8 Fe,Co Ni By 6. W. FITZSIMMONS Department of Chemistry Birkbeck College Malet Street London WClE 7HX 1 Iron Oxide Systems and Compounds having Fe-0 Bonds.-A study of Fe-0 bonding using molecular orbital theory draws attention to the importance of the metal 4s and 4p orbitals relative to the 3d orbitals and some predictions on FeO and FeO are advanced.' Mixed-metal oxides [(Mn,Fel-,)O,] (x range 0 +0.975; y range 0.91 -+0.998)have been prepared and investigated using chemical analysis neutron diffraction and Mossbauer spectroscopy. The Nee1 temperature is linearly depen- dent upon composition and the non-stoicheiometry is accounted for by the formation of defect clusters.2 Iron oxychloride FeOCl forms an intercalate with a crown ether (kryptofix-21) with stoicheiometry FeOCl (kryptofix-21)k.The intercalate was characterized using X-ray powder diffraction and Mossbauer ~pectroscopy.~ Two parallel studies on iron(II1) molybdate [Fe,(MoO,),] have been published.43s The material is antiferromagnetic at low temperatures. There is substantial agree- ment between the two studies the NCel temperature being close to 12 K. Iron(II1) heteropolytungstates involving Fe-0-Fe dimers of the type [XW,,O,,Fe-O-FeO,,W,,X]"-(X = P or As) have been isolated as solids and characterized.6 Iron(I1) malonate dihydrate [Fe(C3H304)2(H20)2] has been shown to be isomor- phous with the magnesium analogue. The crystal field parameters were obtained from the temperature dependence of its Mossbauer spectrum and the lack of an observable magnetic hyperfine interaction at 1.2 K was attributed to its monomeric structure.' The preparation of [FeL2(H20)2] and [Fe(HL'),].3H20 (L = pyrazine carboxylic acid H2L' = 2,3-pyrazinedicarboxylicacid) has been reported' together with magnetic susceptibility results and a molecular structural determination of the first compound a tr~ns-[Fe(H,O)~N,0,] octahedral monomer.The molecular struc- ture of [Fe'"(TCTA)] (TCTA = 1,4,7-triazacyclononane-N,N,N"-triacetate) has ' G. Blyholder J. Head and F. Ruette Inorg. Chem. 1982 21 1539. * D. A. 0.Hope L. A. K. Cheetham and G. J. Long Inorg. Chem. 1982 21,2804. R. H. Herber and R. A. Cassell Znorg. Chem. 1982 21 3713. Z. Jirak R. Salmon L. Fournes F. Menil and P. Hagenmuller Inorg.Chem. 1982 21 4218. P. D. Battle A. K. Cheetham G.J. Long and G. Longworth Inorg. Chem. 1982 21,4223. F. Zonnevijlle C. M. Tournt and G. F. Tournt Inorg. Chem. 1982,21 2751. 'N. Ravi R. Jagannathan B. R. Rao and M. R. Hussain Inorg. Chem. 1982 21 1019. C. L. Klein C. J. O'Connor R. J. Majeste and L. M. Trefonas J. Chem. Soc. Dalton Trans. 1982 2419. 227 B. W. Fitzsimmons been determined. It is a distorted prismatic [FeN303] complex.' The secondary ion mass spectra of iron(II1) and cobalt(I1I) P-diketonates have been recorded."' Stability constants for the complexation of a range of di- and ter-valent metallic ions by sulphonated poly-catecholate ligands have been adduced from poten- tiometric titrations. The molecular structures of a pair of iron(m) phenolate-Schiff base complexes have been determined.These are [Fe"'(saloph)(catH)] (saloph = N,N'-{ 1,2-phenylenebis(salicylideneiminato)} catH = catecholato-0) and a binuclear complex [Fe"' (salen2hq] (salen = N,N'-ethylenebis(sa1i-cylideneiminato} hq = 1,4-benzenediolato-O,0'). Both are square pyramidal com- plexes with the iron atoms some 50 pm above the basal plane." Iron (111) phenoxide complexes have been prepared and characterized for the first time. The complexes [FeL,]-X' (L = 2,3,5,6-tetramethylphenolate,X = Et,N; L = 2,4,6-trichlorophenolate, X = Ph4P) contain intensely coloured distor- ted tetrahedral [FeOJ units. Both complexes undergo reversible one-electron reduction. l3 The reaction between a solution of iron(II1) chloride and 2,3-dihydroxy- pyridine or 2-mercapto-3-pyridinol has been investigated by means of pH and conductance titrations and Mossbauer spectroscopy of the frozen solutions.Some reduction to iron(I1) is observed and the authors conclude that these phenols are unsuitable as analytical reagents for iron analysis. l4 The interest in quinone complexes of iron continues. A molecular orbital study of iron(1Ir) orthoquinone complexes provides predictions of ground-state electronic configurations. Where comparisons are possible there is good agreement between calculated and observed electronic transitions. '' The complexes [Fe'"(phenSQ)- phenCAT)(phen or biby)] (phenSQ = phenanthrene semiquinone phenCAT = phenanthrene catecholate phen = 1,lO-phenanthroline biby = 2,2'-bipyridyl) have been prepared and characterized.The Mossbauer spectra and magnetic susceptibilities are in accord with high-spin iron(Ir1). The complexes are non- electrolytes the semiquinone ligand (1)is accordingly a mixed-valence ligand. This assignment is supported by the observation of an intervalence charge-transfer band at 100 nm in the solid state or in non-polar solvents.16 The electrochemical reduction of iron(I1) or iron(II1) complexes of 3,5-di-t-butyl-O-quinonehas been investigated. K. Wieghardt V. Bossek P. Chaudhuri W. Herrrnann B. C. Menke and J. Weiss Znorg. Chem. 1982,21,4308. "' J. L. Pierce K. L. Busch R. G. Cooks,and R. A. Walton fnorg. Chem. 1982 21 2597. M. J. Kappel and K. N. Raymond Inorg. Chem. 1982,21,3437.l2 R. H. Heistand A. L. Roe and L. Que Znorg. Chem. 1982 21 676. M. Millar and S. A. Koch J. Am. Chem. SOC.,1982 104 5255. l4 B. Howlin R. C. Hider and J. Silver J. Chern. SOC., Dalton Trans. 1982 1433. Is D. J. Gordon and R. F. Fenske Znorg. Chern. 1982,21 2916. I' M. W. Lynch M. Valentine and D. N. Hendrickson J. Am. Chem. SOC.,1982,104,6982. Fe Co Ni 229 In some cases iron(II1) semiquinone complexes are formed but disproportionation also takes ~1ace.l~ The molecular structure of the iron(111) catecholamide complex [C5H N'],[Fe{ 2,3-(02)C6H3CONHCH2C02E t},( acac)] (acac = acetyl-acetonato) has been determined by X-ray diffraction. Co-ordination in this octahe- dral [Fe"'06] complex is from the deprotonated catechol. Some related compounds are also described in this paper.18 Mixed-metal complexes of the type [{Cr211'M"O}(MeCo2)6Py3] (M = Mg Fe Co or Ni) and [{Cr'1'Fe11M1'O}(MeC02)6Py3] (M = Mn Fe Co or Ni) are reported and the electronic spectra of these complexes together with those of the analogous (Fe2"'M"O) systems have been recorded and compared.The introduction of the divalent metal reduces the crystal field about the tervalent ion and the electron-transfer band lies at 6000 cm-' rather than 13 800 cm-' as in earlier assignments.'' A basic iron(rI1) phosphite [Fe30(HP03)3H20)9]C1.3H20 has been formulated as an analogue of the acetates and sulphates. It is antiferromagnetic.20 A bi-nuclear iron(II1) dihydroxamate complex of the type (2) has been prepared and its structure solved by X-ray methods.The two high-spin iron(II1) ions are antiferromagnetically coupled.21 Me 0-0 10-0 \/,oJ/ ,Fe 0 Fe ( 3 Pr'N(OH)C(=O)(CH2)~C( /\'o/\ =O)N(OH)Pr' 0-0 1 0-0 0 Me (2) The molecular structure (3) of a carborane [(Me2C2B4H4),(Fe" Fe"L)]- (L = (Me0)2C2H4),has been determined by X-ray methods. By using Mossbauer spectroscopy and magnetic susceptibility results it is shown that the Fe" ion in the 'ferrocene' position is low-spin whilst that in the 'wedging' position is high-spin.22 (3) " S. E. Jones L. E. Leon and D. T. Sawyer Inorg. Chem. 1982 21 3692. 18 D. H. Buckingham C. R. Clark M. G. Weller and G. J. Gainsford J. Chem. SOC.,Chem. Commun. 1982,779. l9 A. B. Blake and A. Yavari J. Chem. SOC.,Chem.Commun. 1982 1247. *' R. N. Puri and R. 0.Asplund Experientia 1982,38 80. 21 S. J. Barclay P. E. Riley and K. N. Raymond J. Am. Chem. SOC.,1982 104 6802. 22 R.N. Grimes. R. B. Mavnard E. Sinn. G. A. Brewer and G. J. Long J. Am. Chem. Soc. 1982 104 5987. 230 B. W. Fitzsimmons Iron-Sulphur Compounds.-The benzene and dichloromethane solvates of the iron(II1) dithiocarbamato complex [{Fe(S,CN no),}s](s = C6H6 Or CH2CI2) W have been investigated using magnetic measurements and Mossbauer spectroscopy. It is demonstrated that the earlier report of an S = $ electronic ground state for the CH2C12 solvate is in error. The benzene solvate is high-spin (S = :) the dichloromethane solvate is low-spin the effect of the solvent being one of pressure.23 The compound [{Fe(S2CNMe2)212}2] is shown to be an antiferromagnetically coupled dimer.Individual Fedtc,I molecules retain their S = 3identities and couple together through a molecule of di-iodine. The compound [Fe(S2CNEt2)213] is a five-co- ordinate monomer FeS4(I,).24 The reaction of H2S on Na2[Fe(CN),NO] yields Na[Fe4S3(N0)7] Roussin's black Some new reactions of Roussin's red salt have been uncovered. The bridging sulphurs alkylate on treatment with benzyl chloride and related compounds and metallation can be achieved using [NiC12dppe)] (dppe = bis(dipheny1phosphino)ethane). The compound [Fe2(SPh)2(N0)4] dis- plays syn-anti isomerizm.26 The compounds [Fe(SR),]-(R = 2,3,5,6-tetramethylphenyl) are the first examples of stable FeS complexes with monodentate sulphur ligands.The molecular structure of the Et4N salt has been determined the local symmetry is D2d.27 Complexes containing the relatively new bidentate chelate Et3PCS2 have been prepared and characterized. These are [(depe)2Fe(S2CPEt,)](BPh4)2 and [(diphos)Fe(S,CPEt,),](BPh,) {depe = 1,2-bis(diethyIphosphino)ethane diphos = 1,2-bis(dephenylphosphino)ethane}. The molecular structures of both compounds have been determined by X-ray methods; both contain six-co-ordinate Fe.,* An extensive family of iron(I1) thiolato-complexes have been prepared and characterized. These include the complex ions [Fe(SPh),I2- [Fe2(SPh6)12- [Fe4(SPh)lo]2- and [Fe3(SPh)3C16]3-. Treating this kind of complex with sulphur leads to the formation of compounds such as [Fe2S2(SPh),I2- or [Fe3S4(SPh)4]3-.29 Theoretical work on the chemical bonding in Fe-S cluster compounds continues to be published.Molecular orbital calculations in the Xa approximation are repor- ted,' for [Fe4S4(SH),l2- and [Fe4S4(SMe)4]2-. The synthesis molecular structure determination and reactions of the new cluster (Ph4P),[Fe4(sPh),C1,] have been rep~rted.~' Ligand substitution reactions of the double-cubane cluster complexes [M02Fe6S&R),]3- and [M2Fe7S8(SR) (M = Mo or W) have been investigated with a view to defining the points of attack by reagents such as PhSH or MeCOC1.'2 the electroreduction of CO is catalysed by the clusters [Fe4S,(SR),I2-. High yields of oxalate are produced at a reduction 23 A. Malliaris and V. Papaefthymiou Inorg.Chem. 1982 21 770. 24 D. Petridis A. Kostikas A. Simopoulos and D. Niarchos Znorg. Chem. 1982 21 766. 25 C. Glidewell and J. McGinnis Znorg. Chem. Acta 1982,64 L171. 26 T. B. Rauchfuss and T. D. Weatherill Znorg. Chem. 1982 21 827. '' M. Millar J. F. Lee S. A. Koch and R. Fikar Znorg. Chem. 1982 21,4105. 2x C. Bianchini P. Innocenti A. Meli. A. Orlandini and G. Scapacci. J Organornet. Chem. 1982 233 233. ") K. S. Hagen and R. H. Holm. J. Am. Chem. SOC. 1982 104 5496. 30 A. Aizman and D. A. Case J. Am. Chem. SOC., 1982,104 3269. 31 D. Coucouvanis M. Kanatzidis E. Simhon and N. C. Baenziger J. Am. Chem. SOC.,1982,104 1874. 32 R.E. Palermo P. P. Power and R. H. Holm Znorg. Chem. 1982 21 173. Fe Co Ni 231 potential of -2.4 The identification of the iron sites in the FeMo co- factor of nitrogenase has already been aided by EXAFS.Now new models have been prepared a trianion [(p-MeC6H4S)2FeS2FeS2MoS2]3-and a dianion [(PhO),FeS2MoS2l2-. The molecular structures have been determined and the EXAFS spectra The antiferromagnetic exchange interactions in [Fe4S4(SR),]"- (n = 2 or 3) clusters have been investigated. An elaborate model with different J values for different valence state Fen'-Fe"' couplings is employed and a good match with the experimental results is thereby attained.35 A similar kind of attack is made on M8 clusters e.g. [Fe6M2S8(SPh)6(oMe),l3-(M = Mo or W).36 The double cubanes [M2Fe7S8(SEt)12]3- cleave at ambient temperatures in the presence of 3,6-disubstituted catechols yielding new cluster species [M2Fe6S8(sEt)6(R',cat)2]4-(M = Mo or W; R = Pr" CH2CH = CH,).The molecular structure of one of these has been dete~rnined.~' The molecular structure of (Et4N)2[Mo2Fe6S8(SC2H5)9] has been determined. This double-cubane structure exhibits electronic and Mossbauer spectra consistent with non-integral oxidation state iron ions.38 A cubane cluster of the Fe3Mo nitrogenase-mimic type has been prepared and its physical properties examined. It is (Et4N)3[M~Fe3S4(S-p-C6H4Cl)(Et)2cat)]. The molybdenum is bonded to the catecholate and the effective spin of the complex is observed to be $.39 The cluster compound (Me4N)2[Fe4(SPh)lo].PrCN has idealized tetrahedral symmetry with an overall shape similar to that of adamantane.The 'Hn.m.r. spectra reveal rapid pyramidal inversion at the bridging SPh groups. Solutions of mixtures of these complexes having different metals (Fe Co Zn Cd) exhibit rapid metal e~change.~' But s11 I /?\ s; s 78 33 M. Tezuka T. Yajima A. Tsuchiya Y. Matsumoto Y. Uchides and M. Hidas J. Am. Chem. SOC. 1982,104,6834. 34 Eoon-Keng Teo M. R. Antonio R. H. Tieokelmann H. C. Silvis and B. A. Avenil J. Am. Chem. SOC.,1982,104 6126. 35 G. C. Papaefthymiou E. J. Laskowski S. Frota-Pessaa R. B. Frankel and R. H. Holm Inorg. Chem. 1982,21,1723. 