9 Fe,Co Ni By B. W. FllZSlMMONS Department of Chemistry Birkbeck College Malet Street London WClE 7HX 1 Iron Iron Oxides and Compounds Containing Iron-Oxygen Bonds.-The kinetics of the dissolution of Fe304 in the presence of oxalate have been investigated and a heterogenous electron transfer process detected. The double function of the oxalate as complexing and electron-transfer reagent is stressed.' The kinetic isotope effect has been recorded in the oxidation reactions of [Fe(H20)6]2+ [Fe(D20)6I2+ and [Fe('80H2)6]2t by the oxidants [M"' bipy,] (M = Fe Ru or Cr; bipy = bipyridyl). The rate ratios are compared using current quantum theories of isotope effects and the results give support to these theories2 The formation constants of mononuclear and polynuclear hydroxy complexes of metal cations throughout the periodic table have been critically e~amined.~ It is twenty-five years since the 57Fe Mossbauer resonance was first observed spectra of aqueous solutions of iron(I1) and iron(rI1) salts have been reported for the first time.The quadrupole splitting and isomer shift recorded for solutions of iron(I1) sulphate in glass pores are the same as those of solid FeS04-7H20 thus providing the hitherto elusive proof that the aqua complex in solution is the he~ahydrate.~ The structure and stabilities of hydroxy and aquo species of the type [FeOH( H20)J+ [Fe(OH),] etc. have been analysed using electron-delocalization MO theory with the aim of determining a mechanism of anodic iron di~solution.~ The transformation y-FeOOH to stoicheiometric magnetite Fe304 in the pH range 5-9 has been investigated.6 Stoicheiometric zinc-bearing ferrites Zn Fe3-.x 04,have been pre- pared and characterized.' Magnetic exchange-interactions in the orthorhombic perovskite solid solutions Eu,-,Cr,03 0 < x < 1 are sensitive to the substituent atoms.8 In a related study 'I9Sn Mossbauer spectroscopy provides an additional probe in a range of perovskites (&,95C~.05)(Feo.8sMo.olSno.05)03 with A = La Eu or Lu and M = Al Ga Sc Cr Mn Co; or Ni.The supertransferred hyperfine field is seen to be strongly dependent upon the rare-earth metal.' The complex tri-phasic ' E. Baumgartner M. A Blesa H. A. Marinovich and A. J. G. Maroto Inorg. Chem. 1983 22 2224. T. Guarr E. Buhks and G.McLendon J. Am. Chem. Soc. 1983 105 3763. D. W. Barnum Inorg. Chem. 1983 22 2297. K. Burger and A. Virtes Nature 1983 306,353; K. Burger A. Vkrtes and I. Zay Inorg. Chim. Acta 1983 76 L247. A. B. Anderson and N. C. Debnath J. Am. Chem. Soc. 1983 105 18. Y. Tamaura K. Ito and T. Katsura J. Chem. SOC.,Dalton Trans. 1983 189. ' K. Ito Y. Tamaura and T. Katsura J. Chem. SOC.,Dalton Trans. 1983 987. T. C. Gibb J. Chem. Soc. Dalton Trans. 1983 2031. T. C. Gibb J. Chem. Soc. Dalton Trans. 1983 2035. 211 B. W.Fitzsimmons material FePO, has been the subject of a study using Mossbauer spectroscopy neutron diffraction magnetic susceptibility and electron microscopy. lo Polarized electronic spectra of vivianite Fe (PO4),-8H,O have been recorded at different temperatures in a search for spin-forbidden transitions.The spectral region 18 000 to 28 000 cm-' is dominated by bands attributed to transitions from ferromag- netically coupled iron( 11) pairs.' ' The vapours generated by heating various mixtures in the Fe2O3-HC1-H20-FeCl3 system have been investigated with the help of mass spectroscopy. The behaviour observed in the temperature range 140-350 may be explained by assuming that the molecule [H,O.FeCl,] is present.' Its standard enthalpy of formation at 500K is -589.38 kJmol-' and the standard entropy is 472.34 J mol-' K-'. By measuring the vapour-pressure concentrations of Fe,Cl,(g) above solid mixtures of Fe203 and FeCl, the enthalpy and entropy of formation of iron oxy-chloride FeOCI were ca1c~lated.l~ By recording EXAFS spectra for a range of known oxy-bridged dinuclear iron(rI1) complexes it has proved possible to show that the spectra were sensitive to both the Fe-0-Fe angle and the Fe-Fe distance thus providing a technique for estimating these parameters with useful ac~uracy.'~ A further example of a salt containing the p-0x0 anion [(FeCl3),0I2- has been isolated and characterized.This one is linear and diamagnetic." The trinuclear basic iron(Ir1) carboxylates continue to receive attention. It is now shown that inter-cluster interactions have little influence upon the magnetic susceptibility.'6 Solution equilibria of the complexes p-oxobisFe"'salen and Fe(salen)(cate-cholato) {salen = N,N'-ethylenebis( salicylideneiminato)} have been investigated.l7 A reduced Schiff-base ligand (1) forms a hydroxy-bridged iron(II1) dimer [Fe(OH),LFe]2H2O.2Py. The structure of this intramolecular anti-ferromagnet (J = -104cm-' S = 5/2) has been determined" and a dialkoxy-bridged com-plex [{Fe( salen-H)Cl},] has been characterized and its antiferromagnetic nature established. l9 The molecular structure of the piperidinium salt of the p-0x0 anion bis p-l,l'-biphenyl-2,2'-diolato-0,0')-(1,1'-biphenyl-2,2'-diolato-O,0')-ferrate( 111).ethanol0.5 a weakly coupled intramolecular anti-ferromagnet (-J = 14cm-') has been determined and is depicted in (2).,* lo G. J. Long A. K. Cheetham and P. Battle Inorg. Chem. 1983 22 3012. I' H. C. Gudel Inorg. Chem. 1983 22 3812. I* N. W. Gregory Inorg. Chem.1983 22 3750. l3 N. W. Gregory Inorg. Chem. 1983 22 2677. l4 M. S. Co W. A. Hendrickson K. 0. Hodgson and S. Doniach J. Am. Chem. SOC.,1983 105 1144. '' H. Schrnidbauer C. E. Zybill and D. Neugebauer Angew. Chem. Znt. Ed. Engl 1983 22 156. 16 B. S. Tsukerblat M. I. Belinskii and B. Ya. Kuyavskaya Inorg. Chem. 1983 22 995. " F. LLoret J. Moratal and J. Faus J. Chem. SOC.,Dalton Trans. 1983 1749. I8 L. Borer L. Thalken C. Ceccarelli M. Glick J. H. Zhang and W. M. Reiff Inorg. Chem. 1983,22 1719. 19 L. Borer L. Thalken J. H. Zhang and W. M. Reiff Inorg. Chem. 1983 22 3174. *' E. W. Ainscough A. M. Brodie S. J. McLachIan and K. L. Brown J. Chem. SOC.,Dalton Trans. 1983 1385. Fe Co Ni 213 (2) The p-0x0 Schiff-base complex [FeL(OH)C1]2.C4H80 (L3- is the anion of trisalicylidenetriethylenetetramine),illustrated schematically in (3) is a weak antifer- romagnet” with -J = 8 cm-’.p-0x0 acetatobis(tri- 1-pyrazolborato)di-iron(111) has been structurally established using X-ray methods and is suggested as a model for the dinuclear centre of haemerythrin.” EXAFS studies of the dinuclear iron centre in deoxyhaemerythrin give results consistent with a model in which the p-0x0 B. Chiari 0.Piovesana T. Tarantelli and P. F. Zanazzi Inorg. Chern 1983 22 2781. W. H. Armstrong and S. J. Lippard J. Am. Chern. Soc. 1983 105 4837. B. W. Fitzsimmons bridge is replaced by two hydroxy-groups one of them bridging; the other ligands remaining in position as illustrated schematically in (4).23 The nature of the iron His His I ,His ,O-Fe-0, 1 Asp-< OH /C-Glu '0-Fe -0' His' I 'His His (4) Asp = aspartic acid; Glu = glutamic acid; His = histidine centre in porcine allantoic purple acid phosphatase has been inferred by direct comparison of its magnetic behaviour with that of a synthetic Iron(Ir1) acetylacetonate may conveniently be prepared by heating the diketone with freshly precipitated ferric oxide.25 The 57Fe and '"Eu Mossbauer spectra of the perovskites EuFe,-,Co,03 have been recorded and the substitutional effects analysed.26 The equilibria and kinetics of reaction between Fe"' Co" Ni" Cu" and l,l,l,-trifluoropentane-2,4-dione have been investigated and the enol form of the diketone identified as the active specie^.^' An 'H n.m.r.study of the aqueous solution reaction between the phosphate ligand (5) and the ions Mn" Fe"' Co" Ni" Cu" and Zn" reveals a greater degree of aquation than with the corresponding carboxylate com- plexes.28 A series of iron( 111) complexes containing chelating phosphine oxides L-L[L-L = e.g. Ph2P( =O)(CH,),P( =O)Ph2] have been prepared and characterized. -0 0-(5) (6) These include complexes of formula [Fe( L-L),C1,][FeCl4] [FeL-L(ON02),] et~.,~ The stability constant of N,N'-ethylenebis( salicylideneminato)iron( 111) in dimethyl- sulphoxide solution has been e~timated.~' Reactions between iron( 111) Schiff base complexes of N,N'( 1,2-diaminobenzene)bis( salicylideneiminato) and several ortho-and para-quinones have been isolated and characteri~ed.