. 156. C. J. Schaverien Oryanornetallic~s.1992. 11 3476. C.J. Schaverien N. Meijboom. and A.G. Orpen J. Chem. Sot,. Chrm. Commuri.. 1992. 124. N.S. Radu. T. D. Tillet. and A. L. Rheingold. J. Am. Chem. Soc.. 1992. 114 8293. "' G. Fuxing W. Gecheng. J. Zhongsheng and C. Wenqi. J. Organomc~f. Chem.. 1992. 438 289. Sc Y the Lanthanides and the Actinides 26 1 [&f-o ' #'3 0 (1% Other significant investigations involve'88 an yttrium alkoxide as a model for the first insertion step in alkene polymerization lanthanide pyrrolyls,' 89 and the stabiliz- ation of Ln-C 0bonds by chelation.' 90.' 9' Two reports' 92 have concerned lanthanide carboranes.4 The Actinides Highlights this year have included developments in the chemistry of elements 104 and 105,as well as a substantial output in neptunium chemistry. The first uranium fullerene complex UC,, has been reported.lg3 Trends in the properties of the actinyl [AnO,]' + ions have been correlated with relativistic and crystal-field effects. 194 Group theory has been applied to the actinyl ions and metallocene derivatives. 95 As usual most of the reports concern uranium and it has been convenient to break down the general chemistry by element. A. citrobacter sp. accumulates uranium as a uranyl phosphate complex.'96 An extensive Raman study has been made of complex formation by the uranyl ion.'97 [UO,]' +(aq) is now recognized as having five water molecules coordinated; pentakis complexes of this type have now been crystallographically characterized for dmf and drn~o;'~~ a similar geometry is found in the [UO,Cl(thf),]+ ion.lg9 The uranyl ion binds to DNA as a prerequisite for photocleavage."' Several reports discuss molecular C.J. Schaverien. J. Chrm. Soc.. Clirm. Commun. 1992. 11. Y. Fu S. Wang. H. Ma. and Z. Ye. Polyhedron 1992. 11. 265. H. Schumann J. A. Meese-Marktscheflel. A. Dietrich. and J. Pickardt J. Oryanomer. Chetn. 1992 433. 241. H. Schumann J. A. Meese-Marktschefel A. Dietrich. and F. H. Gorlitz J. Orymonzrr. Cheni. 1992,430 299. A. R. Oki H. Zhang and N.S. Hosmane Angew. Chern.. Inr. Ed. Enyl. 1992. 31. 432; R. Khattar M. J. Manning C. 9. Knobler S. E. Johnson. and M.F. Hawthorne. Inory. Chem.. 1992 31. 268. T. Guo. M. D. Diener. Y. Chai. M. J. Alford. R. E. Haufler. S.M. McClure T. Ohno. J. H. Weaver. G. E. Scuseria. and R. E. Smalley .Scienc.e. 1992. 257. 1661. (3. V. lonova. A. A. Kiseleva and G. A. Gerasimova. J. Chrni. Soc.. :Mendelerr. Conimun.. 1992. 163. R. B. King. Inorg. Chem. 1992. 31. 1978. L. E. Macaskie R. E. Empson. A. K. Cheetharn C. P. Grey and A. J. Skarnulis. Science. 1992. 257 787. c'. Nguyen-Trung G. M. Begun and D.A. Palmer. Inory. C'hrm. 1992. 31 5280. L. Deshayes. N. Keller. M. Lance N. Nierlich. and D. Vigner. Acra Crj.stu/logr..Sect. C. 1992.48 (u)1660; (h) 2209. M. Noltemeyer J. W. Gilje and H. W. Roesky Acto Crysrulloyr.. Secr. C 1992. 48. 1665. P. E.Nielsen. C. Hiort. S. H. Sonnichsen. 0.Buchardt. 0.Dahl. and B. Norden J. Am. Chem. Soc.. 1992 114. 4967. 262 S. A. Cotton recognition and uranyl-chelating agents;20' 'OS one paper demonstrates how the coordination preferences of the [U02]" ion were taken into account in ligand design.20'A uranyl-salophene complex (20)with an added crown ether ring203 has the facility to bind other metal ions. Much of the interest in this area is prompted by the possibility of extracting uranium from seawater (a Japanese patent204 describes the use of a calixarene derivative) since estimates put the amount of ocean-dissolved uranium at 4.5 x 10'' kg (3.3ppb) [UO,(CO,),]'~ about three orders of magnitude greater than that available from minerals. In view of the report above,'96 it is interesting that one uranyl-salene complex has been shown to have a high selectivity for dihydrogen phosphate.20s The complex of uranyl nitrate with benzo-15-crown-5 contains [U0,(N0,)2(0H2),] molecules hydrogen-bonded inside the crown ether.206 The mechanism of the gas-phase reaction of UF with alcohols is believed to proceed207viu alkoxy intermediates [U(OR)F,].Monomeric uranyl alkoxide com- plexes [UO,X,(OPPh,),] [X = OBu' N(SiMe,)2] have208 cis-disposed ligands (21). Several reports have concerned the unusual +5 oxidation state including a seven-coordinate ben~amidinate.~'~ MO calculations have been carried out on uranium(v) irnides'l' and the magnetic properties of LiUO and Li,UO have been examined.2' ' Diverse areas of interest in uranium(1v) chemistry include' "a dimeric iodoalkoxide (22),a detailed spectrophotometric study of complex formation by uranium(1v) halides with an amide ligand,2 l3 and the laser-induced decomposition2 l4 of uranium(1v) borohydride.Na2[UI,] has a different structure2' from other halides Na,[UX,]; two different hypophosphite complexes have been made.21 Several reports concerning poly(pyrazoly1)borates have appeared principally involving uranium(iv) but also involving thorium complexes.21 Bond energies have resulted from thermochemical measurements.2 Apart from the review of uranium(u1) chemistry already noted,8' the crystal structure of CsUC1;3H2O shows' ' tricapped 2"1 T.S. Franczyk K.R. Czerwinski and K.N. Raymond. J. .4m.Chem.Soc.. 1992 114 8138. 202 J. L. Sessler. T. D. Moody and V. Lynch Inory. Chem. 1992 31. 529. 203 A. R. Van Doorn. W. Verboorn S. Harkema and D. N. Reinhoudt Synthesis 1992. 119. 204 Chem. Ahstr. 1992 117 1 I1 297. 20s D. M. Rudkevich. W. P.R. V. Stauthamer. W. Verboom J. F.J. Engbersen S. Harkema. and D. N. Reinhoudt J. Am. Chem. Soc. 1992. 114 9671. 206 R. D. Rogers A. H. Bond and W. G. Hipple J. Cryst. Spectroscopic Res.. 1992 22. 365. 207 N. G. Schnautz and P. J. Venter. S. A/;. J. Chem.. 1992 45. 'OR C. J. Burns D. C. Smith A. P. Sattelberger. and H. B. Gray Inory. Chem.. 1992. 31 3724. 209 M. Wedler M. Noltemeyer. and F.T. Edelmann Anyew. Chem.. Int. Ed. Enyl.. 1992 31. 72. 210 G. A. Bowmaker A. Sorling 0.Haberlen. N. Rosch. G. L. Goodman and D.E. Ellis Inorg. Chem.. 1992. 31. 577. "I Y. Hinatsu T. Fujino and N. Edelstein .I. Solid Stu~eChem. 1992. 99,(u)95; (h) 182. 212 W.G. Van Der Sluys J.C. Huffman D. Ehler and N.N. Sauer Inory. Chem. 1992 31. 1316. *I3 J.G.H. du Preez. H.E. Rohwer and K. B. Morris. Inory. Chim. Ac,ru 1992 191 203. 214 S. K. Sarkar K.V. S Rarnarao and J. P. Mittal Polyhedron. 1992. 11 2783. 215 K. Maletka P. Fischer A. Murasik and W. Szczepaniak. J. Appl. Cryst. 1992 25 I. 'Ih P.A. Tanner T.-H. Sze. T.C. Mak and W.-H. Yip. J. Cryst. Spec.1. Res. 1992. 22 25. 217 A. Domingos J. Marcalo. N. Marques and A. Pires de Matos. Polyherlron 1992. 11. 501 ; A. Carvalho. A. Domingos P. Gaspar N. Marques A. Pires de Matos and I. Santos Polyhedron 1992. 11. 1481; A. Domingos.A. Pires de Matos and I. Santos Polyheriron 1992 II 1601. 218 J. P. Leal. N. Marques A. Pires de Marcos M. J. Calhorda. A.M. Galvao and J.A.M. Simoes 0rqunomerallic.s. 1992 1I 1632. 219 (u)K. Krarner. G. Meyer M. Karbowiak. and J. Drozdzynski J. Less Common Met.. 1991.175.347; (h)E. Zych and J. Drozdzynski Eur. J. Solid Stute Inorq. Chem.. 1991 28. 575. Sc. Y the Lanthanides and the Actinides ,QN U o/II‘o ‘0 0 (20) R= (22) R = W trigonal prismatic coordination of uranium (6C1 30) whilst the anhydrous penta- bromouranates M,[UBr,] have been made.2 19’ The most important compound to be reported here220 is the trigonal bipyramidal homoleptic amide anion (23). (23) R = 2,6-H&jH3 Several interesting papers have been published on thorium chemistry.[ThBr,(thf),] has a distorted dodecahedra1 structure;22’ together with the iodo analogue it is a convenient hydrocarbon-soluble starting material for the synthesis of other Th com- plexes. Thorium isopropoxide is the first structurally characterized thorium alkox- ide;222 it is dimeric with five-coordinate thorium in the solid state but there is NMR evidence for monomer-dimer equilibrium in solution. An unusual thorium phosphido complex223 (Figure 12) a polypyra~olylborate,’~~ [NH,]2[Th(N0,),],225 and a crown ether complex in which dimeric [(ThCl(OH)(OH,),) 2]4+ ions are hydrogen- bonded to 18-crown-6,” have been characterized. Synthetic and structural data are reported for a large number of neptunium (v) 220 J.E. Nelson D.L. Clark. C.J. Burns and A. P. Sattelberger Inorg. Chrm. 1992. 31. 1973. ’” D. L. Clark. T. M. Frankcom. M. M. Miller. and J.G. Watkin. Inorg. Chrm.. 1992. 31. 1628. 12’ D. L. Clark J.C. Huffman. and J.G. Watkin J. Chrm. Soc. Chem. Commun.. 1992. 266. 223 P. G. Edwards. M. Harman M. B. Hursthouse and J.S.Parry,J. Chrm.Soc. Ckeni. Commun.. 1992. 1469. 224 A. Domingos. J. Marcalo and A. Pires de Matos. PolJhrdron. 1992. 11. 909. ’” M.R. Spirlet. J. Rebizant. C. Apostolidis. B. Kanellakopulos. and E. Dornberger. Ac,ru Crj.srct//ogr..Secr. C. 1992 48. 1161. ZZh R. D. Rogers and A. H. Bond. Ac,tu Crj,stulloqr.. Sect. C. 1992 48 1199. 264 S. A. Cotton compounds. Electronic spectra of hydrated [NpO,] + salts (Cl NO, c104)227 and of oxalate complexes 228 have been reported.In the solid state neptunyl(v) sulfate Figure 12 (Reproduced with permission from J. Chem. Soc. Chem. Commun. 1992 1469) complexes contain seven-coordinate Np0,(S04) units;2 29 similar pentagonal co- ordination occurs23o in [NH4][Np0,(C20,)].2.67H,0 and in neptunyl(v) chro- mates. ' A macrocyclic tetraphthalamide ligand designed to sequester plutonium has been reported.,, Fluorination studies on americium have confirmed AmF but failed to give support to ArnF,.,, Organometallic Chemistry.-A highlight in this area is the synthesis of the first Uv' organometallic compound,234 namely [U(NPh),CpT]. Ah initio calculations23s on [AnMe,] (An = U Np Pu) predict a pyramidal structure to be more stable than a planar one attributed to 6d involvement in the bonding.The structures of the isomorphous pair [MCl,CpT] (M = U,Th) have2,' very similar geometries. There have been significant developments in the chemistry of uranium hydrides. The thermally stable compounds [UH(qS-CsH4R),] (R = But SiM,) can be synthesized from the corresponding chlorides on reaction with K[BHEt,].237 The crystal structure of the former (R = But) has been determined. The hydride ligand is chemically reactive and undergoes CO insertion (R = SiMe,238).U-H bond disruption energies have "' A. A. Bessonov. T.V. Afonas'eva. and N. N. Krot. Rudiokhimiyu. 1991 333). 47. 22x A. A. Bessonov and N. N. Krot Rtrdiokhimij'u 1992 33(3).35. 229 M. S. Grigor'ev A.M. Fedoseev. N.A. Budantseva A. I. Yanovskii. Yu.T. Struchkov and N.N. Krot. Rudiokhimiyu. 1991 33(3).54. 230 M. S. Grigor'ev A.A. Bessonov A. I. Yanovskii Yu.T. Struchkov. and N. N. Krot Rudiokhimiyu 1991 33(5),46. 23' M. S. Grigor'ev N. A. Baturin A.M. Fedoseev. and N. A. Budantseva. Rudiokhimiyu 1991. 33(5),53. 232 J. Xu T. D. P. Stack and K.N. Raymond Inory. Chum. 1992. 31. 4903. 233 J. K. Gibson and R.G. Haire. J. A//oy.s Compd.. 1992 181. 23. 234 D.S.J. Arney. C.J. Burns and D.C. Smith. J. Am. Chum. Soc,.. 1992 114 10068. 235 J.V. Ortiz. P. J. Hay and R. L. Martin. J. Am. Chem. Soc,. 1992. 114. 2737. 236 M. R. Spirlet J. Rebizant C.Apcstolidis. and B. Kanellakopulos. .4c.1~1 Cry\ra//oyr..SWI. C. 1992.48.2135. 237 J.-C. Berthet J.-F. Le Marechal. M. Lance. M.Nierlich J. Vigner. and M. Ephritikhine. J. Chem.Soc. Dalton Truns. 1992 1573. 23x J.-C. Rerthet and M. Ephritikhine. Nr*rc. .I. Chem.. 1992 16. 767. Sc Y the Lanthanides and the Actinides been measured.239 Corresponding uranium(II1) hydride anions [UH(q5-C5H4R),] (R = But SiMe,) have been synthesized as well as hydride-bridged dimer~.~~' Another significant development lies in the synthesis of phospholyl complexes;241 although the tetramethylphospholyl ligand has similar steric demands to C,Me it is possible to arrange three such ligarids around uranium in (24).242 Three hexamethylindenyl ligands arrange themselves similarly in [UCl,( 1,2,4,5,6,7-he~amethylindenyl]~~~ though there is an indication that the bonding has some monohapto character. Photoelectron spectra have been reported for some [UXCp,] systems.244 Tetraallylthorium adsorbed on dehydroxylated alumina is an active catalyst for exchange of hydrogen in saturated alkanes.245 Elements 104 and 105.-Among recent developments element 104 in 0.2 M HF solution forms anionic fluoro complexes resembling those of Zr and Hf.246 Studies on the complexation of element 105 by 2-hydroxyisobutyric acid indicate247 that the preferred oxidation state in aqueous solution is +5.Gas chromatography experiments with halides of elements 104 and l@5 showed that element 104 formed more volatile bromides than Hf but that 105 formed less volatile bromides than Nb and Ta; the chloride of 104 was surprisingly volatile.248 Calculations on the electronic structure of the chlorides of element 104 Zr and Hf indicate249 an increasing contribution from valence shell s and p orbitals to the bonding as atomic number increases.It is of course possible that the volatility of the halides of element 104 is another manifestation of relativistic effects. 23') X.Jemine. J. GofTart J.-C. Berthet and M. Ephritikhine J. Chem. Soc.. Dalton Traris. 1992 2439. 240 J.-C.Berthet C. Villiers J.-F Le Marechal B. Delavaux-Nicot M. Lance. M. Nierlich J. Vigner and M. Ephritikhine J. Orgunornut. Chem. 1992. 440,53. 24 1 P. Gradoz D. Baudry. M. Ephritikhine I;. Nief and F. Mathey J. Chem. Soc. Dalton 7rans. 1992. 304. 242 P. Gradoz C. Boisson D. Baudry M. Lance. M. Nierlich J. Vigner. and M. Ephritikhine J. Chem. Soc,.. Chum. Commun. 1992. 1720. 243 M. R. Spirlet.J. Rebizant. S. Bettonville. and J. Goffart Acru Crvstullogr.. Sect. C 1992. 48. 1221. 244 A. Gulino E. Ciliberto. S. Di Bella. I. Fragala A. M. Seyam and T.J. Marks. Oryanometullic~s.1992 11 3248. 24s M. S. Eisen and T.J.Marks Orgunomerallics 1992 11 3939. 246 Z. Szeglowski H. Bruchertseifer V. P. Domanov V. Gleisberg L. I. Guseva M. Hussonois. G. S. Tikhomirova I. Zvara. and Yu. Ts. Oganessian Radiokhimiyu 1991 33(6),90. 24' M. Schadel et a!.. Radiochirn. Acta 1992. 57 85. 248 (a)A. Turler et a/..J. Radioand. Nuclear Chem. 1992. 160.327; (h)H. W. Gaggeler er a/. Radiochirn. Acta 1992 57 93. 249 M.V. Ryzhkov and V. A. Gubanov. Rudiokhimiyu 1992. 34(2).4.