36 G. Christou D. Collison C. D. Garner S. R. Alcott F. E. Mabbs and V. Petrouleas J. Chem. SOC. Dalton Trans.,1982 1575. 37 W. H. Armstrong P. K. Mascharak and R. H. Holm J. Am. Chem.SOC.,1982,104,4373. 38 G. Christou P. K. Mascharak W. H. Armstrong G. C. Papaefthymiou R. B. Frankel and R. H. Holm J. Am. Chem. SOC.,1982,104,2820. 39 W. H. Armstrong P. K. Mascharak and R. H. Holm Inorg. Chem. 1982,21 1699. 40 K. S. Hagen D. W. Stephan and R. H. Holm Inorg. Chem. 1982,21,3928. 232 B. W. Fitzsimmons The hexanuclear cluster [Fe,S9(S-B~')2]4- has been synthesized and its molecular structure (4) determined.4' Two iron sulphur cluster systems unrelated to the previous theme have been recently described. These are of formula [Fe4(N0)4(p3-S)4]n (n = 0 -1) and [Fe4(N0)4(~3-S)2(p3-NCMe3)2]n (n = 0 -1). They are both of the cubane type the molecular structures having been determined by X-ray crystallography and the electronic structures are discussed Co-ordination Compounds having N-and N-,U-Donor Ligands.-The molecular structure of iron(r1) hippurate [Fe"(PhCONHCH2C02H)2(H20)3]-2H20 has been determined by X-ray methods.It has a linear chain structure with bridging water molecules. A ferromagnetic phase sets in at 8.1 K.44The Schiff base (5) has been ,(CH2)3 Me GN: -':+Me --N ,:N-\ ((33213 (5) deployed in the synthesis of a series of compounds [LCuMCI,] {L = (4) M = Fe" Ni" or Mn"}. The copper and metal di-positive ions utilize equivalent N,O co-ordination sites; there is a copper-metal antiferromagnetic intera~tion.~' There is a weak antiferromagnetic interaction in the case of the compound [Fe,L(OMe)Cl,] a high-spin iron(II1) binuclear complex having OMe and OPh bridges.L is the trianion of tri~alicylidenetriethylenetetramine.~~ The molecular structure of an iron(Ir1) chloro-complex [ClFe"'L2] {L = N-(2-phenylethy1)-salicylideneirninato} has been determined. It is a high-spin [FeN2O2C1] five-co- ordinate square-pyramidal monomer in contrast to the dimeric structure adopted in a different crystalline modification of this The &octahedral com-plex [Fephen,(CN),] (phen = 1,lO-phenanthroline) adsorbs on montmorillonite clay. The binding capacity ratio for the racemic and enantimorphic forms is 2 1.48 This kind of differentiation is also observed for the adsorption of racemic and enantiomorphic [Fephen3I2' (phen = 1,10-phenanthroline) here investigated with the help of Auger spectroscopy.It is observed that the enantiomorphic form is adsorbed as a di-positive cation the racemic form as a mono-positive i~n-pair.~' It has long been known that di-imine chelates stabilize a wide range of oxidation states. Now the electrochemical oxidation of [Febipy312' has been investigated using SO as solvent. Three oxidations are observed (3+ 0.7 V.; 4+ 2.92 V.; and 5+ G. Christou M. Sabat J. A. Ibers and R. H. Holm Inorg. Chem. 1982 21,3518. '* C. Ting-Wah Chu R. S. Gall and L. F. Dahl J. Am. Chem. Soc.. 1982,104,737. 43 C. Ting-Wah Chu F. Yip-Kwai Lo,and 1.. F. Dahl J. Am. Chem. SOC.,1982,104,3409. O4 M. M. Moreluck M. L. Good L. M. Trefonas R. Majeste and D. G. Kariaker Znorg. Chem. 1982 21 3044. 4s S. L. Lambert C. L. Spiro R. R. Gagni and D. L.Hendrickson Inorg. Chem. 1982,21,68. '' B. Chiari 0.Piovesana T. Tarentelli and P. F. Zanazzi Inorg. Chem. 1982,21,2444. '' C. J. Magurany and C. E. Strouse Inorg. Chem. 1982,21 2348. 48 A. Yamagishi,Inorg. Chem. 1982 21 1778. 49 A. Yamagishi K. Tanaka and 1. Toyoshima J. Chem. SOC.,Chem. Commun. 1982,343. Fe Co Ni 233 3.0 V.) The higher oxidation-state species react with solvent to regenerate the 3+ forms.5o Iron(I1) and iron(II1) trisbipyridyl complexes have been prepared within the cavities of zeolite Y and investigated therein using Mossbauer spectroscopy X-ray powder photograph electronic spectroscopy and electron paramagnetic The electronic spectra of [MX1bipy3l2+ re~onance.’~ (M = Fe Ru 0s; bipy = 2,2‘-bipyridyl) have been recorded and the electronic states cla~sified.’~ The complex [Febipy(NCS),] is polymeric and the various structural possibilities are discussed in a paper which deals with the magnetic susceptibility of this compound.There is weak antiferromagnetism (-J = 2.7 ~m-*).’~ A transformation which seems to be second-order takes place in the range 130-185 K.54 Co-ordination Compounds having P-Donor Ligands.-The complex [Fe(H)(BH4) MeC(CH2PPh2)3] has been prepared and its structure determined by X-ray methods. It is six-co-ordinate (FeH3P3).” A similar ligand is deployed in the preparation of a dinuclear complex [LFe(p-C1)3FeL]’BPhi {L = MeC(CH,PEt,),}. The molecular structure is that of two face-sharing octahedra. Molecular orbital theory is used to rationalize the observed bond distance^.'^ Some 2,6-bis(diphenylphos-phinomethy1)pyridine complexes of iron(II) cobalt(II) and nickel(@ have been prepared and their physical properties in~estigated.~~ A synthesis and some reactions of the organoiron phosphine complex (6) have been publi~hed.~’ Spin Crossover among Iron Complexes.-The compound [FeL3](Cl0J2 {L = (7)) shows first-order spin crossover at about 110K.The perchlorate ions are orientationally disordered above the transition temperature and are ordered below it. The change in cation-anion interaction associated with this order-disorder transition is believed to be the spin-crossover trigger.59 The S = 2S = $ transition in [Fe(salen)NO] {salen = N,N‘-ethylenebis(salicy1ideneiminato)) has been investigated in a combined Mossbauer spectroscopy-magnetic susceptibility study.There are two superimposed Mossbauer spectra observable at the transition tem- perature (175K) corresponding to each spin isomer. This nitrosyl is an intramolecular antiferromagnetic at low temperatures as is the 5-chloro salen 50 J. G. Gandiello P. R. Sharp and A. J. Bard J. Am. Chem. SOC.,1982,104 6373. W.H.Quale G. Peetero G. L. De Roy E. F. Vasant and J. H. Lunsford Inorg. Chem. 1982 21 2226. 52 E. M. Kober and T. J. Meyer Inorg. Chem. 1982,21,3967. 53 B. W.Dockum and W. M. Reiff Inorg. Chem. 1982 21 391. 54 B.W.Dockum and W. M. Reiff Inorg. Chem. 1982,21 1406. 55 C. A.Ghilardi P. Innocenti S. Midollini and A. Orlandini J. Organomet. Chem. 1982,231,C78. C. Bianchini P. Dapporto C.Mealli and A. Meli Inorg. Chem. 1982,21 612. 57 P. Giannoccaro G. Vasapollo C. F. Nobile and A. Sacco Inorg. Chem. Acta. 1982,61,69. ” S.D. Ittel and M. A. Cushing jun. Inorg. Synth. 1982 21 90. 59 E.Konig G. Ritter S. K. Kulshreshtha. and S. M. Nelson Inorg. Chem. 1982,21 3022. B. W. Fitzsimmons derivative which has three impaired electrons over the working temperature range.6o The system [FexM(l-x,phen2(NCS)2] (M = Mn Co Ni Zn; x range is 0.001- 1.00; phen = 1,lO-phenanthroline) has been investigated using Mossbauer spec- troscopy with a view to determining the effects of dilution by metal ions of different radii. Marked effects on the amount of residual paramagnetism remaining below Tc are observed.61 The family of complexes [Fephen2X2] X = I CNS CNSe or N3 have been subjected to a variable pressure-infrared spectroscopy study.The CNS and CNSe compounds show spin-crossover at 8 and 6 kbar respectively.62 Two solution studies of spin-crossover have been reported this year. The first of these utilizes N-methyl(2-aminopyridine)(=L)as co-ordinating agent in a family of complexes [FeL3]X2 x = c104 PF6 c1 or Br. Using electronic spectroscopy e.p.r. and the Evans method for determining magnetic moments 'Als 5T1 equilibria have been identified.63 In the second study of spin-equilibria in solution a pulsed laser is deployed to perturb the equilibrium and relaxation times were measured as a function of temperature. The complexes employed were of the type [FeL3I2+ L = 2-(2-pyridylimidazole),N2-(2-pyridylmethyl)picolinamidine,and 2,2'-bi-1,4,5,6- tetrahydr~pyrimidine.~~ In a rather different kind of investigation the rates of oxidation FeT1 -B Fe'" have been measured for a family of compounds (8) some being high-spin others low-spin.No dependence of rate of oxidation on spin-state was detected.65 Porphyrinato-iron Compounds.-Oxygen atom transfer from an amine oxide to alkenes or alkanes is catalysed by [Fe"'(TPP)Cl] (TPP = dianion of meso-tetraphenylporphin). In this way alkenes are converted into their corresponding epoxides in good yield.66 Models of cytochrome c have been synthesized and tested. One such study involved the incorporation of three donor atoms (N S and N) into a fly-over strap built on mesoporphyrin XII. The Cu-Fe complex was prepared and magnetic measurements indicated a reasonably strong Cu-Fe interaction 6o F.V. Wells S. W. McCann H. H. Wickman S. L. Kessel D. N. Hendrickson and R. D. Feltham Znorg. Chem. 1982 21 2306. '' P. Ganguli P. Gutlich and E. W. Muller Inorg. Chem. 1982,21,3429. '* D.M. Adams G. J. Long and A. D. Williams Inorg. Chem. 1982 21 1049. " H.Li Chum J. A. Vannin and M. I. D. Hilanda Znorg. Chem. 1982,21 1146. 64 J. J. McGarney and I. Lausthas J. Chem. SOC.,Chem. Commun. 1982,906. " K.M. Kadish C. Su D. Schaeper C. L. Merrill and L. J. Wilson Znorg. Chem. 1982,21,3433. 66 M. W. Nee and T. C. Bruice J. Am. Chem. SOC.,1982,104,6123. Fe Co Ni 235 (-3J = 132 * 5 ~m-').~~ Another study utilizes imidazolate as the bridging group in a series of derivatives such as [C1(TPP)Fe"1(imidazolate)Cu"].68 A stable [Fe1"-0-Cu"] complex results from the reaction of [(TPP)Fe'"=O] on an imidazole bearing Cu' complex this has physical properties (magnetic susceptibility Mossbauer spectroscopy and e.p.r.) consistent with S' = 1 electronic ground The p-nitrido iron(II1) complex [{Fe(TPP)},N] has S'= 4 in the temperature range 4-295 K.It is the sole example of two first-row transition-metal ions bridged by a single nitrogen atom. Two complementary electron paramagnetic resonance studies of this compound have been p~blished.~',~' An earlier low-spin assignment is confirmed and complexation by Lewis bases yield unsymmetrical dimers. Progress has been made on the formulation of products of oxidation of iron(II1) porphyrins previously thought to involve iron(1v).The molecular structures of two of these cationic complexes have been established by X-ray methods. Magnetic susceptibility and Mossbauer spectroscopy studies allow unequivocal formulation as iron(I11) radical cations e.g. [Fe"'C1(TPP)]t[SbCl6]-. This has S' = 2 overall with the metal spin (S = 2)interacting with that of the ligand (S = 3). This interaction is seen to ruffel the pyrrole rings as the metal dX2-y2 and the ligand a2, orbitals overlap more effectively in a non-planar macr~cyle.~~ In a complementary investiga- tion the compound [Fe'T'C1(TPP)]fSbC16 was also studied with similar results and conclusions to those discussed above. The diperchlorate [Fe"'(TPP)](CIO,) is somewhat different in that the metal spin ($) and the ligand spin (3) do not interact antiferr~magnetically.~~ A group of cationic radicals have been prepared from [{Fe"' (TPP)},O] [FeCl{TPP(p-OMe)}] and [FeCl( OEP)] (OEP = octae t hyl- porphyrin).Magnetic susceptibility results and Mossbauer spectral parameters indicate that here also the products of oxidation are cationic radicals.74 In the complex [(T"P)( p-C1C6H,)2C=C:Fe1"C1] (TPP = dianion of meso-tetra-p-tolylporphine) the structure (X-ray) is as depicted in (9). Its magnetic I CI (9) 67 C. K. Chang M. Seokoo,and B. Ward I. Chem. SOC.,Chem. Commun. 1982,716. 68 S. E. Dessens C. L. Merrill R. J. Saxton R. L. Ilaria jun. J. W. Lindsey and L. J. Wilson J. Am. Chem. SOC..1982,104,4357. 69 R.J. Saxton L. W. Olson and L. J. Wilson J. Chem. SOC.,Chem. Commun. 1982 984. 70 L. A. Bottomley and B. B. Garrett Inorg. Chem. 1982 21 1260. 7' G. A. Schick E. W. Findsen and D. F. Bocian Inorg. Chem. 1982,21,2885. " G. Buisson A. Deronzier E. Duke P. Gans J. C. Marchon and J. R. Regnard J. Am. Chem. SOC. 1982,104,6793. 73 W. F. Scholz C. A. Reed V. J. Lee W. R. Scheidt and G. Lang J. Am. Chem. SOC.,1982,104,6791. 74 M. A. Phillippi and H. M. Goff,J. Am. Chem. Sw.,1982,104,6026. B. W. Fitzsimmons moment and e.p.r. spectrum indicate an S = 5 ground state presumably brought about by the low-symmetry ligand field.7s Another very similar example of this structure is [(TPP)( p-ClC,H4)C=C:Fe"'C1].76 Carbene complexes [(TPP)Fe:C(Cl)SR] have been isolated after the reaction of [(TPP)Fe"] with C13CSR and a reducing agent.Some of these compounds may be converted into [(TPP)Fe(CS)] complexes by treatment with catalytic quantities or CuC12 of FeC12.77In this connection the structure of the octaethylporphyrin complex [(OEP)Fe"(CS)] has been determined by X-ray analysis. This low-spin five-co- ordinate iron(I1) derivative incorporates a linear Fe-C-S grouping and the Fe atom is displaced by 23 pm from the mean plane.78 The iron(I1) carbene [(TPP)Fe"':CH=CPh2] undergoes a reversible alkylidene migration between Fe and N the N-bonded compound is depicted in (10). By appropriate treatment the iron-free porphyrin may be obtained from this." Oxidation by O2 of the compounds [(TMP)Fe"] {TMP = dianion of rneso-tetrakis(2,4,6-trimethoxyphenyl)porphine or of meso-tetrakis (2,4,6-trimethyl- pheny1)porphine) yields the corresponding [(TMP)FeOH] complex.The same species can be isolated after hydrolysis of the appropriate [(chloro)Fe'"] complexes with NaOH. These hydroxo complexes may be distinguished from the p-0x0 dimers on the basis of the 'H n.m.r. spectral measurements magnetic susceptibilities i.r. and e.p.r. The use of bulky phenyl substituents helps in their isolation the rate of formation of the p-0x0 dimers being slower than for [Fe"'(TPP)OH] which has not yet been isolated.8o In a parallel study this oxidative process was investigated at a lower temperature (-70 "C) at which a new diamagnetic complex [(TPP)Fe02] was detected and its subsequent fate at higher temperatures was elucidated.81 Thus dioxygen complexes of [Fe(TPP)] are unstable at low ambient temperatures with respect to p-0x0 Fe''' species.The matrix isolation technique has been successfully applied at 15 K to the identification of [Fe(TPP)OJ. The 1 1 stoicheiometry was confirmed and a thermal isomerization detected.82 Electrochemical oxidation or reduction leads to reversible redox processes for [(TPP)Fe(NO)]. Oxidation in the presence of NO leads to the formation of an unusual bis nitrosyl complex [(TPP)Fe(NO),]'ClO; which has S = $.83 'Is M. M. Olmstead R. Chang and A. L. Balch Inorg. Chem. 1982,21,4143. 