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.