ISSN:0260-1818    

DOI:10.1039/IC9928900243

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

17 The Coordination Chemistry of Open-Chain Polydentate Ligands By M. D.WARD School of Chemistry University of Bristol Cantock‘s Close Bristol BS8 1 TS UK 1 introduction This review is intended to give an overview of the types of ligand that are currently of interest; due to space restrictions and the ever-increasing body of literature it is quite selective. Since there is now a separate chapter dealing with bioinorganic chemistry complexes which are primarily of interest as bioinorganic models are only included if the ligands are of particular interest. Throughout the diagrams ‘pyl’ signifies 2-pyridyl. 2 Bidentate Ligands N-donor Ligands.-Biipyridines and Phenanthrolines. The crystal structures of [PdL,] [PF,] (L = bipy phen and 3,4,7,8-Me4-phen) show various ligand distortions and 71-stacking interactions.’ Perfluoroalkylated bipyridines (1) form amphiphilic com- plexes [PdLCI,] and [PtLCl,] which are potential anti-tumour agents.[Ru(bipy),L3_,J2+ [n = 0-2; L = (2)-(4)] have lower-lying .n* levels than [Ru(bipy),]’+ due to the electron-withdrawing CF substituents. [Ru(bipy),L]’’ (L = (5)-(7)) contain [Ru(bipy),]” cores with pendant pyridyl or phenol groups for attachment of peripheral metal ions;4 attachment of Mo or W complexes to the pendant phenol of [Ru(bipy),(7)I2 results in quenching of the ruthenium lumines- ~ence.~ [MLJ2+ and [Ru(bipy),L]’+ [M = Fe Ru; L = (8) (9)] undergo oxidative electropolymerization in MeCN; the resulting polymer film shows metal-centred and ligand-centred redox processes.6 Irradiation of [Ru(bipy),(10)12 + at pH 1 generates a long-lived intermediate in which (10) is monodentate (cf.reference 18).7 Derivatives of + [Ru( bipy ),I2 bearing protonatable side-chains (e.q.CH,NEt ) show pH-dependent luminescence properties.’ The effects of steric hindrance on the luminescence and electrochemical properties of [Ru(bipy),L -,I2+ (n = 0-3; L = 6,6’-diaminobipy) ’ S. Geremia L. Randaccio G. Mestroni and B. Milani J. Chem. Soc. Dalton Trans. 1992 21 17. N. Garelli and P. Vierling Inorq. Chim. Acta 1992 194 247. M. Furue K. Maruyama T. Oguni M. Naiki and M. Kamachi Inory. Chem.. 1992 31 3792. M.A. Hayes C. Meckel. E. Schatz and M. D. Ward J. Chem. Soc.. Dalton Trans. 1992 703. ’ A. Das J. A. McCleverty M. D. Ward. C.J. Jones and A.M. W. Cargill Thompson Polyhedron 1992,ll. 21 19. C. P. Horwitz and Q. Zuo Inorg. Chem. 1992. 31. 1607. ’ S. Tachiyashiki K. Nakamaru and K. Mizumachi Chem. Left. 1992 11 19. ’ R. Grigg and W. D. J. Amilaprasadh Norbert J. Chrm. So(,. Chrm. Commun.. 1992 1300. 267 268 M.D. Ward (2) X=H Y=Z=CF (3) X = CF3 Y = 2 = H (4) X = Y = 2 = CF3 (5) X = H Y = 2 = 4-pyridyl (6) X = Y = H 2 = 4-pyridyl (7) X = Y = H Z = 4-hydroxyphenyl (8) X=H Y=Me Z=CH2NHPh (9) X = H Y = 2 = CHzNHPh (10) X=Me Y=Z=H were studied.' The luminescence of [Ru(bipy),(bipy-cy~Iam)]~(bipy-cyclam com- prises a tetradentate macrocycle covalently attached to a bipy) is quenched by coordination of Cut* to the pendant macrocycle.' Attachment of Ni2+ to the pendant cyclam unit of [Ru(bipy),(ll)12+ gives a bi- nuclear complex with a photosensitizer attached to a catalytic CO reduction site.ll Dipyridophenazine (12) intercalates efficiently into DNA; [Ru*"(terpy)(O)( 12)2 + (13) R=H R=Me 2R = -CH2CH2-. 2R = -(CH2)3-N=N N-N (14) n=2,3 K. Araki M. Fuse N. Kishii. and S. Shiraishi Bull. Chem. Soc. Jpn. 1992 65 1220. lo S.C. Rawle P. Moore and N. Alcock J. Chem. Soc. Chem. Comrnun.. 1992 684. I' E. Kimura X. Bu M. Shionoya. S. Wada and S. Maruyama. Inorg. Chem. 1992. 31 4542 The Coordination Chemistry of' Open-Chain Polydentate Liyands 269 effects DNA cleavage," whereas [Ru[phen),( 12)12 * and derivatives undergo lumines- cence enhancement by factors of up to 300 on binding to DNA.' [ReBr(CO),( 13)] are capable of MLCT processes and can undergo two oxidations and two red~ctions.'~ The pendant polyoxoethylene chains of [Ru( 14)J2+ allow binding of Group 1 and Group 2 cations with high selectivity resulting in increased fluorescence quantum yields and lifetimes.' Other Bis-heterocyclic N-donor Liyands.[SnX,(pbz)] and [SnMe,Cl,(pbz)] [X = C1 Br I; pbz = 2-(2-pyridyl)benzimidazole]were evaluated for possible anti-tumour activity." [Ru(bipy),(ptz)]" [ptz = 2-(2-pyridyl)triazole] exists as two linkage isomers with the triazole ring coordinated either by N-2 or N-4. The effects of protonation on their reactivity and excited-state lifetimes were examined.' Complexes of some (2-pyridy1)triazoles and (2-pyridy1)pyrazoles with Ru(bipy)i + were prepared and the coordination mode of the triazole rings determined by NMR studies.Thermal or photochemical excitation results in [Ru(bipy),LX]"+ (X = C1 n = 1; X = MeCN n = 2) where L is now monodentate (cf. reference 7).18There is a correlation between the electrochemical and UV/VIS spectroscopic properties of [ReL,Cl,]Cl (L = one of a series of 2-arylazopyridines).' The dynamic behaviour of Pd" and Pt" complexes of the flexible ligand di(2-pyridy1)sulfide has been studied.,' Other N-donor Ligands. [NiL,X,] [L = l-(o-aminophenyl)-3,5-dimethylpyrazole] have been prepared with various anions X." In-fac-[PtMe,I( 15)] the two pyrazolyl rings are inequivalent and the eigh t-membered chelate ring is fluxional., Several homo- and heteroleptic complexes of (16) have been prepared; they tend to have agostic hydrogen interaction^.^^ The ligands (H17) have a donor group at one end and an acceptor at the other resulting in non-linear optical properties in the tetrahedral complexes [C0(17),].~~ [Mn'v(biguanide)3]+ is a rare example of Mn" in an N coordination environment outside p~rphyrins.~~ [M( 18),] (M = Fe Co)are square planar with axial interactions to cyano groups of adjacent complexes which permit antiferromagnetic exchange.Their UV/VIS spectra are similar to those of phthalocyanine complexes. Reaction with 0 affords bridged superoxide complexes of Felv and CO"'.~~ + [Rh(phen),(phi)]' and [Rh(bipy)(phi),I2+ (phi = 9,lO-phenan-N. Gupta N. Grover.G. A. Neyhart W. Liang P. Singh. and H. H. Thorp. Anqew. Chem.. Inr. Ed. Enqi.. 1992 31 1048. l3 R. M. Hartshorn and J.K. Barton. J. Am Chrm. Soc.. 1992. 114. 5919. 14 S.A. Moya. R. Pastene. R. Schmidt J. Guerro. and R. Sartori Polyhedron 1992 11 1665. lS H. Diirr R. Schwartz. I. Willner E. Joselehich and Y. Eichen. J. Chrm. Six.. Chem. Commun.. 1992. 1338. '' T.A. Kabanos. A. D. Keramidas. D. Mentzafos. U. Russo A. Terzis. and J. M. Tsangaris J. Chmi. So(,.. Dalton Truns. 1992 2729. " R. Wang J.G. Vos R. H. Schmehl and K. Hage J. Am. Chem. Soc,. 1992. 114. 1964. '" B. E. Buchanan. P. Degn. J. M. P. Velasco. H. Hughes. B. S.Creaven C. Long J.G. Vos. R. A. Hourie. R. Hage J. H. van Diemen J.G. Haasnoot. and J. Reedijk J. Chem. Soc.. Dalton Truns.. 1992 1177.1') P. Ghosh A. Pramanik. N. Bag and A. Chakravorty J. Chem. Sot. Dulron Trans. 1992. 1883. *() G. Tresoldi E. Rotondo P. Piraino. M. Lanfranchi and A. Tiripicchio. Inorq. Chim. Acru 1992,194.233. " N. Saha. A. Saha S. Chaudhuri. T. C. W. Mak. T. Banerjee. and P. Roychoudhury Polyhedron 1992. 11 2341. l2 A. J. Canty. R. T. Honeyman B. W. Skelton. and A. H. White J. Chrni. Soc.. Dulron 7iuns.. 1991 2663. l3 S. Trofimenko J.C. Calabrese and J.S. Thompson. Inorq. Chem.. 1992. 31. 974. 24 T Thami. P. Bassoul. M. A. Petit. J. Simon. A. Fort M. Barzoukas and A. Villaeys J. Am. Chrn~.Soc,.. 1992. 114. 915. 25 R. 0.C. Hart. S.G. Bott. J. L. Attwood. and S. R. Cooper. J. Chem. So(,.,Chem. Cornmun.. 1992 894. *' M. Bonamico. V. Fares A. Hamini and N. Poli.J. Chrnt. Soc.. Dulrori Trans. 1992. 3273. 270 M.D. Ward [-I CN (H17) X=OMe NM% (18) threnequinone-diimine) intercalate to DNA via the phi ligand and promote photo- chemical strand cleavage.,' 0 S and P-donor Ligands.-The crystal structures and racemization kinetics of + [Cr"'(bpdo),L] (bpdo = bipy-N,N'-dioxide; L = oxalate malonate) have been determined.28 The new bulky chelating ligands (H19)-(H22) form highly soluble and volatile lanthanide complexes [LnL3].29 2,2'-Biphosphinine (23) acts as a strong n-acceptor in [RuCl,(dmso),(24)] and [R~C1,(24),].~~ Ru" complexes with several chiral diphosphines have been ~repared.~ Pt" complexes with the chiral diphosphines (H19) R' = H R2 =But (H22) (H20) R' = R2 = Bu' (H21) R' = R2= W R2 PPh2 OPPh (24) R' = R2 = E3 (25) R' + R2 = -(CH2)3-" A.Sitlani E.C. Long A.M. Pyle and J. K. Barton J. Am. Chem. SOC. 1992 114 2303. 28 H. Kanno M. Tomita S. Utsuno and J. Fujita. Bull. Chem. SOC.Jpn.. 1992 65 1233. 29 W.A. Herrmann R. Anwander and M. Denk Chem. Ber. 1992. 125 2399. 30 D. Carmichael P. Le Floch L. Ricard and F. Mathey. Inorg. Chim. Acta 1992 198-200.437 31 H. Kawano T. Ikoriya Y. Ishii T. Kodama M. Saburi S. Yoshikawa Y. Uchida and S. Akutagawa Bull. Chem. SOC.Jpn. 1992 65 1595. The Coordination Chemistry of Open- Chain Polydentate Liyands 27 1 (24)and (25) were prepared; optically pure [PtCI2(25)] catalyses hydroformylation of styrene with 37% optical purity.32 Mixed N-0 N-S N-C N-P and N-As Donor Ligands.-The complexes [Fe2(p- S),L2I2-[L = (26k(31)] are possible models for [2Fe-2S] proteins.33 [M(31),] (M = Al Ga In) have meridional octahedral structures and were examined by variable-temperature NMR spectro~copy.~~ Electrochemical reduction of mer-[Mn"'(32),] results in mer-fac equilibration; stereoretentive reoxidation of the resultant fac-[Mn"(32),] permits preparation of fuc-[Mn1"(32),].The Mn"/Mn"' couple is isomer dependent.35 In [(Co(aet),(en)),NiI4+ (Haet = 2-+ aminoethanethiol) two cis-octahedral [Co(aet),(en)] units act as S,S-bidentate (H26) n=0 X=S (H27) n = 0 X = 0 (29) R=Me (H28) n=l X=O (30) R = W HO OH (H3 1) (H32) R = C1 Br Me But donors to the central tetrahedral Ni" ion.36 Similar behaviour occurs in [(C~(aet),),Zn,(p~-O)]~ + which undergoes four successive Co*"/Co" reduction^.^' The six-coordinate homoleptic complexes of V2 or V3+ with pyridine-2-thiol (Hpt) + quinoline-8-thiol and 2-aminothiophenol all have N3S3 coordination spheres.38 The crystal structures of [(V(O)),(pt),] I S-bridged binuclear) [Na(thf),V"'(pt),] (seven-coordinate) and [V"(pt),(tmeda)] (octahedral) were determined.39 The crystal structures of [M(33),] (M = Ni Pd Zn) reveal distorted four-coordinate geometries with a helical disposition of ligands."' Trinuclear S-bridged Cu' complexes of (H34) have unusual luminescence proper tie^.^' Square-planar [Rh(35),] + reversibly binds 0 and CO to an extent depending upon the degree of steric crowding induced by the substituent R; the crystal structure of one 32 A.L. Bandini G. Banditelli E. Cesarotti G. Minghetti and B. Bovia Inorg. Chem. 1992 31. 391. 33 P. Beardwood and J. F. Gibson J. Chem. Soc. Dalton Trans.. 1992 2457. 34 H. R. Hoveyda V. Karunaratne S.J. Retrig and C. Orvig Inorg. Chem.. 1992 31 5408. 3s P. Basu and A. Chakravorty Inorg. Chem.. 1992 31 4980. 36 T. Konno K. Okamoto and J. Hidaka Inorg. Chem. 1992. 31. 161. 37 T. Konno T. Nagashio K. Okamoto and J. Hidaka Inorg. Chem. 1992 31 1160. 38 G. Henkel B. Krebs and W. Schmidt. Angew. Chem. Int. Ed. Engl.. 1992 31 1366. 39 J.G. Reynolds S.C. Sendlinger A. M. Murray. J.C. Huffmann and G. Christou Angew. Chem.. Int. Ed. Engl. 1992 31 1253. 40 T. Kawamoto and Y. Kushi J. Chem. SoL... Dalton Trans.. 1992. 3137. 41 D.M. Knotter G. Blasse J. P. M. van Vliet and G. van Koten. Inorg. Chem. 1992 31 2196. 272 M. D. Ward (33) (Fc = ferrocenyl) (35) R = Et pr" W But X-Me Ph (37) x= P (38) X= As such oxygen adduct shows4 that the 0 is 'side-on' to the Rh'. In [Ir,(c0d),(36),]~ + and [Rh2(nbd),(36),I2' the metal atoms are bridged by the phosphinine moiety whereas the pyridyl rings are terminal.43 NMR studies of square-planar Pd" and Pt" complexes of (37) and (38) show that facile ligand redistribution occurs cia square pyramidal intermediate^.^^ The properties of Rh"' complexes containing cyclometal- lating C,N-donor ligands such as 2-phenylpyridine,45p47 2-thien~lpyridine,~~.~~ and I-phenylpyrazole and substituted derivative^,^' have been studied.Other Mixed-donor Ligands.-Ni" Pd" and Pt" complexes of the 0,P-chelating ligand 2-(diphenylphosphino)hydroquino148 and of the S,P-chelating ligand 2-(dimethypho~phino)ethanethiol~~ were prepared and structurally characterized. Elec- trochemical and UV/VIS spectroscopic studies were performed on technetium and rhenium complexes containing 2-(dipheny1phosphino)thiophenol(Hdpt); [Tc(dpt),] and [Re(dpt),] are near-~ctahedral.~' 3 Terdentate Ligands N-donor Ligands.-Tripodal Ligands. Sterically bulky tris(pyrazoly1) borates have been of particular interest. Thus Co" Ni" and Zn" complexes of (39k(46) were prepared; most are trigonally-distorted tetrahedral with the formula [MLX] = NCS NCO N3) but some are dimeric [ML(p-X),ML].*' [Cu,(42),] has an 42 C.A.Ghilardi S. Midollini. S. Moneti A. OrlandInI and G. Scapacci. J. Cfirm. Snr.,Dulron Truns. 1992 3371. 43 B. Schmid L. M. Venanzi. T. Gerfin V. Gramlich. and F. Mathey Inorg. Chrm. 1992 31. 5117. 44 G. Salem and S. B. Wild Inory. Chem.. 1992 31. 581. 45 G. Frei A. Zilian A. Raselli H. IJ. Giidel and H.-B. Riirgi. Inorg. Chrm. 1992 31 4766. 46 A. Zilian and H. U. Giidel Inorg. Chem. 1992. 31 830. 47 U. Maeder A. von Zelewsky and H. Stoeckli-Evans Hell.. Chim. Acrcc. 1992 75. 1320. 48 S. B. Sembiring. S.B. Colbran. and L. R. Hanton Inorg. Chirn. Acta. 1992 202 67. 49 M. Kita T. Yamamoto K. Kashiwabara and J. Fujita. Bull. Chrm. Sw. Jpn.. 1992 65 2272. SO J. R. Dilworth,A. J. Hutson S.Morton M. Harman M.B. Hursthouse. J. Zubieta. C. M. Archer.and J. D. Kelly Polyhedron 1992 11. 2151. 51 S. Trofimenko J.C. Calabrese J. K. Kochi. S. Wolowiek. F. B. Hulsbergen. and J. Reedijk Inory. Chrm.. 1992 31. 3943. The Coordination Chemistry of Open-Chain Polydentate Ligands H [-I R2 (39) R' = Pr' R2= Me (40) R' = neopentyl R2 = H (41) R' =But R2= Me (42) R' = Pr' R2= H (43) R' =But R2 = H (44) R'=Pr' R2=H also 4-Br on each ring (45) R' =p-tolyl R2 = H (46) R' =p-methoxyphenyl R2 = H (47) R' = R2 = Pr' unusual structure in which each Cu' is linearly coordinated by one donor atom from each (bidentate) ligand. Reaction with NO afforded [Cu(42)(NO)] the first terminal Cu-NO complex.52 [M(40),] (M = Fe Co Ni) were prepared; [Ni(40),] is octahed- ral in the crystal but five-coordinate in solution.Heteroleptic six-coordinate [M(40)(tpb)] [tpb = a tris(pyrazoly1)boratel and four-coordinate [M(40)X] are also de~cribed.'~ In [{Cu(47)),(0,)] the 0 adopts an unusual p-q :q coordination mode. The complex is spectroscopically very similar to oxyhaemocyanin and oxytyrosinase and is diamagneti~.~~ In [Mo(46)(NO)X2] (X = CO C1) the p- methoxyphenyl substituents form a bowl-like cavity and also cause a highly distorted metal coordination ge~metry.~' In the planar complexes trans-[Ni(p-C,H4X)(43)(PMe,),] (X = H Me OMe) (43) is m~nodentate.~~ [(MeGa(pz),},In] [In14] with a tris(pyrazoly1)gallate ligand has been ~repared.~ The enantiomerically pure C,-symmetric tripodal ligands (48) were prepared.58 Electrochemical and spectroscopic properties stability constants and some crystal structures of the six-coordinate complexes [M(bpma),]"+ [bpma = 1,l -bis(2-py-ridy1)methylamine; M = Fe Co Ni Cu n = 2; M = Fe n = 31 have been studied; the complexes show large degrees of steric strain.59 Mono- and binuclear Zn" complexes of tris(2-pyridy1)phosphine and tris(2-pyridy1)arsine were prepared and structurally + characterized.60 In [Pd(Htpm)Cl,'] [tpm = tris(2-pyridy1)methanel the tpm is 52 S.M. Carrier C.E. Ruggiero W. B. Tolman and G. B. Jarneson J. Am. Chem. Soc. 1992 114 4407. 53 J.C. Calabrese and S. Trofirnenko Inory. Chem. 1992 31 4810. 54 N. Kitajirna K. Fujisawa C. Fujirnoto Y.Moro-oka S. Hashirnoto T. Kitagawa K. Toriumi K. Tatsurni and A. Nakarnura J. Am. Chem. Soc. 1992 114 1277. 55 M. Cano J. V. Heras A. Monge E. Gutierrez C. J. Jones S. L. W. McWhinnine and J.A. McCleverty. J. Chem. Soc. Dalton Trans. 1992 2435. 56 E. Gutierrez S.A. Hudson A. Monge. M.C. Nicasio M. Paneque,and E.Carrnona J. Chem. Soc. Dulton Trans. 1992 2651. '' A. Frazer B. Piggott. M. Harrnan M. Mazid and M. B. Hursthouse Polyhedron 1992 11 3013. '* H. Adolfsson K. Warnrnark and C. Moberg J. Chem. Soc.. Chem. Commun. 1992 1054. " P. V. Bernhardt P. Cornba A. Mahu-Rickenbach S. Stebler S. Steiner K. Varagny and M. Zehnder Inorg. Chrm. 1992 31 4194. 6o R. Gregorzik. J. Wirbser and H. Vahrenkarnp Chem. Ber. 1992 125 1575. 274 M. L). Ward OR' (48) R' = R2 = H; R' = H R2 = Me; R' = R2= Me bidentate with a protonated pendant pyridyl group.6' Ligand (49) acts as a terminal capping ligand in the linear trinuclear complexes [Fe3(p-OH)2(p-RC02)4(49)2]3 + .62 Terpyridines and Other Triimines.Terpy can act as a fluxional bidentate ligand in fuc-[ReBr(CO),(terpy)] fuc-[PtCIMe,(terpy)] and ~is-[W(CO),(terpy)].~~ NMR and electrochemical studies on 2 1 homo- and heteroleptic Ru" complexes with terpy and 4'-substituted derivatives were performed; there is a correlation between El,2-(Ru"/Ru"') and the combined electronic properties of the two 4'-sub~tituents.~~ [RuL,]" (L = 4'-Cl-terpy and 4'-MeS0,-terpy) are the first [Ru(terpy),]'+ deriva-tives to be luminescent in fluid solution at room temperat~re.~~ Protonation or (51) X = CH~-~=&-Y=H (52) X = ferrocenyl Y = H (53) X=Y=OMe (54) X = Y = OH alkylation of the pendant 4-pyridyl groups of [Fe{ 4'-(4-pyridyl)terpy} 2]2 affects the + properties of the Fe" centre.66 The photophysical properties of [M(50)J2+ (M = Fe Ru 0s) were examined; the 0s complex has the longest-lived excited state.In [Os"(50)(5 In 1)I"+ the luminescence is quenched by the pendant viologen gro~p.~' [M(52),I2+ and [M(50)(52)I2' there is a weak electrochemical interaction between the ferrocene groups and the M(terpy)i+ cores. Again the luminescence of the 0s" 61 A.S. Canty N. J. Minchin B. W. Skelton and A. H. White Aust. J. Chem. 1992 45 423. 62 V.A. Vankai M. G. Newton and D. M. Kurtz Jr.Inorg. Chem. 1992 31 343. 63 E. W. Abel N. J. Long K. J. Orrell A. G. Osborne H. M. Pain and V. Sik. J. Chem.Soc. Chem. Commun. 1992 303. 64 E.C. Constable A. M. W. Cargill Thompson D. A. Tocher and M. A. M. Daniels New. J. Chem.. 1992 16 855. 65 E.C. Constable A. M. W. Cargill Thompson N. Armaroli V. Balzani and M. Maestri. Poljhedron. 1992 11 2707. 66 E. C. Constable and A. M. W. Cargill Thompson. J. Chem. SOL..,Dalton Trrins.. 1992 2947. 67 E. Amouyal and M. Moullem-Bahout J. Chem. Soc.. Dulton Trans.. 1992 509. The Coordination Chemistry of Open-Chain Polydentate Liyands complexes is quenched by the ferrocenyl substituent.68 Demethylation of + + [Ru(terpy)(53)I2 gives [Ru(terpy)(54)I2 with a pendant catechol binding site to which Ru(bipy)i+ and Pd(bipy) fragments were subsequently attached.69 Reaction + of ferrocenyllithium with terpy affords 3'-(ferroceny1)terpyridine.70 Terpy and 2,6-bis(1-pyrazolyl)pyridine have planar trans,trans structure^.^ The varying ligand-field strengths of (55)-(58) mean that [FeL,] + is low-spin for L = (57) or (58) high-spin for L := (56) and shows spin-crossover behaviour for L = (55); [FeLX,] and some Zn" complexes were also ~tudied.~' The electrochemical properties of Mn" complexes of (57) were investigated.[Mn(57)C12].dmf has a (55) x=s (57) R=H (56) X=O (58) R =Me (59) R = (CH&CH3 (60:)R = Ph (611) R = p-MeOC6H4 (62) R = -(CH&Ph distorted square pyramidal structure.73 Whereas [Cu,(58),I2 is helical the complex + with the analogous bidentate benzene-based (rather than pyridine-based) ligand is non-helical with two two-coordinate linear Cu' centres.The factors affecting adoption of helical as opposed to non-helical structures are discussed.74 Excitation into the ligand-centred excited states of [ML(NO,),(MeOH),] [M = lanthanide; L = (58) (59); n = 0,l) is followed by efficient energy-transfer to the metal which can then luminesce.75 [CoL,]'+ and [CoLX,] [L = (60)-(62); X = C1 Br NCS] were ~repared.'~ Electrocatalytic reduction of CO was effected with [ML,]" [M = Fe hn J.-C. Chambron. C. Coudret. and J.-P. Sauvage New. J. Chem.. 1992. 16. 361. 69 C. Howard and M. D. Ward ,4ngew. Cltem. fnt. Ed. Engl. 1992 31 1028. 70 I. R. Butler N. Burke L.J. Hobson and H. Findenegg Polyhedron 1992 11 2435. 71 C.A. Bessel R. F. See D. L. Jarneson M. R. Churchill and K.J. Takeuchi J. Chrm. Soc. Dalton Trans. 1992 3223. 72 S. Riittirnann C. M. Moreau A. F. Willidms G. Bernardinelli and A. W. Addison. Polyhedron 1992. I i 635. 73 W. Shuangxi Z. Ying Z. Fanglie W. Qiuying and W. Liufang Polyhedron 1992 11 1909. 74 S. Riittirnann C. Piguet G. Bernardinell B. Bocquet and A. F. Williams J. Am. Chrm. Soc. 1992 114 423I. 75 C. Piguet A. F. Williams. G. Bernardinelli E. Moret. and J.-C. Bunzli Nelr. Chirn. Actu. 1992.75. 1697. 16 D. A. Edwards S. D. Edwards. W. R. Martin. T.J. Pringle. and P. Thornton Polyhedron. 1992 11. 1569. 276 M. D. Ward Co Ni; L = terpy 4'-vinylterpy (60) 1,2,4,5-tetrakis(2-pyridyl)pyrazine, and 1,3,5- tris(2-pyridyl) triazine] .77 Other N-donor Ligands.Differences in the spectroscopy and electrochemistry of the homoleptic Ru" complexes of (63) are dominated by the electronic rather than steric properties of the ligands;78 [Mn(63),I2+ and [Mn(63)X2]"+ (X = C1 n = 0; X = H,O n = 2) were also ~tudied.'~ PylCH,NHCH,Pyl (Pyl = 2-pyridyl) forms fac-[ML2l2+ complexes with Mn" Zn" and Cd". The EPR properties of the Mn" complex doped into diamagnetic host lattices were measured.80 Compounds (64)and (65) act as symmetric terminal face-capping ligands in [L2Fe!1(p-O)(p-X)2]2+ (X = carboxylate diphenylphosphate); the complexes show strong antiferromagnetic R2 (63) R' and R2 = H or Me (64) R= H (65) R=Me (66) K=Et 0 PY1' (67) R = H (68) R=Me have the same core structure and under- go two well-separated Ru"'/Ru'" oxidations and a Ru"'/Ru" reduction.82 Reaction of [Mn~V(66)2(p-O),(,u-MeC02)]3+with NaClO,/MeCN affords [Mny(66)3(/i-O),(OH)]3+,a model for the oxygen-evolving site of photosystem II.83The structures and magnetic properties of [{Ni(67)x(~-X)}~] (X = N, NCS) were determined.84 [Cu(67)Br][PF6] has a chain structure with bridging bromides resulting in a triplet ground state and weak antiferromagnetic coupling.85 [Cu(68)(NCS),] is trigonal 77 C.Arana. S. Yan. M. Keshavarz-K. K.T. Potts and H. D. Abruna. Inorq. Chem. 1992 31 3680. S. Mahapatra and R. Mukherjee J. Chem. Soc. Dalton Trans. 1992 2337. 19 S.Mahapatra D. Bhuniya. and R. Mukherjee Polyhedron. 1992 11 2045. 8o J. Glerup. P. A. Goodson D. J. Hodgson. K. Michelsen K. M. Nielsen. and H. Wiehe Inorg. Chem..1992. 31 4611. '' S. Mahapatra N. Gupta and R. Mukherjee J. Chem. Soc. Dolfon Truns. 1992. 3041. '' N. Gupta S. Mukherjee S. Mahapatra M. Ray and R. Mukherjee Inorg. Chem. 1992 31 139. 83 S. Pal M. K. Chan and W. H. Armstrong J. Am. Chem. Soc. 1992 114 6398. 84 R. Cortes J. 1. R. de Larramendi L. LzTarna T. Rojo M. K. Urtiaga and M. I. Arriortua J. Chem. Soc,.. Dalton Trans.. 1992 2723. 8s T. Rojo. R. Cortes J. I. R. de Larrarnendi. and G. Madariarga. J. Chem. SOL... Dulton 7run.s.. 1992 2125. The Coordination Chemistry of Open-Chain Polydentate Ligands bipyramidal; the stereochemistries of other complexes [Cu(68)X2] are discussed.86 The stoichiometries of Co" Ni" and Cu" complexes of carcinine (H,69) were studied by potentiometric and spectroscopic methods.Several different structures from simple [M(69)] (M = Co Ni) to the cyclic tetramer [Cu4(69),] were detected.87 Other Homodentate Ligands.-The anionic cyclopentadienylcobalt species (70)-(72) act as tripodal 0,-donor ligands in various complexes with Zn Al and Tc.88389 The tri-substituted 1,4,7-triazacyclononane derivative (H,73) acts as a tripodal S donor to (70) R = Et '0-SH (71) R= OMe (72) R = OEt (H373) n = 2 or 3 (74) R=Me,Ph [4Fe-4S] cubanes as in [Fe4S,(73)(SEt)I2-,permitting site-specific reactions at the differentiated Fe site." The five-coordinate complexes [Ni(74),I2+ (in which one AsMe group is not coordinated) are members of extended electron-transfer series with oxidation states from 0 to +4 accessible electrochemically.9' Mixed N,O-donor Ligands.-Whereas [Cu,L,(p-OAc)][PF,] [L = (75) (76)] and [Ni2(76),(p-0Ac)(NCMe),][PF6] ,3-MeC02) cores all have similar M2(p-O)2(p-l [[Ni(75)(H75)),][PF6] contains two [Ni(75),] units held together by two strong hydrogen bonds between phenolate oxygen atoms.Intra-ligand n-stacking interac- tions appear to play a significant role in both types of structure.92p94The EPR and magnetic properties of the binuclear Cu" comple~es,~~ and the electrochemical Xh J. I. R. de Larramendi J. L. Mesa R. Cortes. T. Rojo M. K. Urtiaga. and M. I. Arriortua. Polyhedron 1992 11.623. 87 T. Gajda B. Henry. and J.-J. Delpuech J. Chem. Soc,. Dalton Trim.. 1992. 2313. xx A. Looney M. Cornebise D. Miller. and G. Parkin Inorg. Chem. 1992 31 989. 89 J.A. Thomas and A. Davison Inorg. Chem.. 1992 31 1976. YO D. J. Evans G. Garcia. G. J. Leigh M. S. Newton and M. D. Santana. J. Chem. Soc.. Dalton Trans. 1992 3229. 41 A. J. Downard. L. R. Hanton. and R. L. Paul. J. Chem. Soc.. Chem. Commun.. 1992 235. 92 J. C. Jeffery. E. Schatz and M. D. Ward J. Chem. Soc.. Dalton Truns. 1992. 1921. 93 J. C. Jeffery and M. D. Ward J. Chem. Soc.. Dalton Truns.. 1992 21 19. 94 B. M. Holligan J. C. Jeffery. and M. D. Ward. J. Chem. Soc.. Dalton Trans. 1992 3337. 95 J. P. Maher P. H. Rieger. P. Thornton and M. D. Ward J.Chew. Soc. Dalton Trans.. 1992 3353. 278 M.D. Ward (75) X=nothing (77) R=Me (76) X = -CH=CH-(H78) R = H (79) quinone analogue of (H80) properties of Co"' and Ru"' complexes of (75),92396were examined. Ligands (77)-(79) show N,N-bidentate N,N,O-terdentate and N,N,C-cyclometallating modes of coor- dination in Pd" complexes .9 Vanadyl complexes of (80) are the first examples of V" complexes with imidazole ligands and are models for vanadium bromoperoxida~es.~~ The crystal structure of [Vv(0)(80)(cat)] (H,cat = catechol) and 51V NMR spectra of it and related complexes are described.99 [(Mn"'(81)C1(MeOH)},] is the first Mn dimer with unsupported alkoxide bridges. loo Magnetic studies of mixed-valence trinuclear complexes [Mn"Mn~'L2(p-RCO2),X,1 [L = (82) or (83) both of which are O,N,O- terdentate ligands; X = a neutral monodentate ligand] were performed.lo' Reaction crN'R 'OH (H80) R = CH2CH2-(4-imidazolyl) (H28 1) R = CH2CH2OH (H282) R = CH2CH(OH)CH20H 0 (H283) R = CH2C(OH)(CH,OH> (H284) R = CH(CH2OH)COzH (H285) R = o-C&40H (HzS6) R = CH~(O-C~H~OH) (H87) R = CH,CH2-(2-~yridyl) (H288) R = CH2C02H (H289) R = CH2CHZC02H (H29O) R = NH-C(O)-(4-pyridyl) (H291) R = NH-C(0)-Ph of [V0l2 + salicylaldehyde and (m)-serine gives the V"/VV species [{ V0(84)},(p-O)] -.lo [V(85),] (and CH,-substituted analogues) are non-oxo V" complexes which can be reduced to the V"' and V" states.lo3 Ligands (80) and (85)-(89) were used to prepare high-spin Fe"' complexes with N204 N,O, and N40 donor sets.The effects 96 B.M. Holligan J.C. Jeffery M. K. Norgett E. Schatz and M. D. Ward,J. Chem.Soc. Dalton Trans. 1992 3345. 97 R. A. Berthon S.B. Colbran and D.C. Craig Polyhedron 1992. 11 243. 98 C. R. Cornman J. Kampf M. S. Lah and V. L. Pecoraro Inory. Chem. 1992 31 2035. 99 C. R. Cornman J. Kampf and V. L. Pecoraro Inory. Chem. 1992 31 1981. 100 E. Larson M. S. Lah X. Li J. A. Bonadies and V. L. Pecoraro Inorg. Chem.,1992 31. 373. D. P. Kessissoglou M. L. Kirk M. S. Lah X. Li. C. Raptopolou W. E. Hatfield. and V. L. Pecoraro Inorg. Chem. 1992 31 5424. 102 J. C. Pessoa. J. A. L. Silva A. L. Vieira L. Vilas-Boas P. O'Brien. and P. Thornton J. Chem. Soc.,Dalton Trans. 1992 1745. K. Ramesh T. K.Lal and R. N. Mukherjee Polyhedron. 1992. 11 3083. The Coordination Chemistry of Open-Chain Polydentate Ligands 279 of variations in donor set and stereochemistry on their spectroscopic and electrochemi- cal properties were e~amined."~ The kinetics of formation and stability constants of Fe" complexes of the salicylaldehyde hydrazones (90) and (91) and the pyridoxal hydrazones (92) and (93) were measured.lo5 Binuclear Cu" complexes of (92)-(96) were prepared and characterized; reversible oxidations to Cu"Cu"' and CU"~CU"~ states were observed.lo6 A series of bi- tri- and tetranuclear CU" complexes of the compartmental ligand Me,NCH,CH(OH)CH,NMe (HL) were prepared and structurally characterized. The tetranuclear complexes have planar cyclic structures in which each ligand is binucleating with the alkoxide bridging two metals.* 07q1 O8 The structures and R R (98) R= H (99) R=Bu" R (H2100) R = H Me C1 electrochemical properties of 0s'' 0x0 and nitrido complexes with the bulky ligand (97)were studied."' EPR studies were performed on Cu" complexes of (98) and (99).In [Cu(98)(H20),(C10,)] and related species (98) is a fac-N,N,O-donor but in + + [CuL,(X)(CIO,)] [L = (98) (99); X = azide acetate benzimidazole] boths ligands are N,N- bidentate.' lo Octahedral Fe"' and Fe" complexes of (100)were prepared and characterized.' '' Other Mixed-donor Ligands.-Mono- and binuclear Au" complexes with ( 101) were prepared and characterized and their reactions with other N-donor ligands studied.' 12,1l3 Several 1 1 complexes of Co" Ni" Cu' Cu" Zn" and Ag' with (102) were prepared.The ligand often acts as an N,S,N chelate but with Cu' and Ag' it is an Io4 K. Ramesh and R. N. Mukherjee J. Chrm. Soc.. Dalton Trans. 1992 83. 105 J.-E. Dubois H. Fakhrayan. J.-P. Doucet and J.-M. E. Chahine Inorg. Chem. 1992 31 853. 106 M. Mohan N. K. Gupta M. Kurnar N. K. Jha and W. E. Antholine Inorg. Chim. Acra. 1992. 197 39. lo' J.-C. Zheng R.R. Rousseau and S. Wang Inorg. Chrm. 1992. 31 106. 108 S. Wang S.J. Trepanier J.-C. Zheng %. Pang and M. J. Wagner Inorg. Chem. 1992. 31 21 18. Z.-Y. Li W.-Y. Yu C.-M. Che. C.-K. Poon R.-J. Wang and T. C. W. Mak J. Chem. Soc. Dalton Trans. 1992 1657. 'lo G. Batra and P. Mathur Inorg. Chem.1992 31 1575. 'I' M. Koikawa H. Okawa Y. Maeda and S. Kida Inorg. Chim. Acra 1992 194 75. 'I2 A. P. Koley L.S. Prasad P.T. Manorahan and S. Ghosh Inorg. Chim. Acta 1992 194 219. 'I3 A. P. Koley R. Nirmala L.S. Prasad S. Ghosh and P.T. Manorahan Inorg. Chrm. 1992 31 1764. 280 M.D. Ward N,N-bidentate bridge thus leading to polymeric complexes.' The preparation and crystal structure of [{C~(fpt))~(p~-P~O,)] [Hfpt is the N,N,S-donor 2-formylpyridine thiosemicarbazone] are described. The central pyrophosphate ion donates a different oxygen atom to each Cu.' Stereoregular A-helical coordination polymers of Cut and Ag' with (103) were prepared; each ligand ligates via imidazole N imine N and thiophene S atoms to three separate metal ions which have trigonal planar geometries.' l6 In [Cu\( 104)J*+ each Cut is coordinated by one N,S binding pocket from each compartmental ligand.The S atoms are bridging.' ' 6-Thienylbipy (H105) can be N,N,C-terdentate in [M( lO5)Cll uia cyclometallation of the thienyl ring or N,N-bidentate in [M(H105)C12] (M = Pd Pt). In addition [Au(H105)C13] where (H105) is monodentate converts on heating to [(Au(105)Cl2] where the ligand now acts as a bidentate bridge.' l8 Likewise reaction of (H,106) and (H2107) with ds ions results in N,C-bidentate or C,N,C-terdentate binding modes. Reaction of either ligand with Au"' results in coupling of the terminal thienyl rings to give novel hexadentate ligands."' Bipy and phen groups were directly attached to 9:TJ SH N/ N-N N-N (103) R = H Me Me3Si (104) Fc = ferrocenyl R S R aN.NAsAph H (H105) R = 2-pyridyl (H2106) R = Ph (H2107) R = 2-thienyl (H2108) R = H Me C1 Br 114 W.G. Haanstra. W. L. Driessen M. van Roon A. L. E. Stoffels. and J. Reedijk. J. Chem. Soc.. Dulron Trans. 1992. 481. 115 E. W. Ainscough A.M. Brodie. J. D. Ranford J. M. Waters and K. S. Murray Inorcq. Chirn. A<,ru. 1992. 197 107. 116 J. F. Modder K. Urieze A. L. Spek. G. Challa and G. van Koten Inory. Chem.. 1992. 31 1238. I 17 B. Delavaux-Nicot. N. Lugan and R. Mathieu Inory. Chem.. 1992 31 335. I18 E.C. Constable R. P.G. Henney. P. R. Raithby.and L. R. Sousa J. Chem. Soc.. Dulton Trans. 1992,2251. 119 E. C. Constable R. P. G. Henney and D. A. Tocher J. Chem. Soc,. Dulton Truns..1992 2467. The Coordination Chemistrji of 0pc.n-Chain Polydentate Ligands 281 phosphino-substituted ferrocenes to give potential N,N,P-terdentate ligands."' Rhenium complexes of PhN(CH,CH,PPh,) (np2) were prepared; the ligand is N,P-bidentate in [ReOCl,(np,)] but fuc-terdentate in [ReCl,(np2)].'Z1 Zn" com-plexes of pyridoxal thiosemicarbazone and methylpyruvate thiosemicarbazone which are O,N,S-donors were studied as models for Zn-S metalloproteins.'22 The elec- trochemical properties of cis-[MoV'0,(108)(S)] (S = acetone py dmf dmso) and the kinetics of its oxygen-atom transfer to PPh (affording OPPh and Mot" species) were studied.'23 4 Tetradentate Ligands N-donor Ligands.-Bridging Ligands with Two Bidentate Compartments. 2,3-Di(2-pyridy1)pyrazine (109) and the 2,5-isomer have been extensively used as bridging ligands in high-nuclearity complexes comprising multiple (up to 13) photoactive Ru" and/or 0s" polypyridyl centres; iin example is given in Figure 1.Amongst their L ,L YIP BL BL L = bipy or biq I I ,Mi. ,Mi BL = (109) L. BL BL-,BL BL. ,L ?;'. F R;lp M = central metal (RU" 0s") L BL L I M~= intermediate metal (RU") L ,BL ,Mi BL. ,L MP= peripheral metal (Ru" 0s") Yp Mp L L Figure 1 Decunuclear ruthenium (11) and osmium (11) comple-yes showing inter-component energy transfer interesting features are the different electrochemical properties of metals in different 'shells' controllable inter-component energy-transfer on photo-excitation and step- wise synthesis by protecting one binding site of the bridging ligands and then de-protecting it after complexation at the other site.' 24-1 28 The UV/VIS and electrochemical properties of [(bil~y)~Os(p-L)Ru(bipy)~]~+ [L = (109)-( 11 l)] were examined.'29 [Cu(p-L)(H,O),] [L = (109) bipym] are infinite-chain polymers.' 30 [(Re(CO),CI),L] [L = (109) (1 12) (113); n = 1,2] were prepared.All of the 120 I.R. Butler Polyhedron 1992 11 3117 121 D. Michos. X.-L. Luo and R. H. Crabtree. J. Chem. Soc. Dalton Trans.. 1992 1735. 122 M. B. Ferrari G.G. Fava C. Pelizzi and P. Tarasconi J. Chem. Soc. Dalton Trans. 1992. 2153. 123 S. Bhattacharjee and R. Bhattacharyya. J. Chem. Soc. Dalton Trans.. 1992 1357. 124 G. Denti S. Serroni. S. Campagna V. Kicevuto A. Juris M.Ciano and V. Balzani. Inorg. Chim. Acta 1992 198-200 507. 125 G. Denti. S. Campagna S. Serroni M. Ciano and V. Balzani. J. Am. Chem. Soc.. 1992 114. 2944. 126 S. Campagna G. Denti S. Serroni. M. Ciano A. Juris and V. Balzani Inorg. Chem.. 1992 31 2982. 127 S. Serroni and G. Denti Inory. Chem. 1992 31 4251. 128 S. Serroni G. Denti S. Campagna A. Juris M. Ciano. and V. Balzani. Angew. Chem.,Int. Ed. Engl.. 1992 31 1493. 129 M. M. Richter and K. J. Brewer Inorg Chem. 1992. 31 1594. 130 L. W. Morgan K.V. Goodwin W.T. I'ennington and J. D. Petersen Inorg. Chem.. 1992 31. 1103. 282 M. D.Ward (110) R=H (1 11) 2R = fused aromatic ring (112) R=Me (114) (1 15) X = (CH,) (n= 2-7.12). CH,(p-C6H,)CH2 CH2@-cyclohexyl)CH2 RmxmR (117) X = hexadentate macrocycle 4,4'-bipyridiniumdiium polyaminoethylene chain R (118) R=H (119) R=Me The Coordination Chemistry of Open-Chain Polydentate Liyands 283 mononuclear complexes and one of the binuclear complexes are luminescent.' ' A-[Ru(bipy),(ll3)]*+ promotes DNA cleavage in the presence of H,O, Cu" and 3-mercaptopropionic acid probably via formation of a {RuI1(p-1 13)Cu") binuclear complex.'32 The UV/VIS and electrochemical properties of [{ Mo(CO),),( 1 14)] (n = 1,2) indicate that the extra ligand conjugation compared to 2,5-bis-(2-py-ridy1)pyrazine results in a lowering of the LUMO and decreased basicity.' 33 [Cu,(bpp),][CF,S03] [bpp = 3,6-bis(2-pyridyl)pyridaziiie] contains four tet-rahedral Cu' ions each coordinated by bidentate cavities of two near-perpendicular ligands.It is stabilized by intra-ligand n-stacking interactions and undergoes eight ligand-based reduction^.'^^ Attachment of a Ru(bipy)i+ fragment to one bipy site of (115) and quaternization of the other to give a diquat afforded [Ru(bipy),]'+ derivatives with pendant electron-acceptors. The electron-transfer rate after photo- excitation depends on the bridge length.'35 Whereas [Cu"( 1 16)(H20)][C10,] is mononuclear [Cu\(1 16),][C104] I is a binuclear double helix with two four-coordi- nate Cu' ions. The two forms interconvert slowly. Their electrochemical and spectroscopic properties and the photophysics of the Cu' complex were inves-tigated.', The double helical complexes [Cu\( 117),12+ contain a chiral cavity delineated by the 'spacer' groups which may permit inclusion of a chiral guest.Non-helical [Cu(ll7)]+ and [Ag(ll7)]+ also form.',' [M:L,]X2 [L = (118) (119); X = BF, PF,] and [Niy(OAc),( 119),][PF,] are also double helices in which each metal is coordinated to a bipy fragment from each ligand; the octahedral Ni" ions also have bidentate acetate ligand~.'~~ Attachment of a bipy fragment to each ring of ferrocene affords a novel potentially tetradentate ligand." Magnetic studies were undertaken on polynuclear Cu" complexes of 3,5-bis(2- pyridy1)pyra~ole.'~~ [{Rh1X2},(H120)]"+[n = 1,2;X = diolefin,CO +PPh, (CO),] were prepared.I4' Homo- and hetero-binuclear complexes of (120) were prepared with Ru(bpy); +,Rh"'(ppy); or Ir"'(ppy); (Hppy = 2-phenylpyridine) fragments bound in the bidentate sites.Photo-excitation of the M(ppy)l fragment (M = Ir Rh) results in energy-transfer to the Ru(bipy); + fragment which is then luminescent. 14' Elec-trochemical spectroscopic and photophysical studies were performed on [Ru(NN),LI2+ [NN = bipy or biq; L = (121) (122)] in which only one binding site is Transient UV/VIS spectroscopy was used to study the MLCT excited states of [Ru(NN),LI2+ and [{Ru(NN),),(~-L)]~+ [NN = bipy phen dmbipy; L = (123k(125)].'43.144 Control of helix self-assembly according to metal-ion IJ1 B. J. Yoblinski M. Stathis and T. F. Guarr Inory. Chem.. 1992. 31. 5. 132 A. D. Baker R. J. Morgan and T.C. Sirekas. J. Chem. Soc.. Chem. Cornmun. 1992. 1099. R. R. Ruminski C. De Groff and S.J.Smith. fnorg. Chem. 1992 31. 3325. 134 M.-T. Youinou N. Rahmouni J. Fischer and J. A. Osborn. Aiigew. Chem. Int. Ed. Enyl.. 1992.31. 733. 135 C. K. Ryu R. Wang. R. H. Schmehl S.Ferrere M. Ludwikow J. W. Merkert. C. E. L. Headford and C. M. Elliott J. Am. Chem. Soc. 1992 114 430. 13' Y. Yao M. W. Perkovic D. P. Rillema. and C. Woods Inorg. Chern. 1992 31. 3956. 13' P. D. Beer J. W. Wheeler and C. P. Moore J. Chem. Soc. Dulton Trun.5.. 1992. 2667. 13* E. C. Constable M. J. Hannon and D. A. Tocher Anyew. Chem.. fnt. Ed. Engl. 1992. 31 230. 119 J. Pons. X. Lopez J. Casabo. F. Teixidor A. Cambet J. Rius and C. Miravitlles Inory. Chirn. Actu 1992. 195. 61. I40 M. P. Garcia M. Martin and L. A. Ora. Inorg. Chirn. Actu. 1992 191. 221. 141 J.H.van Diemen R. Hage. J.G. Haasnoot H. E. B. Lempers J. Reedijk J.G. Vos. L. De Cola. F. Barigelletti and V. Balzani Inory. Chem.. 1992. 31 3518. 142 G. Giuffrida V. Ricevuto G. Guglielmo S. Campagna and M. Ciano Inory. Chirn. Actu. 1992 194. 23. 143 T. Ohno. K. Nozaki and M. Haga. Inorg. Chem.. 1992 31. 548. I44 T. Ohno K. Nozaki and M. Haga Znory. Chem.. 1992. 31. 4256. 284 M.D. Ward (126) MePy =6-methyl-2-pyridyl stereochemistry is demonstrated by formation of a double-helix [Cu\( 126),12 + and a triple helix [Coy(126)J4+ with the same binucleating ligand. 145 Transmetallation of [Pby( 127)2(MeOH)2(C10,),]2+ with Cu" affords the corresponding bis-Cu" complex which is strongly antiferromagnetically coupled across the diazine bridge.Direct reaction of (I 27) with Cu" only gives Cu' species.'46 [(CoX,),(p-128),] contains N4X2 octahedral Co" (n = 2) or NIX2 tetrahedral Co" (n = 1). For n = 2 the complex contains a large central cavity between the parallel ligands.I4' '" C. Piguet. G. Bernardinelli. B. Bocquet. A. Quattropani and A. F. Wil1iams.J. Am. Chern. Soc.. 1992,114. 7440. 146 S.S.Tandon. L. K. Thompson. and R.C. Hynes Inorg. Chern. 1992 31 2210. 147 S.S. Tandon. L. K. Thompson. J. N. Bridson and J.C. Dewar. Can. J. Chern. 1992. 70. 2771 The Coordination Chemistrji of Open-Chair1 Poljidentate Ligands 285 Other N-donor Liyands. [M2(qtpy)J2 + (qtpy = 2,2' 6',2" 6",2"'-quaterpyridine; M = Cu Ag) have double helical structures with four-coordinate metals (a bipyridyl fragment from each ligand) possibly because the M' ions are too large to bind the ligand in a planar tetradentate array.14* In contrast qtpy is m~nonucleating'~~ in trans-octahedral [Cr(qtpy)C12]C1.4H,0 and nine-coordinate [Y (qtpy )(NO,),(H,O)] [N 0,I. H ,0.'' [ReV0(qtpy )(0hle),][C104] and [ReVN (q t py )(PPh ,)Cl][C104] both display reversible ReV/ReV1 couples and intense MLCT transitions in the visible region.' 5' [PtL][ClO,] (L = qtpy 5,5',5",5"'-Me4-qtpy) are both square planar despite steric interactions between the methyl groups in the second case. Both display long-lived luminescence in the solid state.' 52 + Cis-[Co"'LCl,] [L = the chiral tetradentate ligands (129)' 53 and (130)' s4] were prepared; the chlorides may be replaced with retention of complex stereochemistry.The kinetics of alkene oxidation by trans-[RuV'02( 131)12+ were studied.'5s Cu" complexes of (132) may be five-coordinate mononuclear or binuclear with azide or cyanate bridges. The Ni" complexes are always binuclear.lS6 Affinities for 0 of octahedral Ru"' complexes of (1 33) were measured.'" The spectroscopic and electrochemical consequences of varying the chelate ring sizes in 1 1 Cu" complexes with the ligands (134) were examined.'58 Optically pure Cu" complexes of the chiral tetraamines (135) were prepared.' 59 [Fe"( 136)CllCl is five-coordinate high-spin in the solid state but six-coordinate in solution.'" [Co( 137)LCl)' (L = a substituted pyridine) are possible vitamin B, In [C~;(138),]~' one (138)is bridging donating two N atoms to each Cu' whereas the other two ligands are terminal and bidentate.The complex has two closely-spaced Cu'/Cu" oxidations.' 62 Mixed-ligand Co"' complexes were prepared with ethylene-bis-biguanide and bidentate ligands such as acac or 8-hydroxyquinoline. '63 Square-pyramidal Fe" complexes were prepared and characterized with the bis-isothiosemicarbazones (1 39).'64p1h6 [Fe"'( 140)L2] . (L = PBu, imidazole 4-But-pyridine) have reversible Fe"'/Fe'\' and Fe"'/Fe" redox 118 E. C. Constable. M. J. Hannon. A. Martin. P. R. Raithby and D. A. Tocher. Polj.hrrlron 1992 II 7967. 149 E. C. Constable. S. M. Elder and D. A. Tocher Polj,hedroti. 1992. 11. 1337. 15'1 E. C. Constable. S. M. Elder. and D. A. Tocher Poljhedrori.1992. 11. 2599. I" C.-M. Che. Y-P. Wang. K.-S. Yeung K.-Y. Wong. and S.-M. Peng. J. Chcvi. Soc. Dnlton 7itiris.. 1997. 2675. I52 C.-W. Chan C.-M. Che. M.-C. Cheng. ,ind Y. Wang. Inory. Chtw.. 1992 31. 4874. Is3 R. R. Fenton. F.S. Stephens. R. S. Vagg and P.A. Williams. Inory. Chirn. Ac.ru. 1992. 201. 157. Is4 R. R. Fenton. F. S. Stephens R. S. Vagg and P. A. Williams. Inorcq. Chini '4c.r~. 1992 197. 237. 15' C.-M. Che C.-K. Li W.-T. Tang and W.-Y. Yu. J. Chrm. Soc.. Dulroti 7ictn.s.. 1992. 3153. 15' C. Diaz and J. Ribas Polyhedron. 1992 11. 85. Is' M.M.T. Khan S.A. Mizra Z.A. Shaikh. C. Sreelatha P. Paul. R.S. Shukla. D. Srinivas A. P. Rao. S.H. R. Abdi S. Bhatt and D. Ramachmdraiah. Polyhrtlrori. 1992. 11. 1821. I sx T. Pandiyan. M. Palanidavar. M.1.akshminarayanan. and H. Manohar. J'. C'htwi. Soc,.. Dulrori Trrms.. 1992 3377. ''' P. V. Bernhardt. P Comba. T. W. Hambley. L. L. Martin. K. Viragny. and L. Zipper. Hdr . Chir~:lc.ttr 1992 75. 145. E. Mulliez G.Guillot-Edelheit. P. Leduc. J. C.Chottard. C. Bois. A. Bousseksou. and W. Nitschke. New. J. Chmi. 1992. 16 435. "l A. Gerli and L.G. Marilli Itwry. Chiwi. 1992 31 1152. If" J.-P. Collin and M.-T. Youinou. Inory. Chim. Ac,rii 1992 201. 29. "' R. K. Ray. Polyhedron 1992 11. 469. lh4 N. V. Gerbeleu. V. B. Arion. Y.A. Simonov V. E. Zavodnik. S. S. Stavrov. K. I. Turta D. I. Gradinaru. M S. Birca. A.A. Pasynskii. and 0. Ellert. Iiiory. Chirn. .4ctu. 1992. 202. 173. I"' N. V. Gerbeleu. Y.A. Simonov. V. B. Arion. V. M. Leovac. K. I Turta. K. M. Indrichan.D. I. Gradrnaru. V. E. Zavodnik. and T. I. Malinovski. Itlory. Chm.. 1992. 31. 3265. Ihh V. M. Leovac L. S. Jovanovic V. I. Cesljevic L. J. Bjelica and N. J. Evic Polj~hrdrori,1992. 11. 1029. 286 M. D. Ward (133) X = C6H4 CH2CH2 CH2CH2NHCH2CH.; (134) R = H Me; x y = various (135) R' =Me R2 = NH,; (136) ~ 1 ~2= = H (H137) (H3139) X = NO, H; R = Me Et R Bu RR (H2140) R = H C1 The Coordination Chemistry of Open-Chain Polydentate Ligands 287 couples.'67 0s"' and 0s" complexes of (140) were prepared by reduction of trans-[Osv'O,( 140)]; the 0s"' species catalyse oxidation of alkenes by PhIO.' 68 [Cot''( 14O)X,] -(X = anionic ligand) were prepared and studied by spectroelec- trochemistry.' 69 EPR and UV/VIS spectra were recorded of Cu" complexes with the tripodal ligands N(CH,Bz) (Bz =2-benzimidazolyl or N-ethyl-2-ben~imidazolyl).~ 70 [Fey(tpm) (p-+ MeC0,),I2 [tpm = tris(2-pyridylmethyl)amine] a model for ribonucleotide reduc- tase reacts with 0 to give [Fey1(tpm),(p-O)(MeC0,),]2+ in which the acetates are now terminal.' ' [(Cr"'(tren)) ,(p-CO,)(p-OH)] is weakly antiferromagnetically + coupled. Its crystal structure and luminescence properties at 1.5 K are described.' 