'I6 D. Mansuy I. Morgenstern-Badarun M. Lange and P. Gans Inorg. Chem. 1982,104 1427. 'I7 J.-P. Battioni J.-C. Chottard and D.Mansuy Inorg. Chem. 1982 21 2056. 'I8 W. R. Scheidt and D. K. Geiger Znorg. Chem. 1982,21 1208. 'I9 D. Mansuy J.-P.Battioni D. DuprC E. Sartoni and G. Chottard J. Am. Chem. SOC.,1982,104,4487. *' R.-J.Cheng L. Latos-Grazynski and A. L. Balch Inorg. Chem. 1982 21 2412. '*L. Latos-Grazynski R.-J. Cheng G. N. La Mar and A. L. Balch J. Am. Chem. SOC.,1982,104 5992. K. Nakamoto T. Watanabe T. Ama and M. W. Urban J. Am. Chem. Soc. 1982,104,3744. L. W. Olson D. Schaeper D. Lancon and K. M. Kadish J. Am. Chem. SOC.,1982,104,2042. Fe Co Ni 237 Other related papers are shown in Table l.84-ii3 Table 1 Further papers on the subject of porphyrin complexes of Iron Subject Ref. Quantum mechanical studies of the photodissociation of carbonylhaem complexes 84 Quantum mechanical studies of the photodissociation of oxyhaem complexes 85 A trimeric iron(II1) haem-copper(r1) complex 86 New five- and six-co-ordinate imidazole and imidazolate complexes of iron(II1) TPP 87 Models of the cytochromes b 88 Structure of an iron(m) 'capped' porphyrin 89 O2 and CO affinities of iron(r1) modified capped porphyrins 90 Arylation and vinylation of iron porphyrins 91 Characterization of several iron nitrosyl porphyrins 92 Synthesis of iron(rI1) porphyrins having a Fe-CH3 bond 93 N.m.r.study of a range of [Fe(TPP)(X)] complexes (X = NCS C1 Br or I) 94 Formation constants of [Fe(porphyrin)(CO)] complexes 95 Mossbauer spectroscopic study of [Fe(Pc)(CO)(L)] complexes (Pc = Phthalocyaninato L = nitrogenous bases or oxygendonors) 96 Kinetics of reaction of [Fe(TPP)Cl] on N-methylimidazole 97 Synthesis of porphyrins having an in-built supportive base 98 Molecular structural determination of [{(TPP)Fe}2C] 99 84 A.Waleh and G. H. Loew J. Am. Chem. SOC.,1982,104,2346. " A. Waleh and G. H. Loew J. Am. Chem. SOC.,1982,104,2352. 86 C. M. Elliott and K. Akabori J. Am. Chem. SOC., 1982,104,2671. " R. Quinn M. Nappa and J. S. Valentine J. Am. Chem. SOC.,1982 104,2588. F. A. Walker V. L. Balke and G. S. McDermott J. Am. Chem. SOC., 1982,104 1569. 89 M. Sabat and J. A. Ibers J. Am. Chem. SOC.,1982,104,3715. 90 T. Hashimoto R. L. Dyer M. J. Crossley J. E. Baldwin and F. Basolo J. Am. Chem. SOC.,1982 104,2101. 91 D. Lexa and J.-M. SevCant J. Am. Chem. SOC.,1982,104,3503.92 L. W. Olson D. Schaeper D. Lancon and K. M. Kadish J. Am. Chem. Soc. 1982,104,2042. 93 P. Cocolios E. Laviron and R. Guilard J. Organomet. Chem. 1982 228 C39. 94 D. V. Behene R. Birdy and S. Mitra Inorg. Chem. 1982 21 386. 9s S. H. Strauss and R. H. Holm Znorg. Chem. 1982 21,863. 96 F. Galdertizzo S. Frediani B. R. James G. Pampaloni K. J. Reimer J. R. Sams A. M. Sena and D. Vitali Inorg. Chem. 1982,21 2302. 97 M. C. Doeff and D. A. Sweigart Inorg. Chem. 1982 21,3699. 98 M. Momenteau and D. Lavalette J. Chem. SOC.,Chem. Commun. 1982,341. 99 V. L. Goedken M. R. Deakin and L. A. Bottomley J. Chem. SOC.,Chem. Commun. 1982,607. loo D. Mansuy and J.-P. Battioni J. Chem. SOC.,Chem. Commun. 1982,638. lo' D. Mansuy M. Fontecave and J.-P. Battioni J.Chem. SOC.,Chem. Commun. 1982 317. H. Ogoshi H. Sugimoto Z. Yoshida H. Kobayashi H. Sakai and Y. Maeda J. Organomet. Chem. 1982,234,185. J. E. Baldwin M. J. Crossley T. Klose E. A. O'Rear 111 and M. K. Peters Tetrahedron 1982 38 27. 104 S. Sano and Y. Sugivra J. Chem. SOC.,Chem. Commun. 1982,750. D. J. Liston K. S. Murray and B. 0.West J. Chem. SOC.,Chem. Commun. 1982 1109. D. Brault and P. Neta J. Phys. Chem. 1982,86 3405. lo' A. D. Boersma and H. M. Goff Znorg. Chem. 1982 21 581. lo' A. Shirazi and H. M. Goff J. Am. Chem. SOC.,1982,104 6318. log S. Neya and I. Morishima J. Am. Chem. SOC.,1982,104 5658. 'lo R. M. Richman and M. W. Peterson J. Am. Chem. SOC.,1982,104,5795. lI1 V. P. Chaeko and G. N. La Mar J. A.m. Chem. SOC.,1982,104 7002."* S. Obara and H. Kashiwagi J. Chem. Phys. 1982,77 3155. W. R. Scheidt Y. J. Lee D. K. Geiger K. Taylor and K. Hatano J. Am. Chem. SOC., 1982 104,3367. 238 B. W. Fitzsimmons Table 1-continued Subject Ref. Characterization of the carbene [(TPP)Fe1':C(CI)(CF3)] and the o-alkyl [(TPP)FeCHClCF3] 100 Catalysis of the reduction ArCH2CI + ArCH3 by [Fe(TPP)Cl] 101 The preparation of cr-aryls [(OEP)Fe-Ar] (OEP = octaethyl porphyrin) and magnetic susceptibility-spectroscopic study 102 Synthesis and dioxygenation of strapped iron(rr) porphyrin complexes 103 Preparation of an [(oxymesoporphyrin)Fe1']-2-methylimidazolecomplex 104 Preparation magnetic susceptibility study and reactions of [(TPP)Cr"'-0-Fe"'(TPP)] 105 Kinetics of reduction of iron(rrr) porphyrins with HOCMe2 radicals 106 Spectroscopic study of [(TPP)FeX] (X= SO,CF, ClO, C(CN);.Quantum mechanical mixing of S = $ with S = 5 is proposed 107 Reaction of [(TPP)Fe"] with KOz in MezSO yields a peroxo Fe"' porphyrin complex 108 The formation and magnetic properties of haemin azide 109 The photodisproportionation of [{(TPP)Fe}20] 110 'H n.m.r. and e.p.r. study of bis(1igand) complexes of photoporphyrin IX and deuterohaemin 111 Molecular orbital calculations of electronic states and Mossbauer spectra of [Fe" porphyrins] 112 Preparation and molecular structure of [Fe"(TPP)(Py)(NCS)] and [Fe"'( OEP)( P y)(NCS)] 113 Iron-Halogen Compounds.-The molecular structures of NaK3[Fe"C16] (Rinneite) and of [CO(NH~)~][F~"'CI~] have been determined in order that a comparison of Fen'-CI (n = 2 and 3) bond lengths might be made.'I4 The single-crystal electronic spectrum of the [Fe"'C1,(H20)]2- ion as the di-caesium salt has been recorded and assigned.' '' Formation constants for chloro-complexes of iron(II1) and nickel(I1) in chloroaluminate melts have been established using potentiometric methods.116 The dissociation enthalpies SD(FeBr'-2L) for the gas-phase species FeBr' bis adducts (L = organic molecules) have been determined and the results analysed.'" Kinetic Studies on Iron Complexes.-Table 2 shows recent J.K. Beattie and C. J. Moore Inorg. Chem. 1982 21 1292. V. Kambli and H. V. Gundel Inorg. Chem. 1982,21 1270. T. M. Laher and C. L. Hussey Inorg. Chem. 1982 21,4079.M. M. Kappes and R. H. Staley J. Am. Chem. SOC.,1982,104 1819. I. R. Epstein K. Kustin and R. H. Simoyi J. Am. Chem. SOC.,1982 104 712. 'I9 K. L. Rollick and J. K. Kochi J. Am. Chem. Soc. 1982 104 1319. ''O E. Mentasti F. Secco and M. Venturini Inorg. Chem. 1982 21,2314. '" D. B. Soria M. Del V. Hidalgo and N. E. Katz J. Chem. Sac. Dalton Truns. 1982 1555. E. Mentasti F. Secco and M. Venturini Inorg. Chem. 1982,21,602. B. T. Reagor and D. H. Huchital Inorg. Chem. 1982 21 703. M. Orban and I. R. Epstein J. Am. Chem. SOC.,1982,104 5918. K. J. Pfenning L. Lee H. D. Wohlers and J. D. Petersen Inorg. Chem. 1982 21 2477. 126 B. T. Reagor D. F. Kelly D. H. Huchital and P. M. Rentzepis J. Am. Chem. Soc. 1982 104 7400. 12' F. T. Bonner and K. A. Pearsall Inorg.Chem. 1982 21 1973. L. A. Andrade de Oliveira and A. Haim J. Am. Chem. Soc. 1982,104,3363. Fe Co Ni 239 Table 2 Recent kinetic studies on iron complexes Complex or species Reaction studied Ref. 118 [Fe'sL3]2+ (L = 3,4,7,8- tetramethyl- [Fe1'L3I2++ HN02 + products 1,lO;phenanthroline) 119 [Fe"'L3I3 (L = 1,lO-phenanthroline [Fe1''L3l3+ + R' + products or 2,2'-bipyridyl) 120 [Fe(CN)6]"-(n = 3 or 4) [Fe(CN)6]"-+ Fe2+aq-+ products [Fe(CN),(dmen)I3- (dmen = N,N-di-methylethylenediamine) [Fe(CN),(dmen)13-+ pyridine + productsacH o121 Fe3+aq.- Fe3+aq. + +products 122 COZH R [Fe(CN)6I3-+ [Co edtaI2- + products 123 Fe2+aq. + HNO + products 124 [Fe(CN)5(H20)I3-+ [LM"'(CN),] + 125 dimer (L = pyrazine 4,4'-bipidine or 4- cyanopyridine M = Co or Rh) (NC) ,Fe" -CNCo"'N BETA Intramolecular electron transfer 126 (NC),Fe"-CNCo"'HEDTA (NBETA = N-benzylethylene-diaminetriacetato HEDTA = N-hydroxyethylene-diamine triace tato) Fe2'aq.Fe2+aq. + NO; -+ products 127 -+ products 128 Iron Carbonyls and Related Low-Oxidation State Compounds.-The core valence Auger spectra of [Fe(CO),] and [Co(CO),NO] have been recorded. The electron densities derived therefrom agree with those calculated using Hartree-Fock methods.129 Electroreduction of [Fe(CO),] Fe,(CO),, or [HFe(CO),]- in water-miscible solvents have been investigated both in anhydrous conditions and with addition of controlled amounts of A study of the kinetics of reaction between alkoxide or hydroxide ions and iron or ruthenium carbonyls has been carried out the processes being of relevance to the water-gas shift-reaction (CO + H20 C02 + H2).13' Extremely reactive dianions of the type [Fe(C0),PR3)I2- have been prepared by two stages of reduction starting from [Fe(CO)4(R3P)].'32 The cationic radical [Fe(CO),(PPh,),]+ undergoes oxidative substitution reac-tions with the sulphur ligands [S2CPPh3] and [S2CNMe2]-yielding [Fe(CO)2(PPh,)2S2CR]" (R = PPh3 t = 2; R = NMe2 z = 1).The cationic radical undergoes coupling reactions with NO or NO2 to yield [Fe(CO),NO(PPh3),12+ and mer,tran~-[Fe(NO~)(CO)~PPh~]+. Spin-trapping with 129 G. D. Stucky R. R. Rye D. R. Jennison and J. A. Kelber J. Am. Chem. SOC.,1982,104 5951. '''I N. El Murr and A. Chaloyard Znorg.Chern. 1982 21 2206. 131 D. C. Gross and P. C. Ford Inorg. Chem. 1982 21 1702. Y.-S. Chen and J. E. Ellis J. Am. Chem. SOC., 1982 104 1141 B. W.Fitzsimmons Me3CN0 and the formation of paramagnetic complexes with 1,2-diketones was studied by e.p.r. of the latter cis,trans [Fe(CO)2(PPh3)2(02C6C14)]+ from the cationic radical and 3,4,5,6-tetrachloro-p-benzoquinonewas isolated and fully charac- teri~ed.'~~ The reaction between [Fe(CO)J and Group V donor ligands to give [Fe(CO),L] {L = e.g. R3P (RO),P or R3As} is catalysed by [(q-C,H,R)Fe(CO)] (R = H or Me) or [(q-C5Me5)Fe(C0)2]'34 whilst that between [Fe(CO)J and alkyl- isocyanides RNC to give [Fe(CO),CNR] is catalysed by hydrated cobalt(I1) ch10ride.I~~ The preparation of a pentakis(phosphine)iron(o) complex has been effected by a reductive elimination process.Thus reaction of [(Me,P),(H)FeBr] with Li[HC(PMe,),] gave [Me3P),(H)FeCH(PMe,),1 which rearranged to give [(Me3P)3Fe(PMe2)2CH2].'36 The molecular structures of two alkene phosphine iron carbonyl complexes [Fe(PPh3(CO)2L] (L = q2-diethylfumarate or q ,-diethylmaleate) have been determined. 137 The tetra-azabutadiene derivative [Fe(CO)(PMe,),(N,Me,)] is fluxional in solution in the temperature range 298-473K as observed with the help of 'H n.m.r.13* Irradiation of pentacarbonyliron adsorbed on SiO afforded [Fe3(C0)12] rather than [Fe2(C0)J as is the case in ~olution.'~~ Anionic radicals of the type [alkene-Fe(C0)3]7 (alkene = methylmaleic anhydride) are sufficiently stable to be characterized using e.~.r.'~' Two di-iron phosphine carbonyls that contain met h ylaminobis(dimethoxyp hosp hine) have been prepared.These are [Fe2( CO),L] and [Fe2(CO),L2]. The molecular structure of the former has been determined by X-ray methods; this is depicted in (11).The phosphine is thus established as a bridging chelate.',' (11) The dinuclear complexes of o-phenylenebisdimethylarsine [Fe2(C0)7L] and [Fe2(CO)8L] have been prepared by the thermal method. The molecular structure of the former compounds as established by X-ray analysis is depicted in (12). This compound is fluxional in solution (varytemp I3C n.m.r.) showing CO migration that is rapid at 284 K.142 The synthesis characterization and ligand substitution reac- 133 P.K. Baker K. Broadley and N. G. Connelly J. Chem. Soc. Dalton Trans. 1982,471. 134 M. 0.Albers N. J. Coville and E. Singleton J. Organomet. Chem. 1982 232 261. M. 0.Albers. N. J. Coville and E. Singleton J. Chem. SOC.,Dalton Trans 1982 1069. H. H. Karsch Angew. Chem. 1982,94,322. I" M.V.R.Stainer and J. Takats Inorg. Chem. 1982 21 4044. '38 C. E.Johnson and W. G.Trogler Znorg. Chem. 1982,21,427. 139 R. L. Jackson and M. R. Trusheim J. Am. Chem. Soc. 1982,104,6590. I4O P. J. Krusic and J. S. Filippo jun. J. Am. Chem. SOC.,1982,104 2645. 14' G. M. Brown J. E. Finholt R. B. King J. W. Bibber and J. H. Kim Znorg. Chem. 1982 21 3970. W. I. Bailey A. Bino F. A. Cotton B. W. S. Kolthammer P. Lahuerta P. Puebla and R. Uson Inorg. Chem. 1982 21 789. 14' Fe Co Ni 241 0 ,I o=c (13) (12) tions of the p-phosphido complexes [Fe2(PPh2),(CO),] and Naz[Fez(PPh2)2(CO)6] have been a~hieved.’