~' The crystal and molecular structure of three complexes of [Fe"'(salen)]+ have been determined.These are [Fe(salen)acac] [Fe(salen)psq] and K[Fe(salen)cat] (catHz = catechol psq = phenanthrenesemiquinone). The co-ordination spheres are octahedral [FeN2O4] 23 W. T. Elarn E. A. Stern J. D. McCallum and J. Sanders-Loehr J. Am. Chem. SOC. 1983 105 1919. 24 G. M. Mockler J. de Jersey B. Zerner C. J. O'Connor and E. Sinn J. Am. Chem. SOC.,1983,105 1891. 25 M. K. Chaudhuri and S. K. Ghosh J. Chem. SOC.,Dalton Trans. 1983 839. 26 T. C. Gibb J. Chem. SOC.,Dalton Trans. 1983 873. 27 M. J. Hynes and M. T. O'Shea J. Chem. SOC.,Dalton Trans. 1983 331. 28 J. Oakes and E. G. Smith J. Chem. SOC.,Daiton Trans. 1983 601. 29 T. S. Lobana H. S. Cheema and S.S. Sandhu J. Chem. SOC.,Dalton Trans. 1983 2039. 30 F. LLoret J. Moratal and J. Faus J. Chem SOC.,Dalton Trans. 1983 1743. 3' J. P. M. Tuchagues and D. N. Hendrickson Inorg. Chem. 1983,22 2545. Fe Co Ni 215 in each case.32 The synthesis of a new multidentate ligand (6) has been described and its complexation with Fe" Fe"' Co*I Ni" Cu'I and Zn" investigated using potentiometric methods. Iron( 111) pox0 compounds were detected.33 Iron( 111) N,N'-ethylenebis( 0-hydroxyphenyl)glycinate and octahedral [FeN20,] complex has been evaluated spectroscopically as a model for the binding site in tran~ferrins.~~ An iron(1rr) complex of muginec acid has been prepared and is shown to be a typical high-spin iron( 111) complex. The molecular structure of the Co"' analogue has been determined.35 Iron( 111) complexes [Fe(ent)] or [Fe(MECAM)] (7) and (8), qoH OH c=o I I \ o=c HFH \ OH (7) (JoH 'OH I c=o I NH I (8) have been shown36 by Mossbauer spectroscopy carried out on frozen aqueous solutions to remain as iron(rr1) species over the pH range 2-10 but redox processes 32 R.B. Lauffer R. H. Heistand and L.Que Inorg. Chem 1983 22 50. 33 C. Y. Ng A. E. Martell and R. J. Motekaitis Inorg. Chem. 1983 22 721. 34 M. G. Patch K. P. Simolo and C. J. Carrano Inorg. Chem 1983 22 2360. 3s Y. Mino T. Ishida N. Ota M. Inoue K. Nomoto T. Takemoto H. Tanaka and Y. Sugiura 1 Am Chem SOC.,1983 105,4671. 36 V. L. Pecoraro G. B. Wong T. A. Kent and K. N. Raymond J.Am. Chem. SOC.,1983 105 4617. 216 B. W. Fitzsimmons take place in methanol at low pH. A solid-state i.r. study of iron( 111) catechoylamide complexes indicates that the salicylate bonding mode operates.37 Two iron( 111) hydroximate siderophores coprogen and ferricrocin have been extracted from natural sources and characterized. Their formation constants and redox potentials were recorded.38 Kinetic Studies on Iron Complexes.-Table 1 shows recent papers.3948 Table 1 Complex of species Reagent Re$ [Fe phenJ2+ c102-39 [Fe"'EDTA] [RU(NH3)612+ 40 w2o)i3-N-Bases 41 CF~(CN), Fe3+ [FeI"6 DT A] isopropyltropolone 42 02-43 [Fe(CN) baseI3- light 44 [Fe en(CN),]'- electron transfer 45 [Fe"'DMSO,] exchange 46 Fe"' Fe"' exchange 47 Fe3+,q CNS-48 phen = 1,lO phenanthroline EDTA = ethylenediaminetetra-acetate en = 1,2-diaminoethane DMSO = dimethylsulphoxide Compounds Containing Nitrogen-Donor Ligands.-The complex [Fe(4-~c~~)~(H,O),(NCS),], (4-acpy = 4-acetyl pyridine) contains a trans-Fe[N,OJ centre.The level scheme is xz,yz <xy in consonance with a relatively modest Mossbauer quadrupole splitting of 1.7-1.9 mm s-' and there is no magnetic hyper- fine splitting in the 4.2 K A series of synthetic non-porphyrin reversible dioxygen carriers (9) has been synthesized and tested.50i51 The interaction of some iron(r1) complexes of the type (10) with nitrogen bases CO and O2has been studied and in the latter case a two-electron redox process has been un~overed.'~ The base-catalysed reduction of [Fe(bipy)J3+ yields a variety of products it has been 37 V.L. Pecoraro W. R. Harris G. B. Wong C. J. Carrano and K. N. Raymond J. Am. Chem. SOC.,1983 105 4623. 38 G. B. Wong M. J. Kappel K. N. Raymond B. Matzanke and G. Winkelmann J. Am. Chem. SOC. 1983 105 810. 39 L. A. Lednicky and D. M. Stanbury J. Am. Chem. SOC.,1983 105 3098. 40 F. Moattar J. R. Walton and L. E. Bennett Inorg. Chem. 1983 550. 41 A. L. Coelho H. E. Toma and J. M. Malin Inorg. Chem. 1983 22 2703. 42 K. Ishihara S. Funahashi and M. Tanaka Inorg. Chem. 1983 22 194. 43 C. Bull C. J. McClune and J. A. Fee J. Am. Chem. SOC.,1983 105 5290. 44 K. J. Moore L. Lee J. E. Figard J. A. Gelroth A. J. Stinson H. D. Wohlers and J. D. Petersen J.Am. Chem. Soc. 1983 105 2274. 45 A. M. de C. Ferreira and H. E. Toma J. Chem. SOC.,Dalton Trans. 1983 2051. 46 C. H. McAteer and P. Moore J. Chem. Soc. Dalton Trans. 1983 353. 47 J. J. Hupp and M. J. Weaver Inorg. Chem. 1983 22 2557. 48 S. Funahashi K. Ishihara and M. Tanaka Inorg. Chem. 1983 22 2070. 49 G. J. Long G. Galleazzi U. Rosso G. Valle and S. Calogero Inorg. Chem. 1983 22 507. 50 N. Herron J. H. Cameron G. L. Neer and D. H. Busch J. Am. Chem. Soc. 1983 105 298. 5' N. Herron L. L. Zimmer J. J. Gnybowski D. J. Olszanski S. C. Jackels R. W. Callahan J. H. Cameron G. G. Christoph and D. H. Busch J. Am. Chem. SOC.,1983 105,6585. 52 N. Herron W. P. Schammel S. C. Jackels J. J. Grzybowski L. L. Zimmer and D. H. Busch Inorg. Chem. 1983 22 1433.Fe Co Ni 217 RZ R2 1 B = I-methylimidazole R' = m-xylylene R2= R3 = Me R2=benzyl; R3 = Me 1 Rf = Me;R3 = Ph (9) Rz= benzyl; R3 = Ph studied with a view to establishing rates and st~icheiometry.~~ The electronic infrared Raman and resonance Raman spectra of a number of iron(r1) di-imime complexes have been recorded and analysed. These include [Fe(phen),(CN)J and [Febipy,]( BFJ2 (phen = 1,lo-phenanthroline bipy = 2,2'-bipyridyl) in which the resonance enhancement originates in charge-transfer transition^.^^ Complex formation between iron( 111) and some di-imine polymers has been in~estigated.~'The electronic structures of the bipyridyl complexes [Mbipy J3+ (M = Fe Ru or 0s) have been elucidated with the help of appropriate theoretical models and e.p.r.spectro~copy.~~ Electrochemically generated reduction-products of [ML3I2+ (M = Fe" or Ru" L = 2,2'-bipyridyl) have been identified using variable-temperature e.~.r.~~ A laser-Raman spectral study of iron(r1) complexes of the di-imines (1 1) and (12) has been carried out. The complex [FeL,]*+(PF,), where L = (1 l) hitherto believed to be exclusively high-spin is shown to contain a fraction of the low-spin isomer.58 Spin-Crossover among Fe" Compounds.-This continues to be an active area of research and some progress has been made this year. Methods include variable- temperature magnetic susceptibility Mossbauer and vibrational spectroscopy some groups obtain X-ray diffraction information on both sides of phase boundaries.A linear trinuclear complex of 4-ethyl triazole [Fe (Tr)6(H20)6](CF3S03)6 shows a first-order transition at 203 K and its structure has been solved above and below 53 G. Nord B. Pedersen and E. Bjergbakke J. Am. Chem. SOC.,1983 105 1913. 54 L. Griffiths B. P. Straughan and D. J. Gardiner J. Chem. SOC.,Dalton Trans. 1983 305. 55 J. D. Miller and D. S. Morton J. Chem Soc. Dalton Trans. 1983 151 1. 56 E. M. Kober and T. J. Meyer lnorg. Chem. 1983 22 1614. 57 D. E. Morris K. W.Hanck and M. K. DeArmond J. Am. Chem. SOC.,1983 105 3032. 58 W. H. Batschelet and N. J. Rose lnorg. Chem. 1983 22 2078. B. W. Fitzsimmons this temperature to reveal significant differences in the Fe-N bond lengths.59 A detailed study of the iron(rr) complex [FeL2(NCS)2] where L = (13) reveals a Mexs,H:jMe NN (13) transition temperature of 219.5 K.These authors develop different models for the two main types of spin-crossover sharp or gradual opting for a solid-solution model for the second type.60 The solid-solution model is again taken up in a paper from the same laboratory describing a gradual crossover system.61 The complex [FeL6]- (BF,) (L = n-propyl tetrazole) shows a sharp transition whereas its homologues exhibit the gradual behaviour.62 Variable-temperature Raman spectroscopy has been deployed in an investigation of the spin-crossover complex [FeL]( PF6)2 where L = (11):~ Variable-pressure experiments as applied to spin-crossover systems can be con- veniently monitored using Mossbauer spectroscopy and this year sees the reinvestiga- tion of the classic case [Fe phen,X2J (X = NCSe NCS or N3) over the pressure range 0.001 to 45 kbar at ambient temperature.Sharp5T-'A transitions (Figure I) are observed in a narrow pressure range for the first two compounds with none of the bizzare irregularities earlier reported. The azido compound is more difficult to 'HS t P/k bar 10 20 30 40 50 Figure 1 Area fraction X, of the iron(1r) high-spin doublet from the Mossbauer spectra of Fe(phen)2(X) with X = NCS- NCSe- and N3-as a function of high pressures up to 45 kbar 59 G.Vos R. A. IeF'bbre R. A. G. de Graff J. G. Haasnoot and J. Reedijk J. Am. Chem. Soc. 1983 105 1682. E. Konig G. Ritter S. K. Kulshreshtha and S. M. Nelson 1.Am.Chem. SOC.,1983 105 1924. 