72 High yield routes to five-coordinate (V=O} and (Mo-N} complexes containing the triamide ligand [N(CH,CH,NMe),13 -have been developed.' 73 0,S and P-donor Ligands.-Binuclear Cu" complexes of (141) have both inter- and intramolecular antiferromagnetic interactions. '74 C,-symmetric binuclear complexes of (142) were prepared with (Ir(cod)) +,(Rh(cod))+,or (Rh(nbd))+ fragments in each bidentate cavity.'" CF,C(OH),CH,C(OH),CF (H,L) derived from hydration of hexafluoroacetylacetone acts as a bidentate ligand in [Fe(hfacac),(H,L)] -or as a bis-bidentate bridge in [(Mn"'(hfacac),),(p-L)]*-Reactions of [Ru( 143)(PPh,)] with H,S S, and CS were in~estigated.'~~ Reactions of Ni" complexes of (143) and 00 n R R C.-M.Che W.-H. Leung C.-K. Li H.-Y. Cheng and S.-M. Peng Inory. Chim. Actu. 1992 196. 43. W.-K. Cheng K.-Y. Wong. W.-F. Tong T.-F. Lai and C.-M. Che. J. Chem.Soc. Dalton Trans. 1992.91. M. Ray and R. N. Mukherjee Polyhedron 1992. 11 2929. ''() H. N. Pandley Y. S. Sharma and P. Mathur Polyhedron 1992 11 2631. 171 S. Menage Y. Zang.M. P. Hendrich and L. Que Jr. J. Am. Chem. Soc.. 1992 114 7786. 172 L. Spiccia G. D. Fallon. A. Markiewicz K. S. Murray and H. Riesen Inory. Chem. 1992 31 1066. li3 W. Plass and J. G. Verkade J. Am. Chem. Soc.. 1992 114 2215. 174 J.-P. Costes F. Dahan and J.-P. Laurent Inory. Chem.. 1992 31 284. 175 I. J. Hart Polyhedron 1992 11. 729. 176 E. Bouwman J. C. Huffman E. B. Lobkovsky G. Christou. H.-L. Tsai and D.N. Hendrickson Inory. Chem.. 1992 31 4436. 177 D. Sellmann P. Lechner F. Knoch and M. Moll. .I.Am. Chrm. Soc. 1992 114 921. 288 M. D. Ward (144) with additional monodentate ligands (phosphines pyridines) were investigated as models for Ni-S rnetall~proteins.'~~ Ph,P(CH,),PPh(CH,),PPh(CH,),PPh ('P4')acts as a binucleating ligand in bis-Pt" complexes such as [Pt2( 'P4')C13] + .'79 Binuclear complexes of (145) were prepared in which the ligand coordinates as two bidentate fragments; the crystal structures of [{MC12}2(p-145)] (M = Ni Pd) are described.'8o Mixed N,O-donor Ligands.-Bis(salicylaldimine) Complexes.Complexes of 'salen' (146) and its substituted derivatives continue to be extremely popular. Several Mn"' complexes are efficient organic oxidation catalysts using NaOCl or Ph1O.l 82 '3 [Mn"(147)] reacts with 0 to give [(Mn'V(147)(p-O)),] which can be reduced to the Mn"'/MdV state;'83 [(MnlV(L)(u-O)},] [L = (147) (148)] undergo an irreversible four-electron two 0 atom transfer to [Fe( 146)] giving [MnL] and 2[(Fe"'( 146))&1- O)].'84 Co" complexes of (146) and (149) catalyse the selective conversion of (H2146) X = H (H2147) X = 5-C1 (H2148) X = 5-OMe (H2149) X = 6-Bu' (H2150) X = 5-Br (H2151) X = 3-OMe h (h153) X = (CH& (CH,), CH2C(Me)&X2 (Hz154) R = H R = (CHz),H n = 4-14 (H2155) R = C(0)NH(C6M3-p-Me-m-NCO) arylglyoxals to z-aryl-z-hydroxyacetic esters.' 85 A spectroelectrochemical study of [(Col"( 146)(dmso)),(p-O,)] showed that a two-electron oxidation gives free 0 and [Co( 146)(dmso),] + '86 [Ru( 146)(NO)(H20)][SbF6] performs efficient Lewis-acid catalysis of Diels -Alder reactions.'" [Ti( 146)Cl,] reacts with LiMe to give 17H D.Sellmann S. Schillinger. and F. Knoch Z. Narurforsch.. 7Lil A. 1992. 47. 645. H. Goller and P. Bruggeller Incity. him. Actci. 1992. 197. 75. '"" M.R. Mason. C. M. Duff. L.L. Miller. R.A. Jacobson and J.G. Verkade Inory. Chrm.. 1992. 31. 2746. 1x1 D. R. Reddy and E. R. Thornton J. Ckc~m.Soc,.. Churn. Comtnun. 1992. 172. Ix2 D.S. Thomsen B. Schicatt and K. A. Jsrgensen. J. Chrm. Soc.. Chmi. Commun. 1992 1072. I x1 G.C. Dailey. C. P. Horwitz. and c'.A. Lisek Inorq. Chern. 1992 31 5325. '" G.C. Dailej and C. P. Horwitz Inorcq. Chum.. 1992 31 3693. K. Maruyama. Y. Murakami K. Yoda. T. Mashino. and A. Nishinaga. .I. Chem. Soc,.. Chrm. Commun.. 1992. 1617. 1Xh J. H. Cameron and S. C. Turner. .I. Chcwi. SOC...Dcrlroti /'runs.. 1992. 3285. W. Odenkirk. A. L. Rheingold. and B. Bosnich. J. Am. Chrm. Soc,.. 1992. 114 6392. The Coordination Chemistry of' 0pc.n-Chain Polydentate Liyands 289 [Ti(146)Me2] which on heating undergoes methyl migration from the metal to the electrophilic imine C-atom.Aryl groups behave similarly.'88 [CoL] [L = (146) (147) (150) (I 51)] reacts with Fe" to give binuclear 'CoLFe' species which take up O2faster than [CoL] a10ne.l~~ [Cu(146)] react with [Fe(acac),(NO,)] to give [Cu( 146)Fe(acac),] where the Fe" is coordinated by the two (bridging) phenolates.' " Similarly (M(hfacac),} fragments (M = Co" Ni" Zn") can be attached to the two phenolates of [Cr"'( 146)L,] + (L = neutral axial ligand) to give new phenolate-bridged heterobinuclear species,"' and Cu" or Ni" complexes with (146) (152) and other ligands bind Sn complexes such as [SnCl,(OEt)] at the di-phenol Elec-trochemical oxidation of Co". Ni" Cu" and Zn" complexes of salen-type ligands gives redox-active polymers some of which are conductors.' 93 Mesogenic vanadyl com- plexes of the ligands (153) form polymeric linear chains via head-to-tail V=O ...V interactions.194 [{ Mn"( 152)(p-O); '1 exhibits catalase activity. The correlation be- tween Mn .. . Mn separation and Mn-0-Mn bridge angles was discussed."' Protona-tion of [{Mn1V(152)(p-0)}2] to give [(Mn'V(152)),(p-0)(p-OH)]+increases the Mn .*. Mn separation by 0.1 A and removes the catalase activity.'95 [(Mn"'( 152)(p- OAc},].3H20 is polymeric with (Mn( 152)) + units bridged by acetates.196 Reversible binding of CO and 0 to trans-[Ru"'LCl,]- (L = salen derivatives with C1 and OMe substituents) was studied; reaction with 0 generates Rutv-superoxo species.' 97 [Zr"L,] [L = (154) or (155)] were prepared; [Zr(155),] forms a copolymer with poly(thf) containing alternating metal sites and organic blocks.' 98 Other Mixed N,O-donor Liyands.The EPR spectra of Co" complexes of (H2156) doped into isostructural Zn" complexes indicate a six-coordinate structure. '99 The crystal structure and magnetic properties of [{ Fe"'( 157)),(p-OMe),] were determined.'"" Activation of 0 by [Ni(158)] results in oxidative dehydrogenation of one CH-NH bond.,'' The magnetic properties of [Cu"( 159)M"(dmbipy),] (M = Co Mn) where Cu" is in the N,O cavity and the (M(drnbipy))'+ fragment is attached to the bridging phenolates were studied.' "' A detailed comparison between structural parameters was made for [Fe"'( 16O)Xl (X = Cl NO,) [Fe"'(l60)(CN),] - and [(Fe"'(160)),(p-0)].203 In [M'VL(Cp)2] [M = Ti Zr; L = (160k(162)] the metals lie in the ligand N,O cavity and have two lRX E.Solari C. Floriani A. Chiesi-Villa. and C. Rizzoli J. Chem. Soc.. Dulton Truns. 1992 367. 1HY Y. Abe K. Shinguhara and S. Yano Ciiem. Lett. 1992 897. Iyo D. Laroque I. Morgenstern-Badarau H. Winkler E. Bill A. X. Trautuein. and M. Julve lnory Chim. Acru 1992 192 107. C.T. Brewer and G.A. Brewer Inorg. Chim. Actu. 1992 196. 1. D. Cunningham and J. McGinley. J. Chem. Soc.. Dalton Truns. 1992. 1387. P. Audebert P. Capdevielle and M. Maumy New. J. Chrm.. 1992 16. 697. IY4 A. Serrette. P. J. Carroll and T. M. Swager J. Am. Chrm. Soc.. 1992 114 1887. 195 E. J. Larson. P. J. Riggs.J. E. Penner-Hahn and V. L. Pecoraro J. Chem.Soc.. Chem. Commun.. 1992. 102. IYb N.Aurangzelo C. E. Hulme C.A. McAuliffe. R.G. Pritchard M. Watkinson. A. Garcia-Deibe. M. K. Bermejo. and A. Sousa. J. Chem. Soc.. C'hem. Cornrnun. 1992. 1524. I 9 -M. M.T. Khan Z.A. Shaikh R. I. Kureshy and A. B. Boricha. Polyhrdror7. 1991. 11 91. IYH W. Tong and R. D. Archer. Inory. Chrni 1992. 31. 3332. 199 K. Drabent J. A. Wolny. M. F. Rudolf. and P. J. Chmielewski. Polj,hedron. 1992 11 271. 200 P. Baran A. Bottcher. H. Elias W. Haase. M.Hiiber. H. Fuess. and H. Paulus. Z. Nurur/orsc~h..7i.il B. 1992 47 1681. 20 I A. Bottcher. H. Elias L. Muller and H. Paulus. Ariyew. Chem.. Inr. Ed. Engl.. 1992. 31 623. 202 D. Liao S. Juan. Z.-H. Jiang. S.-P. Yan. P.Cheng. and G.-L. Wang. Polyhrdron. 1991. 11. 7671. 203 X. Wang W. T. Pennington D. L. Anker-s. and J. C. Fanning. Polj,hrdron. 1992 11. 2253. 290 M. D.Ward (H2156) R' =Me Et Bun R2 = H 5-C1 R3 = H 5-C1 3,5-C12 3-OMe (H2157) R=H (H2158) R = But (H2160) R' = Me R2 = H X = CH2CH2 (H2163) R = Me or Ph (H2161) R' = H R2 = C(O)Me X = 1,2-C6H4 (H2162) R' = H R2 = C(O)Me X = 1,2-(4-Me-C6H3) (H,164) R' = H. R2 = Me (H2165) R' = H R2 = CH3 (H2166) R' = Me R2 = CF3 The Coordination Chemistry of Open-Chain Polydentate Ligands 29 1 capping Cp ligand~.~'~ [Fe( 161 )(NO)] changes its spin state from S = 1/2 to S = 312 between 80 and 320 K.,05 The bis-semicarbazone of cyclohexane-l,2-dione (L)acts as a planar tetradentate N,O donor in [Co,L,(H,O),(NO,)]' where the dimer is held together by carbonylic bridges and as a tridentate ONN ligand in [NiL,]"."Oh [VO( 163)] are rare examples of oxovanadium(1v) complexes with amide ligands; they have reversible VlV/Vvand V1V/V11'couples.207 NiI'complexes of (164)-( 166) are chiral.For (1 65) and (1 66) crystallography indicates that an axial Ni . . . F interaction with the CF groups promotes slow enantiomer interconversion which was studied by NMR.~O~ The structure and EPR properties of the diradical [(VO)2(p-d~p)2]2 -(H,dcp = pyrazole-3,5-dicarboxylic acid) were determined.,09 [Co"( 167)Ll (L = py-ridine imidazole) react reversibly with 0 to give Co"'-superoxo species.2' Binding of R MeN4-Q Ho 0 "7 R \ (H,167) R = Me W But (H168) the two ligands to Ni" in trans-[Ni(l68),] brings the oxygen-donor side chains together in the right conformation to bind alkali metal cations.The stability constants of such adducts were measured. l1 The crystal structure of Ba[{ Fe'11(nta)(H,0)),(p-0)]~4H,0,where nta is face-capping was determined.,, Reduction of one carboxylate of H,nta to give N(CH,CO,H),(CH,CH,OH) (H,L) causes a remarkable change in its iron com- plexes; the crystal structures of [Fe,9(p,-O)6(p3-OH)6(p2-OH)sLlo(H20)12] + and [Fe ,(p3-O),(p3-OH),(p2-OH)loL,s(H20)l ,I3+ both have a close-packed AX,-type iron-oxo core surrounded by a shell of Fe atoms and the bridging tetradentate ligands + at the periphery.,' [Pb"(ntam),(NO,)] [ntam = nitrilotriacetamide N(CH,- CONH,),] is the first structurally characterized metal complex of ntam.It is ten-coordinate with ntam acting as an NO donor.214 Square-pyramidal [Cu"( 169)Cl) is a possible galactose oxidase [Mo,Cu,O,( 170),(p3-Me0),].2MeCN has a cubane-like core which forms an infinite chain cia Mo=O.. .Cu interactions.216 '(I4 R. Rai K. D. Mishra 0.P. Pandey. and S. J. Sengupta Polyhedron 1992 11 123. 2os E. Konig G. Ritter. J. Dengler and L. F. Larkworthy. lnorg. Chem. 1992. 31 1196. 'Oh L. P. Battaglia P. G. Berzolla A. B. Corradi C. Pelizzi G. Pelosi and C. Solinas J. Chem. SOL..,Dalton Truns. 1992 3089. "' G. R. Hanson T. A. Kabanos A. D. Keramidas. D. Mentzafos. and A. Terzis lnorg. Chern. 1992.31.2587. M. Kwiatkowski and G. Bandoli J. Chem. Soc. Dalton Trans..1992 379. 2oy C. W. Hahn P.G. Rasmussen. and J.C. Bayon lnorg. Chem.. 1992 31. 1963. 210 M. F. Rudolf J.A. Wolny. T. Lis and P. Starynowicz J. Chem. Soc. Dillton Trans. 1992 2079. "' M. W. James N. Gupta and A. Schepartz lnorg. Chem. 1992 31 1308. 'I2 S. L. Heath. A. K. Powell H. L. Uttig and M. Helliwell J. Chem. So(.. Dultun Trans.. 1992. 305. 'I3 S. L. Heath and A.K. Powell Angew Chem. Znt. Ed. Engl. 1992 31 191. 'I4 D. A. Smith S. Sucheck and A.A. Pinkerton J. Chern. Soc. Chem. Commun. 1992 367. 215 U. Rajendran R. Viswanathan M. Palaniandavar. and M. Lakshminarayanan J. Chem. Soc. Dalton Trans. 1992 3563. 216 D. P. Kessissoglou C. P. Raptopoulou EG. Bakalbassis A. Terzis and J. Mrorinski Inory. Chem. 1992. 31. 4339. 292 M.D.Ward (H169) (H3170) Mixed N,S-donor Ligands.-The interconversion of distorted tetrahedral [Cu( 17 1 )] + between diasteroisomers was studied by variable-temperature NMR spectroscopy. Oxidation gives square-pyramidal [Cu( 171)(H,O)l2+ ; the two are related by a quasi-reversible Cu'/Cu" couple.217 Reaction of [Cu( 171)] + with excess (171) gives [Cu(l71),] +,in which the Cu'is tetrahedrally coordinated by the four N atoms and the Satoms are pendant.,'* Electrochemical studies were performed on [Cu"( 172)XYl (X Y are mono anion^)^^^ and [C~"(173)(H,0)]~+ .220 Neutral lipophilic oxotech- netium(v) complexes of (H 174)-(H 176) labelled with 99mTcwere studied as possible brain perfusion agents for imaging2,' [TcV(N)L] and [TcV(0)L]+ [L = (176)-( 179)] are square pyramidal.222 A titrimetric study of complex formation of (180) with Zn" and Cd" revealed the presence of several species with different metal-to-ligand ratios.,, [Zn2(181),] contains square-pyramidal Zn" ions with a Zn,(p-S) core; [(Ni(181))3Zn2C12]2+ contains three {Ni(181)} groups bound to a Zn core by bridging sulfides.The degree of aggregation of complexes with (1 81) is solvent dependent.224 Oxidation of [Fe( 182)(CO)] causes dehydrogenation of the amines in the ligand to give an u,sc'-diimine; the resulting complex is binuclear with an Fe,(p-S) core.225 Mono- and binuclear complexes of Au"' with (183) were prepared.226 The electrochemical properties of [Sn"( 184)] and [Sn"( 184),] were examined.227 [MVOL]- [M = Tc Re; L = (185) acting as N,S2 donors] have square-pyramidal structures containing seven-membered chelate [ReV(0)( 186)] -were assessed as possible renal imaging agents.229 In [TcVNBr,(187)] (187) acts as an N face-capping ligand in the solid but in solution the pendant thioether displaces a bromide to give a 1 1 ele~trolyte.~~' The crystal structure of [Ni2(188),][C10,] 217 D.A. Nation M. R. Taylor. and K. P. Wainwright J. Chem. Soc.. Dalton Trans. 1992 1557. 2113 D. A. Nation M. R. Taylor. and K. P. Wainwright J. Chrm. Soc.. Dalton Trans. 1992 241 1. 219 M. F. Cabral. J. de 0.Cabral. E. Bouwman W. L. Driessen. J. Reedijk. U. Turpeinen. and R. Hamalainen Inorg. Chim. Acta 1992 196 137. 220 W. G. Haanstra M. F. Cabral J. de 0.Cabral W. L. Driessen. and J.Reedijk Inorg. Chrm.,1992,31.3150. 221 C. S.John L. C. Francesconi. H. F. King S. Wehrli,G. Graczyk.and P. Carroll.Po/yhrdron 1992,11,145. 222 A. Marchi L. Marvelli R. Rossi. L. Magon. V. Bertolasi V. Ferretti. and P. Gilli J. Chem. Soc. Dalton Trans.. 1992 1485. 223 A. Audeef. F. Hartenstein A. R. Chemotti. Jr. and J. A. Brown. Inorg. Chrm. 1992 31. 3701. 224 T. Tuntulani J. H. Riebenspies P. J. Farmer and M. Y. Darensbourg Inorg. Chrm. 1992 31 3497. 225 D. Sellman M. Hannakam F. Knoch and M. Moll Z. Naturfivsch. Teil B 1992 47 1545. 226 A. P. Koley S. Purohit L.S. Prasad. S. Ghosh. and P.T. Manoharan. Inorg. Chem. 1992 31 305. 227 J. E. Anderson. S.M. Sawtelle. J. S. Thompson. S.A. Kretchmar Nguyen and J. Calabrese Inorg. Chrm.. 1992. 31.2778.228 B. Chen M. J. Heeg and E. Deutsch. Inorg. Chpm.. 1992 31. 4638. 229 L. Hansen R. Chi. A. Taylor Jr. and L.G. Marzilli. Inorg. Chem.. 1992. 31 2801. 230 J.R. Dilworth D.V. Griffiths J.M. Hughes S. Morton. W. Hiller C.M. Archer J.D. Kelly and G. Walton Inorg. Chim. Actu 1992 192 59. The Coordination Chemistrj? of Open-Chain Polydentate Ligands n S N-V /N-NW 'Sw\ (173) A (yyJ SH HS RR (H4185) R = H Ph (H174) R' (H175) R' (H176) R' (H177) R' (H178) R' (H179) R' (H180) R' (H181) R' (172) R = H Me; n= 2,3 = Me R2 = H X = 2,2'-(C6H4)2 = Et R2 = H X = 2,2'-(C,H& = Et R2 = H X = CH2CH2 = Me R2 = H X = CHzCH2 = Me R2 = Et X = CH2CH2 = R2 = Me X = CH2CH2 = H R2 = Me X = CH2CH2 = H 2R2 = X = (CH2)3 bridge (187) n=1 R=CH2Ph (H188) n=2 S = H 294 M.D. Wurd reveals a Ni,(,u-S) core with one low-spin square-planar Ni" and one high-spin square pyramidal The stability constants and complexation kinetics were studied for Cu" complexes with N(CH,CH,SR) (R = Me Et).,, Although (H 189) acts as an N,N-bidentate ligand in [M(H189),] (M = Co Ni) with the nickel triad one-dimensional polymers can also result due to occupation of both N,N and S,Ssites. A trinuclear Cu" complex was also isolated.233 Other Mixed-donor Ligands.-Monocationic Tc"' and Tc" complexes of the tetrapodal ligands np and pp3 were prepared.,, [Mn"(np,)I][BPh,] has been crystallographi- cally characterized and is five-~oordinate;~~~ by contrast [Hg(np,)Me] + is four-coordinate with the bridgehead N atom not coordinated.236 In [Ni"(ps,),]' -R' [H,ps = P(o-C,H,SH),] each ligand acts as a PS donor to one Ni" and a P donor to the other.Oxidation to the delocalized Ni"/Ni"' state results in a change of geometry from near-planar to square-pyramidal with bridging thi~lates.~~' Neutral M" complexes of (190) and (191) were prepared electrochemically and their geometries discussed on the basis of magnetic and spectroscopic data.238 5 Pentadentate Ligands N-donor Ligands.-Whereas the Co" complex of qpy (qpy = 2,2' :6',2" 6",2"' :6"',2"''-quinquepyridine) is a binuclear double helix in the solid state in solution the + seven-coordinate mononuclear species [Co(qpy)(S),] (S= solvent) forms which reacts239 with Ag' or Cut to afford heterobinuclear double helices [CoM(qpy),13+.In [Cl,qpy contrast [CO(C~,~~~)(M~OH)(H,O)][PF~]~= 4',4"'-bis(4-~hlorophenyl)-231 M. Mikuriya M. Handa,S. Shigematsu S. Funaki. F. Adachi,and H. Okawa Bull. Chem. Soc.Jpn. 1992. 65 512. 232 T. H. Cooper M. J. Mayer K.-H. Leung L. A. OchryrnowycL and D. B. Rorabacher Znory. Chem. 1992. 31 3796. 233 I. Giirol V. Ahsen and 0.Bekgroglu J. Chem. Soc. Dalton Trans. 1992 2283. 234 J. R. Dilworth. D. V. Griffiths J. M. Hughes S. Morton C. M. Archer and J. D. Kelly Znory. Chim. Acta 1992 195 145. 235 F. Cecconi C. A. Ghilardi S. Midollini and A. Orlandini J. Chem. SOL..,Dalton Trans. 1992 33. 236 C. A. Ghilardi P. Innocenti S. Midollini A. Orlandini and A. Vacca,J.Chem. Soc.. Chem. Commun.. 1992. 1691. 237 J.-D. Franolic W. Y. Wang and M. Millar. J. Am. Chem. Soc. 1992 114. 6587. 238 R. Bastida A. De Blas D. E. Fenton. and T. Rodriguez. Polyhedron 1992. 11 2739. 2 39 E. C. Constable and J. V. Walker J. Chem. Snc. Chem. Commun. 1992 884. The Coordination Chemistry of Open-Chain Polpdentate Ligands (192) R' = R~= H x= CH (193) R' = C(O)NH2 R2 = H X= CH (194) R1 = H R2 =Br X=N (H3196) m=n=l R=H (H3197) m = n = 1 R = 4,6-C12 (H3198) m=2 n=2 R=H (H3199) m=n=2 R=H spy] is mononuclear and seven-coordinate in the crystal as well as in solution.24" Ligands (192)-(194) are bleomycin analogues. Whereas the mode of coordination of (192) and (193) to Fe" Cu" and Zn" is pH dependent,241 (194)is always pentadentate in its octahedral Co"' complexes for which a mechanism for light-induced damage to DNA is Mono- and binuclear complexes of Ni" Cu" and Zn" with (H2195) were prepared.243 Mixed N,O-donor Ligands.-Binuclear and tetranuclear alkoxo-bridged Mn"' com-plexes of (196) were prepared as possible models for Mn-containing photosynthetic rnetall~proteins.~~~~~~~ The variable-temperature EPR properties of the highly asymmetric complex [Mn"'Mn'V( 197),(thf)][C104] closely mimic those of the photo- synthetic 0,-evolving Bis-Ni" complexes of (196) (198) and (199) contain endogenous alkoxide and exogenous pyrazolate bridges.The effect of increasing chain length on distortions from planarity at the metal centre was in~estigated.,~~ Binuclear Fe"' and Mn"' complexes of the asymmetric ligand (200) 240 E.C. Constable J. V. Walker D A. Tocher and M. A. M. Daniels J. Chem. Soc. Chem. Comntun. 1992 768. 241 E. Kimura H. Kurosaki Y. Kurogi hl. Shionoya and M. Shiro Inorq. Chem.. 1992. 31 4314. 242 J. D. Tan S.E. Hudson S.J. Brown M. M. Olmstead and P. K. Mascharak J. Am. Chem. So(.. 1992.114 384 1. 243 G.Paohcci S.Stelluto S.Sitran. D. Ajo F. Benetollo. A. Polo. and G. Bombieri Inorq. Chim. Acru 1992 193 57. 244 M. Mikuriya Y. Yamato and T. Tokii. Bull. Chrm. Soc. Jpn 1992 65. 1466. 245 M. Mikuriya Y. Yamato and T. Tokit. Bull. Chem. Soc. Jpn. 1992 65. 2624. 246 E. Larson. A. Haddy M. L. Kirk. R. H. Sands W. E. Hatfield and V.L. Pecoraro. J. Am. Chem.Soc.. 1992 114 6263.247 M. Mikyuriya T. Sasaski. A. Anjiki S. Ikenoue and T. Tokii Bull. Chem. Soc. Jpn. 1992. 65 334. 296 M.D. Ward (H3201) R' = R2 = H R3 = Me (H3202) R' = Ph R2 = Me R3 = H (H3203) R' = H R2 = NO, R3 = Me HO R2 AO (H3204) R' = H R2 = Me (H3205) R' = R2 = Me (H3206) R' = H R2 = Ph (H2208) X = PI Y = CH R = H or OMe (H210) (H2209) X = CH Y = N R = H or OMe both have M 2(p-0)2cores with weak antiferromagnetic and ferromagnetic interac- tions respectively.248 Five-coordinate [Fe"(201 j] undergoes a redox reaction with [RuV1(tppj(Oj,] to give [(201)Fe111(,u-O)(Ru'V(tpp)}(p-O)Fe'1'(201)J.249 LFe"(202)-(3,4-Me2pyr)]+ exhibits spin-crossover beha~iour.~~' [Mn1"(OH)(203)] is the first structurally characterized mononuclear hydroxo-manganese ~omplex.~ [Cu;(204)- (p-RCO,)] in which each Cu" is nearly square-planar with endogenous alkoxide and 248 M.Mikuriya. Y. Yamato. and T. Tokii Chem. Lett.. 1992 1571. 244 L. D. Schulz G. D. Fallon B. Moubaraki K. S. Murray and B. 0.West J. Chem. Soc. Chem. Commun. 1992 971. 2so Y. Maeda Y. Noda I-I. Oshio. and Y. Takashima. Bull. Chem. Soc. Jpn.. 1992 65 1825. D. M. Eichhorn and W. H. Armstrong. J. Chem. Soc. Chem. Commun.. 1992. 85. The Coordination Chemistry of Open-Chain Polydentate Ligands 297 exogenous carboxylate bridges exhibit antiferromagnetic exchange.,' [{M1'(205)),(p-L)] [M = Ni Cu; H2L = 4,4'-di(3,5-dimethylpyrazole)]contain two { M,(205))'+ units with the bridge L donating one N atom to each metal to complete the square-planar coordination." [Mny'(206) (OMe) (MeOH)( EtOH)] [ClO,] contains an alkoxo-bridged isosceles-triangular core; its low-temperature magnetic properties were examined.254 [Cu"(207)] is a four-coordinate complex with a free external imidazole N atom which can be attached in a subsequent step to other metal complexes to give magnetically interacting polynuclear imidazolate-bridged spe- cies.2ss,2s6 Likewise [M(208)] and [M(209)] (M = Cu Ni) bind axially to iron porphyrins via the external imidazole N atom.2s7 [C~y(210)(p-EtO)(MeOH)]~ + was structurally characterized; [Cu2(210)(p-Br)Br,] was also prepared.Both exhibit moderate antiferromagnetic exchange.,'* Ligands with Other Donor Sets.-The octahedral complexes CFe"(21 l)X] [X = NH, N,H, NH,NHMe P(OR), MeOH thf py] are high-spin if X is a good a-donor and low-spin if X is a good rr-a~ceptor.~'~ Ni" complexes of (211t(214) undergo ligand-transfer reactions with other metals which provides a convenient route to new complexes; [Mo'"(O)L] [L = (21l) (212)] were crystallographically character- ized.260 The reactivity of the nitrosyl ligand of [Ru(214)(NO)]Br was examined.261 [Fe(215)L] (L = CO NO PMe, N,H,) were prepared.262 Cu" complexes of open-chain N,S-containing ligands such as (216),263 (21 7),263.264 (218)-(220),264 and (221)_(222)26s are of interest as possible type I cuproprotein models.In this regard their electrochemical EPR and UV/VIS properties are of interest. [Cuy(223)(p- Cl),Cl] contains endogenous phenolate and exogenous chloride bridges; two of these binuclear units are linked by long Cu-Cl bonds and NH 3..C1 hydrogen bonds to give a tetranuclear dimer in the crystal.2h6 6 Hexadentate Ligands N-donor and 0-donor Ligands.-A new preparation of sexipy (2,2' 6',2" 6",2"' 6"',2"" :6"",2""'-sexipyridine) by coupling 2-bromo-terpy using Ni' was developed; the reaction product is the double-helical [Ni~(sexipy),][PF,] which is demetallated with cyanide to give the free ligand.267 [Eu(sexipy)(NO,),][No,l 252 T. Kawata M. Yarnanaka S. Ohba Y. Nishida M. Nagarnatsu T. Tokii. M. Kato. and 0.W. Steward. Bull. Chem. SOC.Jpn. 1992 65 2739. 253 P. E. Kruger G.D. Fallon B. Moubaraki. and K.S. Murray J. Chum. Soc.. Chem. Cornmun. 1992 1726. 251 M. Mikuriya K. Majirna and Y.Yarnato Chem. Lett. 1992 1929. 2s5 S.Ohkubo K. Inoue H. Tarnaki M. Ohha N. Matsumot0.H. Okawa and S. Kida Bull. Chem.Sot,. Jpn. 1992 65 1603. 256 N. Matsurnoto K. Inoue M. Ohba. H. Okawa and S. Kida Bull. Chem. Soc. Jpn.. 1992. 65. 2283. 25' C.T. Brewer and G. Brewer J. Chem. Soc. Dalton Trans. 1992. 1669. 2sx Y. Shiping. C. Peng L. Daizheng J. Zonghui W. Genglin W. Honggen and Y. Xinkan. Polyhedron 1992. 11 879. "'D. Sellrnann W. Soglowek F. Knoch G. Ritter and J. Dengler Inorq. Chem. 1992 31 371 1. 260 D. Sellrnann S. Fiinfgelder and F. Knoch Z. Nuturforsch. Teil B 1992 47 51. 26' D. Sellrnann. M. Geck and M. Moll Z. Naturforsc,h. Tuil B 1992 47. 74. 262 D. Sellrnann W. Soglawek and M. Moll Z. Naturjorsch.. Teil B 1992 47 1105. 263 S. Liu C.R. Lucas R.C. Hynes and J.-P. Charland Cun. J. Chem. 1992. 70 1773. 264 R. P. F. Kanters R. Yu. and A. W. Addison Inory. Chim. Actu. 1992 196 97. 265 H. Masuda T. Sugimori. T. Kohzurna A. Odani and 0.Yamauchi Bull. Chem. SOC.Jpn.. 1992.65 786. '" J.C. Wilson P. D. Verweiji. W. L. Driessen. and J. Reedijk Inory. Chim. Actu 1992 192 219. '" E. C. Constable and R. Chotalia. J. Chern. Soc.. Chem. Commun.. 1992. 64. 298 M.D. Ward R R (H2211) X=NH R=H (H2212) X = 0 R = H (H2213) X = CH2 R = H (H2214) X = S R= H (H2215) X=NH R=Bu' R R (216) X = S Y = 0,R = H (217) X=Y =S R=H (218) X=Y=S R=Me (221) X=NH Y=S R=H (219) n= 1 (220) n= 2 (222) (H223) is ten-coordinate with the sexipy twisted into a shallow mono-helical geometry.The complex is intensely luminescent.268 Ligands (224) and (225) react with Cu' to give trinuclear double helices [Cu\L2l3' in which each Cu' is tetrahedrally coordinated by two bipy fragments. Assembly of the helices involves positive ~o-operativity.~~~ The bis(terpyridy1) ligand (226) forms binuclear double helices [MY(226),l4+ (M = Fe Ru) with octahedral metal centres.270 By using a lanthanide (capable of nine-fold "* E. C. Constable R. Chotaiia and D.A. Tocher J. Chern. Soc.. Chem. Commun. 1992 771. 269 A. Pfeil and J.-M. Lehn J. Chem. Soc. Chem. Commun.. 1992. 838. 2'o J. D. Crane and J.-P. Sauvage New. J. Chem.. 1992 16 649. The Coordination Chemistry of Open-Chain Polydentate Ligands 299 X pq/o~op-q (224) X=H (225) X = CO2Et R coordination) as template the triple helical [Eu2(227)J6+ can be assembled.27 ' In [Mn2(228)(p-O),(p-MeC02)]"+ (n = 2 Mn"'/Mnlv; n = 3; Mn;") the ligand spans the {Mn,(p-O),} core leaving two syn-oriented sites perpendicular to the Mn202 plane.[{ Mn:V(,u-O)4(OH)(228)} 2(p-228)]6 + comprises two linked {Mn304)4+ (incomplete cubane) cores. The electrochemical magnetic and spectro- scopic properties of these complexes were in~estigated.~~~,~~~ Irradiation of [FeLI2 + [L = (228) (229)] to give the initial 'MLCT excited state is followed by rapid ( <1 ps) inter-system crossing to a long-lived 5T2state.274 [M(228)I2+ (M = Fe Co Ni) can mediate electrocatalytic reduction of C02.77 (228) X = (CH& (229) X = (CH2)3 (230) n= 3 (232) X = 1,3-C6H (231) n=5 27' G.Bernardinelli C. Piguet and A. F. Williams. Angew. Chrm. Int. Ed. Enyl. 1992 31 1622. 272 S. Pal J. W. Gohdes W.C.A. Wilisch and W. H. Armstrong. Inory. Chem. 1992 31 713. 273 S. Pal and W. H. Armstrong Inorg. Chrm. 1992 31 5417. 274 J. K. McKusker. K.N. Walda R. C. Dunn. J. D. Simon D. Magde. and D. N. Hendrickson. J. Am. Chrm. Soc. 1992 114 6919. 300 M. D. Ward Bis-Cu’ complexes of (230) and (23 1) are haemocyanin models. Their binding of and reactivity with CO and 0 was studied in Similarly binuclear Cu’ and Cu” complexes of (232) were prepared and some crystal structures determined. They undergo reversible interconversion between Cuy Cu’Cu” and Cu; at potentials that are strongly solvent-dependent. The binding constant of CO in [Cu;(232)(CO)J2 + was measured.276 Electrochemical measurements showed that two molecules of the bis-Cu’ complexes of the ligand series (233) react with one molecule of 0,.277 bim7 N-X-N bimJ @im = 2-benzimidazolyl) (233) X = (CHZ),, n = 3,4,6 (234) X = nothing 1,4-CH2C,H&H, CH2CH(OH)CH2 (235) x = 1,4-c6H4 OH OH OH (239) m=n=2,3; n=3,m=4 The ‘back-to-back’ bis-terpyridines (234) and (235) can form one-dimensional polymers with Ru”.Binuclear complexes [(4’-X-terpy)Ru(pL)Ru(4’-X-terpy)l4+were also prepared and characterized with a variety of electron-donating or withdrawing groups X on the terminal terpy ligand~~~~ (cf. reference 313). Mono- bi- and K. D. Karlin Z. Tyelkar A. Farcqq M. S. Haka P. Ghosh R. W.Cruse. Y. Gultneh. J.C. Hayes. P.J. Toscano and J. Zubieta Inorg. Chem. 1992 31 1436. *” S. Schindler D. J. Szalda and C. Creutz Inorg. Chem. 1992 31 2255. ’” Y. Nishida I. Watanabe and K. Unoura Z. Naturforsch. Trrl B. 1992 47. 109. ”’ E.C. Constable and A. M. W. Cargill Thompson. J. Chrrn. Soc. Dulton Trans. 1992 3467. The Coordination Chemistry of Open-Chain Polydentate Ligands 301 tri-metallic complexes of hexaazatriphenylene (236) were prepared by attaching {Ru(NN),),' and (Rh(NN),)3+ (NN =bidentate chelating ligand) moieties to its binding sites. Their fast atom bombardment mass spectra were studied in Pd" and Pt" complexes of the achirally and chirally-substituted hexadentate ligands (237) and their mononucleating terdentate 'dien' analogues bind to nucleic acids and may be used as structural probes.280 [M(238)] (M = Cu Ni) where the metal is in the planar N cavity act as bidentate ligands to additional metal ions uia the external pyridazine N atoms.This enables preparation of binuclear complexes such as [Ni(238)Ni(hfacac),] and trinuclear complexes such as [{M(238)),CuX,,] (X =halide) which can show strong antifer- romagnetic couplings.'8 1.282 Vv complexes of the tris-catechol ligands (239) are possible enterobactin models.283 Mixed N,O-donorLigands.-[V"'(240)] is oxidized by 0 to [V'"(240)] which has a ~ cis-N,O donor set with no 0x0-ligands. Reversible V'"/VV and V'"/V"' couples were observed.284 [Mn"'L][PF,] [L = (241) (242)] have Jahn-Teller distorted octahedral structures; spectroelectrochemical EPR studies on [Mn"LI2 indicate rhombically + distorted structures.28s [Mn1"(243)] are also octahedral and undergo quasi-reversible reductions to Mn11'.2X6 contains a linear array [Mn~'(244),(MeO),(MeOH)8][C104]2 of four Mn"' ions with each ligand (244) bridging three of them.In DMF solution it dissociates to a binuclear species that exhibits catalase Spectroscopic and electrochemical studies were performed on [R~"'(245)].~~~ Heterobinuclear complexes of (246) were prepared containing a first-row ion [V(O) + Cu" Ni"] in the internal N,02 cavity and a lanthanide in the external cavity; the fluorescence of Eu"' in such complexes was partially q~enched.~~~,~~' Binuclear complexes of (247) and homo- and heterobinuclear complexes of (248) with first-row transition metal dications are weakly antiferromagnetically coupled ziia the bridging phenolates.291*292 Schiff bases (249) were prepared with different substituents on the aromatic rings and also form phenolate-bridged binuclear complexes.Their magnetic properties and the effects of the ring substituents on their electrochemical behaviour were e~amined.~~~.~~~ 27y P. Didier L. Jacquet A. Kirsch-De Mesrnaeker. R. Huber and A. van Dorsselaer Inorg. Chem. 1992.31 4803. 2x0 R. Alul. M. B. Cleaver and J. S. Taylor. Inorg. Chem. 1992 31. 3636. 2x1 M. Abed Ali Miah. D. J. Phillips and A. I). Rae. Inorg. Chim. Acta 1992 201 191. 2R2 G.C.Chiumia M. Abed Ali Miah and D.J. Phillips Inory. Chim. Actu 1992. 191 19. 283 A.Butler R. de la Rosa. Q. Zhou. A. Jhanji and C. J. Carrano. Inorg. Chem.. 1992. 31 5072. 2"4 A. Neves. A.S. Ceccato I. Vencato Y.P. Mascarenhas. and C. Erasrnus-Buhr. J. Chem. Soc. Chrm. Commun.. 1992 6.52. 2K5 A. Neves. S. M. D. Erthal. I. Vencato. A.S Ceccato Y. P. Mascarenhas. 0.R. Nascirnento M. Horner and A.A. Batista Inorg. Chern. 1992 31 1749. *" S.K. Chandra. and A. Chakravorty. Inorg. Chrm. 1992 31. 760. 2R7 K. Shindo. Y. Mori K. Motoda. H. Sakiyarna. N. Matsurnoto. and H. Okawa Inorg. Chem. 1992 31 4987. 2XH Z. Shirin and R. N. Mukherjee. Polyhrdrori. 1992 11. 262.5. 2H9 M. Sakamoto M. Ohsaki. K. Yamarnoto. 1'.Nakayama A. Matsurnoto and H. Okawa. Bull. Chem.Soc. Jpn. 1992 65,2514. 290 M. Sakamoto. M. Hashimura. Y.Nakayama. A. Matsurnoto and H.Okawa. Bull. Chem. Soc. Jpn.. 1992. 65. 1162. ")' X.Y. Zhou Z. W. Wu R. J. Tao. H.X. Han. D. M. Jin. and D.Z. Liao Polyhedron. 1992. 11. 3041. 2y2 B. Srinivas. N. Arulsamy and P. S. Zacharias Polyhedron 1992 1I 21 1 2Y3 B. Srinivas and P. S. Zacharias Can. J. Chem. 1992 70 2906. 2Y4 B. Srinivas and P. S. Zacharias. Polyhedron. 1992. 11. 1949. 302 M.D. Ward 0 0 H OH HO (H2244) (H3245) R = H 3-Me 4-Me 5-Me (H2248) Z=O (H2249) Z = N-C6H3XY; X,Y = H Me OMe SMe Br in various positions Substituted oxamide ligands such as (250)-(255) can act as binucleating ligands in two ways (cis,with N and 0 compartments or trans with two N20compartments see Figure 2). A potentiometric study of the formation of homo- and heterometallic complexes of (H2250) was performed.[Cu','(250)(NCO),] has a one-dimensional chain structure in which square-pyramidal Cu" are bridged alternately by trans-(250) and cyanato Reaction of (H,250) or (H2251) with Cu(NO,) gives two complexes one where two planar (Cu(cis-L)) units bind to a central Cu" with their 295 F. Lloret M. Julve J. Faus R. Ruiz I. Castro M. Mollar and M. Philoche-Levisalles Inory.Chern.,l992 31 784. The Coordination Chemistry of Open-Chain Polydentate Liyands Cis Trans Figure 2 'cis' and 'trans' hinucieating modes for dioxnmide ligunds pendant 0,O sites giving a {(CuN,)( CUO,)(CUN,)}~ arrangement and a tetranuc- + lear complex in which both bridging modes occur.296 [Cu"(cis-L)Ni"(mac)] + [L =(250)-(252); mac =N or N macrocycle] contain a Ni" centre attached to the external 0,O site of a (CuL) fragment.297 Whereas (253) is structurally versatile and forms polynuclear complexes in which both cis and trans binding modes occur the steric hindrance caused by an additional N-methyl group means that (254) always adopts a trans binding mode.298 In [{Ni"(H20),},(255)] the bridging ligand is trans with two terdentate binding pockets but in the infinite chain [Cu"(H2255)(H,0),] the bridging ligand is bis-monodentate uia the carboxylate groups at each end.299 Variable-temperature magnetic studies were performed on binuclear Cu"/Ni" com-plexes of (256)-(258).300 See also references 334-337.R' R2 OvNH KNR3R4 OANH NR3R4 I I R R w\ (H2250) R' =R2 =R3 =R4=H (H4255) R =C02H (H3257) R =OH (H2251) R' =R2 =Me R3 =R4 =H (H2256) R =2-pyridyl (H3258) R =NHMe (H2252) R' =R3 =R4 =H R2 =OH (H2253) R1 =R2=R3 =H R4 =Me (H22%) R' =R2=H R3 =R4 =Me Cu,[M"(cdta)],(N03),~1 5H,O (M =Cu Ni; H,cdta =cyclohexane-l,2-diamine-tetraacetic acid) are isostructural containing infinite chains in which (M(cdta)) units alternate with hydrated Cu" centres.They have novel magnetic proper tie^.^" The 296 V.G. Albano C. Castellari A.C. Fabretti and A. Giusti Inorg. Chrm. Actu. 1992 191 213. 297 A. Escuer R. Vicente J. Ribas R. Costa and X. Solans Inorg. Chem. 1992 31 2627. 298 F. Lloret M. Julve J.A. Real J. Faus R. Ruiz M. Mollar I. Castro and C. Bois Inorg. Chem. 1992.31 2956. 299 F. Lloret. J. Sletten R. Ruiz. M. Julve J. Faus and M.Verdaguer Inory. Chem. 1992 31 778. 300 M. Ohba M. Shiozuka N. Matsumoto and H. Okawa Bull. Chem. SOC.Jpn. 1992 65 1988. 301 F. Sapifia E. Escriva J. V. Folgado A. Beltran D. Beltran A. Fuertes,and M. Drillon. Inorg. Chem.. 1992. 31,3851. 304 M. D. Ward stability constants of Fe"' complexes with ligands such as (259)302 and (260)303 were found to be higher than those of some natural catechol-based siderophores; stability constants for a series of other metal complexes with (260) were measured.303 (H4259) R = CH2-(3-hydroxy-6-methyl)-2-pyridy1 (261) X = CH2CH2 (H4260) R = 2-hydroxyphenyl (262) X = 1,2-C& Ligands with Other Donor Sets.-Although CNi(261 )][ClO,] contains N3S3-coor- dinated Ni" in [Ni(262)(ClO4)][ClO,] the ligand is N3S2 pentadentate with only two 'arms' and the bridgehead N atom binding.304 Cu" complexes of (263) (264) and their reduced (imine to amine) analogues are six-coordinate with N2S donor sets.All undergo metal-centred reductions and give tetragonal EPR ~pectra.~" In contrast [Cu"L] [L = (265) (266)] can be oxidized to CU"'.~~~ Bis-Cu' complexes of (267)-(269) undergo two one-electron oxidations. K values for the mixed-valence states were mea~ured.~" Ligands (270)-(273) react with [RhCl(PPh,),] to afford a (263) n=2 (H2265) n= 1 (264) n = 3 (H2266) n=2 nrX7n m R2P PR2 Ph2E EPh2 (" I) EPh2 PhzE (270) R = 2-C&SMe (267) E= P X=nothmg (271) R = 2-C&Sh1 (268) E = As X = nothing (272) R = 2-benzimidazolyl (269) E = P x = 1,3-C& (273) R = 2-benzthiazolyl 302 R.J. Motekaitis Y. Sun and A. E. Martell Imry. Chirn. Actu. 1992 198-200. 421. 303 J. F. Gibson and 0.J. Vaughan J. Chem. Soc. Dulton Trans.. 1992 1375. 304 K.G. Ragunathan and P. K. Bharadwaj J. Chem. Soc.. Dalton Trans.. 1Y92. 2417. 305 S. Mandal and P.K. Bharadwaj. Polyhedron. 1992. 11. 1037. S. Mandal R. Shukla. and P.K. Bharadwaj Polyhedron 1992 11. 1855. 30' M. M. T. Khan and P. Paul Polyhedron. 1992. 11. 805. The Coordination Chemistry qf Open-Chain Polydentate Ligands 9-OH HO-Q N*N (274) n=2,3; X=O,S variety of products in which the ligand binding modes vary from P,P-bidentate up to bridging he~adentate.~" [Ni"(274)] have distorted N,O,X,-octahedral structures (X =0 or S)and for X =S may be oxidized to the Ni"' state which was examined by EPR spectroscopy .309 7 Ligands of Higher Denticity N-donor and 0-donor Ligands.-The octadentate ligands (275) bind four Cu" ions in a rectangular structure with the terminal pairs each sharing a hydroxide bridge.There are antiferromagnetic couplings within and between these pain3lo [Cu~(276)(H,O),]-l0H2O contains two square-pyramidal Cu" centres with the molecules linked by a hydrogen-bonding net~ork.~' Molecular mechanics and solution EPR studies on the binuclear Cu" complexes of (276) and (277) indicate that the solution structures are similar to the crystal structure^.^^ 1,3,5-Tris(4 -ter- pyridy1)benzene (ttbz) contains three terpy fragments linked to a central phenyl ring; trinuclear complexes [{Ru(4'-X-terpy)),(p-ttbz)l6+ represent the first steps in the preparation of new cascade polymers with three chains linked at the central ligand.3'3*278 Binding of Cu" or Zn" in the bis-acac sites of (278) brings the polyether xx A H2NqNq YNH NH2 (H4276) X=O (275) R =2-pyridyl or 3- 4- or (277) X =2H 5-methyl-2-pyridyl 30H M.F. M. Al-Dulaymmi A. Hills P. B. Hitchcock D. L. Hughes. and R. L. Richards J. Chem. Soc,.,Dalton Truns. 1992 241. 3"y S.B. Choudhury D. Ray and A. Chakravorty J. Chem. Soc. Dalton Trans.. 1992 107. 310 S.S. Tandon S.K. Mandal L.K. Thompson and R.C. Hynes Inory. Chrm. 1992 31. 2215. 311 Z. Shourong L. Qinhui S. Mengchang D. Anbang and H. Liangren Polyhedron 1992. 11 941. 312 P. V. Bernhardt P. Comba T. W. Hambley S.S.Massous and S. Steber Inorg. Chrm. 1992 31 2644. 313 E. C. Constable and A.M. W. Cargill Thompson J. Chrm. Soc. Chem. Commun.. 1992. 617. 306 M.D.Ward (H2278) n = 1 ,2 chain into the correct conformation for size-selective binding of alkali metal cations. These complexes therefore display positive co-operativity. l4 Mixed Donor Ligands.-Compartmental ligands such as (279)-(290) form binuclear complexes with an endogenous alkoxide or phenoxide bridge and are extensively used to prepare models of polynuclear metalloprotein active sites. Examples include manganese complexes as models for the oxygen-evolving centre of photosystem I1 [ligands (281),' and (285)-(288)3'6]; iron complexes as models for iron-oxo proteins such as catalase haemerythrin and purple acid phosphatase [ligands (281),31 7,3l8 (282),,19 (283),318 (284),320 and (287)321]; and copper complexes as models for type 111 cuproproteins [ligands (279k(280),275 (289),322 and (290)"'l.[VF(H284)2]2-contains a V,(p-O) core with pentagonal-bipyramidal metal centres. Each ligand is + hexadentate with a non-coordinated acid [Ni;(286)(p-RCO2),] may be oxidized to the Ni"/Ni"' and Niy' states which were characterized by EPR spectros-copy.32 The tripodal ligand (245) (with X = H) acts as a heptadentate ligand in [Mn~'02(245)2]2+, with the bridgehead N atom coordinated (cJ reference 288).326 [Ln(H3291)(N0,),] (Ln = a lanthanide ion) dimerize in base to give [(Ln(291)},] in which the bicapped-octahedral metals are linked by bridging phenolates resulting in weak antiferr~magnetism.,~~ Ligand (291 ) can be either N,O,-hexadentate N402-hexadentate or N40,-heptadentate in complexes with Al" Ga"' and In"'.328 Lu"' and Gd"' complexes of (292) are potential magnetic resonance imaging agents.329 314 Y.Kobuke and Y. Satoh J. Am. Chem. Soc. 1992 114 789. 315 M. L. Kirk M. K. Chan W. H. Armstrong. and E. I. Solomon J. Am. Chem. Soc. 1992 114 10432. 316 Y. Gultneh A. Farooq S. Liu K. D. Karlin and J. Zubieta Inorg. Chem. 1992 31 3607. 317 Y. Nishida M. Nasu and T. Akamatsu 2.Naturforsch. Teil B 1992 47 115. 318 Y. Nishida T. Akamatsu T. Ishii and Y. Oda J. Chem. Soc. Chem. Commun. 1992 496. 319 Y. Hayashi M. Suzuki A. Uehra Y. Mizutani and T. Kitagawa Chem. Lett. 1992 91. 320 S.Kawata M.Nakamura Y. Yamashita. K. Asai K. Kikuchi I. Ikemoto M. Katada.and H. Sano Chem. Lett. 1992 135. 321 M. S. Mashuta R. J. Webb J. K. McKusker E.A. Schmitt K. J. Oberhausen J.F. Richardson R. M. Buchanan and D. N. Hendrickson J. Am. Chem. Soc. 1992 114 381 5. 322 M. R. Malachowski. M.G. Davidson and J.D. Davis Inorg. Chim. Acta 1992. 192. 157. 323 M. Mahroof-Tahir N. N. Murthy. K. D. Karlin N. J. Blackburn S.N.Shaikh and J. Zubieta Inorg. Chem. 1992 31 3001. 324 J. C. Robles. M. Shimoi and H. Ogino Chem. Lett. 1992 309. 325 T. R. Holman M. P. Hendrich. and L. Que. Jr. Inorg. Chem. 1992. 31 937. 326 C. Gedye C. Harding V.McKee J. Nelson and J. Patterson J. Chem. Soc.. Chem. Commun. 1992 392. 327 S. Liu L. Gelmini S.J. Rettig R.C. Thompson and C.Orvig J. Am. Chem. Soc. 1992 114 6081. 328 S. Liu S.J. Rettig and C. Orvig Inorg. Chem. 1992 31 5400. 329 P. P. K. Claire C. J. Jones K. W. Chiu J. R. Thornback. and M. McPartlin. Polyhedron. 1992 11,499. The Coordination Chemistry of Open-Chain Polydentate Ligands 307 (H279) X = H R = 2-pyridy1 n = 2 R = (280) X = C(O)C~H~C~HS 2-pyridy1 n = 2 (H281) X = H R = 2-pyridy1 n = 1 (H282) X = H R = 6-methyl-2-pyridy1 n = 1 (H283) X = H R = 2-benzimidazoly1 n = 1 (H5284) X = H R = CO,H R I (H285) R = H n = 2 D = 2-pyridyl (H286) R = Me n = 1 D = 2-pyridyl (H287) R = Me n = 1 D = 1-methyl-2-imidazolyl (H288) R = Me n = 1 D = 1,4,7-triazacyclononyl (H289) R = H n = 1 D = 3,5-dimethyl-l-pyrazolyl (H290) (H3291) R = H C1 Br Eight-coordinate Zr’” and Hf’” complexes of (H02CCH2)2NCH2(CH,0CH2)2- CH,N(CH,CO,H) are i~ostructural.~~~ Stability constants of several complexes of the N,O,-donor N[CH2CH2N(Me)CH2C02H]3were measured and the solution 330 D.F. Evans.G. W. Griffiths C. O’Mahoney D. J. Williams. C.Y. Wang,and J. D. Woo1ins.J. Chern. Soc. Dalton Trans. 1992 2415. 308 M.D. Ward NMR behaviour of the Zn" and La"' complexes studied.331 Luminescence properties of Eu"' and Tb"' complexes with the ligands in Figure 3 were examined to determine the suitability of the complexes for luminescence-based bioaffinity assays.332,333 bridge bridge = 2,6-pyridyl 6,6'-bipyri dyl 6,6"-terpyridyl H 1,lO-phenanthrolinyl 1,8-naphthyridinyl f "'1 f "1 H02C CO,H H02C CO2H Figure 3 Series of' ligands used to prepare luminescent Eu"' and Tb"' complexes [Cu"L]'-[L = (293) (294)] contain a planar Cu" in the central N cavity of the bis-dioxamide ligand.Binding of Ni" at the external 0,O-chelating sites affords trinuclear Ni-Cu-Ni complexes.334 Likewise binding of lanthanides at the external 0,O-chelating sites of [Cu"(295)I2 -permits synthesis of a wide variety of one-dimensional and two-dimensional Such complexes are of interest both for their unusual structures and their magnetic properties (cf references 295-300). OAXH HXAO (b293) X = N R' = OH R2 = H (b294) X = N R' = R2= Me (H4295) X = 0 R' = R2 = H f:JG3N-x-Ny 331 C. F.G. C. Geraldes E. Rrucher S. Cortes S.H. Koenig and A. D. Sherry .I. Chem. Soc..Dalron Truns. 1992 2517. 332 V.-M. Mukkala and J. Kankare Helu. Chim. Acra 1992 75 1578. 333 V.-M. Mukkala. C. Sund M. Kwiatkowski. P. Pasanen. M. Hogberg. J. Kankare and H. Takalo Helu. Chim. Acta 1992 75 1621. 334 R. Vicente A. Escuer. and J. Ribas Polyhedron 1992 11. 857. 335 0.Guillou P. Bergerat 0.Kahn E. Bakalbassis. K. Boubekeur P. Batail and M. Guillot Inorg. Chem. 1992. 31 110. 336 0.Guillou R. L. Oushoorn 0.Kahn K. Boubekeur and P. Ratail .4nyerc. Chem.,Int. Ed. Engl. 1992,31 626. 337 0.Guillou 0.Kahn. R. L. Oushoorn. K. Boubekeur and P. Batail Inory. Chim. Acra 1992,198-200.1 19. The Coordination Chemistry of Open-Chain Polydentate Ligands 309 NH HN (H3298) Ligands (296) and (297) are new tetrahydroxamic acid chelating agents for Fe"' Th" and Nd'1'.338 Electrochemical and spectroscopic studies were performed on mono- and bridged binuclear complexes of (298) with first-row metal di~ations.~~~ Binding of the terminal phosphine groups of Ph,PCH,(CH,OCH,),CH,PPh (n = 3-5) to a (PtCI,) group folds the polyoxoethylene chain into a 'crown-ether-like' confirmation which can bind alkali metal cations.340 A.S. Gopalan V. J. Huber 0.Zincircioglu and P. H. Smith J. Chem. Soc. Chem. Commun. 1992. 1266. 33y B. Adhikary. K. K. Nanda R. Das S. K. Mandal and K. Nag. Polyhedron 1992 11 347. A. Varshney M. L. Webster and G. M. Gray Inoryl. Chrrn. 1992. 31 2580.