~ A new type of zerovalent iron compound has been prepared using an iron atom co-deposition method.This is [q6-(C6H5Me)Fe(bipy)] (biby = 2,2’-bipyridyl). The molecular structure was determined and is shown in (13).144 The reaction between [Fe(C0)4(H)SiPh3] and different nucleophiles L (L = CO PPh3 AsPh, SbPhs Ph,P(CH,),PPh, or P(Et) has been studied. With Ph,P the product is [Fe(CO),(H)(SiPh,)(PPh,)].It has the structure (14). 145 Irradiation of Fe(CO) Ph Ph Ph3P’ 1 ‘SiPh? ’SiPh CO (14) (1.5) (16) in the presence of PhSiH yields the dimer (15). This on treatment with dimethyl- ethyne gives the binuclear complex (16).A mononuclear derivative (17) is the product if diethylethyne is the reagent. The molecular structures of compounds (17) (16) and (17) were established by X-ray A bimetallic iron carbonyl [Zn(Fe(CO),),]’-has a linear Fe-Zn-Fe A detailed analysis of the 57 Fe Mossbauer spectral parameters of some forty derivatives of the type [LFe(CO),] has been carried 143 J. P. Collman R. K. Rothrock R. G. Finke E. J. Moore and R. Rose-Munch Inorg. Chem. 1982 21 146. 144 L. J. Radonovich M. W. Eyring T. J. Groshens and K. J. Klabunde J. Am. Chem. SOC.,1982,104 2816. 145 G. Bellachiomer and G. Cardaci Inorg. Chem. 1982 21 3232. 146 F. H. CarrC and J. J. E. Morean Inorg. Chem. 1982,21,3099. 14’ C. G. Pierpont B. A. Sosinsky and R.G. Shong Inorg. Chem. 1982,21 3247. 148 B. A. Sosinsky N. Norem and R. G. Shong Inorg. Chem. 1982 21,4229. 242 B. W. Fitzsimmons Compounds that contain the [q-CpFe(CO),] Fragment.-The alkenyl complexes are transformed into carbene complexes Me [q-C~(co)~Fe== 3 R by treatment with HBF4. Either [q-Cp(C0)2Fe-C(Me)=CHz] or [q-Cp(CO)2Fe-C(OMe)Me2] give [q-Cp(CO)2Fe=CMe2]’BF; after treatment with HBF4 at 250K. This carbene complex rearranges at 262K to [q-Cp(CO)2Fe-CH2=CHMe]’BF4. Reaction of the carbene complex with P(OMe)3 at 253 K yields q-Cp(C0)2FeC[P(OMe)3Me2]+BFi. 14’ A potential carbene precursor [q-Cp(CO)2FeCH2SMe2]+[FSO]-has been pre- pared in one simple sequence from [CpFe(CO)2]2. Its molecular structure has been determined by X-ray methods and the bond parameters especially the Fe-C distance analysed with a view to understanding incipient carbene reactivity.”’ The carbene complexes (18) have been prepared by a rational synthesis in which the r A i+ 1’ (18) L = CO or PPh3 R = Me Et or CHMez corresponding iron alkanoyl derivative is the starkg substance.These carbene complexes are too unstable to be directly detected but the products of decomposition have been characterized. Thus some undergo H-migration to give alkene com- plexes e.g. (18) (L = CO R = Et; L = CO R = CHMe2) rearrange to (19) (L = CO R’= Me R2 = H; L = CO R’= Me R2= Me) respectively. If (18) (L = CO R = Me) is generated in the presence of an alkene then ethylidene transfer occurs to give good yields of methyl cyclopropanes.This may be a good synthetic method for these latter The molecular structures of a pair of carbene complexes (20) and (21)have been determined. The spectroscopic results for these and related compounds are consistent with the carbene being a strong electron donor to iron back bonding being relatively unimportant.’” The new compounds [q-(CsMe5)Fe(CO)3]’PF and K’[q-(CsMe5)Fe(CO)2]- have been pre- pared respectively by the action of AlC1,-CO upon [q-(C5Me5)Fe(CO)2Br] at 40 atmospheres pressure and by reduction on a potassium mirror in THF at 293 K.153 149 K.A. M. Kremer Gee-Hong Kwo E. J. O’Connor P. Helquist and R. C. Kerber I. .4m. Chem. Soc.,1982,104,6119. E. J. O’Connor and P. Helquist J. Am. Chem. SOC.,1982,104 1869.’” C. P. Casey W. H. Miles H. Tukada and Y. M. O’Connor J. Am. Chem. Soc. 1982,104,3761. P. E. Riley R. E. Davis N. T. Allison and W. M. Jones Inorg. Chem. 1982,21 1321. D. Catheline and D. Astruc J. Organomet. Chem. 1982.226 C52. Fe Co Ni 243 The reaction sequence (22)+(24) leads to a planar [FeC2S2] metallacycle the structure of which has been determined by X-ray method^.'^^ The iron carbonyl Ph (24) hydride (25) disproportionates by way of the formyl derivative (26) to the methyl complex (27). This unexpected outcome was explained in terms of the mechanism a I f PPh2 (25) of Cannizzaro and related H-shift reaction^."^ Optically active enantiomers (28) have been prepared by the HF cleavage of the aminophosphine derivative (29) having the S configuration at the asymmetric C atom.”6 The heterodinuclear complexes (30) have been synthesized.In the case of the iron-rhenium derivative and in certain reaction conditions a compound with (28) (29) (30) M = Mn or Re 154 E. Roman D. Catheline D. Astruc P. Batail L. Ouahab and F. Varret J. Chem. SOC. Chem. Commun. 1982,129. 155 S. G. Davies J. Hibberd and S. J. Simpson J. Chem. SOC.,Chem. Commun. 1982 1404. 156 H. Brunner M. Muschiol and M. F. A. Dove J. Chem. SOC.,Dalton Trans. 1982,8 1527. B. W. Fitzsimmons structure (31)was isolated. This could be methylated at the unco-ordinated sulphur using MeOS02CF3 as methylating agent.ls7 (31) Other recent papers on compounds containing the [q5-CpFe(CO),] fragment are listed below (Table 3 158-162 1.Table 3 Other papers on compounds that include the fragment [q-CpFe(CO),] Compound [q-CpFe( CO)LL'] L' = e.g. SnPh3 oct-1-ene) [q-CpFe(CO)-,]+and related [q-C~Fe(Co)~l~and related (L = CO PPh3 compounds compounds SubjectSolution photolysis Calculation of I3cparamagnetic LiAlH4 reduction -hydrocarbonsshielding Ref. 158 159 160 0 Adduct formation at S with HgX2 etc. 161 162 Ferrocene its Derivatives and [(q-Cp)(q-arene) Iron] Compounds.-The equili-brium geometries of ferrocene and decamethylferrocene have been calculated using the Hartree-Fock method. The calculated metal-ring distances are some 15'/o larger than the observed values in both cases raising doubts as to the usefulness of this pr0~edure.l~~ The electronic energy levels of bis(pentadienyl)iron [(C5H7)*Fe] have been investigated by means of a semi-empirical L.C.A.O.calculation in conjunction with the He" photoelectron spectrum. A significant rotational barrier is predicted and the origin of the preference for the trans structure in the gas phase is in~estigated.'~~ Is' L. Busetto A. Palazzi and M. Monari J. Chem. SOC.,Dalton Trans. 1982 1631. "13 L. Carlton W. E. Lindsell and P. N. Preston J. Chem. SOC.,Dalton Trans. 1982 1483. D. A. Brown J. P. Chester and N. J. Fitzpatrick Inorg. Chem. 1982,21 2111. I6O M. M. Harris J. D. Atwood M. E. Wright and G. 0.Nelson Inorg. Chem. 1982 21,2117. M. H. Quick and R. J. Angelici Inorg. Chem. 1982,21 1674. 162 J. R. Moss J. Organomet. Chem. 1982 231 229.163 H. P. Luethi J. H. Ammeter J. Almlof and K. Faegri jun. J. Chem. Phys. 1982,77 2002. 164 M. C. Boehm M. Ackert-Maksic R. D. Ernst D. R. Wilson and R. Gleiter J. Am. Chem. Soc. 1982,104,2699. Fe Co Ni 245 The synthesis of triferrocylamine [N((C5H4)(C5H5)Fe},] has been rep~rted.'~~ The structure of biferrocene (32) has been redetermined using X-ray methods it proved impossible to elaborate a structural model which accounted for all the observed electron density. Unexplained peaks are believed to be the remains of a low-temperature phase. 166 1,l'-dicyanoferrocene has been utilized as a N-donor ligand in the preparation of the ruthenium complexes [Ru(NH~)~Fc'](PF& and [Fc'{Ru(NH~)~}z](PF~)~. Products of oxidation of these are mixed-valence corn pound^.'^^ The rate of reduction of ferricenium by ferrocytochrome c has been determined.The reaction is 1st-order in both reactants and the results were used to calculate a cytochrome c exchange rate-constant.'68 I I I\ Fe Fe JJiMe2 -_ A reagent that has been used to coat platinum electrodes is the ferrocenophane (33). Solid-state I3C and 29 Si n.m.r. has been deployed in the characterization of these surface ~0atings.l~~ An effort has been made to produce photoelectrochemi- cally useful n-type silicon surfaces using a wide range of ferrocenophanes similar to (33).I7O A family of ferrocenyl-substituted methylidyne tricobaltnonacarbonyls have been synthesized e.g. (34). Other members of the family carry phosphine substituents on cobalt e.g.(35). Stoicheiometric oxidation of this with AgPF6 gives a green solution of a mixed valence compound which exhibits a broad band at 1545 nm I Fe I I (a) R'=H R'=H (b) R'=OAc Me; R2= H (c) R'= H R2 = OAc M. Herberhold M. Ellinger U. Thewalt and F. Stollmaier Angew. Chem. 1982,94 70. 166 J. C. A. Boeyens E. W. Neuse and D. C. Levendis S. Afr. J. Chem. 1982,35,57. N. Dowling and P. M. Henry Inorg. Chem. 1982,21,4088. 16* J. R. Pladziewicz and M. J. Carney J. Am. Chem. SOC.,1982,104 3544. 169 A. B. Fischer J. A. Bruce D. R. McKay G. E. Marciel and M. S. Wrighton Inorg. Chem. 1982 21 1766. A. J. Blake F. R. Mayers A. G. Osborne and D. R. Rosseinsky J. Chem. SOC.,Dalton Trans. 1982 2379. B.W. Fitzsimmons typical of an intervalence tran~ition.'~~ The ferrocenyl group has been introduced into the six- and eight-membered P-N ring systems. Compounds such as N,P,F,Fc and N4P4F7Fc have been isolated and the molecular structure of the first of these has been dete~rnined.'~' Phosphorus- and arsenic-bridged [llferrocenophanes have been prepared from 1,l'-dilithioferrocene by reaction with RMClz (R = Me Ph; M = P R = Ph; M = As).'73 The preparation of a tetrabridge ferrocenophane trimer (36) has been achieved and its molecular structure has been established by -$ I X-ray diffra~ti0n.I~~ A range of 1,3-diselena-[3 Jferrocenophanes of C Si and Sn has been synthesized and the structure of one example confirmed by an X-ray diffraction A method for increasing the carbon chain of multibridged ferrocenophanes having carbonyl groups next to the cyclopentadienyl ring has been elaborated.The reagent is diazomethane with BF,.Et,O as Some reac- tions of azaferrocene lead to the conversion of the hetero ring into a 7-pyrryl group e.g. (37) + (38). Treating (37) with arene-AICI mixtures affords [(arene)Fe(Cp)]' (38) L = RNC CO or R2NPFr specie^.'^' The methyl substituted diphospha ferrocene (39) undergoes the reaction sequence (39) + (40) -+ (41). The molecular structure of the benzoyl derivative was determined using X-ray methods; the bond distances are compatible with a zwitterion q4-structure as used in the S~herne.'~' ''I S. Colbran B. H. Robinson and J. Simpson J. Chem. SOC. Chem.Commun. 1982 1361. ''' P. R. Suszko R. R. Whittle and H. R. Allcock J. Chem. Soc. Chem. Commun. 1982,960. 173 D. Seyferth and H. P. Withers jun. Organometallics 1982,1 1275. M. Hisatome Y. Kawajiri K. Yamakawa K. Mamiya Y. Harada and Y. Iitaki Inorg. Chem. 1982 21 1345. A. G. Osborne R. E. Hollands R. F. Bryan and S. Lockhart J. Organomet. Chem. 1982,226 129. M. Hisatome Y. Kawajiri and K. Yamakawa J. Orgunomet. Chem. 1982,226,71. A. Efraty N. Jubran and A. Goldman Inorg. Chem. 1982 21 868. B. Deschamps J. Fischer F. Mathey A. Mitschler and L. Ricard Organomerallics 1982.1.312. Fe Co Ni 247 Me Me a P LiCMe ROC1 I I A ____* Fe-(39) (41) R=Me or Ph Turning to the subject of [CpFe(arene)] chemistry a review of which has been p~blished,”~ mention must first be made of iron(1) derivatives such as (42) which have received a good deal of attention during the report period.This compound reacts with dioxygen at -10 “C to give the iron(I1) compound (43).Here the N-H bonds have been activated by 0,consistent with electron transfer 0,+0,’The complex (43) reacts with CO to yield (44).18’ I I Me Fe Me Me&NH2--Me% -_-Me Me Me N-H Me (42) (43) (44) The methyl groups in the arene rings of the 18-electron Fe” complex cation [(77-Cp)Fe(s-CsH,Mee_,)]’ are sufficiently nucleophilic for chain lengthening in the presence of alkyl halide/Bu‘OK mixtures. A typical reaction is (45; R = Md-BU‘OK Me) ____* (45; R = Et). The molecular structure of the latter compound has been determined the hexaethyl benzene adopts an unusual conformation due to steric interaction with the neighbouring Cp ring.Another aklylation is (45; R = PhCHZX(X=CIor Br) (45; R = (CH2),Ph). Photolysis of this gives a new hydrocar- ButOK bon C6{(CH2)2Ph}6. It is clear that a range of substituted benzenes are accessible I i PFt I RR H (45) A (46) ‘” W. E. Watts Organomet. Chem. 1982.10.283. P. Michaud and D. Astruc 3. Chem. Soc. Chem. Commun. 1982,416. B. W.Fitzsimmons by way of this roufe.lB1 Conversions e.g. (45; R = H)-(46)NaBH4 or LiAlHI have long been regarded as involving nucleophilic attack by hydride ion on the arene ring. It has now been conclusively shown that the reaction involves electron transfer (ET) followed by atom transfer.Thus the 19-electron Fe' compounds e.g. (47) I Fe' are intermediates in this process and were isolated where possible by quenching the low-temperature reaction. If the intermediates were too unstable for isolation they were identified spectroscopically (e.p.r. and Mossbauer). In this way a new seam of [CpFe(arene)] chemistry has been opened up. The compound [( r)-Cp)Feq-(C,Et,)]' gives [r)4(CsH6)Fe0q6[CgEt6)] and [q6-(C6Me6)2Fe]2'(PF6) gives [(r)6-C6Me6)Fe0(q4- C6Me6H2)] in which both incoming hydrogens are exo.Ig2Variable temperatures e.p.r. results for the 19-electron iron(1) complexes [(q5-CsHs)Fe(q6- C6H6)] and [(q6-c6Me6),Fe]PF6 are consistent with a d7 configuration for the iron with the unpaired electron in a mainly metal centred (d,, dyz)molecular 0rbita1.l~~ 2 Cobalt Low-oxidation-state Compounds.