61 E. Konig G. Ritter S. K. Kulshreshtha and H. A. Goodwin Znorg. Chern 1983 2518. 62 E. W. Miiller J. Ensling H. Spiering and P. Gutlich Inorg. Chem. 1983 22 2074. 63 W. H. Batschelet and N. J. Rose Inorg. Chem. 1983 22 2083. Fe Co Ni 219 convert; it remains a 3 1 mixture at the high-pressure limit.64 A further instance of rapid electronic relaxation in a 6A-2T crossover system has been un~overed.~~ Porphyrinato-iron Compounds.-'H n.m.r. evidence has been adduced in the question of the presence or otherwise of the ferryl group (Fe=O) in ferryl myoglobin and in compound (11) of horseradish peroxidase by comparison of their spectra with those of model compounds.66 Workers in the same laboratory have been successful in incorporating modified haems into horseradish peroxidase and have used n.m.r.spectroscopy to determine the orientation of the haem in its pocket. They consider that their method might be generally appli~able.~~ Evidence for structural changes occurring in the haem environment due to the NO group has been obtained from 14 N and 'HENDOR spectra of nitrosyl derivatives of human haemoglobin and its separate a and p sub-units myoglobin and related nitrosyls.68 Reactions of rel- evence to the disablement of haemoglobin or myoglobin by phenylhydrazine has been looked into by two groups a-bonded iron complexes are implicated. The first of these studies employed the chloro complex [ClFe"'TPP] (TPP here and later is tetraphenyl porphinato) as the model.Both diazine complexes (14) and a-complexes R NH N (14) were The second study deploys natural haems as substrates and n.m.r. as probe for the a-c~rnplexes.~~ The preparation of a new kind of porphyrin-like synthetic macrocycle tetrakis(3,5- di-t-butyl-4-hydroxyphenyl)porphine, has been carried out and the its iron and zinc salts i~olated.~' Mixed-metal face-to-face porphyrin dimers as depicted in (15) have been ~ynthesized.~~ Using the synthetic picket-fence porphyrin models the effect of differing axial bases on O2or CO affinities have been worked As an extension of work on synthetic haem models 'pocket' porphyrins (16) have been prepared and ~haracterized.~~ They form stable and reversible dioxygen complexes. In a further paper kinetic and equilibrium studies of the O2 and CO complexes are 64 J.Pebler Inorg. Chem. 1983 22 4125. 65 H. Ohshio Y. Maeda and Y. Takashima Znorg. Chem. 1983 2684. 66 G. N. La Mar J. S. de Ropp L. Latos-Grazynski A. L. Balch R. B. Johnson K. M. Smith D. W. Parish and R.-J.Cheng J. Am. Chem. SOC.,1983 105 782. 67 G. N. La Mar J. S. de Ropp K. M. Smith and K. C. Langry J. Am. Chem. SOC.,1983 105 4576. 68 M. Hohn J. Hiittermann J. C. W. Chien and L. C. Dickinson J. Am. Chem. Soc. 1983 105 109. 69 P. Battioni J. P. Mahy G. Gillet and D. Mansuy J. Am. Chem. SOC.,1983 105 1399. 70 K. L. Kunze and P. R.Ortiz de Montcllano J. Am. Chem. SOC.,1983 105 1380. 7' T. G. Traylor K. B. Nolan and R. Hildrith J. Am. Chem. SOC.,1983 105 6149.72 J. P.Collman C. S. Bencosme R. R. Durand R.D. Kreh and F. C. Anson J. Am. Chem. SOC.,1983 105 2699. 73 J. P. Collman J. 1. Brauman K. M. Doxsee J. L. Sessler R. M. Moms and Q. H. Gibson Znorg. Chem. 1983 22 1427. 74 J. P. Collman J. I. Brauman T. J. Collins B. L. Iverson G. Lang R. B. Pettman J. L. Slesser and M. A. Walters J. Am. Chem. SOC.,1983 105 3038. B. W.Fitzsimmons -H H- (15) M = Fe M'= Co (16) M = Fe described the factors enhancing O2 affinity over that for CO being further el~cidated.~~ The molecular structure of an iron-chlorin has been established using X-ray methods. The chlorin is Fe(OEC) OEC = trans-7,8-dihydro-2,3,7,8,12,13,17,18-octaethyl porphyrinato diani~n.'~ Like Fe"TPP this compound has S = 1.A low-temperature( 100 K) X-ray diffraction study has been carried out on the methoxy compound [MeOFe(TPP)] and the electron-density difference maps con- structed. The electron distribution at the iron is seen to be spherical in agreement with high-spin iron( III).~~ The trans-difluoro anion [F,Fe(TPP)]- prepared by HF cleavage of the p-0x0dimer is a high-spin porphyrinate with an unusually expanded iron core and a hydrogen-bonded distal imida~ole.'~ Low-spin six-co-ordinate [FeTPP(CN)Py] has been synthesized and its structure together with that of a manganese analogue established by X-ray method^.'^ A monoclinic form of bis(3- chloropyridine)(octaethylporphinato)iron(Ir) perchlorate has been prepared its molecular structure solved by X-ray methods and otherwise physically characterized.Previously reported as a singlet-triplet spin-equilibrium it now emerges that it is the triclinic modification which is a spin-equilibrium but this phase with peff= 4.7 BM at 295 K is a quantum-mixed intermediate-spin state.80 Thin-layer spec- troelectrochemical techniques have been deployed in an investigation of the Fe"/ Fe"' couple in [Fe"'TPP]+X- as a function of counterion.81 Hydrogen-bonding from imidazole has been shown markedly to affect the redox potential of iron-porphyrin complexes the iron( 111) state being significantly stabil- ized.82A study in which electronic spectroscopy and electrochemical techniques are combined is that of the electron-transfer reactions of the complexes [Fe( NO)TPP] or [Fe"(NO)OEP] it has led to the elucidation of a variety of processes including 75 J.P. Collman J. I. Brauman B. L. Iverson J. L. Sessler R. M. Morris and Q. H. Gibson J. Am. Chem. Soc. 1983 105 3052. 76 S. H. Straws M. E. Silver and J. A. Ibers J. Am. Chem. SOC.,1983 105 4108. 77 C. Lecompte D. L. Chadwick P. Coppens and E. D. Stevens Inorg. Chem. 1983 22 2982. 78 W. R. Schiedt Y. J. Lee S. Tamai and K. Hatano J. Am. Chem. SOC., 1983 105 778. 79 W. R. Schiedt Y. J. Lee W. Luangdilok K. J. Haller K. Anzai and K. Hatano Inorg. Chem. 1983 22 1516. 80 W. R. Schiedt D. K. Geiger R. G. Hayes and G. Lang J. Am. Chem. Soc. 1983 105 2625. 81 K. M. Kadish and R. K. Rhodes Znorg. Chem. 1983 22 1090. 82 M. M. C. Doeff D. A. Sweigart and P.O'Brien Inorg. Chem. 1983 22 851. Fe Co Ni 22 1 the formation of bis-nitrosyl complexes and the co-ordination of solvent m01ecules.~~ The injection of two electrons into porphyrinatoiron carbene complexes is a carbene- centred reaction. Thus the dichlorocarbene derivative [TPPFe :CCl,] is smoothly converted into the p-carbido dimer [TPPFe2C].84 The same group of workerss4 have prepared a wide range of nitrosoalkane complexes [( RNO)FeTPP] some having axially co-ordinated .axial base. The molecular structure of one example [(i- C3H7NH2)Fe(TPP)(i-C3H7N0)],established using X-ray methods reveals N-bonding of the RNO ligand and consideration of physical properties reveals a strong similarity between RNO and O2 as ligands to iron.s5 A photogalvanic cell has been constructed in which the illuminated electrode is coated with [ClFe"'TPP(irnidaz~le)]~ and voltages generated by photodissociation of C0.86 Iron(rr )tetrakis ( N-methyl-4-pyridy1)porphyrinhas been shown to convert O2 into H20 in a multistage The effect of the spin-equilibrium in electron-transfer rate-constants in a series of bis-axial ligand octaethyl-porphyrin complexes has been shown to play little role in the processes.88 Porphyrin complexes in the presence of iodosylbenzene a source of oxygen atoms catalyse the hydroxylation of unactivated alkanes.89 This same system brings about the epoxidation of alkenes e.g.cyclohexene -* cyclohexene oxide (93%).90 Chiral iron porphyrins have been successfully employed in reaction with prochiral alkenes to yield chiral epoxides?' Introduction of bulky substituents (t-BuCONH) into the ortho position of TPP ligands leads to isomerism.By recording the * H n.m.r. spectra of the different low-spin bis-ligand complexes it proved possible to assign the pyrrole resonances and to sort out the preferred site for electron delo~alization.~~ Using 13C-enriched CO the mechanisms of spin-lattice relaxation have been established in particular the effect of tr~ns-ligation.