ISSN:0260-1818    

DOI:10.1039/IC9928900267

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

18 The Coordination Chemistry of Macrocyclic Ligands By S. L. W. McWHlNNlE Chemistry Department Brunei University Uxbridge Middlesex UB8 3PH UK 1 Introduction This review of the coordination chemistry of macrocyclic ligands follows the format of previous years. Once again no porphyrin or phthalocyanine coordination chemistry is covered. Pendant-arm macrocycles are discussed in the section appropriate to the parent macrocycle and where a paper refers to macrocycles possessing different donor sets the whole is referenced and discussed in the first section into which one of the ligands falls. 2 Tridentate Macrocycles N-donor Ligands.-The monomeric complexes [Zr'v(acac),] and [H?v(acac),] react in acetone/water (95 :5) mixtures with tacn affording [{ (tacn)M'V(acac),},O][CIO,] (M = Zr or Hf).Each metal is coordinated to two bidentate acac ligands and a + tridentate tacn. The base-promoted decomposition of [Ni"'(ta~n),]~ has been studied using UV/VIS spectroscopy and stopped-flow techniques. Low-temperature single-crystal absorption and far infrared spectra and a single-crystal structure determination of [Ni"(tacn),][ClO,],.H,O have been reported. The Racah par- ameters B and C are in good agreement with those found for other NiN c~mplexes.~ Oxidation of S,OS-by [Ni"(tac~i)~]~+ has been studied in aqueous medium the reaction produces [Ni"(ta~n)~]~ + and S,Oi -. The syntheses of several Pd" complexes of tacn and the molecular structure of two complexes by X-ray diffraction have been reported.The diprotonated bis complex [Pd"(Hta~n)~][ClO,],~H,0, contains the ligands in the anti conformation.' The complex [Tc'(tacn)(CO),(PPh,)]Cl has been synthesized in good yield by treatment of trans-[Tc'Cl(CO),(PPh,),] with tacn.6 The compounds [Mo(CO),L] (M = Zr or Ti L = tacn or Me,tacn) and the molecular structure of [Tio(CO),(Me,tacn)] have been rep~rted.~ Me,tacn reacts with TiCI in CH,CN at 20°C to afford [Ti"'C1,(Me3tacn)] with TiBr to form [Ti"'Br,(Me,tacn)] and with TiC1 to form [Ti'VC1,(Me,tacn)]C1. The reactivity of ' P. Jeske K. Wieghardt B. Nuber and J. Weiss Inorg. Chim. Acta 1992 193 9. ' B. Sonnberger P. Huhn A. Wasserbul-ger and F. Wasgestian Inorg. Chim. Acta. 1992. 196 65. R. Stranger S.C.Wallis L. R. Gahan C. H. L. Kennard and K. A. Byriel J.Chem. Soc.. Dalton Trans. 1992 2971. R. Sarala and D. M. Stanbury Inorg. Chem.. 1992 31 2771. T. N. Margulis and L. J. Zompa Inorg. Chim. Acta 1992 201 61. R. Alberto W.A. Herrmann. P. Kiprof. and F. Baurngiirtner Inorg. Chem.. 1992 31 895. ' J. E. Ellis A. J. DiMaio A. L. Rheingold and B. S. Haggerty J. Am. Chem. Soc. 1992 114 10676. 31 1 S. L. W. Mc Whinnie these novel complexes is reported.8 Ligands (1) and (2) form stable complexes with some 3d metal cations of formula [MI'LIY [M= Fe L = (1) or (2) Y = BPh,; M = Co L = (l),Y = CIO,; L = (2),Y = BPh,; M = Zn L = (2),Y = BPh,]. The complex [Ni"(2)][BPh4] affords the new compound [Ni"(NCMe)(3)][BPh43 by slow recrystallization from acet~nitrile-ethanol.~ The new tripodal ligand (HI,4) has been synthesized and characterized; on reaction with iron-sulfur clusters [Fe,S,(SR),I2 (R = Et or Bu') subsite-differentiated clusters for example [Fe4S,(4)(SEt)12-,are formed." The hexadentate ligand (5) has an affinity for Fe"' which exceeds that of the natural siderophore enterobactin at physiological pH.' ' Complexes of (6) synthesized from (7) with the trivalent lanthanides and with Ca" Mg" Zn" and Cd" have been examined by potentiometry and NMR spectroscopy.The 31P NMR spectra of the Ln(6) complexes show single resonances at low concentrations (below 0.1 mM) but multiple resonances at higher concentrations.'2 The ligand (9) has been synthesized and the structure of [Ni"(9)(NCS),] determined by X-ray crystallography.' I R3 N (1) R1 = R2 = R3 = CH2-f 1 Y CH3 (3) R' = R2 = CH2-NT R3 = H N/ (4) R' = R2 = R3 = 4-mercaptopyridine (5) R' = R2 = R3 = 3-hydroxy-2-pyridylmelhyl ! (6) R' = R2 = R3 = -P-OCH,CH OH 0 (7) R'=R2=R3 = -:-OH I 0ti A.Bodner P. Jeske,T. Weyhermiiller K. Wieghardt. E. Dubler. H. Schmalle. and B. Nuber Inory. Chim.. 1992 31 3737. G. de M. Norante. M. Di Vaira F. Mani S. Mazzi and P. Stoppioni. .I. Chrm. Sot.. Dalton Trans. 1992. 361. LO D. J. Evans G. Garcia G. J. Leigh M. S. Newton and M. D. Santana J. Chern. Soc..Dullon 7runs. 1992 3229. R. J. Motekaitis Y. Sun and A. E. Martell Inorg. Chirn. Actu 1992 198-200. 421. l2 1. Lazar R. Ramasamy E. Brucher C.F.G. C. Geraldes and A. D. Sherry. Inorq. Chirn. Acru. 1992. 195 89.l3 S. C. Rawle A. J. Clarke P. Moore and N. W. Alcock. J. Chern. Soc.. Dukon Trans.. 1992 2755. The Coordination Chemistry of Mtrcrocyclic Liyands 313 An X-ray crystal study of [Zn1'(8)(NCS),] has revealed a five-coordinate trigonal bipyramidal structure with a linear equatorial Zn"-NCS -bond that is shorter than the bent apical Zn"-NCS- bond.14 A Zn" complex of (lo) [Zn"(lO)][PF,] has been synthesized as a model for sulfonamide inhibition of carbonic anhydrase. An X-ray crystal study shows a strong interaction between Zn" and the sulfonamide N- anion [I .925(3)A].' The role of Zn" at the active centre of liver alcohol dehydrogenase has been well-defined for the first time by comparative studies of a number of N-donor macrocyclic complexes.Of the systems tested [Zn"(9)(0H)],~(CF,S03)3CF3S03H was by far the most effective catalyst. l6 The Ni" complex of (10) sequesters CO from air to yield after addition of thiocyanate ion [((H10)Ni"(NCS)},(C0,)]2+, the first example of a p-carbonato dinickel(r1) complex; the Ni atoms are antiferromagnetically coupled17 with a large exchange constant -2J = 94.6 & 0.4cm-'. The Cambridge Structural Database has been used to survey structures based on (9) and other amino(alkylphosphonates) amino(alkyphosphinates) and amino(a1kanecarboxy-lates) and their metal complexes and the crystal structure of (11) has been determined.' R' c"3 R2"uN'R3 (8) R' = R2 = R3 = H (9) R' = R2 = H R3 = CH~CH~CH~NMQ (10) R' = R2 = H R3 = CH~CH~WTS (1 1) R' = R2= R3= CH2PO3H2 The ligands (12) and (13) permit the preparation of pentacoordinate complexes with di-p-hydroxo bridges.The synthesis and magnetic behaviour of two series of these compounds [ML(OH)],[ClO,] [L = (12) M = Cu" Ni" or Co"; L = (13) M = Cu" or Ni"] have been reported. For M = Cu" and Ni" a strong antiferromag- netic coupling is present while for M = Co" the interaction is weakly ferromagnetic." A macrocyclic organometallic trans-[Rh"'( 14)CI,]-(CH,),CO has been prepared from RhC1,.3H20. An X-ray crystal structural study shows that the complex has trans-chloride ligands and the metallated macrocyclic triamine serves as a CN,-type quadridentate ligand. The Rh-C bond is the shortest Rh"'-aryl bond yet reported.,' S-donor Ligands.-The electrochemistry of [Ni"( 15),] [PF,] ,has been re-investigated [Ni"'( 15),][H,O,],[ClO,] has been isolated and an X-ray crystallographic study l4 E.Kimurd T. Koike M. Shionoya and M. Shiro Chem. Lett. 1992 787. Is T. Koike E. Kimura I. Nakamara V. Hasbimoto and M. Shiro J. Am. Chern. SOC. 1992 114 7338. I6 E. Kimura M. Shionoya A. Hoshino. T. Ikeda. and Y. Yamada J. Am. Chrrn. SOC.,1992 114 10 134. S.C. Rawle C.J. Harding P. Moore and N. W. Alcock J. Chern. Sor. Chem. Commun. 1992 1701. In W. Clegg. P. B. Iveson and J.C. Lockhart J. Chem. SOC.,Dalton Trans. 1992 3291. A. Escuer R. Vicente. and J. Ribas Polyhedron 1992 11 453. 20 K. Hiraki. Y. Fuchita Y. Ohta J. Tsutsumida. and K. I. Hardcastle. J. Chrm. Soc.. Dalron Trans.. 1992 833.314 S. L. W. Mc Whinnie carried out; the Ni-S bond lengths are significantly shorter than the Ni" analogue. The electrochemistry of [Zn"( 1 5)2][PF6]2 has also been investigated.,' [Os"( 15),] [PF,] has been synthesized by two methods and studied by X-ray crystallography; the electrochemistry of this complex has also been studied. Additionally [Os"(4- MeC,H,Pr')( 15)][BPh4] and [M"H(CO)(PPh,)( 15)][PF,] (M = Ru or 0s) have been isolated and the osmium complexes investigated by X-ray crystallography.22 Treatment of [Ru"Cl,(PPh,)(l5)] formed in high yield by reaction of [Ru"Cl,(PPh,),] and (15) with TIPF affords the yellow hetero-cluster species [TI'C~,RU"~(PP~,)( ladder; dissol- 15)],[PF,] ,incorporating a [RU"'CI,TI~CI,RU~~~] ution of [TI'C~,RU~~'(PP~,)( 1 S)],[PF,] in acetone leads to precipitation of TIC1 and the formation, of the orange chloro-bridged dimer [{ Ru"'(p-Cl)(PPh,)( 15)},] [PF,],.[Tc"(l5)][BF4],CH,CN has been isolated from the reaction of [NBu,] [TcO,] with (1 5) and characterized by X-ray ~rystallography.~~ Co" and Ni" complexes of (16) have been synthesized and characterized by X-ray crystallography. Both complexes contain the [MI1( 16),12 + cation. By studying 59C0 line broadening in the presence of the corresponding Co" ion the self-exchange + electron transfer rates for both [Co"""( 15),13+'' (1.3 x 105~-'s-')and + [CO"'/II(16)2]3+12 (4.3 x lo5M-'S-~) have been measured.25 Two isomers of [Pd"(16),]2+ (caused by the location of a ten-membered chelate ring) have been synthesized, in which two sulfur donors from each ligand bond to Pd".Ligand (17) reacts with AgX (X = ClO, BF, BPh, CF,SO;) in a 2 1 ligand to metal ratio to give complexes2' of general formula [Ag'( 17),][X]. Studies intended to relate conformational behaviour and selectivity towards silver of the arene thioether ligands (17)-( 19)have been carried out. Molecular dynamics studies provide a new perspective on preorganization of the ligands prior to metal-ion coordination.28 Other donor Ligands.-Ligand (20) forms a complex [(20),(NaSCN),] which has been characterized by X-ray ~rystallography.~~ Transfer to methoxide ion of the acetyl group of a series of crown ether acetates (21 t(25) is accelerated by alkali and alkaline earth metal ions. The magnitude of the rate enhancements is dependent on the substratesation combination the divalent metals being in general much stronger catalysts than the monovalent metals.,' The pentadentate ligand (H,26) has been prepared and its coordination with Mn" Mn"' and Zn" investigated.From methanolic solutions of (H,26) Mn(C1O,),-6H2O and Zn(C104),.6H,0 colourless crystals of [Mn~(p-OH)(H26),][C1O4] and [Zn:(p- OH)(H26),][C104).7H,0 have been obtained respectively. From temperature de- A. J. Blake R.O. Gould M. A. Halcrow A. J. Holder T. I. Hyde and M. Schroder J. Chem.Soc. Dalton Trans. 1992 3427. 22 M.N. Bell A. J. Blake R. M. Christie R. 0. Gould A. J. Holder T.I. Hyde M. Schroder and L. J. Yellowlees J. Chem. Soc. Dalton Trans. 1992 2977. 23 A. J. Blake R.M. Christie Y.V. Roberts M. J. Sullivan. M. Schroder and L. J. Yellowlees J. Chem. Soc. Chem. Commun. 1992 848. 24 D. J. White H.-J. Kuppers A. J. Edwards D. J. Watkin and S.R. Cooper. Inorg. Chem. 1992.31 5351. 25 S. Chandrasekhar and A. McAuley Inorg. Chem. 1992 31 480. 26 S. Chandrasekhar and A. McAuley Inorg. Chem. 1992 31 2663. 2' B. de Groot H.A. Jenkins and S.J. Loeb Inorg. Chem. 1992 31 203. 28 J.C. Lockhart D. P. Mousley M. N. S. Hill N. P. Tomkinson F. Teixidor M. P.Almajano L. Escriche J. F. Casabo R. Sillanpaa and R. Kivekis J. Chem. Soc. Dalton Trans. 1992 2889. 29 D. Seebach H.-M. Miiller H. M. Burger and D.A. Plattner Angew. Chem.,Int. Ed. Engl. 1992,31,434. 30 R. Cacciapaglia A. R.van Doorn L. Mandolini D. N. Reinhoult and W. Verboom.J. Am. Chem. Soc.. 1992 114 261 1. 315 The Coordination Chemistry of' Macrocyclic Ligands *R n ss CJ 0LJ R (20) (21) n=2 (22) n= 3 (23) n=4 (24) n = 5 (25) n = 6 pendent magnetic susceptibility measurements and EPR spectroscopy on [Mny(p- OH)(H26),][BPh4] an intramolecular antiferromagnetic exchange coupling constant J of -2.65 cm- has been determined. Deprotonation of the dinuclear Mn" species affords monomeric five-coordinate [Mn"(26)]. The [Mn"'X(26)] complexes (X = C1 NCS N3) have also been prepared as has [(26)Zn"(H,0)Zn"C12].31 The Pd" and Pt" complexes of (27) [Pd"(27),]C1,.H20 [Pt"(27)2][PF6]2 and [Pd~(27),Cl,]14.2H,0 have been prepared and characterized by X-ray crystallogra- phy. In [Pd"(27),]Cl2.H,O and [Pti1(27),][PF6] the metal centre is coordinated in a square-planar configuration to the N-donor atoms of the two macrocyclic ligands.The thioether groups are non-interacting and dangle away from the metal centre.32 Complexes of (27) with Ag' and Hg" have been prepared and the X-ray crystal structuresof [Ag1(27)Cl] and [Hg"(27),][Hg"Br4] determined. [Ag1(27)C1] consists of molecular units in which Ag' is tetra-coordinated and in [Hg"(27),][Hg"Br4] Hg" is six-~oordinate.~~ The acid-base properties of (27t(30) have been investigated in aqueous solution by pH potentiometry adiabatic calorimetry and 'H NMR spectro~copy.~~.~~ Addition-ally the stability constants of (27) and (29) with Co" Ni" Cu" Zn" Cd" and Pb" have been determined in aqueous solution by pH potentiometry.The magnitude of the 31 C. Flassbeck K. Wieghardt E. Bill. C. Butzlaff A.X. Trautwein B. Nuber and J. Weiss Inorg. Chrm. 1992 31. 21. 32 U. Heinzel and R. Mattes Inorg. Chim. Acta 1992 194 157. 33 U. Heinzel and R. Mattes Polyhedron. 1992 11. 597. 34 D. M. Wambeke D. Van De Vondel E. C'laeys. G.G. Herman and A. M. Goeminne. J. Chem.Soc. Daltoii Trans. 1992 829. 35 D. M. Wambeke W. Lippens G. G. Herman A.M. Goeminne D. Van De Vondel. and G. P. Van Der Kelen Polyhedron. 1992 11 1305. 316 S. L. W. Mc Whinnie macrocyclic effect for the Cu" complexes is dependent upon the choice of open-chain ligand and has been analysed for its enthalpic and entropic contribution^.^^ The complex [Ni"(29),]Br2 has been characterized by X-ray crystallography.Oxidation of the Nil' complex results in the formation of a Ni"' species the EPR spectrum of which suggests a tetragonally elongated geometry.37 Perchlorate salts of [Ni"(31 )2]2+ and [Ni"(32)I2' have been isolated and inves- tigated by X-ray crystallography. Both chemical and electrochemical oxidations of the complex ions result in the formation of the corresponding Nil" ions for which the EPR spectra are consistent with low-spin d7 Nil1' centres in a tetragonally distorted state.38 n (HZW (27) R = H (29) R=H (28) R = CHZCOOH (30) R = CHzCOOH 3 Tetraden ta te Macrocycles N-donor Ligands.-Saturated Tetraamine Mucrocycles. The synthesis and characteriz- ation of di-p-oxodimanganese(m,rv)and (IVJV) complexes employing the tetradentate ligand (33) have been reported.The X-ray crystal structure of [(33)Mn11'0,Mn'V(33)] C13~LiCl~5H,0 is reported. The complexes have been investigated by magnetic and EPR technique^.^^ Cellular ligand field (CLF) analyses have been made for seven tetragonal-octahedra1 Ni" complexes including [Ni"LX,] [L = (33) (34) or (35); X = C1-or NCS-I. The d-d spectra have been re-interpreted within the CLF framework leading to a consistent set of assignments and ligand field parameter^.^' Ah initio MO/SD-CI calculations on several Ni' and Ni"-CO complexes support Sauvage's reaction mechanism for the electrocatalytic reduction of CO by [Ni11(35)C12].41 The cleavage of plasmid DNA (PUB1 10) by several planar Ni" complexes in the presence of either magnesium monoperoxyphthalic acid or iodosyl- benzene has been investigated.No cleavage was observed for [Ni"LI2+ [L = (34) (44) or (4511.42 Nil'-promoted oxidation of accessible guanine residues in 3h D. M. Wambeke W. Lippens. G.G. Herman. A. M. Goeminne. and G. P. Van Der Kelen. Polj'hedron 1992. 11 2989. '' S. Chandrasekhar and A. McAuley. J. Chem. Soc.. Dalton Truns.. 1992. 2967. 3n S. Chandrasekhar and A. McAuley. Inorg. Chem.. 1992 31 2234. 39 P. A. Goodson D. J. Hodgson J. Glerup. K. Michelson. and H. Weihe Inorg. Chim.Acta 1992 197 141. '"R. J. Deeth and C.M. Kemp J. Chem. Soc. Dalton Trans.. 1992. 2013. 41 S. Sakaki. .I. Am. Chem. So(,. 1992 114 2055. 42 J.R. Morrow and K.A. Kolasa. Inorg. Chim. kru. 1992. 195. 245. The Coordination Chemistry of Macrocyclic Liyunds (33) l=O m=0 n=0 o=O R=H (34) f=1 m=0 n=O o=O R=H (35) 1=1 m=0 n=1 o=O R=H (36) 1= 1 m= 1 n=0 o=O R=H (37) Z=1 m=0 n=l o=O R=Me (38) 1=1 m=l n=1 o=l R=Me (39) I=O m=0 n=0 o=O R=CH2-N \ N-3 (40) 1= 0 m = 0 n = 0 o = 0 R = CH2P(O)(OH) (41) 1= 0 m = 0 n = 0 o = 0 R = CH2P(0)(OH)Ph (42) 1= 0 m = 0 n = 0 o = 0 R = CH2P(O)(OH)Bu (43) 1= 0 m = 0 n == 0 o = 0 R = CH2P(0)(OH)CH2Ph deoxyoligonucleotides using KHSO as oxidant was found to be highly dependent upon the macrocyclic ligand employed.Among the ligands tested were (35),(36) (45) and (46); tetraazamacrocycles providing strong in-plane coordination by amine imine or pyridine donors gave the optimum characteristics for DNA rea~tivity.'~ The single-crystal X-ray structure and thermal behaviour of cis-[Ni"(36)(H20),] C1;2H20 have been reported.The complex undergoes thermal deaquation-anation in the solid state to produce cis-[Ni"(36)CI2] which on further heating undergoes isomerization to the trans form.44 (44) (45) R = H (46) R=Me A simple one-step synthesis of tr~ns-[Cr~~'(35)Cl,]Cl and its safe and easy conversion to trans-[Cr11(35)(H,0)2][CF3S03]3 have been reported.45 The 'E +'A2 and 4T2g+-4A, electronic absorption spectra of single crystals of truns-[Cr111(35)(NH3)2][CI04]3 and the 'E +'Azgemission spectra of powder samples of 43 J.G. Muller. X. Chen. A. C. Dadiz. S. E. Rokita. and C. J. Burrows.J. Am. Chrrn.Soc. 1992 114. 6407. 44 Y. Satake Y. Ihara H. Senda. M. Suzuhi and A. Uehara fnory. Chem 1992. 31. 3248. 45 A. Bakac and J. H. Espenson Inorg. Chcm. 1992. 31. 1108. 318 S.L. W. Mc Whinnie trans-[Cr"'(35)(NH,),][N03],[C104]and their deuterated analogues have been measured down to 5 K. The significance of these results for the pathway of reaction of the ,E state is discussed.46 The visible absorption and emission spectra of tr~ns-[Cr"'(35)(NH,),]~ have been + studied along with the emission lifetimes and quantum yields in the liquid phase for a number of solvents. The nature of the solvent has notable effects on the visible electronic spectra and on the vibrational bands observed in the infrared spectra; the calculated rate constants describing the decay of the doublet excited state in the high-temperature region exhibit a semi-logarithmic relationship to the Gutmann + donor numbers of the solvent^.^' Trans-[Cr"'(37)X2] (X = F C1 Br OH NO,) and tran~-[Cr"'(37)(H,O),]~ have been prepared and spectroscopically characterized.+ The redox potentials of the complexes of (37) and the analogous complexes of (35) have been determined by cyclic voltammetry. The potentials of complexes of (37) are 1.1 & 0.1 V more positive than those of (35).48 A trinuclear Ru(IIrCr(II1) chromo- phore-luminophore complex [R~"(bipy)~(p-CN),(Cr(35)(CN)},]~+, has been syn- thesized and characterized. Visible light absorption by the [Ru"(bipy),12 + chromo-phore leads to emission from the [Cr"'(35)(CN),] + luminophore as a consequence of a very fast (sub-nanosecond time scale) chromophore-luminophore exchange energy- transfer pro~ess.~' + Several ruthenium(I1) macrocyclic complexes namely trans-[Ru"(35)ClL] (L = 4-picoline py isonicotinamide or 4-acetyl-pyridine) have been synthesized.The syntheses of these complexes were performed by reducing trans-[Ru1"(35)C1,] + to the Ru" form which undergoes labilization of one chloride ligand in the presence of excess L." The complexes [Re"NCl,( PPh,)] [Re'VC14(PPh3)2] and [Re"'Cl (NCMe) (PPh3),] react with a variety of amines including (35) at room temperature to afford cationic trans-dioxorhenium(v) complexes e.g. [ReV(0),(35)]+ . The X-ray crystal structure of [ReV(0),(35)][PF,] has been reported.'l Relaxation rate measurements on 3C-enriched CN -,NCO -,and NCS- ,as well as on "N-enriched NCS-have been performed in the presence of Co" and Zn" substituted carbonic anhydride (CA) as well as on model compound^'^ such as [Co"(37)Llf.The reaction of truns-[R~"'(38)Cl,]~ with NO in water at 60 "C leads to the formation of trans-[Rurv(38)(0)Cl] $-and tran~-[Ru"(38)(OH)(NO)]~ +,the structures of which have been determined by X-ray ~rystallography.~~ With Mn" the potentially octadentate ligand (39) gives the complex [Mn"(39)][PF6],-(CH,),C0 and with Fe" affords species of the formula [Fe"(39),(47) -,][PF,],~solvent. X-ray crystallographic investigations reveal the Mn" atom is coordinated by the eight nitrogen atoms of (39). Isomorphous crystals of the Fe" species formed with (39) and (47) contain eight- and seven-coordinate Fe" re~pectively.~~ 46 A.D. Kirk and H.U. Giidel Inorg. Chem. 1992 31,4564. 47 L. Vincze D.A. Friesen S. P. Mezyk and W. L. Waltz Inory. Chem. 1992 31 4950. 48 D. Guldi F. Wasgestian and D. Meyerstein Inorg. Chim. Acta 1992 194 15. 49 C. A. Bignozzi 0.Bortolini,C. Chiorboli M. T. Indelli M. A. Rampi and F. Scandola Inorg. Chem. 1992 31 172. 50 R.S. da Silva and E. Tfouni Inorg. Chem. 1992 31 3313. 51 S. A. Luna C. Bolzati A. Duatti G.L. Zucchini,G. Bandoli and F. Refosco Inorg. Chem. 1992,31,2595. '' I. Bertini C. Luchinat R. Pieratelli and A.J. Vila Inorg. Chem. 1992 31 3975. 53 K.-Y. Wong C.-M. Che W.-H. Yip R.-J. Wang and T. C. W. Mak J. Chem. Soc. Dalton Trans. 1992 1417.54 M. Di Vaira F. Mani and P. Stoppioni J. Chem. Soc. Dalton Trans. 1992 1127. The Coordination Chemistry of Macrocyclic Ligands (47) R' = CH2-Nd\ R2 = CHzOEt An optimized synthesis of (40) and its structure and solution dynamics have been rep~rted.~' The synthesis and stability of anionic neutral and cationic gadolinium complexes based on tetraazaphosphinic acid ligands (41 )-(43) and (48)-(56) have been compared. It was found that lipophilic anionic complexes show biliary rather than renal ~learance.~~ Gd"' derivatives of (57)-(60) have been prepared and have been subjected to NMR relaxation rate studies which suggest that the complexes would be useful candidates as contrast agents at low magnetic fields.57 Spectrophotometry and multiscan stopped-flow spectrophotometry has been used to study the kinetics of complex formation of divalent transition metal ions M2+ (M = Ni Cu) with (35) (37) and (61)-(63).Complex formation was found to be a two-step process with an initial fast second-order reaction generating an intermediate species [ML]?" and a subsequent slower first-order reaction5* in which the intermediate is converted to the product [ML],'. A bifunctional complex [R~'~(H,64)(phen),][ClO~]~ (Figure 1) has been synthesized and its spectroscopic and redox properties and catalytic behaviour in the photoreduction of CO have been examined. The [Ru"(phen)J2+ portion of the molecule acts as a photosensitizer for the [Ni"(35)I2 catalytic reduction site.s9 The stereoselective synthesis of various + 0 R' 0 H II I It I HO-AJ HO-LJ -\-P-OH -LP-OH II II II II 0 0 0 0 (48) R =Me R' = H R" = Me (53) X =NMe3Cl R = Me (49) R = Me R' = R" = Ru (54) X = CH2CH2NH3Br,R = Me (50) R = Me R' = R" = CHzPh (55) X = CH2CH2NH3 R = BU (51) R = Bu R' = H R" = Me (56) X = CH2CH2NH3 R = CH2Ph (52) R = Ph R' = R" = Me 55 I.Lazar D. C. Hrncir W.-D. Kim G. E Kiefer and A. D. Sherry Inorg. Chem. 1992 31 4422. 56 D. Parker K. Pulukkody T. J. Norman. A. Harrison L. Royle and C. Walker J. Chem. Soc. Chem. Commun. 1992 1441. 57 S. Airne M. Botta G. Errnondi F. Fedeli and F. Uggeri. Inorg. Chem. 1992 31 1100. J. R. Roper and H. Elias Inorg. Chem. 1992 31 1202. 59 E. Kimura X. Bu M. Shionoya S. Wada and S.Maruyama Inorg. Chem. 1992 31 4542. S. L. W. McWhinnie COOH (57) R' = R2 = R3 = CH2COOH R4= AOJh COOH (58) R' = R2 = C!12COO€I R3 = R4 = AO-Ph cooH (59) K' = R3 = CH2COOH R2 = R4= AO, I'h coo1I (60j R' = CHzCOOH K2 = R3 = R4 = &o,/ Ph 1 &disubstituted derivatives of (35) and (65)-(70) has been achieved and copper and nickel complexes prepared. The X-ray crystal structures of a number of these species are reported.'" Template syntheses of the species [M"LI2+ [L = (71) M = Ni; L = (72) (73)-M = Ni Cu] have been reported." (61) R1= R2 = R3 = H R4=Me (62) R1 = R2 = H R3 = R4= Me H\ f-7," (63) R' = x,x2= k3= R4= Me (64) R' = R2 = K3 = 13 R4= N-R LN N\l H' -H (65) R' = R3 = H R2 = R4= BU (66) R' = R3 = H R2 = K4= Me (71) R=Me (67) R' = R3 = H R2 = Me R4= Bu (72) R = S030CH3 -(H268) R' = R3 = H R2 = R4 = CHZCOOH (73) R=SO~FC (H269) R' = R3= Me R2 = K4 = CH2COON J.Chapman. G. Ferguson. J. F. Gallagher M. C. Jennings. and D. Parker. J. Ckem. So(,. Dalton jr'runs. 1992. 345. ('I A. Dc Blas. G. De Santis. L. Fabbrizri M. Licohelli. C. Mangano and P. Pallaviom. Inorq. Chim..kfU. 1992. 202. 115. The Coordination Chemistry of Macrocyclic Ligands 32 1 Figure 1 The chiral macrocycle (74) reacts with CoBr to give mainly cis-(S,S,S,R)- [Co1"Br(H,0)(74)]Br,; an isomeric complex was isolated from the reaction mixture under mild alkaline conditions. The structures of cis-(R,S,R,S)-[Co"{ (S)-alaO) (74)] [ClO,] (alaO = alaninate) and cis-(R ,S,R ,S)-[Co"( (S)-t hrO) (74)] [ClO,] ,.3H ,0 (thrO = threoninate) have been determined by X-ray analysis.All complexes prepared are cis-octahedral; each Co"' is surrounded by four nitrogen atoms from (74) and by the nitrogen and oxygen atoms of the amino acid and the configurations of the four asymmetric nitrogen atoms are (R,S,R,S)." The pendant arm macrocycle (75) reacts slowly in hot water with RhCl to yield6 exclusively ~is-[Rh"'(75)Cl]~~. The macrocycles (75) (79) and (80) react readily in methanol with Cr" ions to yieldh4 cis-and/or tr~ns-[Cr"LCl]~+. The cis isomer of (76) has been isolated and complexed with Cd"; the complex [Cd1'(76)] [CIO,] has been characterized by X-ray crystallogra- ~hy.~~ The structures of trans-~-[(Co"'(76)),(0,)][CI0,]4~2H,0 truns-x-[Co'" (76)Cll [ClO,] 2 truns-cr-[C0"'(H76)Cl][Zn'~Cl,]CI-H,0, trans-x-[Co1"(H76) (H,O)]-Cl,ClO, trans-y-[Co"'(H76)Cl]C13~3H,0, trans-[~-[Co1''(H76)C1][ZnCl4]Cl~~- H,O- $C,H,OH and trans-~-[Co"'c H,76)C12][ZnC14]Cl~~H,0~~C2HsOH have also been determined by X-ray crystallography.66 [Cu1'(78)][CI04],~H,0 was prepared by a template synthesis and subsequent reduction with zinc in aqueous nitric acid yields free (77).Coordination to Co"' was achieved following reaction with Co" ion and air,67 yielding [C0"'(77)Cl]~ + and [C0"'(77)(H,0)]~ +.Chlorocobalt(lI1) complexes of (75) (79),(80),and (81)have been isolated and characterized by X-ray crystallography. Of the complexes synthesized only two ~C0'~'(81)Cl][C10,]Cl and [C0'~~(79)Cl][C10,], were isolated as trans-isomersh8 The unsymmetric macrocycle (83) was prepared by a 61 S.Tsuboyama Y. Shiga Y. Takasyo. T. Chijimatsu K. Kobayashi K. Tsuboyama and T. Sakurai. J. Chem. Soc. Dalton Truns.. 1992 1783. h3 G. A. Lawrance M. Martinez B. W. Skelton R. van Eldik and A. H. White. Aust. J. Chrm.,1992.45.351 64 G.A. Lawrance. M. Martinez B. W. Skelton. and A. H. White J. Chem. Soc. Dalton Truns. 1992. 823. h5 P.V. Bernhardt P. Comba. T.W. Hambley. G.A. Lawrance. and K. Varnagy J. Cl7em. Sot,.. Dalrori Truns. 1992. 355. " N. F. Curtis W.T. Robinson and D.C. Weatherburn Aust. J. Chrm.. 1992. 45. 1663. 61 T. W. Hambley G. A. Lawrance M. Maeder. and E. N. Wilkes J. Chem. Soc.. Dulron 7rans.. 1992. 1283 68 T.W. Hambley G.A. Lawrance M. Martinez. B. W. Skelton. and A. H. White J. Chem. So(... Dulron 7'Tuns.. 1992 1643. 322 S. L. W. Mc Whinnie copper(I1) mediated template synthesis. Reduction of the Cu" complex with zinc in aqueous acid produced (82) which reacts69 with Co" ion and air to form cis-[Co"'( 83)C1][C104] ,. The complex [Co"'(84)C1][CoC1,]~H20 has been prepared and its crystal structure determined.70 The cation [Cu"(86)]' has been prepared and subsequent reaction + leads71 to the isolation of [C~"(85)]~+. Reaction of [Pt"(87)] with chlorine leads not only to the isolation of [Pt'V(87)Cl,][C104] but also to the isolation of [Pt"(88)C12] [ClO,],Cl in which complete chlorination of the pendant primary amines has occurred.72 The complex [Ni11(89)]2 + is oxidized in aqueous solutions in the pH range 3-7 in the presence of stabilizing anions X (X = HCO, SO;- and H,PO;) by HO; free radicals to [Ni"'(89)X2].The dependence of the rate of formation on [Ni"(89)I2 and + X indicates that the HO; radical reacts with a [Ni"(89)I2+ complex in the ion-pair [Ni"(89) X] forming the final products.73 The Co" complex [C0"(89)(H,0),]~' forms [Co"(89)(OH)(02)]+ on reaction with 0 in aqueous solution at pH > 7.74 Indirect electrochemical radical cyclization of halogeno ethers has been achieved under mild conditions using the Ni" complexes [Ni"(37)I2 +,[Ni"(89)I2+ and [Nii1(90)]* + as electron-transfer catalysts.75 H' 'H (74) (75) (76) (77) R = NH2 (79) (78) R=NO2 G.A.Lawrance M. Martinez B. W. Skelton and A. H. White J. Chem. SOC. Dalton Trans.. 1992 1649. '' T.N. Mali P. W. Wade and R. D. Hancock J. Chem. SOC.,Dalton Trans.. 1992 67. " L. Xin and N.F. Curtis Aust. J Chem. 1992 45 1087. 72 P. V. Bernhardt G.A. Lawrance and T. W. Hambley Inorg. Chrm. 1992 31 631. 73 A. Meshulam H. Cohem R. Van Eldik and D. Meyerstein Inorq. Chern. 1992 31 2151. 74 A. Marchaj. A. Bakac and J.H. Espenson Inorg. Chem. 1992 31 4164. '' S. Ozaki H. Matsushita. and H. Ohmori J. Chem. SOC. Chem. Commun. 1992 1120. The Coordination Chemistry of Macrocyclic Liyands (82) R = NH2 (83) R=N02 (85) R = H (87) R=NCI2 (86) R = COOMe (88) R=NH3 The sterically congested ligands (91 )-(94) and their Ni" complexes have been synthesized.Magnetic susceptibility measurements in the solid state and in aqueous solution show that the less congested complexes [Ni1'(35)I2+ and [Ni"(93)I2+ are high spin in the solid state and a mixture of high spin and low spin in solution. In contrast the highly congested complexes [Ni1'(91)I2+ [Ni"(92)I2' and [Ni"(94)I2+ are low spin in both the solid state and solution.76 Spectrophotometry and stopped-flow spectrophotometry were used to study the kinetics of complex formation between M2+ ions (M = Ni Cu) and (89) (95)-(98).77 The biologically relevant and electrochemically important macrocyclic thioureas (99)and (100)have been synthesized and complexed with Co",Ni" Cu" Zn" and Pt" chlorides. All the complexes synthesized were polymeric.78 A condensation between ethylenediaminetetraacetic dianhydride and ethylenediamine provided the two new macrocycles (H 101) and (H,102).The formation of the macrocycles was confirmed by X-ray crystal analyses79 of their metal complexes [Cu"( 101)]*4H20 and [Mny( 102)] *8H,O. 76 K. Kobiro A. Nakayama M. Suwa and T. Tobe. Inorg. Chem. 1992 31 676. 77 J.R. Roper and H. Elias Inorg. Chem.. 1992 31 1210. L. Mishra and A.K. Pandey Polyhedron 1992 11 423. M. B. Inoue C. A. Villegas. K. Asano. M. Nakamura M. Inoue. and Q.Fernando Inorg. Chem. 1992.31. in 7Y 2480. 324 S.L. W. Mc Whinnie fNQ .I. *.* HHN"N 'H (94) (95) R= H (97) (96) R=Me (99) n=6 (100) n= 8 7 N I 'H Square-planar Ni' complexes of various saturated ligands (103k(109) have been prepared by the reduction of Ni" complexes with Na(Hg) in MeCN and [Ni1L][CI04] [L = (103) (105) (107)-(109)] were isolated as crystals.EPR spectra of the nickel(r) complexes show anisotropic axial g,,and gL(g,,> gl)values or rhombic gl gz,and g3 values.*' 'O M. P. Suh H. K. Kim. M. J. Kim and K. Y. Oh Inorq. Chon.. 1992. 31. 3620 The Coordination Chemistry of Macrocyclic Liyands H3C-(103) R=H (105) R= H (104) R=Me (106) R=Me Unsaturated Macrocycles. New macrocyclic complexes of Ni" with (1 lot(120) have been synthesized either uia reaction of a nucleophilic macrocycle with various acid chlorides or via peripheral functionalization of suitable macrocycles.Some of the new complexes have been incorporated into the structure of synthetic polymers.* * Four cobalt(I1) complexes of the 'lacunar cyclidene' type have been prepared [L = (121k(124)] including two unbridged examples. The reactions of these com- plexes with oxygen have been investigated.82 The single crystal EPR spectrum of [Cu"( 125)CllClhas been measured both in the lattice of the pure compound and from X (H2llO) X = C1 (H2111) X=I (H2112) X = NO2 (Hzll3) X = CH3C02 (H2114) X = Br (H2115) X = CH3 (H2116) X = CHZCH (H21 17) X = Br2CH (H2118) X=NI12 (H2119) X = CH3CONH (H2120) X=HO "' J. H. Cameron H. B. Harvey and I. Soutar J. Chem. Soc.. Dalton Trans. 1992 597 '' J. H. Cameron and S. Graham. J. Chem Soc. Dalton 7runs..1992 385. S. L. W. Mc Whinnie the isomorphous nickel(I1) compound. The 63Cu-doped [Ni”( 125)Cl)Cl compound has an anisotropic ESR spectrum.83 R2 I n c :I The neutral asymmetrically substituted Ni” complex [Ni”( 126)] has been synthesized via the template condensation on an asymmetric acyclic precursor with 1,3-propanediamine. The peripheral aromatic nitro group of the ligand undergoes catalytic reduction with hydrogen to produce the corresponding aromatic primary amine complex.84 The complexes [NEt,][MnV(0)L] [L = (127k(130)] have been synthesized and their vibrational and electrochemical properties studied.” (H4127) X=Cl (H4128) X=H (H4129) X=Me (H4130) X = OMe 83 A. Ceulemans R. Debuyst I;. Dejehet G. S. D. King M. Vanhecke and L.G. Vanquickenborne Inorg. Chim. Acta 1992 192 95. 84 J.H. Cameron H. B. Harvey and I. Soutar. Inorg. Chim. Acto 1992 192. 253. 85 J. M. Workman R. D. Powell A. D. Procyk T.J. Collins and D. F. Bocian Inorg. Chem. 1992,31 1548. The Coordination Chemistry of Macrocyclic Ligands The reduction of alkyl halides by NaBH is efficiently catalysedS6 by [Ni"(132)] a plausible active species being [Ni'( 132)] -. The species [{Cr"( 132)) ,]has been shown to undergo reversible cleavage of the Cr-Cr multiple bond in pyridine to form [Cr"( 132)(py),]. The geometry of the new species somewhat surprisingly for a Cr" d4 electronic configuration has been shown to be ~ctahedral.'~ Reaction of [VCl,(thf),] with (Li,l32) gave [V"'( 132)Cll. This complex was converted into the corresponding alkyl and aryl derivatives [V1"(132)R] (R = Me CH,Ph Ph 2,4,6-Me3C,H,).The V"'-R bond does not behave as expected in the reaction with CO, the reaction leading" to the deoxygenation of the acyl or ketone intermediate forming [V'"( 132)(0)]. The complexes [TitV(132)(0)] and [Ti"( 132)(S)] have highly reactive TitV=O and TitV=S linkages and have been demonstrated to undergo a number of new addition and cycloaddition reactions; [Ti"( 132)(0)] has been found to be involved in a series of acid-base eq~ilibria.'~ Reaction of (Li,132) with organochlor-ides of silicon and tin provides [MIV(132)Me,] and [MtV(132)Cl,] (M = Si and Sn) following halide elimination. The structure of these new species has been assigned on the basis of NMR data." The reactions between n-cation radicals generated by electrochemical or chemical oxidation of pyrrole and [Nit'( 132)] and [Ni"( 138)] have been investigated.There is voltammetric evidence that pyrrolyl units insert between nickel-macrocycle molecules when solutions containing controlled amounts of [Nit'( 132)] and pyrrole are cycled in the range +1.4 to -1.5V (us. SCE).91 Manganese(u1) complexes of peripherally substituted dibenzotetra[14]annulenes [Mn"'L(NCS)] [L = (134)-( 137)] have been (H2131) R' =R2 =R3=R4 =H (Hz132) R' =R2 =H R3=R4 =Me (H2133) R' =Me R2=R3=R4=H (H2134) R' =R2=H R3=Me R4=C6Hs (H2135) R' =H R2=COC&15 R3=R4 =Me (H2136) R' =H R2=COC6H4CI R3=R4=Me (H2137) R' =H R2 =COC& R3=Me R4 =C6H5 86 T.Arai H. Kondo and S. Sakaki J. C'hem. SOC.,Dulton Trans. 1992 2753. 8' S. Hao J. H.H. Edema S. Gambarotta and C. Benismon. Inorg. Chem. 1992 31 2676. 88 E. Solari S. De Angelis C. Floriani A Chiesi-Villa and C. Rizzoli Inorq. Chem. 1992 31 96. R9 C.E. Housmekerides D.L. Ramage C.M. Kretz J.T. Shontz R.S. Pilato G.L. Geoffroy A.L. Rheingold and B.S. Haggerty Inory. Chem. 1992 31 4453. 90 G. R. Willey and M. D. Rudd Polyhedron. 1992 11. 2805. 91 G. Ricciardi and F. Lelj Polyhedron 1992 11. 2089. S.L. W. McWhinnie synthesized from the free ligands and [Mn"'(acac),(NCS)]. The complexes are effective catalysts for the monooxygenase-like oxidation of p-nitroso-N,N-dimethylaniline to p-nitro-N,N-dimethylaniline by iodo~ylbenzene.~~ The electronic structure of the Ni" and Pt" complexes of (130) have been studied by integrated experimental He I/He I1 photoelectron spectroscopic methods as well as theoretical ab initio pseudopotential and first-principle local exchange DV-Xr approaches.Theoretical calculations have provided a complete assignment of the photoelectron spectra as well as useful information on the peculiarities of the valence electronic system that in turn is of relevance in understanding the properties of low-dimensional partially oxidized [M"L"+] [L=(131) or (133)] systems.93 Amines and diamines have been used as nucleophiles towards [Cu"L] [L = (139) and (140)].94The reduction ofO by [C0"(141)]~+ has been studied in aqueous media in the presence of Br-. The otherwise very slow reaction is strongly catalysed by [C0"(142)]~+.The rate law showsa first-order dependence on [C0"(141)]~+ O, Br- and H+,and is second-order with respect to the catalyst.95 The complex [C~"(143)]~+ binds and cleaves DNA in the presence of a reducing agent under anaerobic condition^.^^ (H2139) R=Me (H 140) R = C2H5 92 J.Eilmes Polyhedron 1992 11 581. 93 M. Casarin E. Ciliberto S.Di Bella A. Gulino I. Fragala and T. J. Marks Inorg. Chem. 1992,31,2835. 94 S. Kumar R. Malhotra and K.S. Dhindsa Polyhedron 1992 11 1383. 95 A. Marchaj A. Bakac and J. H. Espenson lnorg. Chem. 1992 31. 4860. 96 M. Hirai K. Shinozuka H. Sawai and S. Ogawa Chem. L,ett. 1992 2023. The Coordination Chemistry of Mucrocyclic Ligunds Electrocatalytic reduction of H ' to H in the presence of [Ni"(45)I2+ has been dem~nstrated.~' The heterobimetallic complex [Cu"Ni"( 144)14+ has been prepared; electrochemical synthesis of [Ni"( 144)12 has also been achieved by removal of the + Cu" [Fell( 145)(phen)][C104] has been isolated and its structure has been established by X-ray crystallography.The macrocyclic ligand (145) is folded in order to allow chelation of the phen ~o-ligand.~~ The binuclear complex [Ni;( 146)(MeOH),(C10,),]~2NEt3HC104 reacts with p-alanine and glycylglycine affording"O the p-carboxylato complexes of composition 146)( -0,CNH; )(H,O),][ClO,],~nH,O. Binuclear complexes of composition [Ni;( 146)B2][C10,] (B = NH, imidazole py or pyrazine) have been synthesized and characterized. With pyrazole 146)(p~)(H,O)~][ClO,] and 146)(pz)(Hpz)(H,0)][C104] have been obtained in which pz- appears to act as a bridging ligand."' The Mn" complex [Mn"( 146)(N,),] has been isolated and characterized by X-ray crystallography.'02 Copper(II)-lead(II) complexes of (149k( 152) have been prepared by 'stepwise' template reactions.