-Stable trimethylphosphite complexes of zero- valent cobalt [Co{P(OMe),),] and [CO~{P(OM~)~}~] have been isolated after reduc- tion of cobalt(r1) chloride in the presence of (Me0),P.lg4 Cobalt compounds [CoL{P(OR),},] (L = ethylfumarate or maleic anhydride R = Me Et or CHMe2) have been prepared and the molecular structure of one of them (L = maleic anhydride; R = Me) was determined and found to have low-symmetry four-co-ordination with q ,-alkene.lB5 Two compounds (48) and (49) were isolated after the reaction of [CoBr(Me,P),] with diphenylethene and + + PMe3 X- X- Ph Ph (49) '*'J.-R.Hamon J.-Y. Saillard A. Le Benze M. J. McGlinchey and D.Astruc J. Am. Chem. SOC. 1982,104,1549. 18' P. Michaud D. Astruc and J. H. Ammeter J. Am. Chem. SOC.,1982 104,3755. M. V. Rajasekharan S. Giezynski J. H. Ammeter N. Oswald P. Michaud J. R. Hamon and D. Astruc J. Am. Chem. SOC.,1982,104,2400. E. L. Muetterties J. R. Bleeke Z.-Y. Yang and V. W. Day I. Am. Chem. SOC.,1982 104 2940. G. Agnts J. C. J. Bart C. Santini and K. A. Woode J. Am. Chem. Soc. 1982 104 5254. Fe Co Ni 249 sodium tetraphenylboron in acetonitrile The reaction of copper(1) bromide with the complex [(triphos)CoP,] gives the copper cluster (50) a hexagonal r (50) copper fragment.187 Cobalt compounds with halogenomercurato ligands [C1HgCoL4] and [B~H~CO(CO)~L~]L = (Ph0)3P were prepared by the reaction HgX2 + HCoL -+ XHgCoL + HX.lg8 An example of a thionitro complex is provided by the square-pyramidal cobalt(1) complex [CO(NSO)C~~{P(OP~),}~].~~~ The enthalpy changes for oxidative additions have been measured for the reactions M(Ph2PCH=CHPPh2),'BF,- + chlorobenzoquinone -P ML2L' (L' = 3,4,5,6-tetra- chlorocatecholate M = Co Rh or Ir) for the cobalt example -AHHo= 19.6 f 1kJm~l-'.'~' Turning now to mononuclear carbonyls of cobalt a study of the vibrational spectra of the hydrides and deuterides [H(D)Co(CO)J has been reported.Isotope effects in the carbonyl region of the infrared spectra were observed the authors suggest that the energy factoring of Co-CEO and CO-H stretching modes is an unwise procedure.'" The photolysis of [HCO(CO)~] has been studied using matrix isolation techniques.Infrared spectroscopy was deployed in sorting out the photo- lytic processes and a factored force-field fit of the parent compound was achieved.192 The addition of CO and MeOH to butadiene is catalysed by a Co,(CO) :pyridine mixture. It has now been shown that the cobalt compound [MeO-CO-Co(CO),] adds to butadiene at 25 "C (Scheme). Treating this ally1 complex (51) with < +MeO-C H0 COOMe /CH2 \CO(CO)4 (-COKOh (51) B. Capelle A. L. Beauchamp M. Dartiguenave and Y. Dartiguenave J. Chem. SOC.,Chem. Commun. 1982,566. '13' F. Cecconi C. A. Ghilardi S. Midollini and A. Orlandini J. Chem. SOC.,Chem. Commun. 1982,229. L. B. Anderson H. L. Conder R. A. Kadaroski C. Kriley K. J. Holibangh and J. Winland Inorg. Chem. 1982,21,2095.R. D. Tiwari K. K. Pandey and U. C. Agarwala Inorg. Chem. 1982 21 845. J. V. Mondal R. Bulls and D. M. Blake Inorg. Chem. 1982 21 1668. 191 H. W. Walker and P. C. Ford Znorg. Chem. 1982,21 2509. 19* R. L. Sweany Inorg. Chem. 1982 21 752. B. W. Fitzsimmons (P~H)[CO(CO)~] gives the normal product (MeCH=CHCH2C02Me) thus provid- ing a basis for new proposals for the mechanism of the carbalkoxylation of alkene~.'~~ Acylcobalt complexes e.g. MeCOCo(CO) react with butadiene to yield (52). This reacts with sodium dimethylmalonate in an alkylation at the unsubstituted r-ally1 terminus to give (53)providing an overall 1,4-acylation-alkylationof 1,3-dienes.lg4 The addition of ethene to [CoBr(PMe,),] can be followed by means of ('Me 0 (':e :,CO(CO)4 (52) CH(COOMe)2 (53) 'H n.m.r.at low temperatures. The product is the diamagnetic species (54).195Both q '-and 7'-benzylcobalt carbonyls result from the reaction of Na[Co(CO),] with benzyl and phenylacetyl chlorides e.g. P~CH,CO(CO)~ and P~CH,COCO(CO)~ the q3-benzyl (55).Ig6 C02Me AYMe3 Me02C ,Co-PMe3 Me3P ! Me02C qI12Me PMe3 Ph The syntheses of [q-(C5Mes)2C~]n(PF6)n = 0; n = 1)have been described.19' (n The molecular structures of four [q-CpCo(diene)J complexes have been determined the dienes being PhCH=CPhCPh=CPhSiEt, NCCH= CHCPh=C(C02Me)CHC02MeCH2COzMe and the cyclic diene (56).198 Water splitting has been effected in an electrochemical process utilizing [(q-C5H4C02H)2Co]+ The iodo complex (58) or [Co(sep)J3' (57) as electron ~e1ays.l~~ 193 D.Milstein and J. L. Huckaby,J. Am. Chem. Soc. 1982 104 6150. 19* L. S. Hegedus and Y. Inoue J. Am. Chem. Soc. 1982,104,4917. 19s B. Capelle A. L. Beauchamp M. Dartiguenave. Y. Dartiguenave and H.-F. Klein I. Am. Chem. SM.,1982,104,3891. V. Galamb and G. Palyi J. Chem. Soc. Chem. Commun. 1982,9,487. '97 J. L. Robbins N. Edelstein B. Spencer and J. C. Smart J. Am. Chem. SOC.,1982,104 1882. lq8 Y. Wakatsuki. K.Aoki and H. Yamazaki. J. Chem. SOC..Dalton Trans. 1982 89. 199 V. Houlding. T. Geiger V. Kolle and M. Gratzel J. Chem. SOC. Chem. Commun. 1982 681. Fe Co Ni 25 1 mimics an alkyl iodide in an Arbuzov reaction on trimethylphosphite yielding (59) as product. A trimethylphosphite adduct is an intermediate in this process as in the original Arbuzov reaction.200 Some related work from the same laboratory is the reaction of [q-CpCo12(CO)]on P(OMe)3.Products isolated and include the adduct [~-C~COI,{P(OM~)~)] an Arbuzov product [q -CpCo{P(0)(OMe)2}2{P(OMe)3}] the structure of which was confirmed by X-ray methods.2o1 The 59C0 nuclear quadrupole resonance spectra of cyclopentadienyl- cobalt complexes e.g. [q-CpCo12(CO)] and related compounds have been recorded and analysed using an electrostatic One-electron oxidation of the 18-electron compounds [q-CpCoL,] affords stable paramagnetic salts [q-CpCoL,]'BF,- (L = tertiary phosphine phosphite). Meta- thesis of [LzCoXz] (X = halogen) with Tl'Cp- gave q-CpCoXL which on treat-ment with T1+BF4- gave [q-CpCoL,]+BF,-.The latter was oxidized to a 16-electron diamagnetic complex [~-C~COL~]~' (BFq-)2.203 The 1,l'-bicobaltacene Co"'Co"' (60) has been prepared and its structure deter- mined.204 Two isomeric compounds [q-CpCoL(PPh,)] (L = 1,4-dicyanobutane TCNQ = tetracyanoquinodimethane (60) (61) 1,4-diyl) have been prepared and their molecular structures determined. They are 1,4-dicyanocobaltacyclopentanesand the isomerism is of the cis-trans type.205 Compounds of the type [q-CpCo(q-CpZn),(PPh3)] have been prepared by the reaction of [CpzZn] with the appropriate hydride. The molecular structure of the example has been determined and it is seen to involve essentially tetrahedral Sulphur(1v) oxide is extruded from the q4-thiophene 1,l-dioxide in the sandwich compound (61) to yield the cyclobutadiene complex (62).'07 0 I co Me (62) 'O0 S.J. Landon and T. B. Brill J. Am. Chem. Soc. 1982,104,6571. '01 D. K. Towle S. J. Landon,T. B. Brill and T. H. Tulip Orgunometullics 1982 1 295. 'O' T. B. Brill S. J. Landon and D. K. Towle Znorg. Chem. 1982 21 1437. '03 R. J. McKinney Znorg. Chem. 1982 21 2051. C. Lau P. Singh S. J. Cline R. Seiders M. Brookhart W. E. Marsh D. J. Hodgson,and W. E. Hatfield Znorg. Chem. 1982 21 208. *OS Y. Wakatsuki T. Skaurai and H. Yamazaki J. Chem. SOC.,Dalton Trans. 1982 1923. '06 P. H. M. Budzelaar J. Boersma G. J. M.Van Der Kerk A. L. Spek and A. J. M. Duisenberg Znorg. Chem. 1982,21 3777. '07 J. S. Drage and K. P. C. Vollhardt Organomerallics 1982 1 1545.252 B. W. Fitzsimmons Cobalt(I1) Compounds.-A range of complexes of N-vinylimidazole [Mviz,]SiF have chain structures with bridging SiF6 groups i.e. trans [-M(N,F,)]. The molecular structure of the cobalt(I1) example has been determined by X-ray diffraction as has its relationship with the Mn Fe Ni Cu and Zn analogues. Magnetic susceptibility results indicate weak antiferromagnetic coupling.208 The molecular structures of the complexes [M2(Py)(acac),] and [Ni,(pip),(acac),] (M = Co Ni; Py = pyridine pip = piperidine acac = acetylacetonato) have been determined. They are face-sharing and edge-sharing octahedra respecti~ely.~'~ The cage complexes [Co(sep)]"+ (n = 2 or 3; sep = 1,3,6,8,10,13,16,19-octa-azabicyclo[6.6.6]eicosane) have been prepared.The molecular structure of the cobalt(I1) derivative [Co"sep]S206.H20 was determined and the redox properties electronic spectra rotatory dispersion circular dichroism and magnetic suscep- tibilities measured or recorded. The cobalt(II)-cobalt(IrI) self-exchange is unusually rapid.210 Much preparative work has been put in on the synthesis of a new terdentate ligand tris(2-pyridy1)methane; its cobalt(I1) and cobalt(II1) complexes were pre- pared and characterized.21' A number of imidazole complexes of Co" have been prepared and their structures solved. The general formula of these complexes is [Co(RCOO),L2] (R = alkyl L = imidazole). The structures were found to be either trans-octahedral [CoN204] with bidentate carboxylato groups or tetrahedral [CoN202] with monodentate carboxylate~.~~~~~~~ The e.p.r.spectra of a series of low-symmetry five-co-ordinate cobalt(I1) complexes containing the 'tren' ligand have been recorded. These tren or tran-type ligands bond through four nitrogen atoms; here halogeno ions occupy the fifth co-ordination position in compounds [CoX(Me6tren)]Y or [CoX(np,)]Y X = C1 Br or I; Y = C1 Br I or BPh,; Me6tren = tris[:!(dimethylamino)-ethyllamine np3 = tris[2(diphenylphosphino)ethyl]amine. The spin Hamiltonian variables were sorted out using the angular overlap Formation constants have been measured for mono- and di-nuclear complexes of M" (M = Co Ni Cu or Zn) with the bistren ('cryptate') ligand. (Bistren = 7,19,30-trioxa-1,4,10,13,16,22,27,33-octa-azabicyclo[ll.ll.l The action llpentatria~ontane).~~~ of NaBH on [Co(terpy)Clz] (terpy = terpyridyl) gives [Co(terpy)(BH4)].The molecular structure of this compound is depicted in (63). Its magnetic moment is 1.01pugat 299 K falling to 0.7~~ at 78K and this is ascribed to temperature independent paramagnetism within a low-spin d6configuration. The infrared spec- trum is not that expected of a chelating BH group.216 The six-co-ordinate bis- terpyridyl series [Co(terp),]X,.nH,O (X= C1- Br- I- NO; or C10,; n = various) is an example of a spin crossover family i.e. a 2E 84T equilibrium as 208 R. A. Driessen F. B. Hulsbergen W. J. Vermin and J. Reedijk Inorg. Chem. 1982,21 3594. 209 M. B. Hursthouse M. A. Laffey P. T. Moore D. B. New P. R. Raithby and P. Thornton J.Chem. SOC.,Dalton Trans. 1982 307. 210 I. I. Creaser R. J. Gene J. Mac. B. Harrowfield A. J. Herlt A. M. Sargeson M. R. Snow and J. Springborg J. Am.Chem. SOC.,1982,104,6016. *11 D. L. White and J. W. Faller Inorg. Chem. 1982 21 3119. 212 W. D. Horrocks. J. N. Ishley and R. R. Whittle Znorg. Chem. 1982,21,3265. 213 W. D. Horrocks J. N. Ishley and R. R. Whittle Znorg. Chem. 1982 21 3270. *14 C. Benelli and D. Gatteschi Inorg. Chem. 1982,21 1788. 215 R. J. Motekaitis A. E. Martell J. Lehn and E. Watanabe Inorg. Chem. 1982 21,4253. 216 E. J. Corey N. J. Cooper W. M. Canning W. N. Lipscomb and T. F. Koetzle Inorg. Chem. 1982 21 192. Fe Co Ni 253 .'17carried out within the angular overlap approximation judged from the temperature dependence of the magnetic susceptibilities over the temperature range 300-4.2 K for all of the compounds listed above except the hemi-hydrated perchlorate which has some 60% high-spin character in the whole temperature range.A complete ligand-field treatment of this phenonomen was The square-pyramidal complexes [Co(L)(H20)I2+ (L = 1,4,8,1 l-tetramethyl- 1,4,8,11-tetra-azacyclotetradecane or tris(3,5 -dimethyl- 1-pyrazole) methylamine) exhibit 'H n.m.r. spectra consistent with a dissociative process [Co(L)(H20)] * [Co(L)(OH)]+ H' demonstrated by observing the pH dependence of the relaxa- tion time.218 Circular dichroic spectra of the [Cox,(-)-a-isospartine] (X = C1-or Br-) complexes have been recorded and discussed in terms of the dynamic ligand-polarization mechanism for the d-d transition probabilitie~."~ The rates of reaction of the oxidation of [Co(dmg),] (dmg = dimethylglyoximato) by dioxygen have been measured and the different phases of this complex process disen- tangled.220 Making and studying dioxygen complexes of cobalt(r1) continues to be of interest this year some pentadentate ligands e.g.(64) have been deployed in (64) this work. Preliminary work with this and several similar co-ordinating agents included the determination of protonation constants and formation constants with M2+(M = Co Ni Cu or Zn) using potentiometric measurements. Finally forma- tion constants of the cobalt(r1)-0 complexes were determined.221 The tetraphenyl- porphin ligand (TPP) has begun to feature in reports of cobalt(r1) chemistry.An [02-Co(TPP)-thiolate] system has been shown to produce superoxide 02-in a cyclic process.222 A Schiff-base complex [Co"L] {L = N,N'-ethylenebis(acety1acetonatoiminato)) has been prepared by the matrix isola- tion technique and the subsequent formation of a dioxygen adduct [CoL-O,] monitored by infrared and resonance Raman The pressure vari- ation of the rate of complex formation between Co2' and N-methyltetraphenylpor- 'I7 S. Kremer W. Henke and D. Reinen Inorg. Chem. 1982 21 3013. 218 I. Bertini G. Canti C. Luchinat and L. Messori Inorg. Chem. 1982,21 3426. 'I9 A. F. Drake S. J. Hirst R. Karoda andS. F. Mason Inorg. Chem. 1982 21 533. 220 L. I. Simindi C. R. Savage Z. A. Schelly and S. NCmeth Inorg. Chem. 1982 21 2765. 