~~ Work has con- tinued on the TPP complexes in which the iron atom carries an inserted ligand. The complexes (17) and (18) have been examined with the aid of resonance Raman Ar ,Ar C II 83 D. Lancon and K. M. Kadish J. Am. Chem. Soc. 1983 105 5610. 84 J.-P. Battioni D.Lexa D. Mansuy and J.-M. Saveant J. Am. Chem. Soc. 1983 105 207. D. Mansuy P. Battioni J.-C. Chottard C. Riche and A. Chiaroni 1.Am. Chem. Soc. 1983 105 455. 86 B. M. Hoffman and P. D. Sima J. Am. Chem. SOC.,1983 105 1776. P. A. Forshey and T. Kuwana Znorg. Chem. 1983 22 699. 88 K. M. Kadish and C. H. Su J. Am. Chem. Soc. 1983 105 177. 89 J. T. Groves and T. E. Nemo J. Am. Chem. Soc. 1983 105 6243. 90 J. T. Groves and T. E. Nemo J. Am. Chem. Soc,1983 105 5786. 9' J. T. Groves and R. S. Meyers J. Am. Chem. Soc. 1983 105 5791. 92 F. A. Walker J. Buehler J. T. West and J. L. Hinds J. Am. Chem. Soc. 1983 105 6923. 93 T. Perkins J. T. Saterlee and J. H. Richards J. Am. Chem. Soc. 1983 105 1350. 222 B. W. Fitzsimmons spectroscopy. There are significant differences between the spectra of these and their four-fold symmetric analogues.The differences are traced to a severe tilting of one of the pyrrole rings in the inserted corn pound^.^^ Mossbauer spectroscopy has been used in a sort-out of the different centres of oxidation in a series of p-0x0 and p-nitrido iron( rrr) complexes.95 The principal component of the electric field gradient as determined using magnetically perturbed Mossbauer spectroscopy is negative in the bis carbonyl of iron( 1I)octamethylbenzporphyrin. It is shown that successive replacement of piperidine by CO increases the negative contribution to Vzz.It is positive in the TPP analogue and negative in the five-co-ordinate monocar- bony1 TPP or OEP complexes.96 Magnetic circular dichroism has been established as a useful technique for the determination of the magnitude and sign of zero-field splitting in iron( 111) porphyrinato complexes such as [ClFe(TPP)] for which a value of 6.9 cm-' has been rep~rted.~' E.p.r.studies of a series of thiolato complexes of the type [(thiolate)FeTPP] have established a correlation between the pK of the thiolate and the tetragonality of the ligand field.98 Electron ionization mass spectra as a function of sublimation temperature between 600 and 670 K have been obtained for iron cobalt and nickel phthal~cyanins.~~ Two crystalline modifications of p-oxobisphthalocyaninatoiron(rrr) have been synthesized and characterized. These seem to be the first iron( 111) phthalocyanin compounds to be isolated it is suggested that different Fe-0-Fe bond angles are involved.loo The crystal and molecular structure of ferrous phthalocyanin has been determined at 110 K.Inspection of the electron-density difference maps has led to direct establishment of the electronic ground state lo' it is 3Eg.Enhanced Fe-02 bonding has been attributed to H-bonding to the unco-ordinated end of the O2 molecule in a model system as judged from the result of an 'H n.m.r. study."* Further Papers on the Subject of Porphinato Complexes of Iron these are listed in Table 2.'03"11 94 B. Chottard D. Mansuy and H. J. Callot Inorg. Chem. 1983 22 362. 95 D. R. English D. N. Hendrickson and K. S. Suslick Inorg. Chem. 1983 22 367. % K. J. Reimer C. A. Sibley and J. R. Sam J.Am. Chem. SOC.,1983 105 5147. 97 W. R. Browett A. F. Fucaloro T. V. Morgan and P. J. Stephens 1. Am. Chem. SOC.,1983 105 1868. 98 M. P. Byrn B. A. Katz N. L. Keder K. R. Levan C. J. Magurany K. M. Miller J. W. Pritt and C. E. Strouse J. Am. Chem. SOC.,1983 105 4916. 99 S. M. Schildercrout J. Am. Chem. SOC.,1983 105 3852. 100 C. Ercolani M. Gardini F. Monacelli G. Pennesi and G. Rossi Inorg. Chem. 1983 22 2584. 101 P. Coppens L. Li and N. J. Zhu J. Am. Chem. SOC.,1983 105 6173. I02 J. Mispelter M. Momenteau D. Lavalette and J.-M. Lhoste J. Am. Chem. SOC.,1983 105 5165. 103 J. D. Saterlee J. D. Erman G. N. La Mar K. M. Smith and K. C. Langry J. Am. Chem. SOC.,1983 105 2099. I04 J. A. Shelnutt J. Am. Chem. SOC.,1983 105 774. I05 J. A.Shelnutt Inorg. Chem. 1983 22 2535. '06 J. S. Olsen R. E. McKinnie M. P.Mims and D. K. White J. Am. Chem. Soc. 1983 105 1522. 107 G. A. Schick and D. F. Bocian J. Am. Chem. SOC 1983 105 1830. I08 P. Jones D. Mantle and I. Wilson J. Chem. SOC.,Dalton Trans. 1983 161. '09 A. Shirazi E. Leum and H. M. Goff Inorg. Chem. 1983 22 360. I10 J. M. Green and L. R. Faulkner 1.Am. Chem. Soc. 1983 105 2950. Ill L. Griffiths B. P. Straughan. and D. J. Gardiner J. Chem. SOC.,Dalton Trans 1983 1193. Fe Co Ni 223 Table 2 Subjecr Ref 'H n.m.r. spectra of cyctochrome c and azido derivatives 103 Resonance Raman spectra of metallouroporphyrins Fe"' Co" Ni" and Cull and their 1,l O-phenanthroline complexes 104 105 Kinetics and mechanism of reaction between alkyl isocyanides and 106 protohaem complexes Resonance Raman spectra of p-nitrido tetraphenylporphyrine com-plexes 107 Reaction kinetics of hydrogen peroxide-iron( 111) porphyrin reactions 108 13Cand 'H n.m.r.spectra of iron porphyrin 1,2-dimethylimidazole com- plexes 109 Redox reactions of thin films of metal (Fey Co Ni Cu or Zn) phthalocyznins 110 Resonance Raman spectra of iron( 11) phthalocyanins 111 Compounds Containing Iron-Sulphur Bonds.-Four new low-spin iron( rv) dialkyl diselenocarbamate complexes [Fe( Se2CNR2),]' have been prepared as BF4 salts and subjected to variable-temperature magnetochemistry Mossbauer spectroscopy hnd X-ray photoelectron spectroscopy. The molecular structure of the N,N-dibenzyl derivative solved by X-ray methods shows an [FeSe6] core intermediate in stereochemistry between octahedral and trigonal prism.112 A range of Fe" and Fe"' complexes of the thio-Schiff bases (19) (20) and (21) have been prepared and the CH=N CH=N NH2 \R \R! \R! molecular structure of a p-0x0 bridged dinuclear example determined by X-ray diffraction.'13 The four-co-ordinate [FeS,] salt NEt,[Fe(SPh),] has DZdsymmetry as determined using X-ray diff raction.'14 The simple monomeric tetrahedral systems [Fe(MS4)J3-(M = Mo or W) have now been satisfactorily prepared and charac- terised."' The electronic ie.and resonance Raman spectra of a series of the type (22) have been recorded and evidence found for extensive Fe-S electron (22) M = Mo or W I12 P. Deplano E. F.Trogu F. Bigoli E. Leporati M. H. Pellinghelli D. L. Perry R. L. Saxton and L. J. Wilson J. Chem. SOC.,Dalton Trans. 1983 25. 113 P. J. Marini K. S. Murray and B. 0. West J. Chem. SOC.,Dalton Trans. 1983 143. 114 S. A. Koch L. E. Maelia and M. Millar J. Am. Chem. SOC.,1983 105 5944. 115 C. D. Friesen J. W. McDonald W.E. Newton W. B. Euler and B. M. Hoffman Inorg. Chem. 1983 22 2202. 224 B. W Fitzsimmons delocalization. ' l6 The e.p.r. spectra of chemically reduced species of formula [Fe,S,(S Aryl),] have been recorded and analysed.' '' The tetrahedral [Fe"S,] complex anions [(C6H5S) FeS2MS,I2-and [(S5)FeS2MS2I2-have been synthesized and spectroscopically characterized.' '*New synthetic methods for the preparation of the dinuclear complexes [Fe S2Cl4I2-and [Fe20Cl6I2-have been developed.' l9 The complex anion [Fe(SEt),12-is a strong reducing agent and serves as a versatile precursor to a series of 2Fe 3Fe and 6Fe [Fe-S-SR] clusters.'20 A detailed study involving isotopic substitution of the resonance Raman and i.r.spectra of spinach ferredoxin adredoxin and an analogue compound has been carried out. The ends of the FezS2complex are inequivalent as a result of the neighbouring protein.'21In a similar study of rubredoxin splittings of the Fe-S modes are again detected but here attributed to coupling between Fe-S and S-C-C modes.'22 Applying the experimental method outlined above to 3Fe and 4Fe ferredoxins evidence is put forward for non-planar conformations (23) or (24) of [3Fe-3-S] structure^.'^^ s\ S S/Fe-S (23) (24) This year sees the full account of the preparation and characterization of a number of salts of a single [MoFe,S,] cubane structure similar in all respects with that thought to be present in nitrogenase.The synthesis and full structural characteriz-ation using X-ray methods ofthe [Fe Mo] cubane cluster (25) has been de~cribed.'~ 3-I \ L SAr (25) R = vinyl I I6 R. J. H. Clark T. J. Dines and G. P. Proud J. Chem. SOC.,Dalton Trans. 1983 2299. I I7 P. Beardwood and J. F. Gibson J. Chem. Soc. Dalton Trans. 1983 737. I18 D. Coucouvanis P. Stremple E. D. Simhon D. Swenson N. C. Baenziger M. Draganjac L. T. Chan A. Simopoulos V. Papaefthymiou A. Kostikas and V. Petrouleas Inorg. Chem. 1983 22 293.I19 Y. Do E. D. Simhon and R. H. Holm Inorg. Chem. 1983 22 3809. 