[Cu"Pb"( 149)] [ClO,],-dmf has been characterized by X-ray crystallography the Cu" is bound to the four-coordination site with planar geometry and the Pb" is bound in the five- coordination site and assumes a seven-coordinate geometry with a unidentate perchlorate ion and dmf in the coordination sphere.lo3 Template condensation of 2,6-diformyl-4-R-phenols with 1,3-diamino-2-hydroxy- propane in methanol or ethanol in the presence of Cu" salts produced the complexes [Cu:(H 153)(MeOH)(C104)][C104] [Cuy(H 1 53)X,]-2H20 (X = NO and Cl) [Cuy(H 153)(NCS),] [Cuy(H 1 54)(H,0),][CI04], and [Cuy(H 1 54)(N03),] .H,O.Template condensation in the presence of copper(i1) acetate and excess azide produced"" the polymeric complexes [Cuy(H 1 53)][Cu~(N,),]. A number of new ligands (147) (148) (1 55)-( 159) including some open-chain analogues have been 97 L. L. Efros. H. H. Thorp G. W. Brudvig and R. H. Crabtree Inorg. Chem. 1992. 31. 1722. YR K. Mochizuki M. Tsutsumi and Y. Yamaji Inorg. Chirn. Actu 1992. 191 35. 99 Y.-S. You and S.-M. Peng Inorg. Chirn. 4cta 1992 192 9. I00 R. Das K. K. Nanda K. Venkatsubramanian P. Paul and K. Nag J. Chern. Soc.. Dalton Trans. 1992 1253. I01 K. K. Nanda R.Das M. J. Newlands R. Hynes E. J. Gabe and K. Nag J. Chrm. Soc. Dalton Truns. 1992 897. 102 M. Mikuriya K. Nakadera and T. Tokii Inorg. Chirn. Actu. 1992 194 129. 103 M. Tadokoro H. Sakiyama N. Matsumoto M. Kodera. H. Okawa and S. Kida J. Chem. Soc. Dalton Trans. 1992 313. 104 S. S. Tandon L. K. Thompson J. N. Bridson V. McKee and A. J. Downard Inorg. Chem. 1992.31.4635. S. L. W. McWhinnie prepared and their coordination properties towards d and/or f metal ions have been tested and cornpared.lo5 z z (H2147) Z=Me (H2148) 2 = C1 R R (H3149) m = 2 n = 1 (H4153) R = Me n = 1 (H3150) m = 3 n= 1 (b154) R = Bu' n = 1 (H3151) m=2 n=2 (H3152) m = 3 n = 2 S-donor Ligands.-The kinetics of electron-transfer reactions involving [Cur/"-( 160)] +12 + reacting with a series of counter reagents have been measured in aqueous solution at 25 "C.Application of the Marcus equation to the cross reaction rate constants for four reduction studies yielded O6 consistent self-exchange rate values of 160)] +i2 + .As a follow-up to earlier work which log k = 3.78 ( 0.26) for [CU'~II( lo5 A.Aguiari E. Bullita U. Casellato P. Guerriero S. Tarnburini and P. A. Vigato Inorg. Chrm. Acta 1992 202 157. '06 N. E. Meagher K. L. Juntunen C. A. Salhi L. A. Ochryrnowycz. and D. B. Rorabacher. J. Am. Chem.Soc. 1992 114 10411. The Coordination Chemistry of Macrocyclic Ligands 331 N OH QOH N OH N. / R\ N 5y \ \ YYoH z (142155) R' = R2 = (CH&NH(CH2)2 2 = C1 (H2156) R' = R2 = (CH2),N(CHzCH&N(CH,)3 Z = H (H2157) R' = C,& R2 = C2& Z = Me indicated that Cu"-macrocyclic tetrathiaether complexes are stabilized by the presence of anions normally considered to be non-complexing the dissociation kinetics of Cu" complexes with (160t(162) have been investigated as a function of perchlorate ion concentration using aquamercury(i1) ion as the scavenging species.For all systems the kinetic data are interpreted to represent a comparison of the direct [CU"L]~+ dissociation pathway in which the Hg" actively displaces the Cu" from the ligand. lo' The complexes [Bit''( 160)ClJ and [Bi"'( 167)Cl,].$MeCN have been prepared and characterized."' Treatment of [Ni"(OH,),][BF,] with (160) or (165) in MeNO in the presence of acetic anhydride affords blue solutions from which the complexes [Ni11L(OH2)2]2+ [L = (160) and (lh5)] can be isolated.Treatment of [Ni"(OH,),] [XI (X = BF and PF,) under the same conditions affords solutions containing the complex [Ni"( 167)12 + which adopts square-pyramidal geometry and forms six- coordinate adducts with MeCN pyridine and chloride.' O9 The stability constants for the interaction of Cu" with (162t(164) have been determined spectrophotometrically in methanol-water mixtures at 25 "C with various concentrations of ClO . The thermodynamic data support the hypothesis that gem-dimethyl pairs reduce the conformational enthalpy cost required to organize the ligand for chelation.' lo [{Mo"Br(,u-Br)(CO),),1 and (166) in CH,CI give the novel seven-coordinate cation-anion complex [Mo"Br(CO),( 166)][Mo"Br,(CO),] the cation of which has a 4 3 'piano stool' geometry.' The anomalous redox properties of [Mo"X,( 166)] (X = C1 or Br) have been rationalized.The authentic reduction of the dibromide occurs at E,, = -2.87 V (us. FcH'/FcH) to give an unstable 17-electron anion which reacts with carbon monoxide and dinitrogen. Facile monoalkylation of 107 L. L. Diaddario Jr. L. A. Ochryrnowycz and D. B. Rorabacher. Inorg. Chrni. 1992 31 2347. I OR G.R. Willey. M.T. Lakin. and N. W. Alcock J. Chrm. Soc. Dalton Trans. 1992. 591. 109 A. J. Blake. M. A. Halcrow and M. Schroder J. Chrm. Soc. Dalton Trans. 1992 2803. 110 A.Y. Nazarenko R. M. Izatt J.D.Lamb. J. M. Desper B. E. Matysik. and S. H. Gellman Inory.Chem. 1992. 31 3990. Ill M. C. Durrant. D. L. Hughes. R. L. Richards. P. K. Baker and S. D. Harris J. Chm. Soc.. Dalton Trans. 1992 3399. 112 T. Adachi M. D. Durrant. D. L. Hughes. (1. J. Pickett R. L. Richards J. Talarmin and T. Yoshida. J. Chem. Soc. Chem. Commun. 1992 1464. S. L. W. Mc Whinnie tran~-[Mo'~(S),( 166)] with Me1 and PhCH,Br proceeds stereoselectively at the terminal sulfur located on the uncongested axial site to give trans-[MoIv(SR)(S)(syn- 166)]+ (R = Me or CH,Ph). The structure of the methyl thiolate complex was elucidated by an X-ray diffraction study.' l3 R' R' x K RR (162) R' = R2 = H (165) R=H (163) R' = H R2 = Me (166) R=Me (164) R' = R2= Me O-donor Ligands.-( 12-crown-4) reacts with [Ti'vC1,(NCMe),][SbC16] in MeCN to form a complex that provides the crown ether titanoxane [{Ti'vC1(p-O)( 12-crown- 4)),][SbC16],.2CH,C1 following inadvertant hydrolysis.The cation contains seven- coordinate titanium atoms.' l4 The reaction of crown ethers with Pb(NO,) in MeCN and MeOH mixtures has produced several crystalline complexes which have been structurally characterized,' ' i.e. [Pb"(NO,)( 12-~rown-4),][Pb"(NO,)~( 12-crown-4)] [Pb"L2][Pb"(N03)3L]z (L = 15-crown-5 or benzo-15-crown-5) and [Pb"(NO,),( 18-crown-6)]. Salts containing the silyltellurolate anion [TeSi-(SiMe,)J have been prepared116 by crowning the Li' cation in (thf),LiTeSi(SiMe,) to form [(12-crown-4),Li][TeSi(SiMe,),l. Lipase from Pseudomonas has been demonstrated to catalyse the hydrolysis of chiral (168) to (169); the reaction rate and enantioselectivity are greatly enhanced by crown-ether metal encapsulation the most significant rate enhancement being noted (167) (168) R= AC (169) R = H '13 T.Yoshida T. Adachi K. Matsumara and K. Baba Chem. Lett. 1992 2447. G. R. Willey J. Palin and N. W. Alcock J. Chem. SOC.,Dalton Truns.. 1992 11 17. 'I5 R.D. Rogers and A.H. Bond Inory. Chim. Acta 1992 192 163. P. J. Bonasia D. E. Gindelberger B. 0.Dabbousi and J. Arnold J. Am. Chem. Soc. 1992 114 5209. The Coordination Chemistry of Macrocyclic Ligands for odium."^ New crown ethers (171) (R = C,H, C8HI7 and C12H2,) and (173) have been synthesized from (170) and (172) respectively. It has been demonstrated that introduction of the pendant arm significantly enhances their ability to extract and transport Li+.The Li' ion would appear to be predominantly coordinated to the phosphate anion of the side arm and to the nearest oxygen atoms to the pendant arm site.' '' n x U U (170) X = OH (172) X=OH 0 0 (171) X=O-P-OR (173) X =O-?-OC,Hg OH OH Other DonorSets.-The luminescence and absorption spectra and emission lifetimes of Eu" complexes with (174) and (181) have been investigated. The stoichiometry of the complexes was shown to be 1 1 by use of the emission intensity molar ratio method and by monitoring the shift and splitting of the 'H NMR lines for the Sr" analogues.' l9 A spironaphthoxazine functionalized crown (175) has been synthesized and shows high lithium ion-selective isomerization to the corresponding coloured open form and also lithium ion-concentration dependent thermal stability.' 2o The stability constants of the complexes formed by (176) with various first row transition metal ions and Zn2 + Cd2+ Pb2+ and Ca2 + were determined by potentiometric measurements.The structure of [Cu"( 176)] has been determined and shows a distorted octahedral coordination sphere.' '' Minimal GL,O basis set ab initio and CND0/2 calculations have been performed for four possible conformations of (177) and their Li' complexes.'22 The stability constants of the complexes formed by (178t( 181) with the alkaline earth metals the first row transition metals ions and Zn2 + ,Cd2+ ,and PbZ + were determined by automated potentiometry .The Irving-Williams order of stability is not obeyed for the metal complexes of any of the ligands probably due to the steric constraints of the rings.'23 A pronounced effect of alkali metal ion on rate and product distribution in the rate of reaction of (1 81t(184) with benzyl oxide-benzyl alcohol has H. Tsukube A. Betchaku Y. Hiyarna and T. Itoh J. Chem. Soc. Chrm. Commun. 1992. 1751 iin Y. Habata M. Ikeda and S. Akabori J. (:hem. Soc. Perkin Trans. I 1992 2651. 11') N. Higashiyama K. Takemura K. Kimura and G. Adachi Inorg. Chem. Actu 1992. 194. 201. 120 K. Kimura T. Yamashita M. Kaneshiga and M. Yokoyama J. Chrm. Six. Chem. Commun. 1992.969. I*' S. Chaves R. Delgado M. T. Duarte J. A. L. Silva. V. Felix and M.A. A. F. de C. T. Carrondo J.Chern. Soc. Dulton Trans. 1992 2519. I22 S. Hannongbua Inorg. Chim. Actu. 1992 202. 85. 123 M. T. S. Amorim. R. Delgado. and J.J. R. F. Da Silva. Polyhedron. 1992 11. 1891. S.L. W. Mc Whinnie ioj-R (175) (174)R = CH2CH20CH3 (176) (177)R=H (179) (178) R = CH2COOH been observed.' 24 The ligands (185) and (186) have been synthesized by a high yielding template synthesis; the structures of [Nil'( 185)]Br2.2H20 and 186)1][BPh,] have been determined.12' The X-ray crystal structure of [Hg"( 187)Cl][HgCl,] has been determined and reveals the cation to contain five-coordinate mercury.'26 The (R*,R*)and (R*,S*) forms of (188) have been isolated in low yield. The crystal structure of [Ni11(R*,R*-188)][C104]2*Me2C0 has been determined.' 27 (181) n= 1 (182) n=2 (183)n= 3 (185)X = CH2 (1 86) X = CH2OCH2 124 M.Belohradsky P. Holy J. Koudelka V. Krchnik and J. Zavada J. Chem. SOC.,Chrm. Commun. 1992 1745. 125 M. Y. Darensbourg 1. Font D. K. Mills M. Pala and J. H. Reibenspies Inorg. Chem. 1992 31 4965. 126 M. E. Sobhia K. Panneerselvam K. K. Chacko I.-H. Suh E. Weber and C. Reutel Inorg. Chim. Acta 1992 194 93. 127 T. L. Jones A.C. Willis and S. B. Wild Inorg. Chem. 1992 31 141 1. The Coordination Chemistry of Macrocyclic Ligands H H "'X. N' HOOCrLNJ COOH (189) X = CH2CH2 'COOH (190) X = CHzCHzCH2 (191) X = CH2CH2CH2CH2 (192) X = CH2CH=CHCH2 (1 93) X = CH2CH2CH2CH2CH2 (194) X = CH2C&CH2 (195) X = CH2CHzOCH2CH2OCH2CH2 4 Pentadentate Macrocycles N-and Odonor Ligands.-Macrocycles (189)-( 196) have been prepared and the protonation constants and Gd"' and Zn" complex stability constants were determined by potentiometric titrations.The stability constants of the Gd"' complexes increase with increasing ring size whereas those of Zn" show no particular trend.'28 The macrocycle (197) has been synthesized and found to bind anions. The X-ray crystal structure of [C1(H2197)][BF,] has been determined and reveals that the chloride ion interacts with four hydrogens.' 29 Gas-phase size selectivities of crown ethers have been investigated by application of the kinetic method. Ion complexes of crown ethers with two different alkali metals were generated by liquid secondary ion mass spectrometry.The following orders of selectivities were observed for alkali metal ions:' 30 15-crown-5 Li % Na+ > Cs '; + 18-crown-6 Na+ 2 K+ > Li+ > Rb' > Cs+; and 21-crown-7 K+ > Na+-> Rb+ > Li+ > Cs'. I HOOC7 /-7 /-COOH 04" "b IZRJ.F. Caravalho S.-H. Kim and C.A. Charig Inorg. Chem.. 1992 31 4065. '29 J. L. Sessler T.D. Mody D.A. Ford and V. Lynch Angew. Chem. In?. Ed. Engl. 1992 31 452 S. Maleknia and J. Brodbelt J. Am. Chem. Soc. 1992 114. 4295. 336 S. L. W. Mc Whinnie Reaction of anhydrous metal salts with 15-crown-5( 15C5) in acetonitrile leads to the isolation of a variety of ionic compounds. Anhydrous CoCl leads to the formation both in solution and crystalline of ionic compounds of three structural types:'31 [Co"( 15C5)(NCMe),] [Co"CI (NCMe)] ,.MeCN [Co"( 1 5C5)(NCMe),] [Co"Cl,] .MeCN and [Co"( 15C5)(NCMe),][Co~C16].Interaction of anhydrous CoCl and CuCl gave the ionic complex [Co"( 15C5)(NCMe),][Cu;C16]; hydration' 32 gave a mixture of CuC1,.2H20 and [CO'~(~~C~)(H,O),][CU"C~,~. Reaction of anhydrous MgCl and CuCl with 15C5 gives the molecular complex [Mg(NCMe)( 15C5)(p2- Cl)Cu"Cl,] and the ionic complexes [Mg( 15C5)(NCl\lle),][Cu'c16] and [{Mg(l5CS)(NCMe),)(Cu,Cl8),]; on hydrati~n',~ the compounds formed are CuC12.2H20 [Mg(15C5)(H20)2][C~"C14]~H20, [{Mg(H2O),).2(15CS)][(C~,C1,- (H,O),}-H,O] and [CuCl,.(H,O),-( 15C5)],. The crystal structures of [Sb"'CI(15C5)][SbCl6] and [Bi"'Cl( 18C6)(NCMe),] [SbCl,] have been determined.'34 The role of the solvent in the dissociation kinetics and cation exchange mechanisms of mono-benzo-15-crown-5 CNa(B1 5C5)] has been + examined by 23Na NMR.In nitromethane the cationic exchange between the complexes takes place via an associative metal interchange mechanism; in acetonitrile it takes place via a dissociative mechanism.' 35 The structures of dicyclohexano-15-crown-5 and its sodium thiocyanate complex have been determined by X-ray ~rystallography.'~~ The first examples of thiolariat ethers (198)-(204) have been synthesized and their selectivity towards transition metal ions have been tested. Ligands (198)-(202) show a remarkably high selectivity towards Agf in comparison to the benzo crowns (203) and (204) and (205) and (206).13' n Ph (198) n = 1 R= Bn (199) n =2 R = Bn (200) n= 1 R=Bu (201) n=2 R=Bu (203) R = Bn (205) n = 1 (202) n = 2 R = C12Hz (204) R = BU (206) n = 2 The novel benzo-15-crown-5 and 18-crown-6 derivatives bearing an ionizable hydrazone group (207) and (208) have been synthesized and complex formation equilibria with alkali metal ions in solvent extraction were evaluated spectrophotomet- 13' 0.K.Kireeva B. M. Bulychev N. R. Streltsova V. K. Belsky. and A.G. Dunin Polyhedron 1992 11 1801. 13' 0.K. Bulychev 0.K. Kireeva V. K. Belsky and N. R. Streltsova Polyhedron 1992 11 1809. 133 T.B. Rubtsova 0.K. Kireeva B.M. Bulychev N. R. Streltsova V. K. Belsky. and B. P. Tarasov Polyhedron 1992 11 1929. 134 M. Schafer G. Frenzen B. Neumiiller and K. Dehnicke. Angew.Chem. Int. Ed. Engl. 1992. 31. 334. 13' K. M. Briere and C. Detellier Can. J. Chem. 1992. 70 2536. 136 G. W. Buchanan S. Mathias. C. Bens,mon. and J. P. Charland Can. .I.Chem. 1992. 70 981. 13' T. Nabeshima K. Nishijima N. Tsukada H. Furusawa T. Hosoya and Y. Yano. J. Chem. Soc.. Chem. Commun. 1992. 1092. The Coordination Chemistry of Macrocyclic Ligands rically. Formation of 2 :2 complexes of the crown ethers with metal ions was observed using chloroform as an extraction solvent. 38 The first multi-receptor [bis(crowns) with polyamine linkers] have been synthesized e.g. (209) and exhibit multiple binding to anions and their counter ions simultaneou~ly.~ 39 (207) n= 1 (208) n=2 The Pb" complexes [Pb"(210)(N03),] and [Pb"(21 l)(N03)2] have been prepared and examined by 3C NMR spectroscopy and X-ray crystallography.140 The mercury(r1) complexes of the same ligands have also been prepared. The complexes [(Hg1'Cl(p-C1)(210)}{ Hg"(p-Cl),)], and [Hg"(21 1)C12] have been characterized by X-ray crystallography. 14' The macrocycles (21 2k(223) have been prepared and among these (214) and (218) selectively extract lead picrate over silver alkali metal and alkaline earth metal picrates and (214) shows a higher order of specificity. IR and 13C NMR studies indicate a preferential coordination of the amide oxygen of these macrocycles with metal ions. 142 Binuclear Ag' complexes of the double-armed diaza-crown ethers (224) and (225) have been prepared.14 S-and Mixed S-donor Ligands.-The crystal and molecular structure of [Cd"(226)] [C10,],.H20 has been reported.The cadmium is seven-coordipate with an oxygen from one of the perchlorate anions and the water molecule making up the coordination sphere.144 Reaction of RhCl with (226) yields [Rh"'C1(226)I2+ while reaction of '38 H. Sakamoto H. Goto K. Doi and M. Otomo Chem. Left. 1992 1535. 13' E. A. Arafa K. I. Kinnear and J.C. Lockhart J. Chem. SOC.,Chem. Commun. 1992 61. 14" K.A. Byriel K.R. Dunster L.R. Gahan C.H.L. Kennard J.L. Latten I.L. Swann. and P.A. Duckworth Polyhedron 1992 11 1205. 14' K. A. Byriel K. R. Dunster L. R. Gahan (1. H. L. Kennard and J. L. Latten Inory. Chim. Acta 1992,196. 35. 142 S. Kumar R. Singh and H. Singh J. Chem. Soc. Perkin Trans. 1. 1992 3049. 143 K.Hirotsu I. Miyahara T. Higuchi M. Toda H. Tsukube and K. Matsumoto Chem. Left.. 1992 699. '44 W. N. Setzer Y.Tang G. J. Grant and 13.G. VanDerveer Inory. Chcm. 1992 31 1116. S. L. W. Mc Whinnie -0cN0 1 voq(210) n= 1 (211) n=2 (212) n= 1 (213) n=2 I. (214) ri= 1 R= H (215) n= 1 R = Me (216) = 1 R = CH7COOEt (217j n = 1 R = CHiCON(CH,Me) (218) n=2 R=H (219) 1i=2 R=Me (220) ri = 2 R = CH2COOEt (221) ti = 2 R = CH2CON(CH2Me)2 (222) n = 2 R = CH,CH,COOMe (223) t1= 2 R = CHZCHZCHZCN (224) n= 1 (225) n= 2 [Ru"Cl,(PPh,),] yields [Ru"(PPh3)(226)]X (X = PF; or BPh,). [Ru"(PPh,)(226)] [BPh,] has been characterized by X-ray ~rystallography.'~~ [Wo(CO),(227)] has been prepared and its molecular structure determined.'46 Reaction of AgNO with (228) affords the complexes [Ag!,(228),][PF6] and [Ag\(228),][PF6],; the former is an S-bridged linear-chain polymer of [Ag'(228)] units while the binuclear species + shows distorted trigonal planar S coordination at Ag' with long-range interactions' 4' to three 0-donors.The Ni" and Ag' complexes [Ni"(229)(C10,)][C104] and [Ag'(229)] [ClO,] have been prepared and characterized by X-ray crystallography. '48 Co" and Ni" interact with a range of 16-to 19-membered ring macrocycles. An X-ray T-7 LJ 145 A. J. Blake G. Reid and M. Schroder Polyhedron 1992 11 2501. 146 H. Wu and C. R. Lucas Inorg. Chem. 1992 31 2354. 147 A.J. Blake G. Reid. and M. Schroder. J. Chem. Soc. Chem. Commun. 1992 1074 148 U. Kallert and R. Mattes Polyhedron 1992 11 617. The Coordination Chemistry of Macrocyclic Ligunds crystallographic study of [Ni"(230)(H20)][N033 confirms that the Ni" is six- coordinate with the complex cation exhibiting a distorted-octahedral geometry.149 (229) Z=S (230) 2 = 0 5 Hexadentate Macrocycles N-donor Ligands.-The effects of [24]ane-N, [32]ane-N and [30]ane-N on the spectroscopic and photochemical properties of the [Co"(EDTA)- .I-3 ion-pair have been investigated. The addition of a macrocycle to aqueous solutions containing [Co"(EDTA)]-and I-causes an increase of the absorbance in the region of the ion-pair charge-transfer band as well as an increase of the quantum yield for the intramolecular photooxidation reduction of the ion pair. 5o Macrocyclic lanthanide complexes [Ln(23 1)13 efficiently promote the transesterification of RNA and the + Eu"' complex exhibits true catalytic behaviour.151 A Gd"' complex of (231) with relaxivities higher than [Gd11'(DTPA)(H,0)]2 -and [Gd"'(DOTA)(H,O)] -has been synthesized and its crystal structure indicates a nine-coordinate gadolinium ion bound to three water oxygen atoms and six nitrogen atoms from the macrocycle.'52 New chiral lanthanide macrocycle complexes [Ln(232)] + have been prepared by template reaction.Strongly circularly polarized luminescence was detected for the Eu"' I49 K. R. Adam M. Antolovich D.S. Baldwin L.G. Brigden P. A. Duckworth L. F. Lindoy A. Bashall. M. McPartlin and P. A. Tasker J. Chem. Soc. Dalton Trtrns. 1992 1869. 1 so F. Pina A. J. Parola. A. Bencini M.Micheloni M.F. Manfrin and L. Moggi inorg. Chim. Acta 1992,195 139. 151 J. R. Morrow L.A. Buttrey V. M. Shelton and K.A. Berback J. Am. Chem. Soc. 1992 114 1903. 152 S. W. A. Bligh N. Choi E.G. Evagorou M. McPartlin W. J. Cummins,and J. D. Kelly Polyhedron 1992 11. 2571. S. L. W. Mc Whinnie and Tb"' complexes due to the twisted conformation of the ligand.'53Ligands (233) and (235)have been synthesized; the formation constants of (233)with Ca" Mg" Cu" Zn" Cd" La"' and Gd"' follow the Irving-Williams series and are consistent with 1 1 metal ion binding. (233) binds as well as or better than its saturated homologue [18]ane-N, but (235) does not bind' 54 effectively in comparison to trans-[ 181 ane-N,O,. The X-ray structure of a mononuclear barium complex of (234) confirms that the macrocycle folds to present a molecular cleft within which the metal is coordinated.Transmetallation with Cu" gives a homodinuclear Cu" complex.'55 The synthesis and X-ray structure of [U'v(0),(236)] has been reported.' 56 The torand (237) forms 1 1 complexes with alkali metal ions; the structures of [Li (237) (H,O),(picrate),] [K(237)][picrate] and [Rb(237)][picrate] have been rep~rted.'~~.'~~ A template condensation in the presence of Cu" nitrate and a base (233) (234) c) .0H N aoMe OMe Me0 'H 153 T. Tsubomura K. Yasaku T. Sato and M. Morita Inorg. Chem. 1992 31. 441. 154 G.L. Rothermel Jr. L. Miao A. L. Hill and S.C. Jackels Inoug. Chem.. 1992 31 4854. 155 N. A. Bailey D. E.Fenton P. C. Hellier P. D. Hempstead U. Casellato and P. A. Vigato J. Chem. Soc.. Dalton Trans. 1992 2809. 156 J.L. Sessler T.D. Mody and V. Lynch Inorg. Chem. 1992 31. 529. 157 T. W. Bell P. J. Cragg M. G.B. Drew A. Firestone and D.-I. A. Kwok Angew. Chrm.,Int. Ed. Engl. 1992 31 348. 158 T. W. Bell P.J. Cragg M.G. B. Drew A. Firestone,and D.-I. A. Kwok Angew. Chem..Inr. Ed. Engl. 1992. 31. 345. The Coordination Chemistry of Macrocyclic Ligands 341 results in the formation' 59 of a novel dimeric dodecacopper(I1) complex [Cu','(238)(~,-OH),I 1'. 0-donor Ligands.-Crystallization of 18-crown-6 from CHC13/CH2C1 in the presence of dipotassium tartrate affords a nine-coordinate potassium complex with chloride as the counter anion [K( 18C6)(H20),](H30)(H,0)C12, which displays'60 an unusual asymmetric conformation of the crown ether ring.2H NMR line shape measurements have been used to confirm and refine a model to account for the large amplitude motions in solid 18-crown-6 complexes. The motion is a combined rotation and conformational adjustment of the macrocycle in which individual -OCH,CH,O- units jump to adjacent sites in the crystal.' 61 Conductometric potentiometric and calorimetric titrations have been performed to determine the stability constants of the alkali alkaline earth and Ag' complexes with 18-crown-6 and the cryptand (222).16 Active methylene compounds have been carboxylated with the reagent system 18-crown-6 potassium carbonate and carbon dioxide.' 63 The complex formed between 18-crown-6 and TI'TCNQ has been studied by X-ray crystallography the lone pair plays an active stereochemical role in the solid Thallium can be immobilized as a thalium-rich mixed-valence solid [(Tl'( 18C6))4Cu"C14][T11C14]2-.nH20(n = 0 or 0.25).Similar complexes are obtained'65 if Cl-is replaced by Br- T1' by Rb+ and Cu2+ by Mn2+ or Co2+.The adduct formation of [M(NH,),L] [PF,] (M = Ru" Ru"'; n = 2 L = isonicotinamide and pyrazine; n = 3 L = 4-aminopyridine and 4-dimethylaminopyridine) with 18-crown-6 has been investigated spectrophotometrically and electrochemically in non-aqueous solution. Adduct Is' S.S. Tandon L. K. Thompson and J. N. Bridson J. Chem. Soc. Chem. Commun. 1992 91 I 16" K. M. Doxsee H. R. Wierman and T.J. R. Weakley. J. Am.Chem. Soc. 1992. 114 5165. Ihl C. I. Ratcliffe J. A. Ripmeester G. W. Buchanan. and J. K. Denike J. Am. Chem. Soc. 1992. 114 3294. 162 H.-J. Buschmann Inorg. Chirn. Acta 1992 195 51. L63 K. Chiba H. Tagaya S. Miura and M. Karasu Chem. Left. 1992 923. M. C. Grossel and S.C. Weston J. Chem. Soc. Chem. Commun. 1992. 1510. 165 I. A. Kahwa D. Miller M. Mitchel F. R. Fronczek R. G. Goodrich D. J. Williams C. A. O'Mahoney A. M. Z. Slawin S.V. Ley. and C. J. Groombridge Inorg. Chem.. 1992 31. 3963. 342 S.L. W. Mc Whinnie formation gave a red shift of the MLCT band for [Ru"(NH,),L][PF,] and a blue shift of the LMCT band'66 for [Ru"'(NH,),L][PF,]~. Other Donor Ligands.-The reaction of BiCI and (239) provides colourless crystals of the adduct [BiC1,(239)].An X-ray crystal structure determination reveals a BiCI pyramidal unit bonded to all six sulfur atoms of the macrocyclic ring which adopts an unusual S-shaped c~nformation.'~~ The reaction between TlPF and (239) or (240) affords the 1 1 complexes [TI'L][PF,] in high yield. The structures of both compounds have been determined by X-ray crystallography.' 68 Reaction of [(Rh"'CI(C,H,,),),] with two equivalents of (239) and 40% HBF affords [Rh"'(239)][BF4],; in the absence of acid a bright red solution is generated from which the ring-opened vinyl thioether complex [Rh"'(239-H)][PF6] can be isolated. The analogous ring-opened complex [Rh"'(241-H)]2 + can be prepared by treatment of [(Rh"'C1(C,Hl,),},] with (241).'69 Reaction of Cu" salts with (240) or (241) affords the cations [CU"L]~+ in high yield.The diamagnetic Cu' species [Cu'L]' can be generated electrochemically from the Cu" precursors by controlled potential electroly- sis although the direct route via reaction of [Cu'(NCMe),]+ with one molar equivalent of the ligand is better. Reaction of (241) with two molar equivalents of [Cu'(NCMe)J affords' 70 the binuclear Cu' species [c~\(241)(NCMe),]~ + +. A cs e,u,4 c SJ u (239) (240) R = H (241) R =Me Lanthanide complexes of ligands such as (242) and (243) have been demonstrated to mediate the effective transport of hydrophilic HisOMe and LysOEt salts via 'two-point' binding.I7' A variety of homometallic Cu' complexes has been isolated with the ligands (243k(245) and fast atom bombardment mass spectroscopic investigations suggest the complexes to be of general formula [Cu\L2][PF6],.Solution 'H NMR spectra of these species imply the existence of additional complex components of 1 1 L Cu' ratio. A variety of mono- and bimetallic silver(1) complexes has also been isolated.' 72 The tetrathiafulvalene derivative (246) has been synthesized and its redox potential has been shown to be sensitive to the presence of sodium ions.' 73 A number of macrocyclic compounds based on 1&naphthyridine and phen 166 I. Ando D. Ishimura M. Mitsumi K. Ujirnoto and H. Kurihara Polyhedron 1992 11 2335. 16' G. R. Willey M.T. Lakin and N. W. Alcock J. Chem. Soc. Dalton Trans. 1992 1339. A. J. Blake G. Reid and M. Schroder J. Chem. Soc. Dalton Trans.1992 2981. D. Collison G. Reid and M. Schroder Polyhedron 1992 11 3165. N. Atkinson,A. J. Blake M. G. B. Drew G. Forsyth R. 0.Gould A. J. Lavery,G. Reid,and M. Schroder J. Chem. Soc. Dalton Trans. 1992 2993. H. Tsukube J. Uenishi H. Higaki and K. Kikkawa Chern. Lett.. 1992 2307. P. D. Beer J. W. Wheeler and C. P. Moore J. Chem. Soc. Dalton Trans. 1992 2667. I73 T. K. Hansen T. Jsrgensen and J. Becher J. Chem. Soc. Chem. Commun. 1992 1550. The Coordination Chemistry of Macrocyclic Ligands have been reported (247)-(254). The compounds were tested for cation selectivity in poly(viny1 chloride)-based potentiometric sensors; a Nernstian response was observed for potassium but with low discrimination in the presence of other cations.'74 (243) R = H Y = 0 (244) R= Me,Y =O (245) R = H Y = S 3 (247) X = H n = 2 (248) X = H n = 3 (249) X=OC8HI7 n=2 (250) X = OC8Hi7 n = 3 (251) X=H n=2 (252) X= H n=3 (253) X = OC8H17 n = 2 (254) x= OC8H17 n = 3 6 Macrocycles of Higher Denticity The major isomer obtained by hydrogenation of dibenzo-24-crown-8 ether has been shown to have the cis-syn-cis configuration as determined from the crystal structure of its sodium perchlorate complex.' 75 The interactions of [2l]ane-N and [24]ane-N with the complex anions [Fe"(CN),]'- and [Co"'(CN),13- have been studied.Both 174 T J. Cardwell R. W. Catrall L. W. Deady K. A. Murphy and S. S. Tan Aust. J. Chem.. 1992. 45 983. "' G. W. Buchanan. Y. Lear and C. Bensimon Can. J. Chem.. 1992 70.1688. S. L. W. Mc Whinnie ligands form stable 1 1 anion receptor complexes.'76 Interaction of the poly- protonated forms of [3k]ane-N (k = 7-12) with the complex anions [Fe"(CN),IZP [Co"'(CN),13- and [Pt"(CN),I2 -has been studied by potentiometry and the stability constants of the second sphere complexes have been determined. The inter- action of (H,[3k]ane-N,)k+ (k = 7-1 1) cations with [Pt'VC16]2- and [Pt"(CN),I2- has been followed by 195Pt NMR spectroscopy. The crystal structures of (Hl,[30] ane-N ,)[Pt"(CN),] ,*2H20 and (H ,[30]ane-N o)[Pt'VC16]2C16'2H20have been determined by X-ray analysis. '77 A 36-membered macrocycle with four en entities (255) has been synthesized and its complexing behaviour towards the Cu" ion investigated. A tetranuclear complex [C~~(255)(0H),][Cl0~]~~2H,O with a cubane-type [Cu~(OH),]"' core surrounded by the macrocycle has been characterized.' 78 The ligand (256) forms 1 1 and 1 :2 ligand to divalent transition metal ion complexes with a variety of protonated forms and one dinuclear hydroxo bridged form.All these cationic complexes exhibit recognition towards malonic acid phosphoric acid glycine acetohydroxamic acid and potassium phosphonous formate.' 79 (255) n=3 (256) The stoichiometric oxidations of a number of substrates with [C~!(257)(0,)]~ and + with [C~!(257)]~' have been studied. In some cases the substrate is oxidized by both the Cu' dioxygen complex and by the Cu" complex while in others the Cu" complex shows no activity.'*' A disilver(1) complex of (258) has been synthesized and its crystal structure shows that the molecule does not possess the cleft-like appearance noted for related disilver(1) complexes.A new tetranucleating macrocycle (259) has been obtained' 82 as a Pb" complex [Pb11(259)(dmf),][C104]4. The thioether-pyridazine macrocycles (260) and (261) have been prepared. A Cu" complex of (260) was isolated [Cu"(260)Cl2] and characterized by X-ray crystallography. With (261 ) two types of complex with copper(I1) have been isolated [Cu"(261)X2] (X = C1 or Br) and I76 J. Arago A. Bencini A. Bianchi. A. Domenech and E. Garcia-Espaiia J. Chem. Soc.. Dalton Trans. 1992 319. 177 A. Bencini A. Bianchi P. Dapporto E. Garcia-Espaiia. M. Micheloni. J. A. Ramirez P. Paoletti and P. Paoli Inorq.Chem. 1992 31 1902. T. Shimada M. Kodera H. Okawa and S. Kida. J. Chem. Soc. Dulron Trcins. 1992. 1121. 1'9 R. J. Motekaitis and A. E. Martell. Inorq. Chem.. 1992. 31 5534. 180 D.A. Rockcliffe and A. E. Martell J. Chem. Soc. Chem. Commun.. 1992 1758. H. Adams N. A. Bailey. D. E. Fenton. C. Fukuhara. P. C. Hellier. and P. D. Hempstead J. Chem. Soc. Dalton Trans.. 1992 729. H. Sakiyama. K. Tokuyama. J. Nishio N. Matsumoto and H. Okawa. Chem. Lrrt. 1992. 1021. The Coordination Chemistry of Macrocyclic Ligands [Cu:'(26l),Cl6] as well as a Cu' complex [Cu1(261)C1] and an Ag' complex [Ag1(261)(C10,)],. The latter two complexes have been characterized by X-ray crystallography. '83*184 nlnln /=N N N N-HO 7 Cryptands and Cages The reaction of Na,Sb with 2,2,2-cryptand in en results in the formation'85 of [Na(2,2,2-crypt)] [Sb The crystal structures of [H30(262)] [ClO,] [K(262)] [ClO,] and [Cs(262)][C104] have been determined.The stability constants of the cryptates formed by (262) and (263) with Li' Na' K' Rb' Cs' Tl' and Ag' have L. Chen L.K. Thompson and J.N. Bridson Can. J. Chem. 1992. 70 1886. L. Chen L. K. Thompson and J.N. Bridson Can. J. Chem. 1992 70 2709. lR5 U. Bolle and W. Trernel J. Chem. SOC. Chem. Commun. 1992 91. S. L. W. Mc Whinnie been measured in various solvents.' 863187 Chloroform solutions of the chromo- ionophore (264) extract lithium cations from aqueous solutions in the pH range 7-8 with very high selectivity as compared with the extraction of sodium potassium magnesium and calcium; the related reagent (265) shows moderate selectivity for sodium.' 88 A new cryptand containing an integral anthraquinone unit (266) has been synthesized.Upon addition of one molar equivalent of Li' in MeCN six reduction waves can be observed two for each of the free ligand the 1 :1 complex and the 1 :2 (266) Li' complex. The existence of the 2 1 complex was confirmed by EPR and 7Li NMR spectroscopies. 2 1 Complexes were also detectedlE9 for Na' and K' .Ligand (267) binds two Li' ions and the resulting complex has been studied by 'Li NMR spectroscopy. Cu" and Cd" complexes with (267) have been investigated in aqueous solution and their stability constants determined by potentiometric tech-(262) n =1 (264) n =1 (263) n=2 (265) n =2 0 P.Clarke J. M. Gulbis S.F. Lincoln and E.R.T. Tiekink Inorg. Chem. 1992 31 3398. S. F. Lincoln and A. K. W. Stephens Inory. Chem. 1992 31. 5067. A. F. Sholl and I. 0.Sutherland J. Chem. Soc. Chrm. Commun. 1992 1716. Z. Chen 0.F. Schall M. Alcalri Y. Li G. W. Gokel. and L. Echegoyen,J. Am. Chem.Soc. 1992,114,444. The Coordination Chemistry of Macrocyclic Liyunds niques. For both metals the following species have been found:190 [M(267)I2' [M (267),H] +,[M( 267)(0H)]+ ,and [M (267)( OH),]. Multinuclear NMR and X-ray crystallography have revealed that the complex formed between yttrium perchlorate (268) and water has a 1 :2 1 stoichiometry [Y"'(268),(H20)]3' and confirmed that in complexes of this kind the amide carbonyl groups act as ligands and adopt the cis configuration within the cryptate.'" Four new Schiff-base sodium cryptates [NaL] + [L = (269t(273)] have been described.The crystal structures of [Na(269).H20]+ and [Na(270)]+ have been reported; in the former case the sodium is five-coordinate the coordination sphere being made up of four nitrogens and an oxygen from water and in the latter the sodium is six coordinate with all three pyridine nitrogens binding.192 The cryptand (275) has been synthesized. In the presence of Cu" and Ag' a convergent form of the macrocycle which allows encapsulation of a pair of cations is adopted. Tetra- and dithiocyanato derivatives [M2(275)(NCS),(Cl0,),1 (x = 2 or 4 y = 2 or 0) have also been ~repared,'"~ with M = Co" Ni" or Cu".The cryptand (277) has been obtained by reduction of (275) and acts as a host for first row transition metal cations. Pairs of transition metal cations coordinated to the amino N-donors accommodate mono- and triatomic bridging ligands such as OH -or imidazolate generating a weak to moderate antiferromag- netic interaction. Dicopper(I1) p-azido complexes have been prepared where the combination of a large zero-field splitting in the EPR spectrum and a near Curie-law dependence of magnetic susceptibility on temperature suggest a triplet ground state.' 94 The complex [(Cro(C0),',(275)] where the chromium atoms are $-bound to the arene units and the dicopper(1) complex of (275) have been ~ynthesized.'~~ A dicopper(r1) complex of (278) [Cu~(278)(C104)][CI04], has been isolated."' New multisite ligands containing either three peripherally linked ferrocene redox centres 190 A.Bencini A. Bianchi M. Ciampolini P. Dapporto V. Fusi M. Micheloni N. Nardi. P. Paoli. and €3. Valtancoli J. Chem. Soc. Dalton Truns.. 1992 2049. 141 C.D. Hall J. H. R. Tucker A. Sheridan. S.Y. F. Chu. and D. J. Williams. J. Chrm. Soc. Dulron Trtrns.. 1992 3133. 192 V. McKee M. R. J. Dorrity J. F. Malone D.J. Marrs and J. Nelson,J. Chrm.Soc. Chern.Comniun.. 1992 383. 193 M.G. B. Drew D. J. Marrs. J. Hunter and J. Nelson J. Chem. Soc.,Dalton 'liuns. 1992 11. I Y4 M. G. B. Drew J. Hunter. D. J. Marrs J. Kelson and C. Harding,J. Chem. Soc. Dulron Truns.. 1992.3235. 195 M.-T.Youinou J. Suffert and R. Ziessel Anyew. Chrm. In:. Ed. Enyl.. 1992 31 775. I96 K.G. Ragunathan and P. K. Bharadwaj J. Chem. Soc.. Dulron Truns.. 1992. 1653. S.L. W. Mc Whinnie (276) and (280) or three externally orientated 2,2'-bipyridyls (274) and (279) have been prepared and their homo- and hetero-polymetallic Zn" and Cu' cryptates incorporating in the case of (274) and (279) externally coordinated Ru" cations have been isolated.'97 (277) R= +-(278) R = -CH2CH2-(280) R = Ferrocene The complex [R~"(281)]~+ has been synthesized and oxidation of Ru" to Ru"' in acetonitrile leads to dehydrogenation of the ligand to form an imine.''' The complexes [C0"'(282)]~+ and [C0"'(283)]~ + have been synthesized and their crystal structures established.19' Clathrochelate complex acids of the general composition H[Co"'L] [L = (284)-(286)] which readily form salts with organic amines have been obtained by template cross-linking of Co"' tris-dioximates with SnCl,.The composition of the complexes was confirmed by amongst other techniques 59C0and 19Sn NMR and I9SnMossbauer.'" Template condensation on the Fe" ion and exchange reactions of cross-linking groups were used to obtain macrobicyclic germanium-containing Fe" tris-dioximates which were isolated as polymeric compounds2" of compo- sition {H,[FeL,(Ge,O,)(s~lvent),])~[L=(287)-(289)l. A crystal structure of yoou YOOEt (284) X = SnC13 R = H (281) (~282) (285) X = SnC13 R = Me (286) X = SnCI3 R = Ph (287) X=Ge03 R=H (288) X = GeO, R =Me (289) X = Ge03 R = Ph Iyi P.D. Beer. 0.Kocian. R. J. Mortimer and P. Spenccr J. Chrm. Soc.. Chrm. Commun. 1992. 602. Iy8 P. Rernhard D.J.Bull W.T. Robinson and A.M. Sargeson Aust. J. Chem. 1992 45 1241. '" R. J. Geue W. R. Petri. A.M. Sargeson. and M. R. Snow. Amr. J. Chrm.. 1992 45 1681. . . y z voloshin V. K. Belsky. and V.V. Trachevskii Polyhedron 1992 11 1939. 2n' Y.Z. Voloshin and E. V. Polshin. Polyhedron 1992 11. 457. The Coordinution Chemistry of Macrocyclic Ligunds (290).4CH2C1 has been prepared from (291). Ligand (290) forms a complex with cerium(Iv) K,[Ce'V(290)] and can remove 56% of injected plutonium(1v) from mice.2O2 (290) R = H (291) R =Me The mechanism of formation of Li' and Cd" catenates with (292) involves two kinetically observable steps; the slower consists of two processes and has a negative activation enthalpy supporting a pre-equilibrium between two complexed species in the mononuclear rearrangement leading to the catenate structure.203 Cu' catenates of (292k(295) have been synthesized and obtained in metal-free form.The Cu' catenates which have been orientated by an appropriate substitution on the core of the macrocycle are topologically chiral. Their chirality has been observed by 'H NMR spectroscopy in an optically active medium.204 (292) R' = R2 = I< (293) R' = R2 = Ph (294) R' = R2 = PhiMe (295) R1=H R2=Phhk *'I2 J. Xu T. D. P. Stack. and K. N. Raymond Inory. Chem. 1992. 31. 4903. 2"3 A.-M. Albrecht-Gary. C. Dietrich-Buchecker.Z. Saad and J.-P. Sauvage. J. Chem. Sor,.. Chem. Commuri.. 1992 280. '04 J.-C. Chambron. D. K. Mitchell. and J.-F'. Sauvage. J. .4m.Chrm Soc.. 1992. 114. 462s.