221 S. A.Bedell J. H. Timmond A. E. Martell. and I. MurasC Inorg. Chem. 1982 21 874. '*' H. Sakurai and K. Ishizu J. Am. Chem. SOC.,1982,104,4960. 223 M. W. Urban Y. Nonaka and K. Nakamoto Inorg. Chem. 1982 21 1046. 254 B. W. Fitzsimmons phin has been determined. The volumes of activation are positive as is consistent with a dissociative process.224 The compound [Co(TPP)] supported on TiOz is an efficient catalyst for the reduction bf either NO or CO by H2.225*226 The 13C and ‘H n.m.r. spectra of a range of cobalt(r1)-tetra-arylporphinatocomplexes have been recorded and assignments made.227 Axial ligation constants for [Co(TPP)] com- plexes show a marked solvent dependence.228 The photo-oxidation of the maleonitriledithiolate complexes [M(S,C,(CN),),]’- (M = Co” or Ni” has been in~estigated.”~ Some cobalt and nickel complexes [CoCl(L)]’BF;,0.8H20 and [NiCl(L)]’BF of the linear terdentate diphosphine diamine CH2[CH2P(Ph)(CHJ3NH2l2 have been prepared and their structures determined.They are both square pyramidal with axial chloride and planar [MP2N2].z30 Co-ordinated dithioformate suffers nucleophilic attack at carbon by R3P to yield231[(triphos)Co(S,C(H)PEt,}]BPh {triphos = (65)). The ligand (66) forms tetrahedral [CoLX2]I (X = C1 Br I or NCS) low-spin five-co-ordinate [CoL2X]C104 (X = C1 Br or I) and planar [COL~]C~O,.~~~ A cobalt(I1) complex containing the didentate chelate Et3PCS2 having the formula [LCo(S,CPEt,)]’+ (BPh,)’ {L = (65)) has been prepared and characterized. The sulphur chelate converts into an (S2C=X) system oq treating the complex with the appropriate chalcogen in the presence of alkoxide The molecular structure of [LCo( S2CSMe)]BPh has been determined the complex having been prepared from [LCo(S2C=S)] by reaction on i~domethane.’~~ The molecular structures of [CoC12(PPh3),] and [CoBr,(PPh,),] have now been determined by X-ray methods.A low temperature susceptibility study reveals Nkel temperatures of 0.21 f0.01 K and 0.25 f 0.01 K respectively. These critical points are associated with specific heat changes.235 Cobalt(II1) Compounds.-Peroxo-cobalt(II1) bonding has been investigated theoretically in the SCF Xa-SW approximation using a hypothetical model com- pound (67).236Efforts to effect syntheses of molecules of biological importance on cobalt centres have been made.Examples of this work are the synthesis of P-carboxy 224 S.Funahashi Y. Yamaguchi K. Ishihara and M. Tanaka J. Chem. SOC.,Chem. Commun. 1982,976. 225 I. Mochida K. Suetsuau H. Fujitsu and K. Takeshita J. Chem. SOC.,Chem. Commun. 1982 166. 226 K. Tsuji M. Imaizumi A. Oyoshi I. Mochida H. Fujitsu and K. Takeshita Znorg. Chem. 1982,21 721. 227 A. Shirazi and H. M. Goff,Znorg. Chem. 1982,21,3420. 228 D. P. Rillema C. M. Wicker jun. R. D. Morgan L. F. Barringer and L. A. Scism J. Am. Chem. SOC.,1982,104 1276. 229 D. M. Dooley and B. M. Patterson Inorg. Chem. 1982 21,4330. 230 L. G. Scanlon Y. Tsao K. Toman S. C. Cummings and D. W. Meek Znorg. Chem. 1982,21,2707. 231 C. Bianchini A. Meli F. Nuzzi and P.Dapporto J. Organomet. Chem. 1982 236 245. 232 A. L. Hale W. Levason and H. E. Tuttlebee Znorg. Chim. Acta 1982,60,73. 233 C. Bianchini A. Meli and A. Orlandini Angew. Chem. 1982,94,212. 234 C. Bianchini C. Mealli A. Meli and G. Scapacci J. Chem. SOC., Dalton Trans. 1982,799. 235 R. L. Carlin R. D. Chirico E. Sinn G. Mennenga and L. J. De Jong Znorg. Chem. 1982,21 2218. 236 J. G. Norman and P. B. Ryan Znorg. Chem. 1982 21 3555. Fe Co Ni 255 (67) aspartic starting from the cobalt(rr1) pentammine [CO(NH~)~O,CCHO]~' and that of (RS)-2- cyclopropylglycine (R)-proline and (S)-prolineZJ8 from the initial condensation of 5-bromo-2-oxopentanoic acid with the aquopentammine [CO(NH,),H,O]~'. The alkaline hydrolysis of A$,-[Co(N,)aa]"' (N4 = a chiral derivative of 3,7-diazanonane-l,9-diammine, aa = aspartate glutamate etc.)yields an epimerized mixture of complexes.An examination of the ratios A-SlA-27 for various amino-acids led to some proposals on the hydrolytic mechanism.239 Investigations continue of the possible resolution of racemic cobalt(rr1) complexes by chromatography on special clays. Some resolution of [C~(acac)~(glycinato)] and [Co(acac)(gly~inato)~] has been achieved using a clay column on which A-[Ni(~hen)~],+ ions have been A similar column has been used in a very efficient resolution of [~o(acac)J.~~* Ion association between halide ions and cis-[Co(en),X,]+ (en = 1,2-diaminoethane X = CN- NO; NCS- C1- or N; has been investigated by n.m.r. and difference circular dichroic spectra.The association is Alkene epoxidation can be brought about via catalysis by [(TPP)CoNO] (TPP = tetraphenylporphinato). An experiment with I8O2indicates that a nitro compound is the active epoxidizing agent.243 An n.m.r. study of [(TPP)CoX] compounds (X = C1 Br I PF6 or C104)reveals a small persistent fraction of a wcationic species. It is suggested that this is formed by a disprop~rtionation.~~~ Tetraphosphorus trisulphide has been used as the reagent for introducing a new ligand SP,. This is a cyclic four-electron donor as present in the complex [Co{MeC(CH2PPh2),}SP2]+BF; prepared by mixing Co(BF4), P4S3 and the triphos ligand. The structure of this complex was determined it is illustrated in (68),245 Me & Q =occupancy 0.67P and 0.33s 237 N.E. Dixon and A. M. Sargeson J. Am. Chem. SOC.,1982,104,6716. 238 P. J. Lawson M. G. McCarthy and A. M. Sargeson J. Am. Chem. SOC.,1982 104,6710. 239 M. Yamaguchi Y. Masui M. Saburi and S. Yoshikawa Znorg. Chem. 1982,21,4138. 240 A. Yamagishi and R. Ohnishi Inorg. Chem. 1982,21,4233. 241 A. Yamagishi Znorg. Chem. 1982 21 3395. 242 H. Nakazawa U. Sakaguchi and H. Yoneda J. Am. Chem. SOC.,1982,104,3885. 243 S. E. Diamond F. Mares A. Szalkiewicz D. A. Muccigrosso and J. P. Solar J. Am. Chem. Soc. 1982,104,4266. 244 J. Huet A. Gandemer C. Boucly-Goester and P. Boucly Znorg. Chem. 1982 21 3413. 245 M. Divaira M. Peruzzini. and P. Stoppioni J. Chem. Soc. Chem. Commun. 1982,894. 256 B. W. Fitzsimmons S-bonded sulphenato CoI’I complexes are shown to be co-ordinating agents to H’ or BF through oxygen and to palladium(I1) through the sulphur atom.246 The molecular structure of the cobalt(Ir1) complex (triphos)Co {S2C(H)PEt3} (BPhJ2 {etriphos = (69))has been determined (70).247 Me I L 1 ‘H Et/p, 1 Et Et Cobalt(Ir1) Compounds.-Properties of several compounds are shown in Table 4.248-265 Kinetic studies are shown in Table 5.266-293 246 J. D. Lydon and E. Deutsch Inorg. Chem. 1982,21 3180. 2*7 C. Bianchini A. Meli and A. Orlandini Inorg. Chem. 1982 21,4161. 248 A. Miyanaga U. Sakaguchi Y. Morimoto Y. Kushi and H. Yoneda Inorg. Chem. 1982 21 1387. 249 E. C. Niederhoffer A. E. Martell P. Rudolf and H. Clearfield Inorg. Chem. 1982 21 3734. R. Job P. J. Kelleher W. C.Stallings C. T. Monk and J. P. Glusker Znorg. Chem. 1982 21 3760. 251 A. Takehata Znorg. Chem. 1982 21 2496. 252 L. A. Meiske and R. J. Angelici Znorg. Chem. 1982,21 738. 2s3 L. A. Meiske and R. J. Angelici Znorg. Chem. 1982 21 731. 254 T. W. Wierenga and J. I. Legg Inorg. Chem. 1982 21 2881. ”’ Y. Nakano and S. Sato Inorg. Chem. 1982 21 1315. 256 D. R. Jones L. F. Lindoy A. M. Sargeson and M. R. Snow Inorg. Chem. 1982,21,4155. 257 F. Abraham C. Bremard B. Mouchel G. Nowogrocki and S. Sueur Inorg. Chem. 1982 21 3225. 2s8 M. Sato Y. Sato S. Yano S. Yoshikawa K. Toriumi H. Itoh and T. Itoh Inorg. Chem. 1982 21 2360. 259 L. R. Gahan T. W. Hambley A. M. Sarceson and M. R. Snow Znorg. Chem. 1982,21,2699. 260 K. Kashiwabara K. Katoh T. Ohishi J. Fujita and M.Shibata Bull. Chem. SOC.Jpn. 1982 55 149. 261 M. G. Patch K. P. Simolo and C. J. Carrano Znorg. Chem. 1982 21 2972. 262 G. J. Garrisford R. J. Gene and A. M. Sargeson J. Chem. SOC.,Chem. Commun. 1982,233. G. R. Brubaker and D. W. Johnson Inorg. Chem. 1982,21,2223. 264 D. J. Roger G. J. Grant D. G. Van Der Veer and M. J. Castillo Inorg. Chem. 1982 21 1902. J. D. Lydon R. C. Elder and E. Deutsch Inorg. Chem. 1982,21 3186. 266 J. L. Laird and R. B. Jordan Znorg. Chem. 1982 21,4127. 267 S. H. McClaugherty and C. M. Grisham Inorg. Chem. 1982,21,4133. W. Bottcher and A. Haim Inorg. Chem. 1982,21 531. 269 N. E. Dixon W. G. Jackson W. Marty and A. M. Sargeson Inorg. Chem. 1982 21,688. ’” J. L. Laird and R. B. Jordan Inorg. Chem. 1982,21,855. 271 K. Angermann R.Schmidt R. Van Eldik H. Kelm and F. Wagestian Znorg. Chem. 1982 21 1175. 272 A. C. Dash and G. M. Harris Znorg. Chem. 1982,21 1265. 273 Y. Sasaki K. Z. Susuki A. Matsumoto and K. Saito Inorg. Chem. 1982 21 1825. 274 D. H. Buckingham C. K. Clark B. M. Foxman G. J. Garrisford A. M. Sargeson W. Wein and A. Zanella Inorg. Chem. 1982 21 1986. 27s R. A. Holwerda and J. D. Clemmer Znorg. Chem. 1982,21,2103. 276 J. F. Glenister K. E. Hyde and G. Davies Inorg. Chem. 1982 21 2331. 277 A. C. Dash and G. M. Harris Znorg. Chem. 1982 21 2336. 278 V. S. Srinivasan A. N. Singh K. Wieghardt N. Rajasekar and E. S. Gould Inorg. Chem. 1982,21 2531. Fe Co Ni 257 Table 4 Compounds ofcobaEt(III) that have recently been studied Compound Ref. mer-[Co(H2NCH2C02)3J 248 cis-[Co(CO,)( bipy),]N03.5 H20(bipy = 2,2'-bipyridyl) 249 cis-[C0(CO~)(phen)~]Br*4H20 (phen = 1,lO-phenanthroline) 249 [Co(citrato)(tet)].5H20 (tet = triethylenetetra-amine) 250 [C~(phen)~-~Arn~]"+ (am = amino-acid anion) 25 1 [Co(N-cm-~-Hist)Am] (N-cm-L-Hist = N-(carboxymethy1)-L-histidinate} 252 [Co(N-cm-~-Pyala)Am] {N-cm-L-Pyala = N-carboxymethyl-L-&( 2-pyridyl)-a-alaninato} 253 [CO(NH,)~(~~CH)](CIO~)~ (nicH = nicotinic acid) 254 [(+)589-3-( 1 -Naphthyl)pentane-2,4-dionato] [tris( 2-aminoeth l)amine]cobalt(~r~)bis( te trafluorobora te)dihydrate 255 1 (CF3S03)2-2H20 rneso-[{Co(en)~(p-03POPh)}2]2 (en = 1,2-diaminoethane) 256 Me Mek-vO fa~-[Co(dmho)~] dmho = 257 VY (-)s46-truns-[Co(N03)2{(-)-2,2'-bipiperidine}2]X-(X-= d-bromocamp horsulphonate.4H20 258 (+)5 lo-[Co(azacapten)]ZnC14~Cl (azacapten = 1-methy1-3,13,16-trithia-6,8,10,19-tetra-azabicyclo[6.6.6]eicosane) 259 [CO(CN)~-~~(~C~C),(P)~]~"-~)+ (acac = acetylacetonato PGPPh, PMePh2 PMe2Ph or PMe3) 260 [CoLI- (L = ethylenebis{(o-hydroxyphen yl)glycine} 261 [CoL]ZnCI4C1(L = 3,11-dimethy1-7-nitro- 1,5,9,13,16,19-hexa- azatricyc10[9.3.3 3*7]icosane) 262 [CoL]CI3 (L = 3,ll -dimethyl-7,15 -dinitro- 1,5,9,13,18,2 1-hexa-azatricyclo[ 9.5.3.33*7]docosane 262 trans-[Co(3,2,3-tet)X2]+(3,2,3-tet = l,lO-diamino-4,7-diazadecan) 263 trans-[Co(2,3,2-tet)X2]' (2,3,2-tet = 1,9-diamino-3,7-diazononane,X = Br C1 N3 NH3 NOz or OAc) 263 [CO(L)](CIO~)~.H~O 1,4,8,11,15,18-hexa-azacycloheneicosane) 264 (L = AS(-)SS-[CO(~~)~(S(SCM~~CO~H)CM~~COZ}]~+(CIO~)~ (en = 1,2-diaminoethane) 265 279 V.S. Srinivasan N. Rajasekar A. N. Singh C. A. Radlowski J. C. K. Heh and E. S. Gould Inorg. Chem. 1982,21,2824. J. H. Espenson M.Shimura and A. Bakac Inorg. Chem. 1982,21,2537. R. Van Eldik J. Van Jouanne and H. Kelm Inorg. Chem. 1982 21 2818. V. Spitzer R. van Eldik and H. Kelm Inorg. Chem. 1982 21 2821. 283 J. L. Reed Inorg. Chem. 1982,21,2829. 284 A. Haim Inorg. Chem. 1982 21 2887. K. Wieghardt P. Chaudhuri B. Nuber and J. Weiss Inorg. Chem. 1982 21 3086. 286 V. Srinivasan S. W. Barr and M. J. Weaver Inorg. Chem. 1982 21,3154. 28' D. H. Buckingharn C. R. Clark and W. S. Webley Inorg. Chem. 1982 21 2353 G. A. Lawrence Inorg. Chem. 1982 21 3687. 289 V.S. Srinivasan and E. S. Gould Inorg. Chem. 1982 21 3854. 290 V. Spitzer and R. van Eldik Inorg. Chem. 1982,21,4008. 291 R. van Eldik Inorg. Chem. 1982,21 2501. 292 D. A. Buckingham J. D. Edwards and G. M. McLaughlin Inorg. Chem. 1982,21 2770. 293 S. Funahashi M.Inamo K. Ishihara and M. Tanaka Inorg. Chem. 1982,21,447. B. W. Fitzsimmons Table 5 Recent kinetic studies of cobalt(III)compounds Reaction studied Ref. [(H3N)&o(NH2SO3)I2+%reduced product related compounds also investigated 266 [(H3N)4Co(adenosine 5'-triphosphate)] product 267 [(H3N)5Co(pyridine)]3+ + MVt -B product 268 (MVt = methylviologen radical) [(H3N)5CoL]3' product 269 {L = (NH2)2CO Me2S0 (Me0)3PO} [(H3N),Co(OS03)]' %product 269 [(H3N)5CoL]%hydrolysis product 270 (L = NH2S02NH- p-MeC6H4So2NH- etc.[CO(CN)~]~-photoaquation product 271 H2O [(H3N)sCo(C204H)]2'-%binuclear complex 272 (C2O4H = oxalato) HI-H,O [(en)2(H3N)Co(p-O~-)Co(NH3)(en)2l4+ .) product 273 cis[Co(en)2(NH2CH2CN)X] [Co(en)(NH2(CH&NC(NH2)CH2NH2)XI2+ 274 (X = C1 or Br) Two isomers formed. Molecular structure of both chloro compounds determined + H+-H,O [(H~N)sC~(O~POC~H~~H)I b products 275 HI-H,O ECo(PY)2(co3)2l-b products 276 (py = pyridine) [(H3N)5Co(salicylato)]2+ %binuclear comp!+ex 277 or Eu2+ [(H3N)3Co(p-OH)2(g-RC02)C~(NH3)3]3+ product ' 278 (R = H CH3 CF3 F~Hs etc.) 279 R= a i~, etc. ' CONHz ' CONH2 [Co(NH3)6l3' or [Co(en),I3' products 280 [(H3N)sCo(OH)]2' + SO2-+ products 28 1 [(H3N)sCo(H20)]3' + C02-* products 282 cis-[C~(acac)~(NH~)(N~)l hv,products 283 [Co(CN),(H20)l2-&products 284 [LCO(~-OH)~COL]~+ %products 285 (L = 1,4,7-trimethyl-1,4,7-triazacyclononane) Au-Pe electrode [(H3N)5CoL13+Aelectroreduced product 286 {L = 4,4'-bipyridine 1,2-bis(4-pyridyl)ethane,trans-1,2- bis(4-pyridyl)ethene pyridine or pyrazine} [(H3N)&oN3I2+ H-products 287 [(H3N)sCoL]3' %aquation product 288 (L = neutral 0-donor.Pressure dependence of rates investigated. AV -0.3-3.8 cm3mol-') -product reducing agent [(H3N)3Co(p-OH)2(p-PhC02)C~(NH3)3]3+ 289 [(H3N)5Co(S03)]'hv,products 290 [(H3N)5C~(H20)]+ products 290 Fe Co Ni 259 Table 5-continued Reaction studied Ref. (H3N)5Ca(S03)2’%products [(H3N)5CoN3]2+%reduced complex 291 [Co(Metren)(NH,)(X)]“+ H20-oHi products 292 (Metren = 2-(methylamino)-2‘,2”-diaminotriethylamine,= halide} X [C~(porphinato)(H~O)~]+ SCN; product 293 (porphinato = anion of meso-tetrakis (N-methyl-4-pyridy1)porphine) Compounds that contain an alkyl-Cobalt(nr) Bond.