120 K. S. Hagen A. D. Watson and R. H. Holm J. Am. Chem. Soc. 1983 105 3905. 121 V. K. Yachandra J. Hare A. Gewirth R. S. Czernuszewicz T. Kimura R. H. Holm and T. G. Spiro J. Am. Chem SOC.,1983 105 6462. V. K. Yachandra J. Hare H. I. Moura and T. G. Spiro J. Am. Chem. Soc. 1983 105 6455. I23 M. K. Johnson R. S. Czernuszewicz T. G. Spiro J. A. Fee and W. V. Sweeney J. Am. Chem. SOC. 1983 105 6671. 124 P. K. Masharak W. H. Armstrong Y. Mizobe and R. H. Holm J. Am. Chem. SOC.,1983 105,475. 12' Fe Co Ni 225 Although the M-S and Fe-S(C1) distances as determined by EXAFS agree with the crystallographic values for the anion [C12FeS2MS2FeC1J2- to better than 9% a comparison of EXAFS parameters of the dianion with those of the MoFe protein of nitrogenase reveal significant difference^.'^^ An interesting stereochemical change has been observed for an [Fe,S,] cubane.This is the anion [Fe,S,-(S-p-C,H,Br),]- which is non-tetragonal in the solid but is tetragonal in solution. A further core change is one associated with electron- transfer and seems to be a general feature of these systems.126 A neutral cubane prepared from either [Fe4(SR),I2- or [Fe4S4Cl4I2- has the structure (26).127 Trinuclear complexes [M3S(S2-~y1)3]2- (M = Fe or Co”’ S,-xyl = 0-xylene-[a,a‘]-dithiolate have been prepared and isolated as their [Et,N] salts. 0-Ph Ph/O ‘ The molecular structure of one example (27) has been determined and the isomorph- ism of the iron and cobalt derivatives established.’28 The structure of the quasi-cubane cluster [Fe,S4(SPh)2( Et,dt~)~]~- contains inequivalent pairs of four- and five-co- ordinate iron atoms.*29 The kinetics and mechanism of an homogeneous H,-evolving system [Mo Fe6S8(SPh),14-”-PhSH have been investigated and a reaction scheme put forward. 130 Compounds with Iron-Halogen Bonds.-In response to the publication of conflicting results a re-examination of the species present in aqueous solutions of iron(m) chloride has been made using X-ray methods. An earlier report of the formation of chloro-complexes has been ~onfirmed.’~’ The 57Fe Mossbauer spectra of the chloro-complexes [M’M”xFel-xC13~2H20] (M’ = K or Rb M” = Mn Co or Ni x = 0.5) have been recorded and interpreted,132 as have spectra of the compounds M,Fel-,C12~yH,0(M = Mn Co or Ni; x = 0.5 or 0.6.133 The complex [FeCl6l3- has been investigated as an impurity in an exact octahedral site using absorption and m.c.d.spectroscopy and the results fitted to a ligand-field 125 B. K. Teo M. R. Antonio D. Coucouvanis E. D. Simhon and P. P. Stremple J. Am. Chem. Soc. 1983 105 5767. 126 D. W. Stephan G. C. Papaefthymiou R. B. Frankel and R. H. Holm Inorg. Chem. 1983 22 1550. 127 W.E. Cleland D. A. Holtman M. Sabat J. A. Ibers G. C. DeFotis and B. A. Averill J. Am. Chem. SOC.,1983 105 6021. 128 KdS. Hagen G. Christou and R. H.Holm Inorg. Chem. 1983 22 309. I29 M. G. Kanatzidis M. Ryan D. Coucouvanis A. Simopoulos and A. Kostikas Inorg.Chem. 1983 22 179. 130 T. Yamamura G. Christou and R.H. Holm Inorg. Chem. 1983 22 939. 131 G. Giubileo M. Magini G. Licheri G. Paschina G. Piccaluga and G. Pinna Inorg. Chem. 1933 22 1001. ‘32 B. Y. Enwiya J. Silver and I. E. G. Morrison J. Chem. SOC.,Dalfon Trans. 1983 1039. ‘33 B Y. Enwiya J. Silver and I. E. G. Morrison J. Chem. Soc. Dalton Trans. 1983 2581. 226 B. W. Fitzsimmons m0de1.l~~ The magnetic properties of the tetragonal phase K Mn Fel- F3 have been studied over a range of comp~sition.'~~ Iron Carbonyls and Related Compounds.-Products of y-radiolysis of frozen glasses containing Fe(CO)5 or [Fe(C0)4]- have been identified using e.p.r one-electron addition dominate^.'^^ The unsaturated species [Fe(CO),]( n = 2,3 or 4) have been identified as products in the pulsed U.V.photolysis of Fe(C0)5.137 The iron carbonyls Fe2(C0)9 or Fe,(CO), interact with hydrated sodium-Y zeolite as the hydrido- species [HFe,(CO) Both unsaturated metallic molecular ions and atomic ions are formed if iron carbonyls or their substituted derivatives are subjected to U.V. and visable multiphoton processes.139 The nature of the bonding in [Fe(C0)4.CH2=CH2] has been looked into with the aid of photoelectron spectros- copy.14o Sulphinylaniline complexes e.g. [Fe( PPh3)2Me(CH20)3 P(ArNSO)] having the structures indicated in (28) have been prepared and ~haracterized.'~' Sulphur dioxide is a two-electron q'-donor in a series of five-co-ordinate compounds [FeL2(C0),S02] [L = (Ph0)3P etc.].These air-stable complexes exist in two forms trans-diaxial phosphite or trans-diaxial carbonyl the molecular structures of examples of each having been determined.'42 The photochemical reactions at 77 K of a series of compounds [alkene.Fe(CO),] are dependent upon the alkene with either allyls or hydrido-allyls identified as The molecular structure of the tricarbonyl derivative [1,2-bis(2',6'-di-isopropylpheny1imino)ethane-NN'Itricarbonyliron has been determined and its m.c.d. and resonance Raman spectra recorded.lM The chelating isocyanide (29) forms complexes [ML3](PF6) (M = Fe z = 2; M = Co z = 3) and ViI+.145 1,2-Ar-O n0-Ar-1,2 ON /PPh \ N N/ ,Fe-H $ C4 OC 'PPh I34 K. Neuenschwander H. U. Giidel J. C. Collingwood and P. N. Schatz Inorg.Chem. 1983 22 1712. 13' E. Banks M. Shone R. F. Williamson and W. 0.J. Boo Inorg. Chem. 1983 22 3339. I36 B. M. Peake M. C. R. Symons and J. L. Wyatt J. Chem. Soc. Dalton Trans. 1983 1171. I37 A. J. Ouderkirk P. Werner N. L. Schulz and E. Weitz J. Am. Chem. SOC.,1983 105 3354. 138 M. Iwamoto H. Kusano and S. Kagawa Inorg. Chem. 1983 22 3365. 139 D. G. Leopold and V. Vaida J. Chem. SOC.,1983 105 6809. 140 D. B. Beach and W. L. Jolly Inorg. Chem. 1983 22 2137. I41 H. C. Ashton and A. R. Manning Inorg. Chem. 1983 22 1440. 142 P. Conway S. H. Grant A. R. Manning and F. S. Stephens Inorg. Chem. 1983 22 3714. I43 J. C. Mitchener and M. S. Wrighton J. Am. Chem. SOC.,1983 105 1065. 144 M. W. Kokkes D. J. Stufkens and A. Oksam J.Chem. SOC.,Dalton Trans. 1983 439. 145 D. T. Plummer and R. J. Angelici Inorg. Chem. 1983 22 4063. Fe Co Ni 227 Protonation of the salt Na+[Fe(CO) NO]- in excess triphenylphosphine affords the new 18-electron hydrido-complex [FeH( CO)( NO)( PPh3)2] which has the distorted trigonal-bipyramidal structure drawn in (30).’& The solid-state and solution struc- tures of the salts M+[Fe(CO),NO]- have been investigated in a study that includes a determination of the molecular structure of the [(Ph,P),N]+ salt in which anion disorder was apparent.14’ This year sees reports of the full characterization of some phosphene complexes (31),’48 (32),’49and (33).I5OA number of sulphane complexes of the type [E.L-S,(C~F~(CO)~](X = 1 2 3 or 4) have been prepared by reaction of the anion on SC12 S2C12 etc.Two examples having x = 3 or 4 were structurally ~haracterized.’~’ /FY0)4 (Me,Si),CH P=P /Fe(CO) (W4Fy /R \ Rip-P=p /\ I ’\R (CO),Fe CH(Si Me,) Fe(C0)4 R I But But The synthesis and characterization of some compounds [Na(thf),],[M{ Fe( CO),},] (M = Zn Cd or Hg) have been described in which metal M bridges the iron atoms in a linear fa~hi0n.l~~ The addition of carbanions e.g. Me,CCN-(R) to 7j4-(l,2- diene)Fe(CO) complexes under a mild pressure of CO followed by methylation leads to the formation of (34). The structure of an intermediate in this reaction has been proposed on spectral evidence.’53 The photochemistry of [( 7j4-cyclo-octatetraene)Fe(CO),] at 12 K in methane has been investigated and analysed with the help of 13C0 labelling in i.r.spectro~copy.”~ The reactions of trimethylphosphite ‘46 M. Cygler F. R. Ahmed A. Forgues and J. L. A. Roustan Znorg. Chem. 1983,22 1026. 147 K. H. Pannell Y. S. Chen K. Belknap C. C. Wu,1. Bernal M. W. Creswick and H. N. Huang Znorg. Chem. 1983 22 418. 148 K. M. Flynn M. M. Olmstead and P. P. Power J. Am. Chem. Soc. 1983 105 2085. I49 K. M. Flynn H. Hope B. D. Murray M. M. Olmstead and P. P. Power J. Am. Chem. SOC.,1983 105 7750. 1 SO A. H. Cowley J. E. Kilduff J. G. Lasch N. C. Norman M. Pakulski F. Ando and T. C. Wright 1. Am. Chem. Soc. 1983 105 7751. 151 M. A. El-Hinnawi A. A. Aruffo B. D. Santarsiero D. R. McAlister and V. Schomaker Znorg. Chem. 1983 22 1585. ’” B.A. Sosinsky R. G. Shong B. J. Fitzgerald N. Norem and C. ORourke Inorg. Chern. 1983,22,3124. 153 M. F. Semmelhack J. W. Herndon and J. P. Springer J. Am. Chem. SOC.,1983 105 2497. R. B. Hitam R. Narayanaswamy and A. J. Rest J. Chem. SOC.,Dalton Trans. 