ISSN:0260-1818    

DOI:10.1039/IC9928900311

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

19 Organometallic Chemistry of Monometallic Species By M.W. WHITELEY Department of Chemistry University of Manchester Manchester M 13 9PL UK 1 Introduction Important reviews of relevance to the material in this chapter have appeared on the reactions of transition metal dihydrogen complexes,' complexes of Buckminsterful-lerene,' electrochemical studies on sandwich and bent sandwich complexes3 and on the use of transition metal sandwiches as reservoirs of electrons protons hydrogen atoms and hydrides. A paper of general interest deals with the factors which influence the relative stabilities of classical and nonclassical isomers of transition metal polyhydride complexe~.~ 2 Ti Zr and Hf The 15-electron alkyl complexes [TiRCpf] (R = Me or Et) undergo insertion into the Ti-R bond via reaction with Bu'NEC or CO but reactivity towards CO or MeCrCMe is R dependent; normal insertion is observed where R = Me but for R = Et ethene and the respective products [Ti(O,CH)CpT] and [Ti(CMe=CHMe)Cpf] result from formal reaction with [T~HCPT].~ Thermolysis of [TiRCpT] (R = Me Et Pr" Ph etc.) yields RH and the tetramethylfulvene complex [TiCp*(q6-C,Me4CH,)] via a reaction catalysed by [T~HCP;].~ Treatment of the titanacyclopentane complex [Ti(CH,),(OAr"),] (OAr" = 2,6-diphenylphenoxide) with PMe results' in ring fragmentation and formation of the ethene complex [Ti(PMe,)(q2-C,H4)(OAr"),]; the elusive 0x0 complex [Zr(=O)CpT] has been generated uia %-elimination of benzene from [Zr(OH)PhCp*,] and its reactions with alkynes leading to the formation of oxametallacyclobutenes have been investigated.' The regioselective oligomerization of RCZCH (R = Me Pr" etc.) to but-1-en-3-ynes and hexa- 1,3-dien-5-ynes is catalysed by [ZrMe{ B(4-C6H4F),)Cpf] ;the isolation of intermediates (1) (R = Pr") and (2) (R = SiMe,) establish a catalytic mechanism.'' ' P.G. Jessop and R. H. Morris Coord. ('hem. Rev. 1992 121 155. P.J. Fagan J.C. Calabrese and B. Malone Ace. Ckem. Res. 1992 25 134. V. V. Strelets Coord. Chem. Reti. 1992 114 1. D. Astruc New'. J. Chem. 1992 16 305. Z. Lin and M. B. Hall J. Am. Chem. Soc. 1992 114. 6102. G. A. Luinstra J. Vogelzang and J. H. Teuben Oryanometallics 1992 11 2273. ' G.A. Luinstra and J. H. Teuben. J. Am. Chem. Soc.1992 114. 3361. 'J. E. Hill P. E. Fanwick and I. P. Rothwell Organomerallics. 1992 11. 1771. M. J. Carney. P. J. Walsh F.J. Hollander and R. G. Bergrnan Oryanomurallics 1992. 11. 761 '" A.D. Horton J. Chem. Soc. Chem. Commun. 1992 185. 35 1 352 M. W. U'hiteley Reaction of [ZrMe(NMe Ph )Cp2][B(4-C H,F),] with excess 2-bu tyne proceeds with double alkyne insertion to give (3) which has a novel o,q2,q2-coordinated pentadienyl ligand,' ' and [ZrMe{ B(4-C,H4F),)CpT] reacts with excess 1,3-butadiene to give (4).12 R l+ (CgMe&Zr -C 0 C-€1 H-C \\ C-CEC-R R/ (3) R=Me (4) Reaction of [Hf(H),CpT] with %,a-dienes CH,=CH,.(CH,);CH,=CH (n = 0 1 2 or 3) in a 1 1 ratio affords' respectively [HfH(q3-CH,CHCHMe)CpT] [HfCH2CH2(CH2)"C HMeCpT] (n = 1 or 2) and the r-hafna-o-alkene [(HfCH2(CH2),CH=CH,)HCpql.The 'half-open' titanocene [Ti(PEt3)(q5-2,4-Me,-C,H,)Cp] undergoes pentadienyl-alkyne coupling with alkynes PhC-CSiMe or hepta-1,6-diene to yieldI4 polycyclic products such as (5). Sodium amalgam reduction of HfCI in the presence of PMe and 2,3-dimethylbutadiene affords [HfCl,(PMe,),(q4-CH,=CMeCMe=CH,)] in which the diene ligand exhibits a 02,n bonding mode;' analogous reductions of MCl (M = Zr or Hf) in the presence of L lL A.D. Horton and A. G. Orpen Orgrrnomctullic~s.1992 11 8. '' A. D. Horton. Orgunometullics 1992 11 3271. l3 J. E. Bercaw and J. R. Moss. Organomutnllic,s. 1992. 11. 639. Is A. M. Wilson. T. E. Waldman A. L. Rheingold. and R. D. Ernst J. Am. Chrm.Sot... 1992. 114 6252. '' G. M. Diamond. M. L. H. Green. N. M. Walker. J. A. K. Howard. and S.A. Mason .I.Chern. Soc. Dalton Trans. 1992 2641. Organometallic Chemistry of Moncimetallic Species 353 (L = cyclohexa-1,3-diene15 or cycloheptatriene16) yield [MCl,(PMe,),(q4-L)]. The anionic sandwich complexes [Ti(q6-arene),] -(arene = biphenyl or 4,4'-Bu\-biphenyl) have been prepared by reaction of TiC1;Zthf with K(arene) and isolated as K(C2.2.2.lcryptand) salts." 3 V Nb and Ta Reduction of [TaCl,(OEt,)(DIPP),] (DIPP = 0-2,6-Pr;C,H3) in the presence of HCrCBu' yields the metallacyclopentadiene complex [Ta(CBu'=CHCH=C But)-Cl(DIPP),] which isomerizes to [Ta(CBu'=CHCBu'=C H)Cl(DIPP),] on ther-molysis probably uia the metallacyclopropene [Ta(HC=C Bu')Cl(DIPP),]; subse- quent reaction with HCGCBu' affords the arene complex [TaCl(DIPP),(q6- C,H,BU',)] as the final product of a formal [2 + 2 + 21 cycloaddition.'8 The viability of transition metal mediated conversion of CO to CO has been conclusively established via isolation of [Nb(CH,Ph)(t12-C0,)Cp',] from the reaction' of 0 with [Nb(CH,Ph)(CO)(Cp',] and the reductive coupling of coordinated CO with coordinated CNMe has been achieved uia reduction of [MCl(CO)(CNMe)(dmpe),] (M = Nb or Ta) followed by addition of Me3SiC1 to give" the novel alkyne product [MCI( (Me3Si)( Me)NC=CO(SiMe,))(dmpe),].The imido complexes [Nb(N-2,6- Pr;C,H,)(PMe,)(q'-L)Cp] (L = ethene or propene) have been prepared by respective treatment" of [NbCI,(N-2,6-Pr;C6H,)Cp] with ethyl and n-propyl Grignard reagents in the presence of PMe, and [NbX(CO),(dppe)] and [NbX(CO),(PEt,),] (X = halide) are precursors to rare non-Cp containing Nb' alkyne complexes.22 A series of 'open' titanocene and vanadocene adducts [M(CO)(q'-pd),] (M = Ti or V; pd = pentadienyl 3-methyl-pentadienyl etc.) has been prepared and structurally ~haracterized.~~ extensive chemistry of half-sandwich cycloheptatriene and An cycloheptatrienyl niobium complexes has been developed;, reduction of [NbCl,(thf),] in the presence of cycloheptatriene and appropriate ligands affords [N bC1 (PMe ) (q6-c7 H8 )I [Nb( CO 3 (q -C7 H 7 )] Or [Nb( PM e 3 )(q4-c7H8 q'-C,H,)] the latter providing the first example of a crystallographically characterized q"-cycloheptatriene complex.A series of cycloheptatrienyl sandwich complexes [MCp'(q7-C,H,)] (M = Nb or Ta) and [NbLCp'(q7-C,H,)]+ (L = thf CO or PMe,) has been prepared; photoelectronic and electrochemical studies on [MCp(q7- C7H,)] (M = V or Nb) suggest an effective d' configuration at the metal centre with the implication that in these complexes the C,H ligand has a formal trinegative charge.25 The bis(indeny1) complex [NbCl,(q'-C,H,),] has been obtained ria treatment of [NbCl,(thf),] with Li[C,H,] and reacts with NaBH to give [Nb(p- I' G.M. Diamond M. L. H. Green P. Mountford. N. M. Walker.and J. A. K. H0ward.J. Chmi.Soc..Dulron Truns.. 1992. 417. D. W. Blackburn D. Britton and J. E. Ellis Anyew. Chrm.. Inr. Ed. Enyl.. 1992. 31. 1495. l8 D. P. Smith J. R. Strickler. S.D. Gray. M.A. Bruck. R. S. Holmes. and D. E. Wigley. Orytrnomercrl/rc.s. 1992. 11 1275. ") P.-F. Fu M.A. Khan and K. M. Nicholas. J. Am. Chrm. Sot.. 1992. 114. 6579. E. M. Carnahan and S. J. Lippard. J. Am. Chrm. Soc.. 1992. 114. 4166. '' A. D. Poole V.C. Gibson. and W. Clegg. J. Chem. Sot.. Chem. Cornmun.. 1992. 237. 1, -F. Calderazzo C. Felten. G. Pampaloni and D. Rehder. J. Chrm. Soc.. Dulron Trun.5.. 1992. ,003. 23 T. D. Newbound A. L. Rheingold and R. D. Ernst. Oryunomerullits. 1992 11. 1693. 24 M. L. H. Green A. K. Hughes P.C. McGowan P. Mountford P. Scott. and S. J. Simpson. J.Chrm.Soc. Dulton Truns.. 1992. 1591. '' J.C. Green M. L. H. Green. N. Kaltsoyannis P. Mountford. P. Scott. and S. J. Simpson. Oryurionirtu/lic,.s. 1992 11 3353. 354 M.W. Whiteley H,BH,)(q5-C,H,),] which is a precursor to a range of complexes26 [NbH(L)(q5- C,H,),] (L = PMe,Ph q2-styrene etc.). The bonding modes of cyclooctatetraene in [V(q4-cot)(q8-cot)] have been established crystallographically2’ and sequential treat- ment of [Nb(q6-mesitylene),] with [FeCp,][BPh,] then MeCZCMe yields [Nb(q2- MeC-CMe)(B(q6-C6H5),(C,H,),)I in which the tetraphenylborate exhibits an unprecedented coordination mode as a bent 12-electron donor ligand.28 4 Cr Mo and W Kinetic studies reveal that the protonation of [WH,(PMePh,),] by anhydrous HCl to give [WH,(PMePh,),] proceeds29 viu both direct protonation at W and the + intermediate [WH,(q’-H,)(PMePh,),] + ; reaction of the imido complex [W(NPh)(CO),Tp’] + with LiBH yields the formyl complex [W(CHO)(NPh)(CO)Tp’] which undergoes intramolecular hydride migration from formyl to carbonyl to imido ligands.,’ In acetonitrile the dication [WMe(CO),(NCMe),Cp12+ undergoes CO insertion and substitution to give the q2-acetyl product [W(q2-COMe)(NCMe),CpI2 + .An analogous CO insertion process was not observed for [WMe(C0),(NCMe)Cpl2 + suggesting that in these examples CO insertion is promoted by good electron donor ligands at the metal centre.31 The nitrosyl complexes [Mo(NCMe) (NO)Cp*]’ + and [MX(NCMe) (NO )L] + (M = Mo or W; X = halide; L = Cp or Cp*) have been obtained via reaction of [MX,(NO)L] with Ag+ or NO’ in MeCN,, and the stepwise reduction of the + coordinated acetonitrile in [W(CO)(NCMe)(RCECR’)Tp’] (R,R’ = Me or Ph) to an amine ligand proceeds uia azavinylidene imine and amide intermediates generated by sequential addition of electrophiles and nu~leophiles.~~ A remarkably stable W”‘ imido carbene complex [W(CHCMe,Ph)(NAr)(pzH)Tp’][OTfl = 2,6-PriC6H,; (Ar pzH = 3,5-dimethylpyrazole; OTf = SO,CF,) has been reported,, and the W”’ carbene complex (6)(R = CH,Bu‘) is an active catalyst for the ring-opening metathesis polymerization (ROMP) of cycloheptene; the reaction intermediate (7) has been identified spectroscopically thus providing unprecedented confirmation for the involvement of a carbene-alkene intermediate in ROMP reaction^.,^ Treatment of the anionic carbene complexes [M(C(CH,),N Me}(CO),Cp] -(M = Mo or W) with PhCH,Cl affords the benzyl complexes [M(CH,Ph)(C(CH,),N Me}(CO),Cp] which subsequently isomerize to (8) cia formal insertion of the carbene into the C-H bond of CH,Ph.36 A rare example of a stable paramagnetic carbyne complex trans-[MoF(CCH,Bu‘)(dppe),] + has been obtained via reaction of trans-2h M.L. H. Green and A. K. Hughes J. Chem. Soc. Dalton Trans. 1992. 527. 2’ D. Courier E. Samuel B. Bachrnann. F. Hahn and J. Heck Inorg. Chem. 1992 31 86. ’* F. Calderazzo U. Englert G. Pampaloni. and L. Rocchi Angew. Chem. Int. Ed. Engl. 1992 31. 1235. 29 K. E. Oglieve and R. A. Henderson J. Chem. Soc.. Chem. Commun 1992. 441. 3o L. Luan M. Brookhart and J. L. Templeton Organometnllics 1992. 11 1433. 31 V. Skagestad and M. Tilset Organomerallics. 1992 11. 3293. 32 T.T. Chin P. Legzdins. J. Trotter and V.C.Yee. Organometallics 1992 11 913. 33 S.G. Feng and J.L. Templeton. Oryanornetallics. 1992 11 1295. 34 L. L. Blosch A. S. Gamble. K. Abboud and J. M. Boncella Organometallics 1992 11 2342. ’’ J. Kress and J.A. Osborn. Angen. Chem.. lnt. Ed. Enyl. 1992 31. 1585. 3b H. Adarns N. A. Bailey. G. W. Bentley. C. E. Tattershall. B. F. Taylor. and M.J. Winter J. Chem. Soc. Chem. Commun. 1992 533. Organometallic Chemistry of Monometallic Species RO ,Br RO ,Br Br3Ga-Br I RO Me' H [MoH,(C-CBu')(dppe),] with [Et,OH][BF,] ;,'an X-ray crystallographic study of the redox pair truns-[WBr(CPh)(dmpe)J"+ (n = 0 or 1) reveals a shortening of the W-C bond by only 0.024A as a consequence of one-electron oxidation thus indicating a HOMO of essentially non-bonding character with respect to the W-carbyne bond.38 The carbyne-alkynyi complexes trans-[W(CH)(C-CR)(dmpe),] (R = H SiMe, Ph etc.) prepared via reaction of alkynyl lithium reagents with [ W (CH)( O,SCF )(dmpe),] possess a n-conjugated C-W -C-C metalla butadiyne backbone.,$ Treatment of [WCl(CMe)(PMe,),] with CO proceeds ria [WCl(CMe)(CO)(PMe,),] to gice (9) the product of carbyne coupling with two PM e3 H3C / c=c I\ o=c ,o molecules of CO; [WCI(CMe)(PMe,),] also reacts with PhCeCPh to give the spectroscopically detected carbyne-alkyne complex [WC1(CMe)(q2-PhC-CPh)(PMe,),] which on heating affords [WCI(CPh)(q'-PhC-CMe)-(PMe,),] in an unprecedented example of stoichiometric alkyne metathesis by a low-valent carbyne complex.40 The bis(imido) alkene complexes [Mo(NBu*),(q2- CH,=CHR)(PMe,)] (R = H or Me) have been synthesized via treatment of [MoCI,(NRu'),(dme)] with two equivalents of RCH,CH,MgCl in the presence of PMe,,,' and Na/Hg reduction of the imido complexes [MoCl,(NBu')(q-C,H,R)] (R = H or Me) under an ethene atmosphere yields42 imido-alkene complexes [MoC1(NBu')(q2-C2H,)(q5-C5H4R)] which in turn are precursors to imido sandwich species4 such as [Mo(NBu')Cp,].3' M. A.N.D. A. Lemos. A.J. L. Pombeiro. D. L. Hughes. and R. L. Richards. J. Orgunornet. Chem.. 1992. 434 C6. 3x J. Manna T. M. Gilbert R. F. Dallinger S.J. Geib and M. D. Hopkins J. Am. Chem.Soc.. 1992.114.5870. 30 J. Manna S.J. Geib and M. D. Hopkins. J. Am. Chem. Soc.. 1992 114 9199. 40 L. M.Atagi S.C. Critchlow and J. M. Mayer. J. Am. Chem. Soc.. 1992 114 9223. 41 P. W. Dyer V.C. Gibson. J. A.K. Howard B. Whittle. and C. Wilson. J. Chem. Soc. Chem. Cnmmun.. 1992 1666. 42 M. L. H. Green P. C. Konidaris. P. Mountford and S.J. Simpson. J. Chem. Soc. Chem. Conimun.. 1992. 256. 43 J. C. Green. M. L. H. Green J.T. James P.C. Konidaris G. H. Maunder and P. Mountford J. Chem. Soc. Chem. Commun.. 1992. 1361. M.W. Whiteley One-electron reduction of the n-bonded tetracyanoethene complex [W(CO),(q2- tcne)] results in a redox-induced isomerization leading to the formation of the radical anion [W(CO),(q'-tcne)] -in which tcne coordinates via a nitrile nitrogen lone pair.44 An unprecedented redox-induced alkyne-vinylidene interconversion has also been reported.Photolysis of [Cr(Co)3(q6-C6Me6)] with Me,SiCrCSiMe gives the vinylidene [Cr{ C=C(SiMe3),)(CO),(q6-C6Me6)] which is converted to the alkyne radical cation [Cr(CO),(q2-Me3SiC=CSiMe3)(q6-C6H6)] + via one-electron oxida- tion with [FeCp,] + ; subsequent reduction affords the neutral alkyne complex [Cr(C0),(q2-Me,SiC-CSiMe3)(q6-C6Me6)] which slowly isomerizes back to the neutral vinylidene isomer.45 An efficient synthesis of enantiomerically pure alkyne complexes [WL(CO)(q'-PhC-CMe)Tp']''+ (L = NCMe n = 1; L = I n = 0) has been reported46 and reaction of [WL(q2-PhCrCPh),] (L = CO or NCMe) with PhC-CPh proceeds with alkyne-alkyne coupling to yield4' the cyclobutadiene products [WL(q2-PhC-CPh),(q4-C4Ph4)]. Deprotonation of the trans-buta-l,3- diene complex [Mo(CO),(q4-C4H6)Cp*] with Li[N(SiMe,),] affords the (1,2,3- + q)-trans-butadienyl product (10); subsequent protonation of (10) with CF,SO,H progresses via an q3-vinylcarbene intermediate to give48 the vinylketene (1 1).In the presence of BF,.Et,O the q3-allyl complex [Mo(CO),(q3-anti-l-Me,2-(CH ,=C Ph )C 3H ,}Cp] undergoes ligand centred carbon-carbon bond formation with benzaldehyde to give49 the q4-trimethylenemethane cation (12); analogous M = Mo(C0)2Cp (10) (1 1) (12) BF,-catalysed stereoselective C-C bond formation occurs for the 2-substituted pentadienyl complexes [W(CO),(syn-q3-2-R-C,H6)Cp] (R= COOMe or CMe=CH,) leading to the isolation of s-trans-diene cations which are precursors to coordinated allyl- 1,3-di0ls.~' One-electron oxidation of the 'half-open' chromocene carbonyl complexes [Cr(CO)(q'-pd)L] (pd = 2,4-Me2C,H, L = Cp; pd = 3-Me-C,H6 L = Cp*) affords the corresponding 17-electron radical cations which by comparison with neutral isoelectronic 17-electron vanadium analogues [V(q5-pentadienyl)L] are relatively inert to CO exchange.,' Sodium amalgam reduction of 44 T.Roth and W. Kaim Inory. Chem. 1992 31 1930. 45 N. G.Connelly A. G.Orpen. A. L. Rieger. P. H. Rieger. C. J. Scott. and G.M. Rosair. J. Chem. Soc. Chem. Commun.. 1992. 1293. 46 J.L. Caldarelli. P.S. White. and J. L. Templeton J. Am. Chem. Soc.. 1992 114 10097. 41 W.-Y. Yeh and L.-K. Liu J. Am. Chem. Soc. 1992. 114 2267. 48 S. A. Benyunes. R. J. Deeth A. Fries.M. Green M. McPartlin. and C. B. M. Nation. J. Chem. Soc. Dalton Trans. 1992 3453. 49 G.-M. Su G.-H. Lee S.-M. Peng and R.-S. Liu J. Chem. Soc.. Chem. Commun.. 1992 215. SO M.-H. Cheng Y.-H. Ho S.-L. Wang C.-Y. Cheng. S.-M. Peng. G.-H. Lee and R.-S. Liu J. Chem. Soc. Chem. Commun. 1992 45. 51 J. K. Shen J. W. Freeman. N.C. Hallinan. A. L. Rheingold. A.M. Arif. R. D. Ernst and F. Basolo Organomerullics 1992. 11. 321 5. Organometallic Chemistry of Monometallic Species 357 WC1 in the presence of cycloheptatriene affords the cycloheptadienyl-cyclohepta-trienyl mixed sandwich complex [W(q5-C7H9)(q7-C,H7)] which is a novel and efficient precursor to half-sandwich and sandwich cycloheptatrienyl tungsten com- plexes uia facile displacement of the cycloheptadienyl ring.52 The electron transfer chain (ETC) catalysed ligand substitution of I-by C1-in 17-electron [MoI,(PMe,),Cp] to afford [MoCl,(PMe,),Cp] proceeds cia the paramagnetic 16-electron intermediate [MoI,(PMe,),Cp] which undergoes rapid halide substitu- + tion; thus exceptionally ETC catalysis is effected by the conversion of an odd-electron system into an even-electron 5 Mn Tc and Re Reaction of [ReH,(CO)(PMe,Ph I,]with CO affords ~is,rner-[ReH(CO),(PMe,Ph)~] which on protonation with HBF;OMe, yields54 an equilibrium mixture of the classical dihydride complex [ReH,(CO),(PMe,Ph),] and its non-classical dihydro- + gen tautomer [Re(q2-H,)(CO),(PMe,Ph),] +.The complex [MnH,(dmpe),] which is probably best formulated as [MnH(q'-H,)(drnpe),] provides a rare example of a complex of a first row transition metal which can promote C-H a~tivation,~~ and photolysis of [Re(CO),Cp*] in hexafluorobenzene gives (13) which is formed by Me&H Re.C&' \ "CO co (13) concomitant intermolecular C-F and intramolecular C-H a~tivation.'~ The poly- hydride complex [ReH,(PPh,),(inq)] (mq = 2-mercaptoquinoline monoanion) re- acts with terminal and internal alkynes in the presence of H+ or Ph,C+ to give hydrido-carbyne products [ReH,(CCH,R)(PPh,),(mq)]' (R = Pr' Bun Ph et~.).~~ The reaction of fac-[MnMe(CO),(bipy)] with ,CO affords cis,trans-[Mn(CO),( "CO)(COMe)(bipy)]. establishing conclusively that in this and related bipyridyl complexes exceptionally the incoming ligand enters trans to the acyl The anionic alkynyl complex [Mn(C-CMe)(CO)(PPh,)Cp'] - generated by treatment of the carbene complex [Mn(C(OMe)CH,Me}(CO)(PPh,)Cp'] with Bu"Li adds a wide range of electrophiles at the alkynyl fl-carbon to give ~inylidenes,~~ and reaction of [ReCl(CO),L,] [L = P(OPh), PMe, etc.] with LiBu'and PhCECH " M.L. H. Green and D. K. P. Ng J. Chrm. Soc.. Chem. Comrnun. 1992 I1 16. 53 R. Poli B. E. Owens and R.G. Linck J. Am. Chem. Soc. 1992. 114 1302. 54 X.-L. Luo. D. Michos. and R.H. Crabtree Organomrtallics 1992 11. 237. 55 C. Perthuisot M. Fan. and W. D. Jones Orqanometallics 1992. 11. 3622. 56 A. H. Klahn M.H. Moore. and R.N. Perutz. J. Chern. Soc.. Chrm. Commun.. 1992 1699. 5' hi. Leeaphon P.E. Fanwick. and R.A. Walton J. Am. Chem. Soc..1992. 114. 1890. '* F.1. Garcia Alonso. A. Llamazares. V. Riera. M. Vivanco S. Garcia Granda. and M.R. Diaz. Oryunometallics. 1992. 11 2826. 59 C. Kelley. N. Lugan. M. R. Terry G. L Geoffroy. B. S. Haggerty. and A. L. Rheingold. J. .4m.Chem. Soc.. 1992. 114. 6735. 358 M. W. Whiteley affords the acylvinyl complexes ( 14) uiu a metal-induced vinylidene-acyl coupling process.60 Photolysis of disilylalkynes RMe,SiC-CSiMe,R’ (R,R’ = Me or SiMe,) with [Mn(CO),Cp] yields 2,2-disilylvinylidene complexes [Mn(C=C(SiMe,R)- (SiMe,R’)}(CO),Cp] viu a 1,2-silyl shift but monosilylalkynes such as Me,SiC=CPh do not react analogously.61 The vinyl-propargyl complex (15) (R = CH,CMe,) rearranges to the allenyl-vinyl ketone (16); effectively an ql-to q3-propargyl hapticity change promotes vinyl to CO migration.62 The synthesis of a series of Re”” mixed carbene<arbyne complexes [Re(OR),(CBu‘)(CHBu‘)] [R = Bu‘ CMe,CF, CMe(CF,) erc.] has been reported.63 oc R C Ph’ HO Hydride abstraction from the but-2-yne complex [Re(CO),(q’-MeC”CMe)Cp*] provides a novel synthesis of a rare q3-propargyl complex [Re(CO),(q3-CH,CrCMe)Cp*] + ; subsequent addition of nucleophiles (PMe, -CECBu‘ etc.) proceeds exclusively at the central propargyl carbon to yield rhenacycl~butenes.~~ The synthesis of the allene complexes [Re(PPh,)(NO)(q’-CH,=C=CRR‘)Cp] + (R,R’ = H or Me) has been reported; the derivative R = R‘ = H reacts with KOBu‘ to yield the alkynyl [Re(C=CMe)(PPh,)(NO)Cp] probably uia an intermediate allenyl species.65 Diphenylphosphine addition to the pentadienyl ligand of [Mn(CO),(q5- C,H,)] proceeds stereoselectively at the terminal pentadienyl carbon to give (17) in which a phosphahexenyl ligand is bonded to Mn through an q3 interaction and also through phosphorus coordination.66 The cyclohexadienyl complexes [Mn(CO),{ q5-(eXO-R)C6H6)] (R = H Me or C6H4Me-4) react with LiR’ (R’ = Me or Ph) to give acylmetalates [Mn(COR’}(CO),(qS-(exo-R)C6H6}]-which in turn are precursors to agostic cyclohexenyl complexes such as (18) and the carbenes [Mn(C(OE)R’)(CO),{q5-(exo-R)C6H6}] (E = Me Et or SiMe3).67 Treatment of the tris(imid0) complexes [MI(NAr),] (M = Tc or Re; Ar = 2,6-PrkC6H,) with KCp yields68 the monohapto-bonded cyclopentadienyl species [M(NAr),( q1-C,H,)].60 S.Feracin H.-U. Hund H. W. Bosch E. Lippmann W. Beck and H. Berke Helr. Chim. Actu. 1992.75 1305. 61 H. Sakurai T. Fujii. and K. Sakamoto Chem. Lett. 1992. 339. 62 C. P. Casey T. L. Underiner. P. C. Vosejpka J. A. Gavney Jr. and P. Kiprof. J. Am. Chem. Soc. 1992,114 10 826. 63 R. Toreki. R. R. Schrock and W. M. Davis J. Am. Chem. Soc.. 1992 114. 3367. 64 C. P. Casey and C.S. Yi. J. Am. Chem. Soc. 1992. 114 6597. 65 J. Pu T.-S. Peng. A.M. Arif and J. A. Gladysz. Organometallics 1992 11 3232. 66 M. A. Paz-Sandoval P. J. Saavedra N. Z. Villarreal. M. J. R. Hoz P. Joseph-Nathan. R. D. Ernst and A. M. Arif Organometallics 1992. 11. 2467. 67 J. B. Sheridan R.S. Padda. K. Chaffee. C. Wang Y. Huang and R. Lalancette J. Chem. Soc. Dalton Trans.1992 1539. 68 A.K. Burrell and J.C. Bryar, Oryunometullics 1992 11 3501. Organometallic Chemistry of Monometallic Species H RI 6 Fe Ru and 0s A series of studies has been made to elucidate the r61e of g2-dihydrogen complexes in catalytic hydrogenation. In the case of [MH(g’-H,)(pp,)]+ [pp3 = P(CH,CH,PPh,),; M = Fe69 or Ru7’] the Fe derivative possesses a remarkably strong Fe-q2-H bond; reaction with HCrCPh proceeds cia alkyne coordination facilitated by pendant arm decoordination of pp3 with a subsequent intramolecular acid/base reaction between cis disposed g2-H and o-vinyl ligands. By contrast the ruthenium analogue [RuH(g2-H,)(pp3)] reacts with HC-CPh via initial dissocia- + tion of a weakly bound q2-H ligand; the reaction products are H2C=CHPh and + depending on reaction stoichiometry [Ru(C-CPh)(pp,)] or the g3-butenynyl complex (19).Protonation of [FeH(dppe)Cp*] with HBF4.Et20 at -80 ‘C affords the Ph (19) nonclassical dihydride [Fe(g2-H,)(dppe)Cp*] + which on warming to -40 -C isomerizes to [FeH,(dppe)Cp*] +,the first example of an organoiron (IV)dihydride.” One-electron oxidation of [FeH(dppe)Cp*] with [FeCp,][PF,] yields” [FeH(dppe)Cp*] + ,an unprecedented example of an isolable 17-electron radical cation iron-hydride species which reacts reversibly with CO to give the 19-electron Fe”’ radical [FeH(CO)(dppe)Cp*] + ; the 19-electron complex undergoes reversible one- electron reduction with formation of the g4-cyclopentadiene [Fe(CO)(dppe)(g4- C,Me,H)] via redox-induced hydride migration.72 Measurement of protonation enthalpies of the complexes [OsX(PPh,),Cp] (X = H.C1 Br or I) reveals that the hydride is significantly more basic than the corresponding halide^.'^ The application of [RuC1,L(q6-arene)] (L = P-donor ligand) in the synthesis of novel carbene complexes 69 C. Bianchini A. Meli M. Peruzzini P. Frediani. C. Bohanna M. A. Esteruelas. and L. A. Oro. 0rgunometallic.s. 1992 11 138. ~ 70 C. Bianchini. C. Bohanna M.A. Esteruelas P. Frediani. A. Meli L.A. Oro and M. Peruzzini. Orgunomerallics. 1992. 11. 3837. 71 P. Hamon. L. Toupet J.-R. Hamon and C. Lapinte Oryanometallics 1992 11. 1429. ’2 P. Hamon. J.-R. Hamon. and C. Lapinte J. Chem. Soc.. Chrm. Commun. 1992. 1602. 73 M. K. Rottink and R.J.Angelici. J. Am. Chrm. Soc.. 1991. 114. 8296. 360 M. W. Whiteley continues. Treatment of [RuC1,(PMe,)(q6-C6Me6)] with prop-2-yn-l-ols HC-CC(R)(R')OH (R R' = Me Ph etc.) in methanol in the presence of [NH,]-[PF,] affords alkenylcarbene (20) via allenylidene intermediates,' and a modification of the synthesis carried out in allylic or homoallylic alcohols H,C=CH(CH,),OH (n = 1 or 2) yields analogous alkenyloxy-alkenylcarbene species.75 The exception is the reaction between [RuC1,(PMe,)(q6-C,Me4H2)] HC-CC(Me),OH and H,C=CHCH,OH which leads to the formation of the q5-allyl-alkene complex (21 ). A new strategy for the synthesis of [Fe(ql -carbene)(CO),Cp] complexes has been developed. Thus sequential treatment of [Fe(CO),Cp] -with aldehydes RC(0)H (R = Me Ph etc.) and then Me3SiC1 affords siloxyalkyl complexes [Fe{q'- CHR(OSiMe,))(CO),Cp] which are carbene precursors via reaction with trimethyl- silyl triflate.76 The participation of Group 8 carbene complexes in ROMP catalysis has been established via reaction of the vinylcarbene complex [RuCl,{ q1-C(H)CH= CPh,)(PPh,),] with n~rbornene,~' and synthesis of the carbene-alkyl complexes (22) lt R c=c Me,P HI 'R' (M = Fe or Ru) has permitted a direct comparison of the rates of carbene migratory insertion; the process is at least lo7 times faster in the iron deri~ative.~~ The osmacyclopentatriene complex [Os(CMeCMe=CMeC Me)(en)2]2 provides an op- + portunity to study metalkarbene reactivity in the presence of a novel ligand set; it has been converted to the osmahexatriene (23) via a base-induced 1,2-hydrogen shift." Sequential treatment of [RuCl,(dppm),] with the diyne HC-C-C-CCPh,-(OSiMe,) followed by HBF,/MeOH provides a convenient synthesis" of the novel metallacumulene (24).The reaction of [RuCl(PMe,Ph),Cp] with HC-CH and + . Tl[BF,] affords the q2-alkyne product [Ru(q2-HC=CH)(PMe2Ph),Cp]This unusual example of a d6 q2-alkyne complex is probably favoured by the small steric requirements of phosphine and alkyne substituents but above 60 "C rapid isomeriz- ation proceeds to give the vinylidene isomer; X-ray crystal structures both of the alkyne and vinylidene isomers are reported." Protonation of the bis(alkyny1) 74 D. Pilette K. Ouzzine H. Le Bozec. P. H. Dixneuf C.E. F. Rickard and W. R. Roper Oryonomrrallics. 1992 11 809. 7s D. Pilette H. Le Bozec. A. Romero. and P. H. Dixneuf J. Chem. Soc. Chrm. Commun. 1992 1220. 76 R. M. Vargas R. D. Theys and M. M. Hossain J. Am. Chrm. Soc. 1992. 114. 717. 77 S.T. Nguyen. L. K. Johnson R. H. Grubbs and J. W. Ziller. J. Am. Chrm. Soc.. 1992. 114 3974. 78 R. L. Trace J. Sanchez. J. Yang. J. Yin. and W. M. Jones Oryanometullics 1992 11. 1440. 79 L. Pu T. Hasegawa S. Parkin and H. Taube J. Am. Chem. Soc.. 1992 114. 7609. no N. Pirio D. Touchard P. H. Dixneuf M. Fettouhiand L. Ouahab Angew.Chrm. Inr. Ed. Engl.. 1992.31. 651. 81 J. R. Lomprey and J. P. Selegue J. Am. Chem. Soc. 1992. 114. 5518. Organometallic Chemistry of Monometallic Species 361 complexes trans-[Fe(C-CR),(dmpe)J (R = Me But Ph etc.) gives transient alkynyl-vinylidene species which rearrange via alkynyl coupling to the vinyl-idene sr-carbon to formE2 q3-but-I "en-3-yn-2-yl complexes (25).H 12+ An X-ray crystallographic study on the tetrafluoroethene complex [Ru(acac)(q2- C,F,)Cp*] establishes a metallacyclopropane description for metal-alkene bonding yet unexpectedly NMR studies reveal a low activation energy (A(? = 55 kJmol-') for propeller rotation of the alkene ligand., Nucleophilic addition to the coordinated alkyne of [Fe(CO)L(q2-PhCECPh)Cp]+ (L = CO) yields metallacycle and cis-alkenyl products (26) (Nu = OMe SBu') probably via primary attack at CO; these results contrast with the trans-alkenyl stereochemistry resulting from nucleophilic addition to the derivative (L = PPh,).84 X-ray crystallographic studies on (27) (R = SiMe,) revealE5 that the coordination mode of the butadienyl ligand is shifted significantly towards ql.Reaction of [(Ru(OMe)Cp*},] with ethene at 60 "C yields" the alkene-ally1 complex [RU(~~~-C,H,)(~~-C,H,M~)C~*], and photolysis of the matrix-isolated propene complex [Fe(CO),(q2-CH,=CHMe)] proceeds with loss of CO to give8' the hydrido-ally1 product [FeH(C0),(q3-C,H,)] thus exemplifying an intramolecular C-H bond insertion process operative at 5 K. The butadiene complexes [RuBr(q4-C,H,)L] (L = Cp or Cp*) react with butadiene in the presence of silver + triflate to give the octa-l,3,7-triene complexes [Ru(q6-C,H,,)L] uia a formal [47c + 47c] cycloaddition;88 reaction of the derivative (L = Cp*) with CO results in cyclization to give [Ru(CO)(q4- 1,5-cod)Cp*] + but failure of the analogous reaction for the derivative (L = Cp) suggests the configuration of the octatriene ligand in [Ru(q6-C,H ,)L] + depends on L.Reaction of the trimethylenemethane complex x2 L. D. Field A. V. George. G. R. Purches and 1. H. M. Slip Organornetallics 1992. 11 3019. 83 0.J. Curnow R. P. Hughes and A. L. Rheingold J. Am. Chem. Soc. 1992. 114 3153. 84 M.Akita. S. Kakuta S.Sugimoto. M. Terada. and Y. Moro-0ka.J. Chern. Soc. Chem. Commuri.. 1992.451. x5 Y. Wakatsuki H. Yamazaki Y. Maruyarna and I. Shimizu. J. Organomer. Chem.. 1992 430. C60. 86 U. Koelle B.-S. Kang T. P. Spaniol and U. Englert. Orgunometallics 1992 11.249. " T. M. Barnhart and R. J. McMahon. J. Am. Chem. Soc.. 1992 114 5434. *' K. Masuda K. Nakano T. Fukahori. H. Wagashima. and K. Itoh. J. Organomer. Chem. 1992.428. C21. M.W. Whiteley [Fe(CO),(q4-C(CH,),)] with isoprene in the presence of Me,NO proceeds via metal-promoted coupling to giveB9 (28) and intramolecular carbonylative coupling of a o-diynes with [Fe(CO),] in a sealed CO atmosphere provides a high yield synthesis of [Fe(CO),(q4-cyclopentadienone)] complexes.90 Gas-phase pyrolysis of the ‘open’ metallocenes [M(q5-2,4-Me,C,H,),] (M = Ru or 0s) results in disrotatory elec- trocylic ring closure with subsequent dehydrogenation to give the ‘half open’ 1,3-dimethylcyclopentadienylcomplexes9’ [M(qs-2,4-Me,C,H,)(q5- 1,3-Me,C,H3)]; the synthesis of the related ‘half-open’ metallocene [Ru (q -2,4- Me,C H ,)Cp*] proceeds in high yield uia reaction of [{ RuCl,Cp*},] with 2,4-dimethylpenta- 1,3-diene in the presence of Zn powder.92 The 2,4-dimethylpentadienyl sandwich complex [RuH(q5-2,4-Me,C,H,),] is an efficient precursor to half-sandwich pentadienyl + species [RuL,(q5-2,4-Me,C,H5)]+ (L = CO PMe, etc.) and [Ru(q5-2,4-Me,-C,H,)(q6-L’)]+ (L’ = cht cot or arene).93 The character of the metal-hydrogen + interaction in the complexes [MH(diene)(q6-arene)] (M = Ru or 0s; diene = chd or 2,3-dimethylbutadiene; arene = C6H6 or C6H3Me3) has been examined by NMR spectroscopy; the derivatives (M = 0s) are terminal hydrides which exhibit reversible H-migration between 0s and the diene ligand whereas [RuH(chd)(q6-C,H6)] is an + agostic hydride species for which exceptionally AG for C-H bond cleavage is less than that for cleavage of the metal -H bond.94 Deprotonation of [R~(q~-c,Me,),]~+ with excess KOBu‘ affords the o-xylylene complex [Ru(q4-C6Me4(CH,),}(q6-C6h4e6)] in which the q4-o-xylylene ligand is bonded to Ru via the endocyclic diene unit;95 more + remarkably KOBu’ deprotonation of [Ru(ON0,)L,(q6-arene)] [L = PMe,Ph P(OMe) etc.,L = dppe; arene = 1,2-Me,C6Me,,H4-,,,n = 4,2 or 0) in the presence of L’ (L’ = P-donor ligand) gives [RuL,L’{~~-C,M~,,H,~~(CH~),)] in which the o-xylylene ligand is coordinated via the exocyclic diene.96 Investigations using NOESY have demonstrated intramolecular ligand exchange in [RuH,(CO)(PPh,),]; the most credible mechanism involves a trigonal In contrast to the normal periodic effect on reactivity observed for 18-electron complexes the kinetics of halide-induced disproportionation of the 17-electron radicals [M(CO)3(PCy3)2]+ (M = Fe Ru or 0s) reveal98 only a very small reactivity 89 L.Girard M. C. Baird B. S. Haggerty and A. L. Rheingold. Orgunomrrullics. 1992 11 2329. 90 A. J. Pearson R. J. Shively Jr. and R. A. Dubbert Organometallics 1992 11. 4096. 91 R. U. Kirss Organometallics 1992 11. 497. 92 H. W. Bosch H.-U. Hund D. Nietlispach. and A. Salzer Orgunomrrallics. 1992 11. 2087. 93 T. Lurnini D.N. Cox R. Roulet and K. Schenk J. Organomet. Chem.. 1992.434. 363. 94 M. A. Bennett I. J. McMahon. S. Pelling M. Brookhart and D.M.Lincoln. Organometallics 1992 11 127. 95 J. W. Hull Jr. C. Mann and W. L. Gladfelter Organomrtallics 1992 11 31 17. 96 M.A. Bennett L. Y. Goh. I. J. McMahon T.R. B. Mitchell G. B. Robertson. T. W. Turney. and W.A. Wickramasinghe Organometallics 1992 11 3069. 97 G. E. Ball and B. E. Mann. J. Chem. Soc.. Chrm. Commun.. 1992 561. Orgunometallic Chemistry of Monometallic Species dependence upon M. The ligand dfepe [dfepe = (C,F,),PCH2CH,P(C,F5),] is a very weak a-donor and therefore the complex [RuCl(dfepe)Cp] exhibitsg9 properties most similar to [RuCI(CO),Cp] with a non-labile halide ligand and an accessible anion [Ru(dfepe)Cp] -; the special steric and electronic properties of the pentaphenylcyc- lopentadienyl ligand have been utilized in the synthesis of [Fe(C(O)H}(CO)(PMe,)-(q5-C,Ph,)] the first example of a neutral 3d transition series metal formyl complex stable at room temperature.' O0 Flash vacuum pyrolysis of the perfluorinated oxocyclohexadienyl complex (29)yields [RuCp*(q5-C,F,)] the first transition metal complex containing a perfluorocyclopentadienyl ligand,lo' and a synthesis of the o-quinodimethane complex (30) has also been deve1oped.lo2 The synthesis of the Me Ru & F .--__ 0 FeCp F F (30) (29) permethylindenyl sandwich complexes [M(q5-C,Me7),]"+ (M = Fe or Co; H = Oor 1) has been described,Io3 and the separate single-electron transfer events in the + two-electron reduction of [Ru(q6-C,Me,),12 to [Ru(q4-C,Me,)(q6-C,Me6)] have been resolved by exploiting the quasi-reversible character of the second electron transfer.O4 7 Co Rh and Ir An investigation of the energetics of hydride uersus alkyl migration for the P-migratory insertion reactions of [RhRL(q2-ethene)L'] [R = H or Et; L = P(OMe) or PMe,; L' = Cp or Cp*] revealslo5 a relative migration rate k,/k,, in the range 106-108.A further unusual example of ethene insertion into a metal-alkyl bond is provided by the reaction of [RhMe,(OTf)(Cn)] (Cn = 1,4,7-trimethyl-1,4,7-triazacyclononane) with ethene to give the allyl-hydride [RhH(q3-C,H5)(Cn)]; the use of good donor ligands attached to rhodium holds the promise of significant reactivity modifications by comparison with the chemistry of classical complexes of n-acid ligands.' O6 Treatment of the indenyl complexes [TrMeR(PMe,)(q5-CgH7)] (R = Me Ph or '"L.Song and W.C. Trogler J. Am. Chem. Soc. 1992 114. 3355. M. S. Keady J. D. Koola. A.C.Ontko. R. K.Merwin and D. M. Roddick,Organometallics 1992.11,3417. lo" P. Bregaint J.-R. Hamon and C. Lapinte. Organometullirs. 1992 11 1417. lo'0.J. Curnow and R. P. Hughes J. Am. Chem. Soc. 1992 114 5895. W. S. Trahanovsky and J. M. Ferguson Organometullics 1992. 11 2006. '03 D. O'Hare J.C. Green. T. Marder. S. Collins G. Stringer A. K. Kakkar N. Kaltsoyannis. A. Kuhn R. Lewis C. Mehnert P. Scott M. Kurmoo and S. Pugh Orgunometullics 1992 11 48. lo4 D.T. Pierce and W. E. Geiger J. Am. Chem. Soc.. 1992. 114 6063. Ins M. Brookhart E. Hauptman and D. M. Lincoln J. Am. Chem. Sor,..1992 114 10394. Ioh L.Wang and T.C. Flood J. Am. Chem. Soc. 1992 114 3169. M. W. Whiteley C,H,Me-4) with CO gives [IrMeR(CO),(PMe,)(q'-C,H,)] which react with Me,NO to yield the acyl [Ir(COMe)R(PMe,)($-C,H,)I. By contrast the hydride complexes [lrHR(PMe,)(q'-C,H,)] react with CO to give [Ir(CO),(PMe,)(q'-C,H,)] via elimination of arene or methane. lo7 The thiapentadienyl complex [Ir(PEt,),( 1,2,5- q3-C4H,S)] rearranges by intramolecular C-H bond activation to give (31) as the thermodynamic product,'" and a double C-H activation process has been observed in the formation of the cyclic carbene complex (32) via reflux of [Ir(q2-ethene),Tp'] in THF; effectively an unprecedented double dehydrogenation of a THF a-methylene group generates both a hydride ligand and a hydrogen atom for incorporation in the n-butyl ligand which originates from ethene coupling.lo9 By contrast thermolysis of [Ir(q2-ethene),Tp'] in cyclohexane proceeds via the vinyl-hydride intermediate [IrH(CH=CH2)(q2-ethene)Tp'] to give' lo the hydrido-ally1 complex [IrH(q3- CH,CHCHMe)Tp']. The vinylidene complex (33) reacts with electrophiles (GaMe, MeI etc.) via sequential oxidative additionjvinylidene migratory insertion;' '' with MeI the final product is the ally1 complex [IrI(q3-C3H,)-(N(SiMe2CH2PPh,),)l. H Substantial modifications in reactivity have been observed for ring-to-metal intramolecular chelate derivatives of [Co(CO),Cp]. The phosphinoalkyl chelated complex (34) provides access to q2-alkyne and unprecedented vinylidene derivatives because chelation inhibits the customary alkyne cyclotrimerization process;' the alkene-containing chelate complex [Co(q2-ethene)(q' :q2-C5Me4CH,CH2-CH=CH,)] undergoes selective substitution of the q2-ethene ligand to yield [C0L(q5:q2-C,Me,CH,CH,CH=CH,)] (L = CO trans-MeO,CCH=CHCO,Me etc.).'13 The site of nucleophilic addition to the allyl ligand of [Rh(PPr;)(q3-crotyl)Cp] + is controlled by the allyl ligand configuration.Thus the exo,syn isomer (35) is the precursor to metallacyclic products via addition at the central allyl carbon but the endo anti derivative (36) affords (Z)-alkene products via addition at a terminal lo' T. Foo and R.G. Bergman Organometallics 1992 11 1811. J. R. Bleeke M. F. Ortweth and M. Y. Chiang Organometallics 1992 11 2740. lo9 0.Boutry E.Gutierrez A. Monge M. C. Nicasio P. J. Perez and E. Carmona J. Am. Chem. Soc. 1992 114 7288. 'lo P. J. Perez M. L. Poveda and E. Carmona J. Chem. Soc. Chem. Commun. 1992 8. M. D. Fryzuk L. Huang N.T. McManus P. Paglia S. J. Rettig and G. S. White Organometallics 1992 11 2979. H. Butenschon R.T. Kettenbach and C. Kruger Angew. Chem. fnt. Ed. Engl.. 1992 31 1066. 'I3 K. H. Zimmermann R.S. Pilato I. T. HorvLth and J. Okuda Organometallics 1992. 11 3935. Oryanometallic Chemistry of Monometallic Species CO-PBu~ (34) ally1 carbon.' l4 The reaction of [(RhBr,(q5-C5Ph5)),] with either 1,3-cod or 1,5-cod under reducing conditions gives as the major product [Rh(q4-l ,3-cod)(y5-C5Ph5)] which is an unprecedented example of a cycloocta- 1,3-diene complex of rhodium.' ' An unusually stable mononuclear paramagnetic Ir" complex [Ir(q '-C6C15),(q4- 1,5-cod)] has been isolated.' l6 Reaction of [(Ir(,u-OMe)(q4-l ,5-cod)),] with dppm in methanol yields' '' [IrH(dppm)(q' ,q3-C,H1 2)] probably uia intramolecular C-H activation of the intermediate [Ir(dppm)(q3-C,H 3)].The synthetic redox chemistry of a series of cyclobutadiene-containing sandwich complexes [M(q4-C4R4)(q"-L)] + (R = Me or Ph; M = Ni n = 5 L = Cp; M = Co n = 6 L = C,Me,) has been investigated;' where R = Ph one-electron reduction yields the corresponding 19-electron radicals but Na/Hg reduction affords cyclobutenyl products [M(q3- l,2,3-endo-4-C4HPh4)(q"-L)]; Na/Hg reduction of the derivative (R = Me M = Co) generates ligand-bridged binuclear products.The photochemical reaction of [Ir(q2-C2H4),L] (L = Cp or Cp*) with hexafluorobenzene effects sequential replacement of coordinated ethene by hexafluorobenzene yielding' l9 [Ir(q2-C2H4)(q2-C,F6)L] followed by [Ir(q4-C,F,)L]. and the stepwise reduction of q4-coordinated benzene to y2-coordinated cyclohexene has been effected' 2o via successive H-/H+ addition to [Ir(MeC(CH2PPh,),)(q4-C6H6)] + . 8 Ni Pd and Pt The rate of CO insertion into the Pd-Me bond in the complexes [PdMeL(P-P)]"' [P-P = Ph,P(CH,),PPh, x = 2,3 or 4; L = C1 n = 0; L = NCMe n = 11 is ligand dependent with the slowest rate observed for the derivative (P-P = dppe L = CI)."' The cis-diacyl complexes cis-[Pt(C0R)(COR')(PPh3),](R R' = Me Et or Ph) have been obtained', by sequential treatment of trans-[PtX(COR)(PPh,),] (X = Br or C1) with ZnR; followed by CO.The a-alkoxycarbony1,o-vinyl complex trans-[Pt(C(O)OEt)(q'-CMe=CH2)(PPh3),] has been synthesized and applied in an investigation of the mechanism of metal-mediated carbalkoxylation of vinyl elec- 114 E. B. Tjaden and J. M. Stryker Orgunometullics. 1992 11 16. I IS J. Baghdadi. N. A. Bailey A.S. Dowding. and C. White. J. Chem. Soc. Chem. Commun. 1992. 170. 116 M. P. Garcia M. V. Jirnenez L. A. Oro. F. J. Lahoz and P. J. Alonso Angew. Chem. Inr. Ed. Engl.. 1992. 31 1527. 117 M.A. Esteruelas M. Olivlin. L.A. Oro M. Schulz E. Sola and H. Werner Orgunometullics. 1992. 11 3659. I18 G. E. Herberich W. Klein U. Kolle and D. Spiliotis Chem.Ber. 1992 125. 1589. I I9 T. W. Bell M. Helliwell M.G. Partridge. and R. N. Perutz. Orgunometullics. 1992 11. 191I. 120 C. Bianchini K. G. Caulton K. Folting A. Meli. M. Peruzzini. A. Polo and F. Vizza J. Am. Chem. Soc.. 1992 114 7290. 121 G. P. C. M. Dekker C. J. Elsevier K. Vrieze. and P. W. N. M. van Leeuwen. Organornetullics 1992 11 1598. 122 G.-L. Huang T.-M. Huang and J.-T. Chen Inorg. Chem. 1992 31,4034. M. W. Whiteley tr~philes,'~~ and an X-ray crystallographic study on the ketene complex [Ni(q2- (C,O)-Ph,C,O}(dtbpm)] (dtbpm = Bu\PCH,PBu\) provides the first established example of the q2-(C,0) ketene coordination mode at Ni; the preference for q2-(C,O) bonding may originate from a small P-Ni-P angle.'24 Reaction of [PtH(q'-CH,Bu')(dtbpm)] with C6F6 proceeds at room temperature with elimination of CMe to give [PtF(q'-C,F,)(dtbpm)]; this reaction which probably involves the 14-electron intermediate [Pt(dtbpm)] appears to be a novel example of intermolecular C-F a~tivation.'~' The unusually stable bis(sily1) complex [Pd(q'-SiH,Me),(dcpe)] [dcpe = 1,2-bis(dicyclohexylphosphino)ethane],which has been prepared via reaction of [(Pd(dcpe)),(p-H)] with H,MeSi-SiMeH, is an effective reagent for the bis- silylation of alkynes.'26 Insertion of unsaturated molecules into the Pd-0 bond of the enolate complex (37) provides a novel method of Pd-C bond formation as exemplified by the generation of the alkenyl complex (38) from (37) and dmadc (dmadc = dimethylacetylenedicarboxylate);'27 reaction of the amide complex trans-[Pd(NHPh)Ph(PMe,),] with dmadc affords (39) via insertion into the Pd-N bond.I2' C02Me Treatment of the ally1 complex [Pd(q3-C3H,),] with R,PCH,CH,PR (R = Pr' or Bu') below -30 "C affords [Pd(q1-C3H,),(R,PCH2CH2PR2)], which above -30 "C undergoes allyl-ally1 coupling to yield' 29 the 1,5-hexadienes [Pd(q2-C6H,,)(R,PCH,CH2PR2)] and [{ Pd(R,PCH,CH,PR2},(p-q2 :q2-C,H ',,)I.The oxidative addition of trans-5-R-2-cyclohexenyl chloride (R = Me COOMe) to [Pd(q2-alkene),] proceeds with unusual syn selectivity to give q3-allyl complexes in which the metal and ring substituent R are disposed trans.'30 The anti isomer (40) of complexes [Pd(N-N)(q3-C3H,R)] (R = Et Pr" Ph etc.; N-N = 2,9-&-l,lO-phenan-throline R' = Me C1 etc.) is selectively stabilized by 2,9-substituents on the phenanthroline ligand thus providing a potentially selective synthesis of (2)-alkene~.'~' Bicyclo[4.1.0]hept-2-ene reacts with Zeise'sdimer to give (41) which can be stereospecifically transformed to trans-disubstituted cyclohexane and cyclohexene derivative^,'^^ and treatment of the allenyl complex trans-[PtBr(q'-P.J. Stang and Z. Zhong Organometallics 1992 11 1026. P. Hofmann L. A. Perez-Moya 0.Steigelmann and J. Riede Organometallics 1992. 11 1167. P. Hofmann and G. Unfried Chem. Ber. 1992 125 659. Y. Pan J.T. Mague and M. J. Fink Organometallics 1992 11 3495. F. Balegroune D. Grandjean D. Lakkis and D. Matt J. Chem. SOC.,Chem. Commun. 1992 1084. L. A. Villanueva K. A. Abboud and J. M. Boncella Organometallics 1992 11 2963.J. Krause W. Bonrath and K. R. Porschke Organometallics 1992 11 1158. H. Kurosawa H. Kajimaru S.Ogoshi H. Yoneda K. Miki N. Kasai S. Murai and I. 1keda.J.Am. Chem. Soc. 1992 114 8417. 131 M. Sjogren S. Hansson P.-0.Norrby B. Akermark M. E. Cucciolito and A. Vitagliano Organometallics 1992 11 3954. 13* J.O. Hoberg and P. W. Jennings Organometallics 1992 11 3452. Organometallic Chemistry of Monometallic Species CH=C=CH,)(PPh,),] with amines NHRR' (R = H R' = Pr'; R = R' = Et) affords (42) the first examples of q3-azatrimethyIenemethanes.'33 An X-ray crystallographic study on the cycloheptatetraene complex (43) reveals an unprecedented allene bonding mode of the C,H liga~~d,'~~ and (44) a remarkable complex of the cyclohep- tadienynylium ligand (effectively the tropylium analogue of benzyne) has been prepared',' via hydride abstraction from (45).Reaction of [PtX(CO)Cp*] (X = Br or C1) with PR [PR = PPh,(C,H,-OMe-2)] proceeds via isolable ring-slipped intermediates [PtX(CO)(PR,)(q -C Me,)] [Pt Br (PR,)C p *] or [Pt (CO) (PR ,)Cp *IC1. to yield' 36 substituted products 'ih (43) 133 J.-T. Chen T.-M. Huang M.-C. Cheng Y.-C. Lin and Y. Wang Organometallics 1992 11 1761 I34 K. A. Abboud 2. Lu and W. M. Jones Acta Crystallogr. Sect. C 1992. 48 909. 135 2. Lu K. A. Abboud and W. M. Jones J. Am. Chrm. Soc. 1992 114 10991. 136 N. M. Boag R. Quyoum and K. M. Rao. J. Chem. Soc. Chem. Commun. 1992 114.