-Crystals of the dimethylgly- oximato complex (71; R = (S)-cyanoethyl L = pyridine) undergo racemization on exposure to X-rays.The rates and their temperature variation were deter- mined.294 Another radiation study is one in which a series of derivatives (71) R = PhCH2 L = Py; R = Me L = Py; R = Me L = imidazole; R = Me L = H20; were exposed to gamma irradiation (“Co) at 77K. The decomposition processes were monitored using e.p.r. the dominant chemical process was reductive Co-C cleavage.295 (72) Using the compound (71) R = CH2CN L = Py; as a starting compound a procedure for the preparation of base-sensitive cobaloximes has been developed.296 The reactions of a wide range of compounds like (71) with trifluoroacetic acid have been investigated using n.m.r.With excess acid dealkylation takes place with the formation of (72).297The molecular structures of the compound (71) R = Me2CH L = MeC(CH,O),P; has been determined by X-ray The elec-trochemical oxidation and reduction of methylcobalamine and coenzyme B12 have (73) 294 Y. Ohashi K. Yanagi T. Kurihara Y. Sasada and Y. Ohgo J. Am. Chem. SOC.,1982,104,6353. 295 M. Hoshino S. Konishi Y. Terai and M. Imamura Inorg. Chem. 1982,21,89. 296 D. G. H. Livermore and D.A. Widdowson J. Chem. Soc. Perkin Trans 1 1982 1019. 297 N. W. Alcock M. P. Atkins B. T. Golding. and P. J. Sellars,J. Chem. SOC.,Dalton Trans. 1982 337. 29s N. Bresciani-Pahor,G. Nardin L. Randaccio and E. Zangrando. Inorg. Chim. Acra 1982,65 L143. 260 B. W. Fitzsimmons been inve~tigated.’~~ The kinetics of the transfer of methyl from compound (73) to Zn” or Cd2+ have been in~estigated.~” Cluster Compounds of Iron and Cobalt Homonuclear Iron Clusters.-A semi-quantitative procedure for assessing the magnitudes of steric effects in metal cluster compounds has been developed from the concept of a cluster cone angle. A table of these angles for some common M-L fragments is given.3o1 The vibrational spectra of M4 and M6 cluster systems have been theoretically investigated with regard to the effect of asymmetries in the distribution of either the force constants or the atomic masses upon degenerate vibrations.302 The butterfly carbido anion [Fe4(C0)12C]2- yields the tetrahedral species [Fe4(C0)12(p3-CMe)]- after treatment with the methylating agent MeS03CF3.The tetrahedral [Fe4(C0)12(~3- COMe)]- a tetrahe- CO)]’- species gives [Fe4(C0)12(p3- dral cluster after treatment with the same reagent. The molecular structures of two tetrahedral clusters [Fe4(C0)12CMe] were determined by X-ray methods. Whilst the requirement for a tetrahedral cluster is 60 valence electrons 62 is the number for a butterfly In contrast to the above instances wherein methylation was seen to take place on carbido carbon the reaction of MeS0,F with the square-pyramidal carbido cluster [Fe5(CO)14C]2- leads to methylation at a bridging carbonyl.This observation has been correlated with charge-density calculations which indicate a lack of electron density at the carbido carbon in these [Fe5C] clusters compared with the [Fe4C] butterflys which do undergo methylation at that point. The triangular [M3C] 48-electron cluster is predicted to have some stability and might be detectable.304 A spectroscopic (57Fe Mossbauer ESCA) investigation of a series of iron carbido clusters has been reported. These clusters include [Fe6(CO)10C]2- [Fe4(C0)12C]2- and 8-[Fe,C]. A trend of carbon charge- density with co-ordination number is established.,05 The adsorption of [Fe(CO)J or [Fe,(CO),,] on metal oxides has been investigated.On A1203 MgO or ZnO an ionic hydride [HFe3(CO),,] is formed.306 The preparation properties and structure determination of the cubane cluster [Fe,(NO),(p,-S),]-and of its neutral parent have been reported and the geometrical changes associated with the 0/-1 electron transfer couple have been worked out.,” A useful improvement in the preparation of derivatives by CO displace- ment from [Fe3(C0)12] or [Co,(CO),CCl] is one in which a catalytic quantity of the benzophenone radical anion is included with a stoicheiometric amount of the displacing base.,” Controlled potential electrolysis of solutions of the cluster (74) in the presence of P(OMe)3 affords displacement products [Fe3S2(CO)8-n (S2C3H2){P(OMe)3)n 299 K.A. Rubinson E. Itabashi and H. B. Mark Inorg. Chem. 1982,21 3571. 300 J. H. Dimmit and J. H. Weber Inorg. Chem. 1982 21 700. 301 D. M. P. Mingos Inorg. Chem. 1982,21,464. 302 J. A. Creighton Inorg. Chem. 1982,21 1. 303 E. M. Holt K. H. Whitmire and D. F. Shriver J. Am. Chem. SOC.,1982 104 5621. 304 J. W. Kolio F. Basolo and D. F. Shriver J. Am. Chem. SOC.,1982 104 5626. 305 B. A. Sosinsky N. Norem and J. Shelly Inorg. Chem. 1982 21 348. 306 F. Hugues J. M. Basset Y. Ben Taarit A. Choplin M. Primer D. Rojas and A. K. Smith J. Am. Chem. SOC.,1982,104,7020. 307 C. Ting-Wah Chu F. Yip-Kwai Lo and L. F. Dahl J. Am. Chem. SOC.,1982 104,3409. 308 M. I. Bruce D. C. Kehoe J. G. Matisons B. K. Nicholson P. H. Rieger and M. L. Williams J. Chem.SOC.,Chem. Commun. 1982,442. 309 A. Darchen C. MahC and H. Patin J. Chem. SOC.,Chem. Commun. 1982 243. Fe Co Ni 26 1 (74) Other homonuclear iron clusters to have been prepared and characterized this year are listed in Table 6.310-327 Table 6 Homonuclear iron clusters that have recently been characterized Fe Skeleton Other ligands Comment Ref. Fe-Fe CO RS,RHgs - 310 "SXS" (OC)3Fe-Fe(C0)3 - - 311 Preparation 312 0 F-CO,77-Cp Molecular structure 313 H CO \/ OC\ ,c FP Fe-Fe Molecular structure 314 0 310 C. Chieh D. Seyferth and L. C. Song Organometallics 1982 1 473. 311 G. Dettlaf P. Huebener J. Klimes and E. Weiss J. Organomet. Chem. 1982 229 63. 312 C. P. Casey P. J. Fagan and W. H. Miles J. Am. Chem. SOC.,1982,104 1134.313 G. M. Dawkins M. Green A. G. Orpen and F. G. A. Stone J. Chem. SOC.,Chem. Commun. 1982 41. 314 C. P. Casey P. J. Fagan and V. W. Day J. Am. Chem. SOC.,1982 104,7360. 315 D. A. Lesch and T. B. Rauchfuss Organometallics 1982 1,499. 316 A. B. Rives Y.Xiao-Zeng and R. F. Fenske Inorg. Chem. 1982 21 2286. 317 A. Winter L. Zsolnai and G. Huttner J. Organomet. Chem. 1982 232,47. J. A. S. Howell and P. Mathur J. Chem. SOC.,Dalton Trans. 1982 43. 3'9 J. W. Kolis E. M. Holt M. Drezdou K. H. Whitmire and D. F. Shriver I. Am. Chem. SOC.,1982 104,6134. 320 K. S. Wong K. J. Haller T. K. Dutta D. M. Chipman andT. P. Fehlner Znorg. Chem. 1982,21,3197. R. L. De Kock K. S. Wong and T. P. Fehlner Znorg. Chem. 1982,21 3203. 322 J. Doherty A. R. Manning and F.S. Stephens Inorg. Chem. 1982 21 3332. 323 M. I. Bruce T. W. Harnbley and B. K.Nicholson J. Chem. SOC.,Chem. Commun. 1982 353. 324 L. L. Nelson F. Y.K. Lo A. D. Rae and L. F. Dahl J. Organomet. Chem. 1982 225 309. 325 K. S. Wong W. R. Scheidt and T. P. Fehlner J. Am. Chem. SOC.,1982 104 111. 326 P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Chem. Commun. 1982,140. 327 H. Vahrenkamp and D. Wolters J. Organornet. Chem. 1982 234 C17. 262 B. W. Fitzsimmons Table 6-continued Fe Skeleton Other ligands Comment Ref. Fe Te CO Reactions with Lewis Fe’LFe bases 315 Fe Fe-Fe/\ s co M.O. study 316 Fe p-haiogeno Molecular structure /\Fe.-Fe p3-SCMe3 of chloro-compounds 317 Synthesis 318 II N R’ ‘R /, (OC)3Fe-.H\-Fe(C0)3\/ Synthesis 318 Molecular structure 319 Molecular structure 320 U.V. Molecular structure of c-hexyl derivative 322 Molecular structure Synthesis molecular structure 325 photoelectron spectroscopy M.O. theory 321 323 Synthesis molecular structure 324 -co,cL3-s co Fe Co Ni 263 Table kontinued Fe Skeleton Other ligands Comment Ref. I Molecular structure 326 P Me I Synthesis molecular structure 327 Me Homonuclear Cobalt Clusters.-The stability of r-bonded dicobalt complexes [co2(co)6(px2)] (X = N2,P2 S22+ or C2H2)has been investigated theoretically by means of comparative molecular orbital calculations based on the extended Huckel method.328 Isotopic labelling of the interstitial atom (C or N) in the trigonal prismatic hexacobalt clusters [co~(co)&]'-and [c~~(co),~N]-has led to the establishment of vibrational assignments of the Co-C and Co-N groups.329A paramagnetic ionic cluster [CO,~C,(CO),~]"-is the product of a diglyme reflux of [co6c(co)~~]2-.Its molecular structure was determined by X-ray methods.330 Other work on the subject of homonuclear cobalt clusters is summarized in Table 7.33 1-348 328 K.I. Goldberg D. M. Hoffman and R. Hoffman Inorg. Chem. 1982,21,3863. 329 J. A. Creighton R. D. Pergola B. T. Heaton S. Martinengo L. Strona and D. A. Willis J. Chem. Soc. Chem. Commun. 1982,864. 330 V. G. Albano D. Braga P. Chini G. Ciani and S. Martinengo J. Chem. Soc. Dalton Trans.1982 645. 331 S.Hayashida T. Kansamura and T. Yonezawa Inorg. Chem. 1982,21,2235. 332 B. E. Hanson P. E. Fanwick and J. S. Mancinila Inorg. Chem. 1982 21,3811. 333 L.M. Cirjak R. E. Ginsberg and L. F. Dahl Inorg. Chem. 1982,21,940. 334 W. Malisch H. U. Wekel I. Grob and F. H. Koehler 2.Nahrrforsch. Teil B. 1982,37 601. 335 M. Arewgoda P. H. Rieger B. H. Robinson J. Simpson and S. T. Visco J. Am. Chem. SOC.,1982 104,5633. 336 F. Wochner E. Keller and H. H. Brintzinger J. Organornet. Chem. 1982,236 267. 337 G. M. Brown J. E. Finholt R. B. King and J. W. Bibber Inorg. Chem. 1982,21 2139. 338 U.Koelle F.Khouzami and B. Fuss Angew. Chem. 1982,94 132. 339 K. H. Theopold and R. G. Bergman Organometaflics,1982,1 1571. 340 L.D. Hutchins R. W.Light and R. T. Paine Inorg. Chem. 1982 21,266. 341 B. E.Hanson P. E. Fanwick and J. S. Mancini Inorg. Chem. 1982,21,3811. 342 C. M. Arewgoda B.H. Robinson and J. Simpson J. Chem. SOC.,Chem. Commun. 1982,284. 343 W. A. Herrmann J. M. Huggins C. Bauer M. Smischek H. Pfisterer and M. L. Ziegler J. Organomet. Chem. 1982,226,C59. 344 G. Gaetan E. Tondello D. Ajo M. Casarin S. Aime and D. Osella Inorg. Chem. 1982 21 1081. 345 W. I. Bailey F. A. Cotton J. D. Jamesson and B. W. S. Kolthammer Inorg. Chem. 1982,21 3131. 346 D.E.Horn and K.P. C. Vollhardt J. Chem. SOC.,Chem. Commun. 1982 203. 3*7 G.Gervasio R. Ronetti P. L. Stanghellini and G. Bor Inorg. Chem. 1982,21 3781. 348 F. Cecconi C. A. Ghilardi and S. Midollini Inorg. Chim. Acta 1982.64 L47. N o\ Table 7 Homonuclear cobalt clusters that have recently been characterized or investigated P Cobalt skeleton Other ligands Comment Ref.co-co CO R3P R~As y-irradiation study 33 1 (oc),co-co(co) P-H P-PPh, Synthesis molecular structure 332 t-phosphine 0 n-II WCP rl-C5Me5 Synthesis molecular structure bonding theory 333 II 0 Synthesis characterization 334 R I C (OC)3CO-11I-c0(c0) Electrochemical reduction 335 C I R’ 0 !I cpco-cocp x-/N\ I+ Molecular structure 336 b’ 2 Me I 3 N (Me02)P/ ‘P(0Me)l I (0c)2~0-~0(c0)2 Synthesis molecular structure 337 3 P ,P(OMeh ‘N I Me X = NH2Cl Br or I Synthesis 338 00 II II Molecular structure 339 H,C ,CHZ CHz n MeN ,NMe oc ,p /co Synthesis molecular structure 340 ,co so, oc ,p co MeN NMe Synthesis molecular structure 341 bJ m LA B.W. Fitzsimrnons (u m d m \o Q d m d % m d m z z s ti 8 I I Fe Co Ni 267 N o\00 Ref. 349 349 structure structure molecular Commenr molecular Synthesis Synthesis 6’ ligands Other 349-prepared been recently have that compounds skeleton metal or cluster metaf Heteronucfear Compound PEt / ‘PEt3 Table OrC-Me OSB-H Fe Co Ni 269 C m In m + N m d m v m In m m m U e x v) -c 0 Y c t B. W. Fitzsimmons v, 3 v, Q cr \o v cr 2 Y 2 c v) & -1 e -0 E I-v, m 8 00 v cr 8 0 Y $ 3.Synthesis molecular structure. [FeRb(CO) 360 Table 8-continued p3 N Compound or metal skeleton Other ligands Comment Ref. Synthesis molecular structure. NiR~~(co)~(w-PPh~) (p&rCPr') 361 349 G. K. Barker M. P. Garcia M. Green F. G. A. Gordon A. Stone and A. J. Welch J. Chem. Soc. Dalton Trans. 1982 1679. 350 P. Brun G. M. Dawkins M. Green H. D. Miles A. G. Orpen and F. G. A. Stone J. Chem. SOC., Chem. Commun. 1982,926. 351 V. W. Day D. A. Lesch and T. B. Rauchfuss J. Am. Chem. SOC.,1982,104 1290. 352 S. Aime L. Milano D. Osella A. Tiripicchio and A. M. M. Lanfredi Znorg. Chem. 1982 21 501.353 M. J. Chetcuti P. A. M. Chetcuti J. C. Jeffrey R. M. Mills P. Mitrprachachon S. J. Pickering F. G. A. Stone and P. Woodward J. Chem. SOC., Dalton Trans. 1982,699. bf 354 F. W. B. Einstein B. H. Freeland K. G. Tyers D. Sutton and J. M. Waterous J. Chem. SOC.,Chem. Commun. 1982 371. 3 355 M. Green J. C. Jeffery S. J. Porter H. Razay and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1982 2475. 356 S. P. Foster K. M. Mackay and B. K. Nicholson J. Chem. SOC., Chem. Commun. 1982 1156. 3 357 M. R. Churchill C. Bueno W. L. Hsu J. S. Plotkin and S. G. Shou Inorg. Chem. 1982,21,1958. 5 358 J. Lewis R. B. A. Pardy and P. R. Raithby J. Chem. SOC. s-Dalton Trans. 1982 1509. 359 See ref. 350. 360 A. Ceriotti G. Longoni M. Manassero M. Sansoni R. D. Pergola B.T. Heaton and D. 0.Smith J. Chem. SOC.,Chem. Commun. 1982 886. 8 361 M. Lanfranchi A. Tiripicchio E. Sappa S. A. MacLaughlin and A. J. Carty J. Chem. SOC.,Chem. Commun. 1982 528. 5 Fe Co Ni 273 3 Nickel Compounds that contain q-Alkene q-Alkenyl or Related Ligands.