1983 1351. 228 B. W. Fitzsimmons complexes [Fe(CO),- { P(OMe)3}nq4-C,H8R]+ with chloride ion yield phosphonate species arising from CH3 C1 elimination. Investigations have continued on the use of diene( tricarbonyliron) complexes as enantioselective synthons. Diasteriosomeric pairs obtained from nucleophilic attack by chiral phosphines on ( 1-5-q-cyclohexadienyl)irontricarbonyl salts have been separated and successfully deployed in asymmetric induction^.'^^ The reactions Of [q4-C7H8*Fe(Co)3] with diazonium cations have been developed as a route to hydrazone derivative^."^ The possibility of metal-metal double bonding in the dinuclear complex [Fe2(C0)6S2] has been considered and reje~ted.'~' The phosphido-bridged species (35) is a product of methylation of an anion obtained from [Fe2(C0)6( PPh2)2].159 The bridged vinylidenedi-iron complex (36) has been prepared by a multi-step procedure.Me PPh2Me (35) (36) The acetylide complexes (37) undergo a wide range of reactions with amines to yield compounds of the type (38). Some of the broad scope of this reaction has now been revealed.161 R2 \ R'-N+ \7-y.-/H (CO),Fe-Fe(C0)3 \P' Ph/' 'Ph Ph/' 'Ph (37) R = various e.g. Ph But (38) R,R1,R2 = various Electrochemical studies reveal that Prussian Blue deposits from a solution of Fe3+ and [Fe(CN),I4- by two dominant electroreductions and that redox to Prussian Green [Fe1"(CN)6]2,3[Fe11(CN)6],J3 is partially achieved.'62 The 57Fe Mossbauer spectral parameters of a number of pentacyano(base) fer- rates( 11) have been recorded and 1i~ted.I~~ N.G. Connelly A. R. Lucy and M. W. Whiteley J. Chem. SOC.,Dalton Trans. 1983 117. lS6 J. A. S. Howell and M. J. Thomas J. Chem. SOC.,Dalton Trans. 1983 1401. 157 N. G. Connelly A. R. Lucy and J. B. Sheridan J. Chem. SOC.,Dalton Trans. 1983 1465. 158 R. L. DeKock E. J. Baerends and A. Oskam Inorg. Chem. 1983 22 4158. lS9 Y.F. Yu J. Gallucci and A. Wojicki J. Am. Chem SOC.,1983 105 4826. 160 G. M. Dawkins M. Green J. C.Jeffrey,C. Sambale and F. G. A. Stone J. Chem. SOC.,Dalton Trans. 1983 499. 16' G. N. Mott and A. J. Carty Inorg. Chem. 1983 22 2726. I62 R. M. C. Goncalves H.Kellawi and D. R. Rosseinsky. J. Chem. SOC.,Dalton Trans. 1983 991. 163 K. J. Moore L. Lee and J. D. Petersen Inorg. Chem. 1983 22 1244. Fe Co Ni 229 Ferrocene its Derivatives and Related Compounds.-The molecular quad-rupole moments of ferrocene and ruthocene have been determined the results are in agreement with a model in which charge is transferred from ring to metal.164 Electrochemical investigations of [FeCp,]+ and its permethylated analogue in liquid SO2 show both an oxidation and a reduction wave. A magnetic moment of one of the iron( IV)species was Once again the ferrocenium cation has been utilised in the isolation of a new anion.Photo-induced O2oxidation of ferrocene in the presence of BiBr3 yields [Fc]+~[B~~B~,,] with BiOBr as a by-product. The anion has an open double-cubane structure with the intermediate-conformation Fc+ units lying on either side.’66 The interaction of the 19-electron species [CpFe’( q6-C6%)] with dioxygen to give superoxide and an iron(rr) species is shown to be subject to a very strong salt effect.167 The photochemically-induced release of arene from [CpFe(arene)]+ has been studied as a function of anion and solvent; a wide range of quantum yields is observed.’68 Some solvents e.g. acetonitrile play a major role in this reaction. By running the reaction at -40 “C a purple intermediate [CpFe(NCMe),]+PF, was detected and this proved to be a useful intermediate in the preparation of phosphine and phosphate derivatives [CpFe( NCMe)( L)( L’)]+PF6-.16’ An extensive review of the area of [CpFe Arene] chemistry has been p~b1ished.l~’ A series of elaborate ferrocenyl-containing acylating agents have been prepared and their acylating rates with cyclodextrin determined.”’ A full account of the preparation and Mossbauer spectral details of phosphenium cations e.g.(39) has appeared.172 Redox properties of ferrocenylalkyl-substituted quaternary ammonium cations in aqueous organic and molten-salt phases have been determined.’73 The synthesis of cations of the type [FeCp{ PhP(CH2CH2PPh2)2}]+ has been described. They are reduced regioselectively by LiA1H4 via direct attack on the Fe Fe 00 I64 L.D. Ritchie M. K. Cooper R. L. Calvert G. R. Dennis L.Phillips and J. Vrbaneich J. Am. Chem. SOC., 1983 105 5215. I65 P. R. Sharp and A. J. Bard Inorg. Chem. 1983 22 2689. I66 A. L. Rheingold A. D. Uhler and A. G. Landers Inorg. Chem. 1983 22 3255. I67 J.-R. Hamon and D. Astruc J. Am. Chem. SOC.,1983 105 5941. 168 J. L. Schrenk M. C. Palazzotto and K. R. Mann Inorg. Chem. 1983 22 4047. I69 T. P. Gill and K. R.Mann Inorg. Chem. 1983 22 1986. I 70 D. Astruc Tetrahedron 1983 39 4027. 171 R. Breslow G. Trainor and A. Ueno J. Am Chem. SOC.,1983 105 2739. 172 S. G. Baxter R. L. Collins A. H. Cowley and S. F. Sena Inorg. Chem. 1983 22 3475. I73 R. J. Gale K. M.Motyl and R. Job Inorg. Chem. 1983 22 130. 174 S. G. Davies S. J. Simpson H. Felkin F. Tadj and 0.Watts J. Chem. SOC.,Dalton Trans. 1983 981. B. W. Fitzsimrnons Iron-zirconium compounds (40) and (4 1) have been synthesized by metathesis from e.g. Cp2ZrC1Me and K[CPF~(CO)~].~~~ CP\ /Me Zr Photoelectron spectral data backed up by MO calculations reveals a similarity in bonding between ethene and B2H5 in the two species (42) and (43).176 H H \ co H-c I ,co H-bTCO H/ co (42) (43) Nucleophilic replacement of CO by isocyanide in the compound [CpFe( CO)2X] (X = halogen) is catalysed by [CpFe(CO)J2; electron-transfer processes are in~0ked.l~~ A new FeRu dimer (45) has been prepared from (44) by the route shown in Scheme 1.17* (44) (45) Scheme 1 Gamma irradiation of [CpFe(CO),X] (X = C1 or I) affords radical anions which were detected by e.p.r.The spectra are dominated by hfs involving coupling to ha10gen.l~~ The silanes (46) and (47) have been synthesized and characterized.'" Electrophilic attack by the cations [Fe(C0)3( 1-5-pentahaptodienyl)]' (dienyl = C6H7 or 2-MeOC6H,) on reaction with aryltrimethyl-silanes and -stannanes yields a variety of diene-substituted arenes and heterocycles in a reaction that was also studied kinetically.'" 175 C. P. Casy R. F. Jordan and A. L. Rheingold 1. Am. Chem. Soc. 1983 105 665. I76 R. L. DeKock P. Deshmukh T. P. Fehlner C. E. Housecroft J. S. Plotkin and S. G. Shore J. Am. Chem. Soc. 1983 105 815. 1 ?? N. J. Coville M.0. Albers and E. Singleton J. Chem. Soc. Dalton Trans. 1983 947. 178 H. R. Alcock L. J. Wagner and M. Levia J. Am. Chem. Soc. 1983 105 1321. I79 M.C. R. Symons S.W. Bratt and J. L. Wyatt J. Chem. SOC.,Dalton Trans. 1983 1377. 180 W. W. McConnell G. 0. Nelson and M. E. Wright Znorg. Chem. 1983 22 1689. 181 G. R. John L. A. P. Kane-Maguire T. I. Odika and C. Eaborn J. Chem. SOC.,Dalton Trans. 1983 1721. Fe Co Ni 23 1 Me Me Q'iq I 'BF OC-Fe Fe-CO oc \/Lo (46) R = HorMe (47) OC-Fe, oc/ O-S0,CF3 (48) The synthesis and molecular structure of the trifluoromethylsulphonate (48) has been reported.18* Compounds of the type [CpFe(C0)2SPh] react with NOPF to undergo oxidative coupling to the cationic species (49).'83Hydride ion adds initially to the Cp ring Me$Me Me I Me OC-Fe ,Ph 1s oc I (-0 + ph/S' Fe-CO pF6-1 1 Me Me (49) and then to the alkyne to yield an alkene in which H i's cis to the iron atom (50) +(51) (Scheme 2).lg4External-source CO adds to the carbene (52) to yield (51) Scheme 2 182 M.B. Humphrey W. M. Lamanna M. Brookhart and G. R. Husk inorg. Chem. 1983,22 3355. 183 P. M.Treichel L. D. Rosenhein and M. S. Schmidt inorg. Chem. 1983,22 3960. I84 D.L.Reger K. A. Belmore J. L. Atwood and W. E. Hunter J. Am. Chem. SOC.,1983 105 5710. B. W. Fitzsimmons the ketene derivative (53) (Scheme 3) which is stable at ambient temperat~re.'~~ Photochemically-induced substitution of CO in [CpFe( CO),] by phosphine or phosphite yields a single mono-substituted product a radical mechanism is involved.186 Enantioselective cyclopropane synthesis has been achieved by reaction of [CpFe(CO),:CRR]+ with alkenes and it is shown that chiral carbenes of the type [Cp(CO)( PR,)Fe:CHR]+ will be generally useful for asymmetric synthesis of cyclo- propanes.187 2 Cobalt Low Oxidation-state Compounds of Cobalt.