ISSN:0260-1818    

DOI:10.1039/IC9928900351

出版商:RSC    

年代:1992

数据来源: RSC

摘要:

20 Organometallic Chemistry of Bi-and Polynuclear Complexes By G. HOGARTH Department of Chemistry University College London London WC1H OAJ UK 1 Introduction This report will follow in much the same vein as last year’s contribution. No attempt will be made to present a comprehensive review of the literature since this is documented elsewhere.’ Instead the most significant publications and areas of interest will be highlighted. The material is organized under headings which relate to the topic of interest and while many of these survive from last year a significant proportion are new. 2 Reversible Metal-Metal Bond Scission The reversible cleavage of metal-metal bonds in bi- and polynuclear transition metal complexes is often invoked to account for the physical properties and reactivity of such species.An interesting publication highlights the delicate balance between the adoption or not of a metal-metal interaction.2 Thus binuclear [Li(Et,O)],[Cr,Me,] is known to contain an extremely short unsupported quadruple chromium-chromium bond. Dissolution in an ethereal solution of TMEDA results however in the formation of monomeric high spin [Me,CrLi,(tmeda),] as a result of metal-metal bond cleavage. Remarkably dissolution of the latter in THF results in the unprece- dented reformation of the chromium dimer. This demonstrates that the role of the alkali cation is vital in stabilizing the chromium-chromium bond and specifically the Cr-Me-Li-Me-Cr bridges seen in the structure of the dimer may be responsible for holding the metal atoms together.A second publication reports on the fractional cage-recombination efficiency of photochemically generated radical cage-pair intermediates formed via metal-metal bond cleavage of [(M(CO),Cp’),] (M = Mo W). The rate of recombination was investigated in a range of solvents of different viscosities and it was found that the viscosity of the solution had a significant effect. Electrochemically induced metal-metal bond cleavage and reformation is reported for trinuclear phosphinidene clusters [Fe,(CO),(p3-PM(CO)2Cp}2](M = Fe Mn). G. Hogarth ‘Specialist Periodical Reports Organometallic Chemistry’. ed. E. W. Abel Royal Society of Chemistry Cambridge 1993 Vol. 22 Chapter 9. * S. Hao. S. Gambarotta and C. Bensimon J.Am. Chem. Soc. 1992 114. 3556. K. J. Covert E. F. Askew J. Grunkemeier.T. Koenig.and D. R. Tyler,J. Am. Chem.Soc. 1992.114.10446. 369 370 G. Hogarth Thus the closed 48-electron complex (M = Mn) shows a two-electron reduction affording a 50-electron dianion which has been structurally characterized. The closed triiron frame is transformed into an open structure in which one of the iron-iron vectors is clearly non-bonding [3.532( 10)A]. The neutral 50-electron complex (M = Fe) known to have an open metal framework undergoes a two-electron oxidation affording what is believed to be the closed 48-electron dication. Somewhat related is the further opening up of the 50-electron open complex [Fe,(CO),(p3-Te),] upon carbonylation. Hence a stable decacarbonyl complex is formed which has been shown by crystallography to contain one bonding [2.582(1) A] and two non-bonding [3.972(1)A] metal-metal interaction^.^ Electrochemically interconvertible cubane clusters [(Fe(p3-S)Cp'),]"+ (n = 0,l) show a similar alternation of bonding and non-bonding metal-metal vectors.Thus the 68-electron neutral cluster contains two short C2.61 A(av)] and four long C3.38 A(av)] metal-metal interactions while the 67-electron cation contains four intermediate C2.90 A(av)] and two long C3.30 A(av)] contacts.6 3 Physical Studies and Calculations Ab initio calculations into the origin of the bridging carbonyl geometry in the dinuclear core M,(CO) (M = Sc,Mn) show some interesting findings. For configurations in which bridging carbonyls are energetically favourable a bent semi-bridging or symmetrically bridging coordination mode is always preferred.In contrast configur- ations whose energy favours terminal carbonyls but which are however forced into occupying bridging sites because of steric crowding prefer to adopt a linear semi-bridging mode. Thus the authors conclude that the presence of linear semi- bridging carbonyls is a consequence of steric crowding and that also since in the latter case more metal-metal bonding orbitals are occupied it follows that the adoption of linear semi-bridging carbonyls signifies strong metal-metal bonding.' In other papers concerning bridging carbonyls application of the ligand polyhedral model to [co,(c0)8] affords an explanation as to why the structure with bridging carbonyls is found in the solid state while isomeric forms co-exist in solution.8 Related to this is a publication describing the crystal structures and interconversion of bridged and non-bridged isomers [C~,(CO),(p-CO),(p-dppm)~] and [Co,(CO),(p-dppm),].In solution at room temperature the unbridged isomer is favoured while at low temperatures the equilibrium shifts to favour the bridged complex.' Photolysis of [Mn,(CO),,] in 3-methylpentane glass at 93 K results in photo-dissociation of a carbonyl and formation of a solvated intermediate which slowly converts to the semi-bridging species [Mnz(CO)8(p-q1 :q2-CO)]. The rate of this transformation has been monitored by infra-red spectroscopy and the rate constant measured as 4.9(3) x 10-3s-1.Y. Koide M.T. Bautista P.S. White and C.Y. Schauer Inorg. Chem. 1992 31 3690. G. Gerassio J. Organomet. Chem. 1992 441 271. H. L. Blonk J. G. M.van der Linden J. J. Steggerda R. P. Geleyn J. M. M. Smits G. Beurskens P.T. Beurskens and J. Jordanov Inorg. Chem.. 1992. 31. 957. ' C.Q. Simpson I1 and M.R.Hall J. Am. Chem. SOC. 1992 114 1641. B. F.G. Johnson and E. Parisini Inorg. Chim. Acta. 1992 198 200 345. D. J. Elliot D. G. Holah A. N. Hughes V. R. Magnuson 1. M.Moser. and R.J. Puddephatt Bull. SOC. Chim. Fr.. 1992 129 676. lo S. Zhang H.-T. Zhang and T.L. Brown Orqanometnllics 1992 11 3929. Organometallic Chemistry of Bi-and Polynuclear Complexes 371 '3C The fluxionality of the diiron complex [(Fe(CO),Cp),] has been reinvestigated using EXSY and DANTE NMR spectroscopy.The rate constant for the bridge-terminal carbonyl exchange in the cis-isomer was found to be zero at 224 and 234 K and probably remains so at higher temperatures. This contradicts earlier studies and suggests that pathways to direct terminal-bridge exchange through bridged-opened rotamers have an activation barrier higher than that previously assumed.' Two crystal structures of the bimetallic dianion [Fe,(C0)J2 -have been reported. In the tetraethylammonium salt. the unsupported metal-metal bond length of 2.844(1)A is considerably longer than that found in other salts an observation which suggests that the interaction is soft the length being a function of the electrostatic repulsion between metal centres.' In the salt [Na(py),],[Fe,(CO),] the metal-metal distance is somewhat shorter at 2.815(1)& and the structure consists of an extended two-dimensional array held together by interactions between the sodium ions and carbonyl oxygens.The thermodynamic parameters for chromium-chromium bond dissociation in [{Cr(CO),LL'),] (L' = Cp or Cp*) have been obtained from various methods including VT-FTIR magnetic susceptibility solution calorimetry and NMR spectro-scopy. Values for the chromium-chromium bond strength are in the range 11-1 5 kcal' mol- '. However results obtained from NMR measurements differ an effect thought to be a result of a multiplicity of populated states for the radical monomers.' Three publications concern the photochemically induced substitution reactions of [{ Fe(CO),Cp},]and the intermediates involved.Flash photolysis studies suggest that three intermediates are generated,' monomeric [Fe(CO),Cp]. doubly bonded [Fe,(p-CO),Cp,] and [Fe,(p-CO),(p-q' :q2-CO)Cp,] and the kinetics of the reactions with nucleophiles have been studied.' In closely related studies micro- and nanosecond time-resolved infra-red spectroscopy has been used to study photochemi- cal substitution reactions in cyclohexane or n-heptane. By using both UV and visible photolysis wavelengths it has proved possible to distinguish between pathways that involve the photoejection of carbon monoxide (UV initiated) and those involving metal-metal bond homolysis (UV and visible initiation).' Other physical studies of note include the use of solution EXAFS to gain kinetic and structural information on the metal cluster rearrangement during the isomerization of the spiked-triangular acetylide-hydride complex [Ru (CO) (p-H)(p4-C2 R)Pt(q,-dppe)] to the alkenylidene butterfly cluster [(q2-dppe)PtRu,(CO) (p4-C=CRH)] '* and a study of the molecular organization in crystals of [Co,(CO),] and [Fe,(CO),] which shows that while the two molecules pack in nearly identical ways the diiron complex forms a compact solid while for the dicobalt species large.empty channels result.'' + + 1 kcal = 4.18 kJ l1 L.J.Farrugia and L. Mustoo Organometallics. 1992 11 2941. J. M. Cassidy K. H. Whitmire. and G. J. Long J. Organornrr. Chem. 1992 427 355. l3 H. Deng and S.G.Shore Inorg. Chem. 1992 31 2289. l4 W. C.Watkins T. Jaeger C. E. Kidd S. Fortier M. C. Baird G. Kiss G. C. Roper and C. D. Hoff. J. Am. Chem. Soc. 1992 114 907. l5 S. Zhang and T. L. Brown J. Am. Chem Soc.. 1992 114 2723. l6 S. Zhang and T. L. Brown Organometallics 1992. 11 4166. A. J. Dixon M. W. George C. Hughes M. Poliakoff and J. J. Turner J. Am. Chrm. Soc. 1992,114. 1719. 1R A. J. Dent L. J. Farrugia A.G. Orpen and S. E. Stratford J. Chrm. Soc. Chem. Commun. 1992 1456. 372 G. Hogarth Full details of the structural changes associated with the oxidation of alkyne complex [Co,(CO),(p-MeC,Me)(p-dppm),] have appeared. Thus while in the neutral species the alkyne lies orthogonal to the dicobalt vector upon oxidation it is twisted by 12 " while the cobalt-cobalt bond is shortened.These results are consistent with the behaviour predicted from theory.,' 4 Multiple Bonds A review2' has appeared detailing the synthesis and reactivity of triply-bonded cyclopentadienyl molybdenum and tungsten dihalides [(MX2Cp),] while other publications give details of the reactivity of the ditungsten complexes towards Lewis bases2 and alkyne~.,~ A paper entitled 'The Delta Bond -an Old Story with a New Twist' details a plenary lecture presented to the 29th International Conference on Coordination Chemistry.24 Three report on the synthesis and structural characterization of doubly-bonded phosphido-bridged diiron complexes [Fe (CO),(p-PR,)(p-PR;)] (2). They are formed upon thermolysis of the hexacarbonyl complexes (l) and are only stable in the presence of bulky substituents on the phosphido-bridges.The X-ray crystal structures of both penta and hexacarbonyl derivatives [Fe,(CO),(pPPh,)(p- PBu;)] (n = 5,6) have been solved.26 In the hexacarbonyl (l) as expected the Fe,P core is puckered (fold angle 1 17.1") and the iron-iron distance of 2.707( 1 ) A is typical (Scheme 1). In contrast the electron-deficient pentacarbonyl (2) contains a very short R PR oc oc-K2 (2) Scheme 1 metal-metal bond length of 2.462(1)& while the central core tends towards a planar arrangement (fold angle 166.0"); indeed the bis(tertiarybuty1)phosphidocomplex has an essentially planar core. Extended Hiickel molecular orbital calculations confirm that the short metallic distance in the pentacarbonyl complexes is consistent with the presence of an iron-iron double bond and that in order to maximize this interaction a planar core geometry is necessary.19 D. Braga F. Grepioni P. Sabatino and A. Gavezzotti J. Chem. Soc.. Dalton Trans.. 1992 1185. 20 R. P. Aggarwall N. G. Connelly M. C. Crespo. B. J. Dunne. P. M. Hopkins and A. G. Orpen J. Chem. Soc. Dalton Trans. 1992 655. 21 M. L. H. Green and P. Mountford Chem. SOC.Rec. 1992. 21 29. 22 Q. Feng M. Ferrer M. L. H. Green P. Mountford. and V. S. B. Mtetwa J. Chem. Soc.. Dalton Trans. 1992 1205. 23 Q. Feng M. L. H. Green and P. Mountford J. Chem. Soc. Dalton Trans. 1992 2171. 24 F. A. Cotton. Pure Appl. Chem. 1992 64 1383. 25 B. Walther H.Hartung J. Reinhold. P. G. Jones H.-C.Bottcher. U. Baumeister and A. Krug Chem. Ber. 1992 125 1379. 26 B. Walther H. Hartung J. Reinhold P.G. Jones C. Mealli H.-C. Bottcher U. Baumeister. A. Krug and A. Mockel Oryanometallics. 1992 11. I 542. 27 M. R. Adams J. Gallucci A. Wojcicki and G.J. Long lnory. Chem. 1992. 31 2. Organometallic Chemistry of Bi- and Polynuclear Complexes Two publications give details of cyclopentadienyl-stabilized multiply-bonded diruthenium complexes. Thus a preparation of the known triply-bonded dimer [Ru2(p-H),(p-CO)Cp;] is described,28 while the acid-catalyzed reactivity of doubly-bonded [Ru2(p-CO)(p-RC2R)Cp2] (3) (R = Ph,CF,) has been assessed.29 Acidifica- tion in the presence of ethylene initially affords [Ru,(p-CO)(p-RC=CHR)Cp,]' (4) which reacts with ethylene via a carbon-hydrogen bond activation process affording the p-alkylidene complex [Ru2(p-CHMe)(p-RC=CHR)Cp,l (5),which loses H+ to + give the neutral bis(alkeny1idene) complex [Ru,(p-RC=CHR)(p-CH=CH,)Cp,](6) (Scheme 2).Acid-catalysed reactions of (3) with alkynes result in the production of metallacyclopentadiene complexes as a result of carbon-carbon bond formation. R R oc' .c&H Scheme 2 Finally addition of two equivalents of LiC,Me to triply-bonded [( WCl,(PMe,),),] affords the 1,l-disubstituted acetylide complex [{ WCI(C,Me)(PMe,),),] in which the two acetylide ligands adopt a trans disposition. Both structural and spectroscopic data provide evidence for conjugation of the 6(M-M) and n(C-C) ~ysterns.~' 5 Organic Ligands The synthesis of p-alkylidene and alkylidyne complexes continues to attract attention.Addition of diethylsilane to [(Ru(CO),Cp},] at high temperatures results in a slow reaction to afford sequentially the mono-and bis-p-methylene complexes [Ru2(CO),(p-CO)(p-CH2)Cp2]and [{Ru(CO)(p-CH,)Cp)J. The mechanism of the reaction is not known but initial carbonyl loss ionic hydrosilylation and intermolecu- lar processes have been ruled out." In an interesting publication it is reported that addition of four equivalents of 28 U. Koelle. B.-S. Kang and U. Thewalt Organomerallics 1992. 11. 2893. 2y L. A. Brady A. F. Dyke S. E. Garner. V. Guerchais. S. A. R. Knox. J. P. Maher S. M. Nicholls. and A. G. Orpen J. Chem.Soc,. Chem. Commun. 1992. 310. '() T.C. Stoner. S.J. Geib and M. D. Hopkins J. /Im. Chem. Soc. 1992. 114 4201. 31 M. Akita. T. Oku and Y. Moro-oka J. Chrm. Soc.. Chrm. Commun. 1992 1031. 374 G. Hogarth methyllithium to [Mo,Cl,,] at -70 "C initially affords thermolabile methylated products which decompose at 20 "C to give the new complex [{ MoCl,(p-CH,)},] characterized on the basis of NMR data. The reactivity towards a range of organics has been assessed and it is found to act as a good methylene source.32 Reaction of [Mn(CO),(thf)Cp'] with BuiSiHCl unusually affords the bis(a1- kylidyne) complex [{ Mn(CO)(p-OSiHBu\CP'),] as a result of a nucleophilic substitu- tion reaction the oxygen atom of the carbonyl acting as the n~cleophile.~~ Addition of the dilithium butadiene 1,4-Li,C,Ph, to [l ,2-W2CI,(NMe,),] leads to a facile carbon-carbon bond cleavage reaction affording the benzylidyne metallacy- clobutadiene complex [W,(NMe,),(p-CPh)(p,v3-C,Ph3)] (7).," Ph Reports of triply-bridging alkylidyne complexes include the synthesis and structural characterization3' of the high-valent trimolybdenum 0x0 cation [Mo,(MeOH),(p- O,CPh),(p,-CMe)(p3-0)] +,while reaction of the phosphorus ylide Ph,P=CHCN with [(Fe(CO),Cp},] does not give the expected binuclear p-alkylidene complex but rather3 a trinuclear cyano substituted p3-alkylidyne complex [Fe3(p-CO),(p3- CCN)CP,l.Addition of phthaloyl chloride 1,2-C6H,(COC1), to [Fe,(CO),(CN)Cp,] -fol-lows an unexpected course to afford the new complex [(Fe,(CO),(p-CO)Cp,}2(p-C=N=C)] (8)in which bimetallic centres are linked via an aza-allenium ligand.The + @Fe OC\ Fe@ IC0 ocJ"&=c~[)o (8) mechanism of the transformation is not known but the reaction is postulated to occur via a bis(p-acylisocyanide diiron) complex the expected product of two nucleophilic subs tit u tion reactions. Examples of the reaction of organic ligands containing more than one carbon atom include the reversible formation3* of the bis(ethy1ene) complex [{W(OR)(q-C,H,)(p- 32 T. Kauffmann P. Fiegenbaum M. Papenberg R. Wieschollek and J. Sander Chem. Ber. 1992,125,143. 33 H. Handwerker H. Beruda M. Kleine and C. Zybill Organornetallics. 1992 11 3542. 34 M.H. Chisholm R.-M. Jansen and J.C. Huffman Organornetallics 1992 11 2305.35 K. Nakata T. Yarnaguchi Y. Sasaki and T. Ito Chem. Lett. 1992 983. L. Busetto S. Bordoni V. Zanotti V.G. Albano and D. Braga New J. Chern. 1992 16 693. 37 W. P. Fehlhammer A. Schroder J. Fuchs and E.-U. Wiirthwein Anyew. Chem. Int. Ed. Engl. 1992,31 590. Organometallic Chemistry of Bi- and Polynuclear Complexes OR),},] (R = CH'Bu') and the preparati~n,~ of bis(ally1) complexes of the form [{ W(NMe,),(allyl)),]. In the case of the unsubstituted ligand the ally1 moieties bridge the metal-metal vector; however introduction of a methyl group on an external carbon results in an increase in the steric demands of the ligand which forces them into terminal sites. Reaction of the phosphorus ylide Ph,P=CHCHO with the bis(acetonitri1e) complex [Os,(CO),,(NCMe),] affords two isomeric products [Os,(CO),,(p-H)(p- C(=PPh,)CH=O}] (9)and [Os,(CO),,(p-H){ p-(CH=PPh,)C=O}] (lo),resulting H I PPhi from the oxidative addition of the ylide and aldehyde carbon-hydrogen bonds to the triosmium centre respectively.Interestingly in the presence of sunlight both lose carbon monoxide affording new complexes in which the ligands cap the osmium triangle.40 Thermolysis of [Fe,(CO) ,] with tetraphenylhexapentaene initially affords a binuclear complex in which the ligand binds in a bis(ally1)mode. At higher tempera- tures however carbonxarbon bond cleavage occurs to afford4 the trinuclear bis(p- allenylidene) complex [Fe,(CO),(p-C=C=CPh,),] (1 1). Two papers report on the synthesis of binuclear complexes of Group 9 metals in which a ring-opened thiophene ligand bridges the dimetal centre.Thus reaction4' of [Co(C,H,),Cp*] with thiophene at 70 "C affords [Co,(p-C,H,S)Cp:] (12) while thermolysis of monomeric [Cp*Rh(q4-thiophene)] at 100"C affords the analogous rhodium complex in low yield.43 The X-ray crystal structure of (12) shows that the sulfur atom is coordinated to inequivalent metal centres. In solution however the molecule is fluxional and the metal centres equilibrate this being attributed to a 'flip-flop' motion of the thiophene ligand. 30 S.T. Chacon M.H. Chisholm 0.Eisenstein and J.C. Huffman J. Am. Chem. Soc. 1992 114 8497. 39 R. H. Cayton M. H. Chisholm M. J. Hampden-Smith J. C. Huffman and K. G. Moodley Polyhedron 1992 11 3197. 40 A.J. Deeming D. Nuel N. 1. Powell and C. Whittaker J. Chem. SOC.,Dalton Trans. 1992 757. 41 M. Iyoda Y. Kuwatani and M. Oda J. Chem. Soc. Chem. Commun. 1992 399. 42 W. D. Jones and R. M. Chin Organometallics 1992 11 2698. 43 S. Luo A. E. Skaugset T. B. Rauchfuss and S. R. Wilson J. Am. Chem. SOC. 1992. 114 1732. 376 G. Hogarth H 6 Organic Transformations At 100"C the tricobalt complex [Co,(PMe,),(p-CO),(p,-H)] is an effective catalyst for the linear trimerization of phenylacetylene the reaction proceeding with high regioselectivity and stereo~electivity.~~ Triruthenium dodecacarbonyl has also been found to be a catalyst for the acylation of aromatic heterocycles. Thus at 150T and under 150psi of carbon monoxide pyridine and monosubstituted olefins are transformed into mixtures of linear and branched pyridyl ketones.45 Coupling of all four metal-bound organics in [Rh,(CO)R(p-CH,),Cp*,l has been found to produce butan-2-one (R = Me) or pentan-2-one (R = Et).46 Reaction of [W,(OBu'),] with [W,(OBu'),(p-CO)] in the presence of alcohols ROH affords products including the carbido cluster [W4(OR),(p-O)(p-OR)4(p4-C)],formed via the reductive cleavage of carbon monoxide.47 Somewhat related are the rearrangements of the mixed-metal acyl cluster [CpMoOs(CO) (p3,q4-RC-O)] (R = CH,tol).Thus addition of hydrogen results in the quantitative formation of the dihydride [C~MOOS(CO),,(~-H),(~~,~~-RC-O)],undergoes carbon-oxygen which in turn bond cleavage upon thermolysis affording three isomers of the 0x0-alkylidene complex [CpWOs,(CO),(p-H)(p-O)(p-CHR)].Structural characterization of one of these shows that the 0x0 ligand bridges a molybdenum-oxygen vector quite asymmetrically [Mo-0 1.89(5) 0s-0 2.03(5)A].48 The synthesis and reactivity of the methylene complex [Ir,H(CO),(p-CH,)(p- dppm),] are described. Carbonylation results in carbon-hydrogen bond formation + and carbonyl insertion to sequentially and reversibly afford [Ir (CO),(CH,)(p- dppm),]' and [Ir,(CO),(COCH,)(p-dppm)2]+ re~pectively.~~ Reaction of the multiply-bonded ditungsten complex [W,(ONp),(py),] (Np = neopentyl) with aldehydes affords alkylidene complexes [W,(ONp),(O)(py)(p- ONp),(p-CHR)] which undergo further reaction with aldehydes or ketones thus affording olefins as a result of carbon-carbon bond formation and mononuclear tungsten complexes.That the coupling reaction occurs at the binuclear centre is 44 H.-F. Klein M. Mager S. Isringhausen-Bley U. Fliirke and H.-J. Haupt Organometullics 1992,l I. 3174. 45 E. J. Moore W. R. Pretzer T.J.O'Connel1 J. Harris. L. La Bounty L. Chou and S. S. Grimmer. J. Am. Chem. SOC.,1992 114 5888. 46 G.J. Sunley I. M. Saez and P. M. Maitlis. J. Chem. So<.,Dalton Truns.. 1992 2193. 47 M. H. Chisholm C. E. Hammond. V. J. Johnson W. E. Streib. and J. C. Huffman J. Am. Chem. SOC.,1992 114 7056. 48 J.T. Park M.-K. Chung K. M. Chun S.S. Yun and S. Kim Organometullics. 1992 11. 3313. 49 F. Antui-Nsiah and M. Cowrie Organometullics 1992 11 31 57. Organometallic Chemistry of' Bi- and Polynuclear Complexes 377 supported by the observation that reaction of [W 2(ONp)6(py)2] with cyclohexenone affords binuclear [W,(ONp),(0)(p-ONp)2(pOC 2H 6)] (1 3) a result of the coupling of a phexenylidene ligand with a second equivalent of cyclohe~enone.~~ The related alkyne complex [wz(oR),(py)(p-Hc,H)] (R = SiMe,Bu') reacts with ethylene to give a vinyl alkylidyne complex [W,H(OR),(p-OR)@-C-CH=CHMe)] (14),again as a result of carbon-carbon bond f~rmation.~' The synthesis and reactivity of other alkyne complexes has been reported.Examples include the preparation and reactivity of the vinylalkyne complex [Mo,(CO),(~-HCC(CH=CH~)}CP,],~~ and a report of photochemically induced carbon-carbon coupling reactions of alkynes olefins and dienes with the metal-bound acetylene ligand in [M2(CO),(p-HC,H)Cp2] (M = ~o,w).53 Ferraazetine complexes [Fe,(Co),(~-CHCH=NR)] (1 5),formed from reactions of [Fe,(CO),(p-CH,)] with phosphinimines react with a variety of alkynes under photolysis affording 2-ferrapyridine complexes [Fe,(CO),(p-R 'CC(R2)CHCH= NR}] (16) as a result of alkyne insertion into an iron-carbon bond.In the case of terminal alkynes high regioselectivity is noted with the substituted carbon adjacent to the iron atom however with disubstituted alkynes isomeric mixtures are obtained (Scheme 3). When heated the 2-ferrapyridine complexes release both 2-pyridinones and pyrroles the ratio of which is highly dependent upon ring sub~tituents.~~ Two papers report the synthesis of substituted ferracyclopentadiene complexes [Fe,(Co),(~-RC=C(R)-C(R)=cR~].Thus addition of alkynes to cationic azaal- 50 M.H. Chisholm J. C. Huffman E.A. Lucas. A. Sousa,and W. E. Streib,J. Am. Chem. Soc. 1992,114,2710. S. T. Chacon M. H. Chisholm C. M. Cook M. J. Hampden-Smith and W. E. Streib. Anqew. Chem. In?. Ed. Engl. 1992 31,462. '' N. Le Berre-Cosquer R. Kergoat and F'. L'Handon Organometallics 1992 11 721. 53 C.G. Kreiter A. Wurtz and P. Bell Chem. Ber.. 1992 125 377. 54 T. E. Snead C. A. Mirkin K.-L. Lu H. L. Beckman G.L. Geoffroy. A. L. Rheingold and B. S. Haggerty Organometallics 1992 11 942. 378 G. Hogarth lylidene complexes [Fe2(CO),(p-CH(CH=NR)}] affords 1,2-imino-hydroxyl sub- + stituted derivatives,” while reactions of ynamines RC,NEt with [Fe2(C0)7(p- PhC,NEt,)] affords 2,3-diamino adducts.s6 7 Hydrides The number of publications concerning hydride complexes is especially high this year reflecting the current interest in such species.Thus two papers address the nature of the putative dicobalt complex [Cp*Co=CoCp*] reported last year. Calculated electronic structures for it and hydrido complexes derived from it suggest that the reported magnetic behaviour could be attributable to the presence of bridging hydride ligands.” This suggestion was confirmed when a synthetic reinvestigation showed that reaction of two equivalents of [{ Co(p-Cl),Cp*} with LiAlH affords two structurally characterized paramagnetic products [Co,(p-H),CpT] (17) and [CO3(pL-H)3(p3-H)Cp:] the data for the former fitting that of the putatively formulated doubly- bonded complex.58 Somewhat related is the synthesis and structural characterization of the paramagnetic chromium hydride complex [(Cr(p3-H)Cp*},] formed from the hydrogenation of chromium alkyls [(Cr(p-R)Cp*},] and shown to possess a cubane str~cture.’~ Two groups have independently reported the synthesis of the unusual diruthenium hydride complexes [Ru,(H)(p-H)(p-SiR,H),CpT] (18) which contain both terminal and bridging hydride ligands together with p-silyl groups involved in three-centre two-electron Ru-H-Si interactions.60r61 Toluene thermolysis of one of these com- plexes (R = Ph) results in loss of hydrogen6’ to give [{Ru(p-H)(p-SiR,)Cp*},].Protonation of the mixed-metal complex [CoRh(CO),(p-CO)(p-dppm),] affords the seemingly simple cationic hydride [CoRh(CO),(p-H)(p-CO)(p-dppm),] + .Struc-tural studies however reveal that the metal-metal vector shortens from 2.6852(7) to 2.6480(8)A upon protonation. This unusual behaviour is believed to be a consequence 55 T. E. Snead C. A. Mirkin K.-L. Lu S.-9.T. Nguyen W.-C. Feng H. L. Beckman G. L. Geoffroy A. L. Rheingold and 9.S. Haggerty Organometallics 1992 11 2613. 56 9. Hein J.C. Daran Y. Jeannin 9. Eber G. Huttner and W. Imhof J. Organomet. Chrm. 1992,441,81. 57 H. 9.AbrahamsoqG. P. Niccolai D. M. Heinekey C. P. Casey and 9.E. Bursten Angew. Chem. Int. Ed. Engl. 1992 31 469. 58 J. L. Kersten A. L. Rheingold K. H. Theopold C. P. Casey. R. A. Widenhoefer and C. E. A. Hop Angew.Chem. Int. Ed. Engl. 1992 31 1341. 59 R. A. Heintz B. S. Haggerty H. Wan A. L. Rheingold and K. H. Theopold. Angew. Chem. Int. Ed. Engl. 1992 31 1077. 60 H. Suzuki T. Takao M. Tanaka and Y. Moro-oka J. Chem. Soc. Chrm. Commun. 1992 476. 61 9.K. Campion R. H. Heyn and T. J. Tilley Organometallics 1992. 11. 3918. Organometallic Chemistry of Bi- and Polynucleur Complexes 379 of the electronic demands of the metal centres. Thus in the neutral species the complex is essentially a 16e-18e system and possesses a highly asymmetric bridging carbonyl while in the protonated form it moves towards an 18e-18e complex in which the carbonyl bridges more symmetricaly and the metal-metal interaction increases.62 The syntheses of two complexes in which hydride ligands support a multiply bonded diruthenium centre have been reported.These are the known28 triply-bonded complex [Ru,(p-H),(p-CO)Cpq] and the new63 doubly-bonded compound [Ru,(p-H),(p- P hC ,Ph)Cpq]. In a series of papers the reactivity of the doubly-bonded dimanganese complexes [Mn,(CO) (p-H) (p-diphosphine)] are described .64-6 With a1 k ynes mixtures of hydrido-alkenyl (formed uia alkyne insertion) and alkenylidene (a result of dihydrogen loss) complexes result,64 while with nitriles and isonitriles similar competition between insertion and hydrogen loss is noted.65 Insertion of sulfur into a hydride occurs smoothly affording66 the thiolate complexes [Mn,(CO),(p-H)(p-SH)(p-diphos-phine)] while mixed-metal trimers are formed6? upon addition of coinage metal salts [M(PPh,)] +.Similar trinuclear complexes result from reactions with [Fe,(CO j,] however the precise nature of the reaction product is diphosphine dependent. Thus when the diphosphine is tedip [(EtO),POP(OEt),] simple addition of an iron tetracarbonyl fragment affords [Mn,Fe(CO) o(p-H)2(p-tedip)] while with dppm phosphorus<arbon bond cleavage and benzene loss also occur68 to give [Mn,Fe(CO) (p-H )(p -P h PCH ,P P h ,)] . Several publications concern diiron hydrides in which the metal-metal bond is also stabilized by the presence of a bridging phosphorus ligand(s). Thermolysis of [(Fe(CO),Cp},] with HPMen (Men = menthyl) affords, the chiral complex [Fe,(CO),(p-H)(p-PMen,)Cp,] while a one-pot synthesis of the related diphosphine stabilized complex [Fe2(p-H)(p-PPh2)(p-dppm)Cp,] starting from FeCl, dppm Mg and C,H is reported.” AdditionT1of HBF;Et,O to [Fe,(CO),(p-H j(p-dppm)] affords [Fe,(Co),(p-H)(p-Co)(p-dpprn)]+,an analogue of the unknown protonation product of [Fe (CO),] while photolysis in the presence of diphenylphosphine” affords [Fez(CO),(p-H)(p-CO)(p-PPh,)(p-dppm)].Both of these hydrides and the related complex [Fe,H(CO),(p-PPh,)],73 react with primary alkynes ciu a regioselec- tive insertion reaction to give a-substituted alkenyl complexes. The last also inserts diynes in a similar manner affording acetylide substituted alkenyl complexes [Fe,(CO),{p-C(C,R)=CHR](p-PPh,)l (19) the first reported examples of such compounds.’ 62 D. J. Elliot J. J. Vittal R. J. Puddephatt D.G.Holah and A. N. Hughes. Inorg. Chem. 1992. 31. 1247. 63 H. Omori H. Suzuki T. Kakigano and Y. Moro-oka Organomera//ics,1992 11 989. 64 F. J. Garcia Alonso V. Riera M. A. Ruiz A. Tiripicchio and M. Tiripicchio Camellini Organometullics 1992 11 370. ” F.J. Garcia Alonso. M. Garcia Sanz V. Riera A.A. Abril. A. Tiripicchio and F. Ugozzoli Organometallics 1992 11 801. h‘ F. J. Garcia Alonso M.G. Sanz V. Riera S. Garcia-Granda and E. P. Carreiio J. Chem. Soc. Dalton Trans. 1992 545. 67 R. Carreiio V. Riera M. A. Ruiz. C. Bois. and Y. Jeannin Orgunometallics 1992. 11 2923. “ R.Carreiio V. Riera M. A. Ruiz. C. Boii and Y. Jeannin Organometallic.s 1992 11. 4022. 6q H. Brunner and M. Rotzer J. Organomel. Chem. 1992 425. 119. 70 H.G. Raubenheimer F.Scott S.Cronje and P. H. van Rooyen. J. Chrm. Soc. Dalton Trans. 1992 1859. ” J. Boothman and G.Hogarth J. Organomet. Chem. 1992 437 201. 72 G.Hogarth and M. H. Lavender J. Chem. Soc. Dalton Trans.. 1992 2759. 73 S.A. MacLaughlin S. Doherty N. J. Taylor and A. J. Carty Organomerallic.s 1992 11 4315. 380 G. Hogarth Two publications report on the crystallographic location of hydrides in unexpected positions. Thus the structure of [Os,,H,(CO),,(p6-C)] provides strong evidence that the hydrides are on the periphery of the cluster and not in interstitial sites as previously presumed,74 while in [Mo2(CO),(p-dppm)(p,-H)(p-AuPPh3)] (20) the hydride appears to lie in the plane of the three metal atoms an assertion which is supported by its indirect location by a potential energy technique and theoretical calculation^.