-The chemistry of cyclohexane 1,3- and 1,4-~yclohexadiene and cyclohexene on nickel surfaces has been investigated. Some conversion of cyclohexene and the cyclo- hexadienes into benzene was Relative bond dissociation energies for two-ligand complexes of Ni' have been estimated using ion cyclotron resonance Alkyne-nickel bonding in complexes of the type [L2Ni(g-ethyne)NiL2](L = various) has been assessed using quantitative molecular orbital theory364 and the electronic structures of some other dinuclear complexes e.g.[{Ni(q-Cp)(~-CO)}2] have been discussed in terms of extended Huckel calculations and the photoelectron spectrum of the a-Alkoxyvinylnickel(I1) complexes of the type trans-[(L)2RNi(C=CH(CH2)20)] (R = C6H2Me3-2,4,6 or C6c15 L = PMe3 or PMe2Ph) have been prepared. Treatment of these com- pounds with HC10 gives the corresponding cationic cyclic carbene complexes trans-[(L)2RNi:C(CH2)4].36" Bis( 1,4-diaryltetra-azabutadiene)nickel complexes [Ni(Ar2N4)2] or [Ni( 1,5-~yclo-octadiene)~] have been synthesized from [Ni(~pCp)~] by reaction with arylazides. The structure of the 3,5-dimethylphenyl derivative was determined. Isocyanides e.g. Bu'NC displace one molecule of the tetra-aza ligand to yield a mixed-ligand complex [Ni(Ar2N4)(Bu'NC)].Another mixed-ligand com- plex to be prepared and structurally characterized as part of this work is that depicted as (75). Some exchange and rearrangement reactions of these and related complexes have been observed and mechanisms advanced. 367-369 Alkene N-N, ,_-_ 0 R 4-MeH4Ch-N" ;N-ChH4Me-4 Ill 'Ni C i_l /!Jq -CP) (q-Cp)Ni'L'Ni( q-Cp) (7.5) (76) \/ -_ cIll (7.5) 0 R = Pr or Me2CH R'=Me (77) nickelalkyl complexes [RNi(q-Cp)(q 2-alkene)] have been synthesized starting with [Ni(q-C~)~l and reacting it with the appropriate Grignard reagent RMgX and an alkene. If Me,CHMgX and propene be employed in this synthesis then a mixture of isomers (76) is the prod~ct.~'" Work continues on the experimental analysis of the highest occupied molecular orbital in the trinickel compound (77).The electroni- cally equivalent triangular compounds [q-C,Me,CoNi,(.rl-C~)~(g~-CO),]- [Ni3(q- 362 M.-C.Tsai C. M. Friend and E. L. Muetterties J. Am. Chem. Soc. 1982 104 2539. 363 M. M. Kappes and R. H. Staley J. Am. Chem. SOC.,1982 104 1813. 364 D. M. Hoffman and R. Hoffmann J. Chem.SOC.,Dalton Trans. 1982 1471. 36s G. Granozzi M. Casarin D. Ajo and D. Osella J. Chem. Soc. Dalton Trans. 1982 2047. 366 M. Wada K. Samaeshima K. Nishiwaki and Y. Kawasaki J. Chem. SOC.,Dalton Trans. 1982 793. 367 P. Overbosch G. Van Koten and 0.Overbeek Inorg. Chem. 1982 21 2373. "* P. Overbosch G. Van Koten A. L. Spek G. Roelofsen and A. J. M. Duisenberg Znorg. Chem. 1982,21,3908.36q P. Overbosch G. Van Koten and K. Vrieze J. Chem. Soc. Dalton Trans. 1982 1541. 370 H. Lehnkuhl C. Naydowski R. Benn A. Rufinska and G. Schroth J. Organomet. Chem. 1982,228 c1. 274 B. W. Fitzsimmons C5Me5),(p3- CO),] and [Ni3(q-Cp),(p3- CO),]- were prepared and their structures solved by X-ray methods. The detailed stereochemistry of these and other com- pounds was analysed in terms of a bonding molecule in which the HOMO is an inplane anti-bonding orbital (a5 under D, The chloro-compound [q-CpNi(PPh,)CI] reacts with the sodium diazolate anti Na[4-N02C6H4N20] to give [(q-Cp)(PPh3)NiON2C6H4N02C)-4].The molecular structure of this compound was determined. It revealed N-co-ordination from this unidentate ligand.372 But-2-yne cyclodimerizes in the presence of AlCl to give a-complex [Me4C4-AlC13].With Ni(CO) in CH2C12 this yields [Ni(~-c~Me~)~].~~~ The 20 19 and 18-electron complexes [Ni(q-C4Me4),]"+ (n = 0 1 or 2) are the starting points for some new nickel compounds. Treatment of the neutral compound with RX (R = H CCl, Ph or PhCH,; X = hal) affords the cationic complexes (78). Complexes of this type are also accessible by addition of nucleophiles (H-,CN-) to the dications [Ni(~-c~Me~),]~+ or by the addition of radicals Me,(NC)C. Ph. to the mono-cation~.~~~ I Ni Compounds of Nickel(II).-The reactions NiC12(g) + EC13 NiEC15 or NiE2Cls (E = A1 or Ga) have been investigated over the temperature range 573-1 113K. The entropy change AS' was found to be independent of E.375The pbromo dimeric complex [Nl2en2Br4I2+ (en = 1,2-diaminoethane) has been the subject of a magnetic susceptibility and inelastic neutron scattering study.The intramolecular magnetic coupling is ferromagnetic(J = 3.55 f 0.2 cm-') whilst the intermolecular coupling is antiferromagnetic (-J' = 0.25 f0.05 cm-1).376 An unusual 0-donor complex is one in which [Ni(salen)] {salen = N,N'-ethylenebis(salicy1idene-iminato)} is the donor and the guanidinium cation is the acceptor. The formula of this complex is {[Ni(~alen)l~[C(NH~)~]}BPh~. A determination of its molecular structure reveals that the guanidinium cation is held in place by six hydrogen bonds to the salen oxygen^.^^^ The binuclear complex ion [Ni,(PhSal),MeCO,]- (Sal = N-phenylsalicylaldimine) contains a bridging acetate and both bridging and non- bridging sal ligands.Each nickel is cis-octahedral [Ni04N2] and a magnetic suscepti- 371 J. J. Maj A. D. Rae and L. F. Dahl J. Am. Chem. SOC.,1982 104 3054. 372 F. J. Lalor T. J. Desmond G. Ferguson and P. Y. Siew J. Chem. SOC.,Dalton Trans. 1982 1981. 373 H. Hoberg and H. J. Riegel J. Organomet. Chem. 1982 229 85. 374 U. Koelle F. Khouzami and H. Lueken Chem. Ber. 1982 115 1178 37s F. P. Emmenegger P. Favre and M. Kluczowski Inorg. Chem. 1982,21 2934. 376 A. Stebler H. V. Gudel A. Furrer and J. K. Kjens. Inorg. Chem. 1982.21 380. 377 G. Giacomelli C. Floriani and G. Perego J. Chem. SOC.,Chem. Commun. 1982,650. Fe Co Ni 275 bility study over the temperature range 4-100 K shows that it is an intramolecular antiferromagnet with -J = 4.66 ~rn-'.~'~ A linear trinuclear nickel(r1) complex [Ni3(TFDA)2(0H)2(H20)6] {TFDA = (CF,COCH2COMe)-} has been the subject of a variable-temperature magnetic susceptibility study.Adjacent nickels are ferromagnetically coupled and terminal nickels are antiferromagnetically coupled (J = 10 -J = 6 cm-' respec- tively). The molecular structure has not yet been established the model adopted is a trans-diaquo system with two terminal hydroxide^.^'^ The molecular structure of the venerable trinickel cluster [Niacac213 (acac = acetylacetonato) has been refined and the original high symmetry somewhat lowered.209 The monothiocarbamato ligand (79) bonds to nickel(I1) in the distorted trans-octahedral complex [Ni(SOCNC4H4)2py2] (py = pyridit~e).~" The maleonitriledithiolate complexes [NiS2C2(CN),]'- (z = 1 or 2) undergo photo- oxidation in CC14 CHC13 or CH2C12with the photo-oxidizing wavelength showing significant solvent dependence.381 The electronic structures of the sulphur-ligand nickel complexes (80) and (8 1) have been investigated using molecular-orbital methods thereby aiding the assignment of the electronic Tin(Iv) chloride forms an adduct with a dithio-oxalato complex (82).This undergoes a one-electron reduction as detected by cyclic voltammetry. An e.p.r. study reveals that the unpaired spin occupies a n* orbital on the dithio-oxalato ligand.383 The complex [Ni(bipy)(NCS)2](bipy = 2,2'-bipyridyl) may be prepared by thermolysis of a tris bipyridyl thiocyanate and it has a polymeric structure.The co-ordination about nickel is octahedral-[NiN4S2] with trans-thiocyanate sulphur atoms and cis-thiocyanate nitrogen atoms. Variable temperature magnetic suscepti- bility measurements reveal a transition temperature at 3.5 K which is associated with the onset of ferromagnetic ordering."' 378 R. J. Butcher C. J. O'Connor and E. Sinn Inorg. Chem. 1982,21 616. 379 G. J. Long D. Lindner R. L. Lintvedt and J. W. Guthrie fnorg. Chem. 1982 21 1431. R. D. Bereman D. M. Baird J. R. Dorfman and J. Bordner Inorg. Chem. 1982,21 2365. A. Vogler and H. Kunkely Znorg. Chem. 1982 21. 1172. 382 Z. S. Herman R. F. Kirchner G. H. Loew U. T. Mueller-Westerhoff A. Nazzal and M. C. Zerner Inorg. Chem. 1982 21.46. 383 G. A. Bowmaker P.D. W. Boyd and G.K. Campbell fnorg. Chem. 1982,21,3565. B. W. Dockum and W. M. Reiff Inorg. Chem. 1982,21 2613. 276 B. W. Fitzsimmons The electronic spectrum of a crystal of the trans-octahedral species [Ni(NH3)4(N02)2] has been recorded and assigned. A transition at 20 000 cm-' has its origin in a metal-+.rr* (nitrite) charge-transfer rather than a d-d tran~ition.~'~ The structures of catena-[( p-nitrito)bis(en)Ni"]X-(en = 1,2-diaminoethane X = c104or 13) complexes have been established by X-ray methods. Both are strongly antiferromagnetic = 33.0 -J13 = 31.9 cm-*). A molecular orbital treatment of infinite chains of paramagnetic ions is advanced.386 The complex [Nien2(N02)2]BPh4 has an unusual structure (83)in which a terdentate nitrito group chelates one nickel ion and bridges to the other.The unidentate nitrito group is grossly disordered and the nickel ions are antiferromagnetically coupled with TN= 25 K.387 Sodium or lithium metal reacts with nickel(I1)salophen (salophen = N,N'-o-phenylenebis-salicylideneiminato)to give a dimer with a C-C bridge as in (84).This dimer can transfer two electrons to various substrates 0 (83) (84) N-N = 1,2-diaminoethane L = tetrahydrofuran to regenerate the original c~rnplex.~'' The exchange interaction in a Co"- or CUT'-doped binuclear nickel(I1) complex [Ni2(dhph)2(H20)4]C14 (dhph = 1,4-dihydrazinophthalazine)has been investigated using e.p.r. The spectra were interpreted in terms of an antiferromagnetic interaction within the S = 4 Hamil-t~nian.~" The trans-dibromo complexes of the macrocyclic ligands (85) and (86) (85) (86) have been synthesized and the structures solved by X-ray as have the trans-dichloro complexes of the ligands (87).39' 385 M.A. Hitchman and G. L. Rowbottom Inorg. Chem. 1982 21 823. 386 A. Meyer A. Gleizes J. Girerd M. Verdaguer and 0.Kahn Inorg. Chem. 1982,21 1729. 387 A. Gleizes A. Meyer M. A. Hitchman and 0.Kahn Inorg. Chem. 1982 21 2257. 388 S. Gambarotta C. Floriani A. Chiesivilla and C. Gustiori J. Chem. Soc. Chem. Commun. 1982,756. 389 L. Banci A. Bencini C. Benelli and D. Gatteschi Inorg. Chem. 1982 21 3868. 390 H. J. Goodwin K. Henrick L. F. Lindoy M. McPartlin and P. A. Tasker Inorg. Chem. 1982,21,3261. 391 L. A. Drummond K. Henrich M. J. L. Kanagasundaram L.F. Lindoy M. McPartlin and P. A. Tasker Inorg. Chem. 1982 21 3923. Fe Co Ni 277 (87) X = 0,NH or S A seven-co-ordinate pentagonal bipyramidal [NiN502] complex of the ligand (88) having the formula [Ni(H20)2L](BF4)2 can be electrochemically reduced to a d9Ni' species detected as an acetonitrile glass at 77 K.392Another example of stabilization of univalent nickel by macrocyclic N-donor ligands is provided by the systems (89). The formal aqueous solution potentials Ni(L1)'+/Ni(L1)+ and Me R' R' Me (88) Ni(L2)"/Ni(L2)' have been established.393 Isomeric diperchlorates [NiL](C104)2 {L = (90)) have been prepared and ~haracterized.~~~ The reactions of the square planar complexes (91) (R',R2 = alkyl) with a range of oxidizing agents have been in~estigated.~~' The complexes (92) and (93) have been synthesized and character- ized; the molecular structure of the second compound was established by an X-ray diffraction study on a hemih~drate.~~~ The nickel(I1) halide phosphine complexes 3yz C.W. G. Ansell J. Lewis P. R. Raithby J. N. Ramsden and M. Schroder J. Chem. SOC.,Chem. Commun. 1982,546. 3y3 N. Jubran G. Ginzburg H. Cohen and D. Meyerstein J. Chem. SOC.,Chem. Commun. 1982 517. 394 R. A. Kolinski B. Korybut-Daszkiewicz Z. Kubaj and J. Mrozinski Znorg. Chim. Acra 1982,57,269. 3y5 S. Dilli A. M. Maitra and E. Patsalides Inorg. Chem. 1982 21 2832. 396 L. G. Scanlon. Y. Tsao. K. Toman S. C. Cummings and D. W. Meek Inorg. Chem. 1982 21 1215. B.W. Fitzsimmons H (92) (93) [NiX2{Ph2P(CH2)8PPh2}](X = C1 or Br) are tetrahedral but the thiocyanato derivative is square planar.397 Electrochemical reduction of [Ni(dtc) (Ph2P(CH2CH2PPh2)2-,] (dtc = R2N-CS2-) affords Ni' complexes. Gamma irradiation of the [Ni(dtc),] family also leads to the formation of reduced species.398 A combination of electrochemistry and e.p.r. spectroscopy has been applied to a range of complexes [Ni(PPh3)2L]n+ (L = dithiolate N,N'-dialkyl- dithiocarbamate) and [Ni(dpe)L'] (dpe = bis(diphenylphosphino)ethane L = dithiolate or catecholate). All show one-electron reduction processes and the e.p.r. spectral parameters are characteristic of d9 nickel(1) Thus a steady increase in interest in nickel(1) systems is evident. Silica-supported Ni2+ ions undergo reduction in H at 443 K yielding Ni' species detected by e.p.r.(ga= 2.75 gl = 2.097). These Ni' compounds are similar to those formed on zeolites they are effective catalysts for the dimerization of ether~e.~" By the same token a good deal has been printed on the subject of nickel(rr1) compounds e.g. the complex [C12Ni"'(diphos)]'(C104)-(diphos = 0-diphenylenebis(dimethy1-phosphine) a d7 nickel(II1) 397 W. E. Hill J. C. Taylor C. A. McAuliffe and W. Levason J. Chem. SOC.,Dalton Trans. 1982 841. 398 G. A. Bowmaker P. D. W. Boyd G. K. Campbell J. M. Hope and R. L. Martin Znorg. Chem. 1982,21 1152. 399 G. A. Bowmaker P. D. W. Boyd and G. K. Campbell fnorg. Chem. 1982 21,2403. 400 L. Bonneriot D. Oliver and M. Che J. Chem.SOC.,Chem. Commun. 1982,952. 40' E. Balasivasubramanian C. N. Sethulekshmi and P. T. Manoharan fnorg. Chem. 1982,21 1684.