-Dicobalt octacarbonyl is a catalyst in the transformation of alkyl acetates into [(trialkylsiloxy)methylene]alkanes (54) -+ (55) (Scheme 4).lg8 It reacts photochemically with [co2(co)&] (L = phosphine) to give an equilibrium mixture of the starting compound [Co2(C0),L2] (55) R = various Scheme 4 and [CO,(CO)~L]. Kinetic evidence in favour of a homolytic fission mechanism is presented and a reaction scheme The complexes [Co(CO)L(Cp)] (L = P( C6H1 1)3 or PPh3) undergo one-electron electrochemical oxidation to the corres- ponding radical-cations.Chemical oxidation with ferrocenium hexafluorophosphate gives [CO(Co)L(Cp)]+(PF,)- with L = P(C6H11)3.If L = PPh3 the product is [CoL2(Cp)]+( PF6)-. Substitution reactions to give paramagnetic [CoL{P(C,H ,),)Cp]+(PF6)- (L = PPh or pyridine) are also reported.'" Nitrosonium hexafluorophosphate reacts with [Co(CO) (Cp)] to yield [Co,( p-CO)(p-NO)( Cp),]PF, which can be subsequently chemically or electrochemically reduced to the paramagnetic complex [Co2( p-NO)(Cp)2].'91 The molecular structure I85 T. W. Bodner and A. R. Cutler J. Am. Chem. SOC. 1983 105 5926.I86 D. R. Tyler M. A. Schmidt and H. B. Gray J. Am. Chem. SOC.,1983 105 6018. 187 M. Brookhart D. Timmers J. R. Tucker G. D. Williams G. R. Hurk H. Brunner and B. Hammer J. Am. Chem. SOC. 1983 105 6721. I88 N. Chatani S. Murai and N. Sonoda J. Am. Chem. SOC.,1983 105 1370. 189 R. W. Wegman and T. L. Brown Inorg. Chem. 1983 22 183. I90 K. Broadley N. G. Connelly and W. E. Geiger J. Chem. SOC.,Dalton Trans. 1983 121. 191 N. G. Connelly J. D. Payne and W. E. Geiger J. Chem. Soc. Dalton Trans. 1983 295. Fe Co Ni 23 3 of the p-methylene dicobalt species (56) one of a range of compounds prepared by the action of gem-di-iodoalkanes on Na[Cp(CO)] has been e~tab1ished.l~~ The Me Mk (56) compounds (57) e.g. R’= R2= H;R3= Bun,R4= C1 have been prepared in good yields by the reaction of the compound (58) with a1k~nes.I~~ (57) R1-4= various (58) R1,R2 = various The mechanism of the reduction of [v4-(1,5 -C8 H,)CoCp] to the isomerized anion [( 1,3-c8 H8)CoCp]- has been established using electrochemical technique^.'^^ The adduct [{(CO),Co},alkyne] reacts with MeCN or other Lewis bases under conditions of electron-transfer catalysis to yield mono- or di-substitution products e.g.[(CF,),Co,(CO),L] (L = MeCN phosphine or pho~phite).’~’ The kinetics of the reaction between [Cp( R3P)Co.alkene] complexes and alkenes to yield cobaltacyclopentadienes (59) has been investigated and mechanisms advanced.196 Alkynes react readily with the phosphine complexes [CoBr( PMe,)3] to yield a range of mononuclear alkyne-cobalt complexes of which (60) is one example others to be fully structurally characterized include (61) which has a molecule of co-ordinated ~olvent.’~’ (59)R1-4= various (60) (61) I92 K.H. Theopold and R. G. Bergman J. Am. Chem. SOC. 1983 105 464. I93 I. T.Horvath G. Paiyi L. Marko and G. D. Andreetti Inorg. Chem. 1983 22 1049. 194 M. Grzeszczuk D. E. Smith and W. E. Geiger J. Am. Chem. Soc. 1983 105 1772. 195 M. Arewgoda B. H. Robinson and J. Simpson J. Am. Chem. Suc. 1983 105 1983. 196 Y. Wakatsuki 0. Nomura K. Kitaura K. Mokokuma and H. Yamazaki J. Am. Chem. SOC.,1983,105 1907. 197 B. Capelli M. Dartinguenave Y. Dartinguenave and A. L. Beauchamp J. Am Chem. SOC.,1983,105 4662. 234 B.W. Fitzsimmons MO calculations have been carried out for a range of compounds of the type [CpCo(CO),]. These reveal the origin of the bond length alternation as observed in crystallographic studies to be the intramolecular interruption of the conjugated system.'98 The dicobalta cyclohexane (62) demetallates on reaction with phosphines. Both the organic and inorganic products from this have been identified and a reaction scheme established.'99 w Q G?2,Q ,C? co-co ago gD \-co ss An interesting case of a reversible reaction (63) e(64) in a single crystal has been discovered and studied both crystalline phases have the same space group.200 The 59C0 nuclear quadrupole resonance spectra of a range of compounds typified by [CpCo( 1,2-benzoquinone)] have been recorded and interpreted."' Compounds of Cobalt(II).-The oxidation of water to oxygen by [Ru bipy313+ is catalysed by cobalt(I1) ions.A detailed study of the kinetics of this process has revealed that a cobalt(1v) compound is involved.202 The Angular Overlap Model has been applied in an e.p.r. study of a range of cobalt(I1) complexes in which anisotropic bonding interactions were inve~tigated.~'~ Complexes of formula [CoXL,] are either dimeric or polymeric for a wide range of X and L. The factors favouring either form have now been analysed the~retically.~'~ Variable-temperature 'H n.m.r. studies of complexes [ML2(RC02),] {M = Co" or Ni"; L = 3MePy 4MePy or 4EtPy (Py = pyridine); R = CF, CF2H CFH2 or C3H7} have led to a determination of accurate activation energies for cis-trans con~ersion.~'~ The six-co-ordinate antiferromagnetic co-ordination polymer [Co bipy( NCS)2] (bipy = bipyridyl) has been prepared and a zig-zag chain structure established by X-ray methods.206 Although the octahedral complex ion [Co bipy312+ is long-established as a high-spin complex with S = 3/2 it now emerge.that it lies close to the cross-over point an e.p.r. study of this ion as embedded in zeolite-Y reveals a spin-equili- bri~m.~'~ J. W. Chinn and M. B. Hall J. Am. Chem. Soc. 1983 105 4930. I99 W. H. Hersh and R. G. Bergman J. Am. Chem. SOC.,1983 105 5846. 2oo E. J. Miller T. B. Brill A. L. Rheingold and W. C. Fultz J. Am. Chem. SOC.,1983 105 7580. 20 I E. J. Miller and T. B. Brill Inorg.Chem. 1983 22 2392. 202 B. S. Braunschwig M. H. Chou C. Creutz P. Ghosh and N. Sutin J. Am. Chem. Soc. 1983 105,4832. 203 A. Bencini C. Benelli D. Gatteschi and C. Zanchini Znorg. Chem. 1983 22 2123. 204 E. Canadell and 0. Eisenstein Inorg. Chem. 1983 22 2398. *05 A. Goodacre and K. G. Orrell J. Chem. Soc. Dalton Trans. 1983 153. 206 B. W. Dockum G. A. Eisman E. H. Witten and W. M. Reiff Inorg. Chem. 1983,22 150. 207 K. Mizuno and J. H. Lunsford Inorg. Chem. 1983 22 3484. 19' Fe Co Ni 235 The molecular structures of two closely related complexes differing by one unit of oxidation have been determined with a view to comparing electron-transfer reactivity. These are [Co' bipy,]Cl and [Co"bipy,]Cl,. Geometrical changes are very small if compared with the corresponding Co"/Col" couple.208 t-Butyl peroxide reacts with bis( dimethylglyoximato)cobalt( 11) to yield an organocobalt complex.The dependence of product and stoicheiometry upon solvent has been determined in a study of the kinetics.209 The molecular structure of a bis-nitrosyl iodo-complex [CoI( NO) PPh,] has been determined in a 203 K X-ray diffraction study. The nitrosyls are nearly linear in this tetrahedral species and the authors suggest that observations of bent nitrosyls in this stereochemistry may be a result of disorder.210 The structure of another nitrosyl [Co( NO){S,CN( Pri)2}2] has been determined it has a significantly bent NO in the familiar [MS,(NO)] structure. It is noted that this compound is isomor- phous with the iron analogue in which the nitrosyl is perfectly linear.211 As preliminary work to studying [CoS,] chromophores in enzyme systems the circular dichroism and m.c.d.of a range of mononuclear and polynuclear systems have been recorded to establish spectral differences between bridging and terminal thiolates.,12 The complex [Co"(L,Rb)] where L = (65) has been prepared its structure determined and a comparison made with that of the analogous potassium compound with a view to investigating its Rb/K selectivity.,13 The oxidation path- ways of the complex [Co1*(L)Cl]C104 where L = (66),and its Ni" bis-thiocyanato analogue in reactions with [Fe phenJ3+ have been investigated.,14 A green complex CH,C02H U (65) (66) [Co (tren),( OH)]( C1OJ3 (tren = tris[2-(amino)ethylamine)has been characterized by means of electronic spectroscopy and magnetic s~sceptibility.~'~ The kinetics of the bromate oxidation of the cobalt( 11) complex of trans-cyclohexane- 1,2-diamine N,N,N' N'-tetra-acetic acid have been followed and a mechanism advanced.216 The complexes (67),2'7 (68),,18 (69),'19 and (70),,*O form 1 :1 adducts with dioxygen.208 D. J. Szalda C. Creutz D. Mahajan and N. Sutin Inorg. Chem. 1983 22 2372. 209 J. H. Espenson and J. D. Melton Inorg. Chern. 1983 22 2779. 210 B. L. Haymore J. C. Huffman and N. E. Butler Inorg. Chem. 1983 22 168. 21 I G. A. Brewer R. J. Butcher B. Letafat and E. Sinn Inorg. Chem. 1983 22 371. 212 M. Nakata N. Ueyarna A. Nakarnura T. Nozawa and M. Hatano Inorg.Chem. 1983 22 3028. 