^^ Hence the latter suggest that the interaction of the hydride with the metal orbitals is optimum when it sits in the plane of the Mo,Au triangle and thus the molecule appears to contain a rare example of a four-centre two-electron bond whereby the hydride holds the three metal atoms together.PPh Au 8 Phosphorus-containing Ligands Phosphorus-containing ligands have been traditionally used to stabilize transition metal centres. This section deals with the synthesis of some unusual ligands of this type and also novel transformations that such ligands can undergo at bi- and polynuclear metal centres. Thermolysis of [Fe(CO),] with the cyclic triphosphine P,Bu\ affords binuclear [Fe2(CO),(p-Bu'PP(Bu')PBut)] in which the metal centre is spanned in a bis(phosphid0) manner by the ring-opened ligand,76 while from the reaction of white phosphorus with [Fe,(CO),] the unusual cluster ([ (Fe2(CO),)(p-PFe(CO),P)1,) (21) has been isolated and crystallographically ~haracterized.~~ At temperatures above -40 "C the non-(metal-metal) bonded phosphinidene complex [W,(CO),(PH,Mes)(p-PMes)Cp*,] loses phosphine to afford7 metal-metal bonded [W,(CO),(p-PMes)CpT] while at similar temperatures the metastable metallo-methylenephosphine complex [Fe(CO),(q3-allyl)( P=CR2)] (R = SiMe,) 74 D.Braga F. Grepioni S. Righi B. F.G. Johnston. P. Frediani M. Bianchi F. Piacenti and J. Lewis Orgunometallics 1992 I I. 706. 75 M. Ferrer. R. Reina.0. Rossell. M. Seco S. Alvarez. E. Ruiz M. A. Pellinghelli and A. Tiripicchio Orgunometullic~s,1992. 11 3153. 76 Y. W. Li. M.G. Newton N. K. Bhattacharyya and R. B. King. Inorg. Chem. 1992 31. 2069. 77 M. Scheer M. Dargatz K. Schenzel. and P.G. Jones. J. Orgunomet. Chem. 1992. 435 123. 78 W. Malish U.-A. Hirth T.A. Bright H. Kab T. S. Ertel. S. Hiickmann and H. Bertagnolli. Angew. Chem. Inr. Ed. Enyl. 1992. 31. 1525. Organometallic Chemistry of Bi-arid Polynuclear Complexes 381 dimerizes with extrusion of C3H4 to afford79 the novel binuclear complex [Fe,(CO),(p-P=CR ,)(p-cyclo-PC R ,C H Et )] (2 2 ). Me3Si ,SiMe3 C II P (CO)3Fe-''Fe(CO) 'P' H / \ ,SiMe3 Gt/C-C' SNe3 (21) (22) Thermolysis of [Co (CO) (p-HC,H)] with Ph PSH affords the phosphido- bridged complex [Co,(CO),(p-PPh,)( p-CH=CHC(O)SPh}] as a result of carbon-sulfur and carbon-carbon bond formation reactions.Interestingly while addition of one equivalent of P(OMe) simply results in carbonyl substitution thermolysis in the presence of a second equivalent of phosphite affords [CO,(CO),(P(OM~)~),(~- SPh)(p-C(O)CH=CHPPh,}] resulting from extrusion of the thiol from one end of the bridging ligand and insertion of the phosphido-bridge into the other.80 Addition of dppm to [Fe2(Co),(p-PPh,)(p-C2Ph)]initially affords the complex in [Fe2(CO),(p-PPh,)(p,q3-C=C(Ph)P(Ph2)CH,PPh,)]which the diphosphine spans a metal atom and the p-carbon of the acetylide. Later thermolysis however affords the expected disubstitution product [Fe,(CO),(p-PPh,)(p-C,Ph)(p-dppm)] in which the diphosphine bridges the metal-metal bond.81 A number of other unusual transformations of diphosphorus ligands have been reported.One of the products from the addition of halogeno-diphosphines RXPCH,PXR to [Fe,(CO),] is the trinuclear phosphinidene complex [Fe3(CO)9(p3- PR)(p3-RP=CH2)] formed as a result of a phosphorus-methylene bond cleavage reaction,82 while related oxidative-addition reactions are seen upon thermolysis of diphosphine complexes [Fe,(CO),(p-CO)(p-R2PCH2PR2)]Me Et Ph OEt) (R = giving phosphidomethyl products [Fe,(CO),(pPR,)(pCH2PR2)].The nature of the latter transformation is however sensitive to substitution at the carbon-backbone of the diphosphine and thus thermolysis of [Fe,(CO),(p-CO)(p-Ph,PCH(Me)PPh )] affords [Fe,(CO),{p,q4-PhPCH(Me)P(Ph)C,H,}] as a result of the 'competitive oxidative-addition of a phosphorus-aryl bond to the dirron centre.83 Reaction of o-chloranil with [Ru,(CO)4(p-CO)(p-R2PN(Et)PR2)2]OMe, (R = OPr') affords the novel complexes [R~,(C~),(I~~-R,POC,C~~O){ p-R2PN-(Et)C(O))(p-R,PN(Et)PR,)] (23) as a result of the insertion of o-chloranil and a carbonyl into the fragments formed upon phosphorus-nitrogen bond scission of the diph~sphine.~~ Heating the planar-butterfly cluster [Ru,(CO) 3(p-PPh2)2] to 97 ' C -Y H.J. Metternich. E. Niecke and J. F. Nixon J. Chem. SOL,.,Chum Commitn.. 1992. 232. x o A. J. Edwards. A. Martin M. J. Mays. P. R. Raithby. andG. A. So1an.J. Chem. Soc..Chrrn.Conimun..1992. 1416. A. A. Cherkas S. Doherty M. Cleroux G. Hogarth L. H. Randall. S. M. Breckenridge N. J. Taylor. and A. J. Carty Organometallics 1992 11 1701. X2 S. Adelt F. Bitterer J. Fischer J. Rothe 0.Stelzera and W.S. Sheldrick Churn. Bur.. 1992. 125 1999. X3 N. M. Doherty G. Hogarth S.A. R. Knox K. A. Macpherson. F. Melchior. D. A. V. Morton and A.G. Orpen Inorg. Chim. Acta. 1992 198-200 257. H4 J. S. Field R. J. Haines J. Sundermeyer M W. Stewart. and S.F. Woollam J. Chem. SOL...Dalrnn 7nms.. 1992. 3161. 382 G. Hogarth affords the novel complex [Ru4(CO),,(p-H)(p-PPh,)(p4-PhPC,H,)I(24) in which the orthometallated phosphido-ligand is five-coordinate by a process which is readily reversed upon ~arbonylation.~~ cl (231 (24) The dimanganese complex [Mn,(CO),(p-PPh,),] undergoes novel rearrangements upon reaction with unsaturated organics.Thus two molecules of ethyne insert into one of the phosphido-bridges to afford the quaternized phosphole complex [Mn,(CO),(q4- C,H,PPh,)(p-PPh,)] (25) while with allene a similar double insertion reaction occurs to give86 the ally1 phosphine complex [Mn,(CO),(p-PPh,)(p-Ph PC (=CH ,)CHCM eC H ,>](26). 9 Arene Complexes The synthesis structure and reactivity of transition metal complexes containing arene ligands have received particular attention this year. A review documents recent developments in benzene derivatives of tran~ition-metals,~~ while a number of publications describe routes to cluster-bound arene complexes uia the step-wise dehydrogenation of cyclohexadienyl ligand~.~~-’ Thus for example reaction of [Os,(CO),,(p-H)2] with cyclohexa- 1,3-diene initially affords the cyclohexadienyl 85 J.F. Corrigan S. Doherty N. J. Taylor and A. J. Carty J. Am. Chem. Soc. 1992 114 7557. 86 L. Manojlovic-Muir M. J. Mays K. W. Muir and K. W. Woulfe J.Chem. Soc. Dalton Trans. 1992 1531. 81 H. Wadepohl Angew. Chem. lnt. Ed. Engl. 1992 31 241. 88 M. A. Gallop M. P. Gomez-Sal C. E. Housecroft B. F. G. Johnson J. Lewis S. M. Owen P. R. Raithby and A.H. Wright J. Am. Chem. SOC. 1992 114 2502. 89 P. J. Bailey D. Braga P. J. Dyson F. Grepioni B. F. G. Johnson J. Lewis and P. Sabatino,J. Chem. Soc. Chem. Commun. 1992 177. 90 D. Braga F. Grepioni S. Righi P. J. Dyson 9.F. G. Johnson P.J. Bailey and J. Lewis Organometallics 1992 11 4042. 91 D. Braga F. Grepioni S. Righi €3. F.G. Johnson P. J. Bailey P. J. Dyson J. Lewis and M. Martinelli J. Chem. SOC. Dalton Trans. 1992 2121. 92 R. D. Adams and W. Wu Polyhedron 1992 11 2123. Organometallic Chemistry of Bi-and Polynuclear Complexes 383 complex [Os ,(CO) (p-H)(p,-C6 H 7)] from which the triphenylmet h yl cation a b- stracts hydride from the dienyl ring generating cationic [o~,(Co),(p-H)(p,-~~H~)]+ . Subsequent reaction of this cation with DBU affords88 the neutral benzene-capped cluster [Os,(CO),(p-C6H6)]. Reactions proceed similarly at carbido-stabilized ruthenium cluster centres. Thus thermolysis of [Ru,(CO) 5(,us-C)] with cyclohexa-l,3-diene initially results in a simple carbonyl substitution reaction affording the diene complex [Ru,(CO) ,(q4-C6H8)(,u5- C)].Further decarbonylation and dehydrogenation is induced by Me,NO giving mixtures of isomeric [Ru5(CO),,(p3-C6H6)(p5-C)] and [Ru,(CO),,(~~~-C,H,)(~~-C)]. Both clusters consist of a square-based pyramidal array of metal atoms but while in the former the arene sits on a triangular face in the latter it binds to a single basal metal site. Interestingly it is the latter conformation that is thermodynamically stable and thus heating the face-capped isomer results in migration of the arene ligand onto a single metal centre.* Similar behaviour is noted for hexanuclear bis(arene) complexes. Although [RU6(CO) (q6-1,3,5-Me3C6H,)(p3-C6H6)(p6-c)] can be prepared it con- verts to isomeric [Ru6(CO) ,(q6-1,3,5-Me,C,H,)(r16-C,H,)(p6-c)] upon standing in solution.90 Structural studies have shown that these hexanuclear complexes consist of an octahedron of metal atoms capped top and bottom by arene ligand~.”.~~ The nature of the arene interaction with the metal centres when in a face-capping mode has been probed using molecular orbital calculations and comparisons made with benzene absorbed on to metal surfaces.88 Substitution reactions of the trinuclear complexes have also been explored phosphine and olefin derivatives are easily prepared.88 The products of the latter namely [OS,(CO)8(?Z-CH,CHR)(p3-c6H6)] (R = H,Me Ph Bu’) are highly fluxional in solution and five independent processes have been identified which include a 1,2 ring-hopping motion that permutes nuclei in the face-capping benzene ligand., The related ethylene complex [OS,(CO)7(~2-C2H4)(NcMe)(p3-c6H6)] reacts with alkynes to afford the new complexes [Os3(CO),(r16-C6H,)(p3-Rc2R)], a result of alkyne addition and benzene migration.94 Reactions of the triruthenium complex [Ru3(CO),(p3-C6H6)] with alkynes proceed similarly to afford [Ru,(CO),($-C6H,)(p3-RCCRC(o))] resulting from benzene migration and carbonyl insertion reaction^.,^ 10 Large Clusters The new binary metal carbonyl [Os,(CO) ,(,u-CO)] has been prepared via pyrolysis of the known cluster [Os,(CO),,] at 55°C in a sealed tube for three days.The configuration of metal atoms is not as expected. Thus the 76-electron cluster consists of a raft-like arrangement of metal atoms more formally described as a doubly-edge bridged triangular cluster the third edge of which is spanned by a carbonyl ligand.At temperatures above 70°C further carbonyl loss occurs to afford95 the more closed cluster [os5(co),6]. The pentaruthenium complex [Ru,(CO),,(CO),~(~-PP~,)(~~-C,PP~~)] reacts ” M. A. Gallop B. F. G. Johnson J. Keeler J. Lewis S.J. Heyes and C. M. Dobson J.Am. Chem. Soc.,1992 114 2510. 94 D. Braga F. Grepioni B. F.G. Johnson E. Parisini M. Martinelli M.A. Gallop and J. Lewis J. Chem. Sac.,Dalton Trans. 1992 807. 95 W. Wang F. W. B. Einstein and R.K. Pomeroy J. Chem. Soc. Chem. Commun. 1992 1737. 384 G. Hoyarth with dimethyldisulfide upon thermolysis to afford [Ru,(CO) ,(p-SMe),(p-PPh,),(p,- C,)] (27) a chain cluster formed as a consequence of oxidative-addition of the sulfur-sulfur bond and carbon-phosphorus bond cleavage.Further thermolysis of (27) leads to carbonyl loss and metal-metal bond formation giving the pentagonal cluster [Ru,(CO) (p-SMe),(p-PPh,),(p,-C,)] (28) (Scheme 4).96Molecular orbital calculations suggest that the /)-carbon of the C ligand should behave as a nucleophile and this prediction is borne out in reactions with hydrogen and ethylene which afford (R alkenylidene complexes [Ru,(CO),,(p3-SMe),(p-PPh2)(p3-C=CHR)]= H CH=CH,) consisting of an edge-bridged butterfly arrangement of metal atoms.97 Me Scheme 4 Publications on hexanuclear clusters include the synthesis of the first octahedral hexapalladium cluster [Pd,(y,-CO),(PMe,),] formed98 upon carbonylation of ~ [Pd(PMe,),].Chemical oxidation of [Ir6(CO)l ,I2 by ferrocenium ion in the presence of diphenylacetylene gives [Ir,(C0),,(p3-PhC,Ph)] which reacts further with a second equivalent of alkyne upon therrnolysis affording [Ir6(CO)l *(p-PhC,Ph),] an octahedral iridium cluster with two face-capping alkyne~.~~ Two publications detail the synthesis of [Re,(CO) 8(p-CO)(p,-C)]2- via the removal of the capping [Re(CO),] + moiety from heptanuclear [Re,(CO) ,(p6-C)I3-.The reaction is induced upon addition of iodine or acetonitrile."' In the second paper reaction with P(OPh) in the presence offerrocenium ion is shown to afford an intermediate complex [Re,(CO), (P(OPh),)(p-CO),(p,-C)] - in which the phosphite is attached to the capping-metal centre.This decomposes upon stirring for 30 minutes in acetonitrile to give the hexanuclear dianion."' The reverse of this behaviour is found upon reflux of [CO,(CO),~(~~-N)] -with [Co(CO),] -,whereby cluster expansion occurs to yield the heptanuclear complex [Co,(CO) s(p6-N)]2 which consists of a capped trigonal ~ prismatic array of metal atoms the capping atom sitting on a square face." A number of synthetic methods have been described for the preparation of the heptaosmium alkyne complex [Os,(CO),,(p-H),(p,-MeC,Me)], the thermolysis of Yb C.J. Adams M. I. Bruce. B. W. Skelton. and A. H. White. J. Chcm Soc.. Chem. Comrnun. 1992. 26. Yl C.J Adams M. I. Bruce. M. J. Liddell B. W. Skelton. and A.H. White. J. Chern. Soc... Chem. Commun.. 1992 1314. 4X H.-F. Klein M. Mager. U. Fliirke. and H.-J. Haupt Oryunornetu//ic~.~, 1992 II 3915. Y9 A. Ceriotti P. Della Pergola F. Demartin L. Garlaschelli. M. Manassero. and N. Masciocchi. Oryunornerul!ic~.s,1992. 11 756. I00 T. Beringhelli. G. D'Alfonso H. Molinari. and A. Sironi. J. Chem. Soc... Dulton Trctns.. 1992 689. 101 S. W. Simerly. S. R. Wilson and J.R. Shapley Inory. Chem. 1992. 31 5146. 102 G. Ciani N. Masciocchi A. Sironi A. Fumagalli and S. Martinengo Inory. Chem.. 1992. 31. 331. Organometallic Chemistry of Bi-and Polynuclear Complexes 385 which results in hydrogen loss and carbon-carbon bond cleavage to give'' the bis(alky1idyne) complex [Os,(CO 8(p3-CMe)2]. Two papers document the reactivity of [Ni,(CO),,]2-.Thus addition of PC1,Me affords mixtures of phosphinidene clusters containing between eight and ten nickel atoms.'04 With PhSeCl the major reaction product is [Nil 1(CO),,(p5-Se),]2- which consistsofanickel-centredNi,oSe,icosahedron,'05while with Ph,Te,centredand non-centred icosahedral clusters [Ni,,,(CO)I s(ps-Te),]2 and [Ni,(CO),,(~c,-Te),]2 - respectively are obtained.lo5 A further large tellurium-containing cluster [{ Fe,(CO)lo(p3-Te),)(p4-Te,)]2-is isolated from the reaction of an excess of [Fe(CO),] with polytelluride. A review entitled 'Large Clusters and Colloids. Metals in the Embryonic State' considers the link between some large transition-metal clusters and the colloidal metallic state.lo7 This theme is pursued in a theoretical paper in which a local density functional method is applied in order to understand the developing magnetic and metallic behaviour in high-nuclearity nickel carbonyl clusters.Thus for clusters with nine or ten vertices all metal atoms lie on the surface of the cage and the molecule possesses well defined HOMO and LUMO orbitals accounting for the lack of magnetic behaviour. In the case of' Ni, and Ni, clusters however the developing magnetic behaviour is believed to be connected with the high density of states near the Fermi level a consequence of the presence of nickel atoms in the interior of the metal cage. 'O8 Some large metal clusters resemble fragments of close-packed metals. Thermolysis of [Ru,(CO),,] in a methanol/water mixture affords [Ru ,H(C0),,I3 - the metal core of which is a fragment of a hexagonal close-packed array,"' while pyrolysis of [Rh,(CO) 5(p6-N)]- affords [Rh23(CO),o(p-co),,(p(,-N),]3 ,which consists of a metallic polyhedron of C symmetry containing 21 surface metal atoms with the remaining two metal centres occupying interstitial sites.The four nitrido ligands are also interstitial each being bound to five rhodium atoms."' Examples of large mixed-metal clusters include [Ag 3Fe,(C0)3,]4-,which consists of a cuboctahedron of silver atoms stabilized by iron tetracarbonyl ligands,' and the synthesis of the 'cherry-like' cluster [Pt,Rh 8(CO),5]4- formed upon pyrolysis of [PtRh,(CO) -. This consists of a slightly distorted body-centred cubic framework at the centre of which is a semi-exposed tetrahedral Pt The reactivity of hexanuclear [Ru,Pt,(CO) is detailed in two papers.High temperature hydrogena- tion affords [Pt,Ru,(CO) (p-H),(p,-H)] which in turn reacts with diphenylacety- lene to give [P~,RU,(CO),~(~-H)(~,-H)(~~-P~C,P~)]. Both of these nonanuclear 103 D. Braga. F. Grepioni. €3. F. G. Johnson J. Lewis and J. A. Lunniss. J. Chem. Soc.. Dulton T'runs. 1992. I101. I04 D. F. Rieck J. A. Gavney Jr. R. L. Norman R. K. Hayashi. and L. F. Dahl. J. Am. Chrm. Soc.. 1992,114 10 369. 105 A. J. Kahaian J. B. Thoden and L. F. Dahl J. Chem. So(,. Chem. Commun. 1992. 353. 1Oh L. C. Roof. W. T. Pennington. and J. W. Kolis Anyew. Chem. Int. Ed. Enyl. 1992. 31. 913. '07 G. Schmid. Chem. Rea.1992 92 1707. IoXN. Rosch L. Ackermann and G. Pacchioni J. Am. Chem. Soc. 1992. 114 3549. 'OY P. J. Bailey M. A. Beswick B. F.G. Johnson. J. Lewis P. R. Raithby and M. C. Ramirez J. Chem. Soc,.. Dalton Trans. 1992. 3 159. S. Martinengo G. Ciani and A. Sironi. .I. Chern. Soc. Chem. Commun.. 1992. 1405. 'I1 V.G. Albano L. Grossi G. Longoni M. Monari. S. Mulley and A. Sironi. J. Am. Chem. Soc. 1992. 114. 5708. 'Iz A. Fumagalli S. Martinengo. G. Ciani. N. Masciocchi. and A. Sironi Inorq. Chem.. 1992. 31. 336. 386 G. H ogarth clusters are layer segregated and comprise of a triangle of platinum atoms sandwiched between two triangular ruthenium centres. Such complexes are anticipated to display novel catalytic properties and indeed the alkyne cluster is a catalyst for the selective hydrogenation of diphenylacetylene to cis-stilbene.'' The hexanuclear cluster also reacts with [RU,(C~)~,(~-H),] to give [Ru8Pt2(Co),,(p,-H),] which adds dppe to yield [Ru,Pt,(CO),,(q2-dppe)(p-H),] a cluster containing a new type of carbonyl coordination whereby the carbon bridges two metal atoms of an open triangle while the oxygen atom is coordinated to the third.' l4 11 Heterometallic Complexes Two methods have been developed towards the synthesis of phosphido-bridged heterometallic complexes of palladium and platinum with a range of transition metals. In the first method linear trimers generated in situ from the reaction of trans-[MCI,(NCPh),] (M = Pt Pd) with two equivalents of the sodium salts of transition metal carbonyls Na[M'(CO)] [M' = Cr(CO),Cp Mo(CO),Cp W(CO),Cp Mn(CO),] react further with three equivalents of secondary phosphines R,PH (R = Ph Cy) affording heterobimetallics [(R,PH),M(p-PR,)M'] in good yields.The second method is similar and involves the reaction of the Pto complex [Pt(PPh3),(q2- C,H,)] with terminal phosphido complexes [M'(CO)(PPh,)] generated in situ. The products of the second method are thus [(PPh,)Pt(p-PPh,)M']. Slight modification allows the synthesis of bis(phosphid0-bridged) linear trimers. Thus addition of two equivalents of [Mn(CO),(PPh,)] (generated in situ) to [Pt(cod),] affords [(CO),Mn(p-PPh,)Pt(CO)(p-PPh2)Mn(CO)4] (29) which converts to the closed cluster [{Mn(CO),(p-PPh,)),Pt(PPh,)] (30) upon reaction with PPh in toluene (Scheme 5).The nature of the bonding in these related trinuclear complexes has been analysed by extended Huckel calculations.' ' PPhp 0 (29) Scheme 5 In a second paper the addition of electrophiles to the metal-metal bonds is assessed. For example protonation readily occurs to give bridging hydrido complexes while the nature of the product of CuCl addition to heterobimetallic [CpMo(CO),(p-PPh,),Pd(PPh,H),] is solvent-dependent. Thus isomers are formed in which the copper halide either bridges the metal-metal vector (toluene) or is bound solely to molybdenum (CH,CI,).' l6 Another phosphido-bridged heterobimetallic complex [(R ,Si)Fe(CO) (p-PPh )Pt(PPh,),] reacts with carbon monoxide to give 'I3 R. D. Adarns Z. Li P. Swepston W. Wu and J.Yarnarnoto J. Am. Chem. Soc. 1992 114 10657. 'I4 R.D. Adams Z. Li J.-C. Lii and W. Wu J. Am. Chem. SOC. 1992 114. 4918. 'I5 P. Braunstein E. de Jesus A. Dedieu M. Lanfranchi and A. Tiripicchio Inorg. Chem. 1992 31 399. P. Braunstein E. de Jesus A. Tiripicchio and F. Ugozzoli Inorg. Chem.. 1992 31 41 1. Organometallic Chemistry of' Bi- und Polynuckar Complexes [(CO),Fe(p-PPh,)Pt(PPh,)(SiR,)] whereby the silyl group has migrated from iron to platinum.' '' Novel heterobimetallics synthesized include the early-late thiolate' ' complexes [CpNbCl,(p-SEt),NiCp] and [CpNb(q2-PhC,Ph)(~c-SPri),Mo(CO),].com-and plexes' '9*12o of the coinage-metals [{ q2-Ph2PCH2P(Ph,)=O},(CO)MoAu(PPh,)] + and [(CO),(PPh,),OsAg{q'-OC(O)CF,)]. The last of these is interesting since it can be considered as a model for the first step in an electron-transfer reaction.The nature of the reaction of the unsaturated heterobimetallic [H(PPh,),Ru(p- H),Re( PPh,),H(CO)] towards nitriles is highly dependent upon the substituent. Thus with MeCN hydrogen elimination affords [(PPh,),(MeCN)Ru(p-H),Re(PPh,),-(CO)] while with PhCN elimination and insertion occur'" to yield [( PPh,) (PhCN)Ru(p-H),(p-N=CHPh)Re( PPh3)2(C0)]. Publications concerning heterometallic complexes with three or more metal atoms include the synthesis' 22 of [W,(OR),(p-OR),CoCp] (R = CH,Bu') from the addition of [Co(C,H,),Cp] to triply-bonded [W,(OR),] and' 23 the butterfly cluster [{ Fe(CO),(p-CuPBu;)} ,I. The latter contains a puckered Fe,Cu core geometry while the iron<opper distances differ by 0.1 A attributable to a second-order Jahn- Teller distortion.Addition of [Ir(CO),] -to [Re,(CO),(p-H),] initially affords [Re,Ir(CO) 'H(p-H)] -which undergoes reductive coupling to yield', the linked triangular cluster [{ Re,Ir(CO) (p-H),]'- (31) while addition of two equivalents of [ReH(CO),(PMe,),] to [Os,(CO),,(coe)] (coe = cyclooctene) affords'25 the bis(spiked) triangular cluster [{ (PMe3)(C0),Re(p-H)},0s,(C0)~,] (32). 2-Two isomeric linear chain trimers [(CO),LOsOs(CO),LW(CO)5] and [(CO),L,0sOs(CO),W(CO)5] (L = Bu'NC) have been prepared in which dative metal-metal bonds are in tandem.' 26 The nature of the reaction products formed upon addition of copper(i) iodide to the ketenylideneclusters [M3(C0),(p,-C=C=O)l2 -(M = Fe Ru)is highly metal depen- dent.Thus with iron addition occurs at an Fe,C face to give the butterfly cluster P. Braunstein. M. Knorr B. Hirle G. Reinhard. and U. Schubcrt Angew. Chem. Int. Ed. Engl. 1992.31. 1583. 1IR S. Woodward M. D. Curtis A. L. Rheingold and B. S. Haggerty Organometullics. 1992 11 2140. 'I9 A. I,. Balch B.C. Noll. M. M. Olrnstead. and D.V. Toronto Inorg. Chem. 1992 31 5226. I20 L. Song and W.C. Trogler Angew. Chem.,Int. Ed. Engl. 1992. 31. 771. Z. He D. Ncilbcckcr N. Lugan and R. Mathieu Organomeru1lic.s. 1992 11. 817. I22 M. H. Chisholm. V.J. Johnson 0.Eisenstein and W. E. Streib Angew. Chem. Inr. Ed. Engl. 1992,31,896. 123 H. Deng D. W. Knoeppel and S.G. Shore Orgunometallics 1992 11 3472. I24 T.Beringhelli G. Ciani G. D'Alfonso. L. Garlaschelli M. Monct and A. Sironi J. Chem. Soc. Dulton 7ians. 1992 1865. 12' W. Wang R. J. Batchclor H. B. Davis F.W. B. Einstein. and R. K. Porneroy Inorg. Chem.,1992,31,5150. I26 R.J. Batchelor. F.W. B. Einstein R. K. Pomeroy and J.A. Shipley Inorg. Chem.. 1992 31. 3155. 388 G. Hogarth [Fe3Cu(CO)gI(p4-C=C=O)]2-(33) while with ruthenium tetrahedral [Ru,Cu- (CO),I(pL,-C=C=O)]' -(34) results in which the copper atom sits on the triruthenium face. 0 1 I1 2-C The butterfly cluster [Cp' Mo ,Co2 (CO),(p 3-S)2 (p4-S)] has one four-coordinate sulfido group sitting in the wing pocket. Nucleophiles such as PMe and MeCN add to cobalt resulting in the cleavage of a cobalt-sulfur bond to the unique sulfido ligand a transformation which is reversible.28 Three papers document the reactivity of the borane cluster anions [M,H(CO) ,(p4-BH)] -towards metal halide~.'~~-l 31 Addition of [(RhCl(CO),),] (M = Fe) affords trans-[Fe,Rh,(CO),,(~~,-B)]in which the boride occupies an interstitial site within -the metal octahedron.' 29 With [ClAu(dppf)AuCI] [dppf = 1,l'-bis(dipheny1phos-phino)ferrocene] complexes of the type [M,H(CO) ,BAu,(p-dppf)] are formed the nature of which depends upon the metal. Thus for ruthenium [Ru,H(CO),,Au,(,u- dppf)(p6-B)] (35) results in which the boron is interstitial and the digold unit bridges the wingtips of the ruthenium butterfly. For iron the metallaborane [Fe,(CO) ,Au,(p,- dppf)(p,-BH)] (36) predominates whereby the digold unit bridges across a wingtip-hinge vector and the boron-hydrogen interaction remains intact .'30 Reaction + of the ruthenium cluster with [M(NCMe),] (M = Cu Ag) affords the unusual boride '" A.S. Gunale. M. P. Jensen D. A. Phillips. C. L. Stern and D. F. Shriver Inory. Chern. 1992 31. 2622. 0. J. Curnow J. W. Kampf M.D. Curtis and B. L. Mueller Orgunornetallics 1992 11 1984. A. K. Bandyopadhyay R. Khattar J. Puga T. P. Fehlner and A. L. Rheingold. Inorg. Chern. 1992. 31 465. S. M. Draper C.E. Housecroft and A. L. Rheingold J. Orgunornet. Chem.. 1992 435,9. S. M. Draper A. D. Hattersley C. E. Housecroft and A. L. Rheingold. J. Chern. Sac.. Chern. Commun. 1992 1365. Organometallic Chemistry of Bi-and Polynuclear Complexes clusters [(Ru,H(CO) ,(p6-B)),M,(p-Cl)] in which two ruthenium butterfly units are ' linked to a tetrahedral coinage-metal cluster uia interstitial borides.Three independent groups have reported the synthesis of phosphine-stabilized gold clusters into which a transition metal atom is included.'32-'34 Thus the photochemi- cally induced reaction between [Mo(CO),] and [Au(N,)(PPh,)] affords [(Ph,PAu),Mo(CO),] +,while the relatedcobalt complex [(Ph,PAu),Co(CO),] + has also been prepared.' 32 Reaction of [W(CO),] with [Au(PPh,)(AuPPh,),12 + affords two clusters [(Ph,PAu),W(CO),]+ (37) and [(Ph,PAu),W(CO),]+ (38) both of (37) AU = Au(PPh3) (38) which have been structurally characterized. The former reacts reversibly' 33 with [AuPPh,]' to yield [(Ph,Au),W(CO),]'+ while the syntheses of the related manganese and rhenium clusters [(Ph,PAu),M(CO),] and [(Ph,PAu),M(CO),]+ (M = Mn Re) are also reported.', 12 Assorted Complexes The chemistry of organometallic complexes containing high-valent 0x0 sulfido and imido ligands continues to be an area of intense interest.Irradiation of [(Mo(CO),Cp*),] in the presence of oxygen gives two 0x0-bridged complexes [Mo,CI,(p-O)(p-Cl),Cp~] and [MozC1,(~~-O)(p-C1)(p-OzCOH)Cp~], for which ex- tended Huckel molecular orbital calculations suggest that there is very little direct metal-metal bonding. '3s The dicobalt complex [C~,(CO)~(p-CO)(p-dpprn)~] reacts with thiirane C,H,S to give sulfido-bridged [C~,(CO),(p-CO)(p-S)(p-dpprn)~], which itself reacts', with SO to afford [Co,(CO),(p-S)(p-SO,)(p-dppm),].A second sulfido complex [Cr,(p- S)(p-S,)(p,q'-S=S)Cp~] reversibly adds SO to the ql-S ligand to give [Cr,(p- S)(p-S2)(p,q1-S=S-S02)Cpf], while further SO addition results' 37 in the irreversible formation of [Cr,(p-S)(p-S,)(p,qi-S=S-S03)Cp;]. The synthesis and reactivity of imido complexes is the concern of a number of publications. Addition of the 1,3-dipolar reagents 2-H-azirines to [{ M(C0)L),] (L = Cp Cp*; M = Mo W) affords vinylimido complexes [M,(CO),(N-13' G. Beuter A. Brodbeck M. Holzer S. Maier. and J. Striihle Z. .4nory. Ally. Chrm.. 1992. 616 27. 133 T.G. M. M. Kappen. A. C. M. van den Hroek P. P. J. Schlebos J. J. Bour W. P. Bosman J. M. M. Smits P. T. Beurskens and J. J. Steggerda Inory. Chrm..1992 31. 4075. 134 B. K. Nicholson M. I. Bruce. 0.bin Shawkataly and E. R.T. Tiekink J. Oryanomrr. Chrm. 1992. 440 411. I35 F. Bottomley and J. Chen Oiganometullics 1992 11. 3404. 136 0.Heyke G. Beuter and I.-P. Lorenz. J. Chem. Soc. Dairon Trans. 1992 2405. 13' A. Toupadakis G. J. Kubas and C. J. Burns Inorg. Chem. 1992. 31 3810. 390 G. Hogarth CR=CR,)L,] as a result of the metal-induced ring-opening reaction. '38 Two papers document the carbonylation of imido complexes. Thus the dirhodium complexes [Rh,(CO),(p-NR)(p-dppm),l react with low concentrations of carbon monoxide to afford [Rh2(CO),(p-RNC0)(p-dppm),l while at higher concentrations demetalla- cycloimides [Rh2(CO),(p-CO)(p-0CNRCO)(p-dppm),] result from a double car- bony1 insertion.',,The carbonylation of [Os,(CO),(p3-CO)(p3-NPh)]is halide promoted. Addition of chloride gives the open cluster [Os,(CO),(p-C1)(p3-NPh)]- which reacts with carbon monoxide to afford [Os,(CO) lC1]- and PhNCO while with acids amido complexes [Os,(CO),(p-Cl)(p-NPhH)] result.'40 Addition of the activated alkyne RC,R (R = CF,) to the mixed-metal imido clusters [WRu,(CO),(p- H)(p3-NPh)L] (L = Cp Cp*) aff~rds'~' alkenylidene complexes [WRu,(CO),(p,- NPh)(p3-RC=CHR)L] one of which undergoes further reaction with hex-3-yne to give [Cp*WRu,(CO),(NPh){p,-EtCC(Et)CR=CHR}], a rare example of a cluster complex containing a terminal imido ligand. '42 Imido and amido complexes have also been synthesized via the reduction of metal-bound nitrosyl ligands.The reaction' 43 of [Fe(CO),(NO)] with [MoCl(CO),Cp'] affords [Cp'MoFe,(Co),(p-Co)(p-NO)(p3-NH)] (39) while Raney nickel reduction of [(Co(p-N0)Cp') ,] and [{Cr(NO)(p-N0)Cp)2] affords [Co,(p-NO)(p-NH,)Cp;] and [Cr,(NO),(p-NX)(p-NH,)Cp,] (X = 0,H,) respect- ively.' 44 The dimolybdenum nitrosyl complex [Mo,(NO)( = CHBu')(p-CHBu')(p-NO)Cp,] (40) has been prepared and shown by crystallography to contain a unique p-'1' :q2-N0ligand.145 H Other publications of interest include the synthesis and reactivity of triosmium clusters bearing trialkoxysilyl ligands. Reaction of [Os,(CO),,(NCMe),] with HSi(OMe) affords [Os,(CO),,(NCMe)(Si(OMe),}(p-H)] in which the oxysilyl ligand occupies a terminal site. Thermolysis however affords new products in which the ligand becomes doubly or triply bridging,'46 while addition of primary alkynes 138 M.D. Curtis M. S. Hay W. M. Bulter J. Kampf A. L. Rheingold and B. S. Haggerty Orgunometullics 1992 11 2884. 139 Y.-W. Ge and P.R. Sharp Inory. Chem. 1992 31 319. 140 D. L. Ramage G. L. Geoffroy A. L. Rheingold. and B. S. Haggerty Oryunometallics 1992 11 1242. 14' Y. Chi H.-F. Hsu L.-K. Liu S.-M. Peng and G.-H. Lee Oryanometallics 1992 11 1763. R.-C. Lin Y. Chi S.-M. Ping and G.-H. Lee J. Chem. SOL..,Chem. Commun. 1992 1705. 143 W. Sun S. Yang H. Wang Y. Yin and K. Yu Polyhedron 1992 11. 1143. 144 J. Muller. I. Sonn and M. Strampfer J. Organomet. Chem. 1992 427 C15. 145 P. Legzidins S.J. Rettig and J. E. Veltheer J. Am. Chem. SOL..,1992 114 6922. Organometallic Chemistry of Bi-and Polynuclear Complexes 39 1 initially affords alkenyl complexes [Os,(CO) o{Si(OMe),)(p3-CH=CHR)] which upon ~arbonylation'~~ at 68 "C eliminate vinylsilyloxyls (MeO),SiCH=CHR.Some unusual ligands have been prepared at bimetallic centres. The reaction of cyclohexene sulfide with [Mo,(CO),(p-o;q2-C=CR,)Cp2] (41) (R = H Me) affords thioketone complexes [Mo,(CO),(p,q3-SC=CR,)Cp,] (42) as a result of sulfur insertion. Subsequent sequential addition of H and H- converts the thioketones into + thioaldehyde complexes [Mo,(CO),(p,q3-SCHCHR2)Cp2] (43) (Scheme 6).'48 The -Mo, \ co co (431 Scheme 6 thermolytic reaction of [{ Mo(CO),Cp) ,] with cycloalkeno- 1,2,3-~elenadiazole in- itially affords [Mo,(CO),{p,q3-SeC6H,C(0)}Cp2] via extrusion of dinitrogen and later the cyclic alkyne complex [Mo,(CO),(p-C(CH,),C)Cp,] upon loss of sele- ni~m.',~ Reaction of RhC1 with 1,2,3,4-tetramethyl-5-trifluoromethylcyclopentadiene (Cp'H) affords binuclear [{ RhCl(p-Cl)Cp'} ,I.This unusual substituted cyclopen- tadienyl ligand has the steric properties of Cp* and electronic properties of Cp.' 50 Reactions of [PtClR(cod)] with TlC5H,PPh2 affords bimetallic complexes [Pt,R,(p,q5-Ph,PC,H,)(p,q'-Ph,PC,H,)] in which the donor-acceptor metal-metal interaction is spanned by inequivalent phosphido-substituted cyclopentadienyl ligands. lS 146 R. D. Adams J. E. Cortopassi and M. P. Pompeo Inorg. Chem. 1992 31 2563. 14' R. D. Adams J. E. Cortopassi and M. P. Pompeo Organometallics 1992 11 1.14' M. Bamber S. F.T. Froom M. Green M. Schultz and H. Werner J. Organomet. Chem. 1992,434. C19. A. J. Mayer B. Carrasco-Flores L. Parkanyin and K. H. Pannell J. Am. Chem. Soc. 1992 114 5467. P.G. Gassman J. W. Mickelson. and J. R. Sowa Jr. J. Am. Chem. Soc. 1992 114 6943. 15' M. Lin K. A. Fallis. G.K. Anderson N. P. Rath and M. Y. Chiang J. Am. Chem. Soc. 1992 114.4687. 14'

ISSN:0260-1818    

DOI:10.1039/IC9928900369

出版商:RSC    

年代:1992

数据来源: RSC