213 D. L. Hughs and J. N. Wingfield J. Chem. Soc. Dalton Trans. 1983 915. 214 J. A. Switzer J. F. Endicott M. A. Khalifa F. P. Rotzinger and K. Kirnar J. Am. Chem. Soc. 1983 105 56. 215 A. Bencini C. Benelli and D. Gatteschi Inorg. Chem. 1983 22 470. 216 M. P. Pujari and P. Banerjee J. Chem SOC.,Dalton Trans. 1983 1015. 217 D. A. Roberts J. M. Busch Y. Tsao V. Katovic J. J. Fortman and S. C. Curnmings Inorg. Chem. 1983 22 1804. 2'8 R. Machida E. Kimura and M. Kodarna Inorg. Chem. 1983 22 2055. 219 P. Zanello R. Cini A. Cinquantini and P. L. Orioli J. Chem. SOC.,Dalton Trans. 1983 2159. 220 M. D. Braydich J. J. Fortman and S. C. Cumrnings Inorg. Chem. 1983 22 484. B. W.Fitzsimmons H H \ / N -(CH z)n -N 'N /W& Nj H (67) 2-X or 4-X=H Me OMe Br or C1; Y =0 or S (68) n =0 1 2 3 4 5 or 6 (69) R =H X =H 3-OMe 4-OMe 5-OMe H Me 5-Cl or 5-N02;R =Me X =H 3-OMe (70) R =H Me or Ph; 4-OMe 5-OMe 5-C1 or 5-N02 R' =Me CF, or Ph The six-co-ordinate cobalt(I1) complexes [Co(salen)L] (L =pyridine or other nitrogen bases) are found to have S =3/2 in solution the magnetic moments vary with temperature and a spin-equilibrium is likely.221 As with other spin-crossover systems a search has been made for possible influences of this on electron-transfer rates.222 Cobalt( 11) and nickel( 11) complexes of 2,6-bis benzoyl hydrazone have been prepared and ~haracterized.~~~ As is evident from the above the bulk of work reported this year has been on nitrogen-donor ligands.A few papers dealing with phosphorus and sulphur ligands were noted. The complex (71) has been prepared and characterized224 and 1,4,7-trithianonane has been reported to form complexes of formula [ML,](BF,) (M = Co Ni or CU).~~~ A phosphorus-donor ligand (72) has been synthesized and its cobalt(11) and nickel( 11) complexes synthesized and fully characterized.226 Cobalt(rn) Compounds.-The oxidation of 2,6-di-t-butyl phenol by dioxygen is catalysed by the p-peroxo-compound tetrakis( bipyridyl)( p-peroxo)p-22 I K. Migita M. Chikara and M. Iwaizumi Inorg. Chem. 1983 22 2281. 222 T. Zhu C. H. Su B. K. Lemke L. J. Wilson and K. M. Kadish Inorg. Chem. 1983 22 2527. 223 C. Lorenzini C. Pelizzi G. Pelizzi and G. Predieri J.Chem. SOC.,Dalton Trans. 1983 721. 224 C. Bianchini and A. Meli 1. Chem. SOC.,Dalton Trans. 1983 2419. 22s W. N. Setzer C. A. Ogle G. S. Wilson and R. S. Glass Inorg. Chem. 1983 22 266. 226 M. Ciarnpolini P. Daporto N. Nardi and F.Zanobini Inorg. Chem. 1983 22 13. Fe Co Ni 237 hydroxodicobalt(III).~~’The transfer of energy from the ’Eg state of [Cr bipyJ3+ to [Co(NH3)6I3+ has been studied in aqueous solution. Electronic energy transfer takes place.,,’ Complexes of cobalt( 111)with hydroxamic acid have been shown to undergo a spin-crossover induced by pr~tonation.~~~ The crystal structure of the compound cis-a-A( -)589-[C~{( +)PAPH},eniMy]+CI- has been determined by X-ray methods.230 The complex PAPH is the mono-ion of 1-phenyl-2-amino- 1,3-dihy- drox ypropane.(p)-[{Tris (2-aminoethyl) amine}{ 2-(dih ydroxymethy1)gl ycinate}]-cobalt( 1II)zinc tetrachloride-water has been prepared its molecular structure solved and its chemistry in~estigated.~~’ Cobalt-59 n.m.r. spectra of a wide range of octa-hedral cobalt( 111) compounds have been recorded and analy~ed.’~~ The electro- chemistry of macrobicyclic cobalt(m) complexes has been studied and a number of metal-centred and ligand-centred reductions identified.233 The complex [en2Co{ (S)CHCONH( Et)CO(CH,) NH,}] has been synthesized and its structure determined234 and a M2+sequestering agent [en2Co{0,P(OH)CH2P(OH)02}]C104 has been prepared its structure determined and its association constant with Ca2+ determined.235 Surprisingly P4Nz donor sets are uncommon in cobalt( 111) chemistry the preparation of cis-and trans-[Co{ (EtO),P},( NCS)J+ has been achieved and the structure of the trans isomer determined.236 Cobalt(111) Compounds.Properties of several compounds are shown in Table 2 237-259 2. 227 S. A. Bedell and A. E. Martell Inorg. Chem. 1983 22 364. 228 M. T. Gandolfi M. Maestri D. Sandrini and V. Balzani Inorg. Chem. 1983,22 3465. 229 K. Abu-Dari S. J. Barclay P. E. Riley and K. N. Raymond Inorg. Chem. 1983 22 3085. 230 A. Clearfield P. Rudolf and J. G. Wardeska Inorg. Chem. 1983 22 2713. 23 I W. G. Jackson G. M. McLaughlan A. M. Sargeson and A. D. Watson J. Am. Chem. SOC.,1983 105 2426. 232 N. Juranic Inorg. Chem. 1983 22 521. 233 A. M. Bond G.A. Lawrance P. A. Lay and A. M. Sargeson Inorg. Chem. 1983 22 2010. 234 L. Roecker M. H. Dickman D. L. Nosco R. J. Doedens and E. Deutsch Inorg. Chem. 1983,22,2022. 235 S. S. Jurissson J. J. Benedict R. C. Elder R. Whittle and E. Deutsch Inorg. Chem. 1983 22 1332. 236 G. Albertin G. Pelizzi and E. Bordignon Inorg. Chem. 1983 22 515. 237 E. J. Evans C. J. Hawkins J. Rodgers and M. R. Snow Inorg. Chem. 1983 22 34. 238 J. M. Harrowfield A. M. Sargeson J. Springborg M. R. Snow and D. Taylor Inorg. Chem. 1983 22 186. 239 R. D. Peacock J. Chem. SOC.,Dalton Trans. 1983 291. 240 N. Juranic and R. D. Lichter J. Am. Chem. SOC.,1983 105 406. 24 1 C. B. Storm C. M. Freeman R. J. Butcher A. H. Turner N. S. Rowan F. 0.Johnson and E. Sinn Inorg.Chem. 1983 22 678. 242 A. Yamagishi J. Chem. SOC.,Dalron Trans. 1983 679. 243 W. G. Jackson and C. M. Begbie Inorg. Chem. 1983 22 1190. 244 G. R. Brubaker and D. W. Johnson Inorg. Chem. 1983 22 1422. 245 W. Clegg C. D. Garner and M. H. Al-Samman Inorg. Chem. 1983 22 1534. 246 H. Okazaki U. Sakaguchi and H. Yoneda Inorg. Chem. 1983 22 1539. 247 U. Sakaguchi A. Tsuge and H. Yoneda Inorg. Chem. 1983 22 1630. 248 U. Sakaguchi A. Tsuge and H. Yoneda Inorg. Chem. 1983 22. 3745. 249 K. D. Grande A. J. Kumin L. S. Stuhl and B. M. Foxman Inorg. Chern. 1983 22 1791. 250 J. N. Cooper C. A. Pennell and B. L. Johnson Inorg. Chem. 1983 22 1956. 25 I T. Damhus and C. E. Schaffer Inorg. Chem. 1983 22 2406. 252 M. Watabe M. Takahashio and A.Yamasaki Inorg. Chem. 1983 22 2650. 253 D. A. Buckingham C. R. Clark and R. F. Tasker Inorg. Chem. 1983 22 2772. 254 D. A. Buckingham C. R. Clark M. M. Deva and R. F. Tasker Inorg. Chem. 1983 22 2754. 255 J. N. Cooper J. G. Bentsen T. M. Handel K. M. Strohmaier W. A. Porter B. C. Johnson A. M. Carr D. A. Farnath and S. L. Appleton Inorg. Chem. 1983 22 3060. 256 P. J. Toscano and L. G. Marzilli Inorg. Chern 1983 22 3342. 257 A. M. Bond A. R. Hendrickson R. L. Martin J. E. Moir and D. R. Page Inorg. Chem. 1983,22,3440. 258 A. F. Lindmark and R. C. Fay Inorg. Chem. 1983 22 2000. 259 C. J. Hawkins and J. Martin Inorg. Chem. 1983 22 3879. Table 3 Complex or System [Co( NH,),tripeptide] [Co en2{(S)-Tyr}12' [Co acac,] [Co(ox),(gl~),(en),l [Co(NH,),(4-NO,-imidazo1ato)lCl [Co acac2.amino acid] A( +)-[Co en2C1,]+ truns-[CoC~,L',] [cO I2 (OH)6(CH3 C02)6L21 21 [CO en,] [coL33I B.W.Fitzsimmons Study Ref Determination of structure 237 Reaction with MeCHO 23 8 C.D. study 239 "N n.m.r. 240 Determination of structure 24 1 Montmorillonite clay resolution 242 Bailar inversion 243 Preparation 244 Determination of structure 245 C.D. study 246 247 248 &[(CN),CoC(CO Me)=C(CO,Me)Co(CN),] cis-and trans-[Co en,(NO,)(ox)] Chirality reference system [Co bis( a asp)] [Co en,aa] trans-[Co en2C1(S,0,)] [CO L41(N03)2 [CO(S C NRd3I [CO(S,C NRAI tr~ns-[Co(NH,)~gly-gly-~-his] Determination of structure 249 Bonding of oxalate 250 -25 1 "N n.m.r.252 Liquid chromatography 253 254 Preparation 255 Determination of structure 256 Electrochemistry 257 Rotation kinetics 258 Preparation 259 en = 1,2-diaminoethane; tyr = tyrosinato; acac = pentan-2,4-dionato; gly = glycinato; ox = oxalato; L' = 1,lO-diamin0-2,9-dimethyl-3,7-diazadecane; L2 = 6-methyl-2-oxypyridine; L3 = 1,I ,I-tris(2-aminoethy1)aminoethylethane;L4H= NH2CH2CONH(CH2)S(CH2)NH2 Cobalt(11:) Complexes. Recent papers on reaction kinetics are listed in Table 4.26L289 260 M. A. Hussein A. A. Abdel-Khalek and Y.Sulfab J. Chem. SOC Dalton Trans. 1983 317. 26I D. Smith M. F. Amira P. B. Abdullah and C. B. Monk J. Chem. SOC.,Dalton Trans. 1983 337. 262 R. van Eldik Inorg. Chem. 1983 22 353. 263 R.C. McHatton and J. H. Espenson Inorg. Chem. 1983 22 784. 264 A. C. Dash Inorg. Chem. 1983,22 837. 265 A. Ichimura D. L. Nosco and E. Deutsch J. Am. Chem. Soc. 1983 105 844, 266 W. G. Jackson M.L. Randall A. M. Sargeson and W. Marty Inorg. Chem. 1983 22 1013. 267 I. M. Sidahmed and C. F. Wells J. Chem. Soc. Dalton Trans. 1983 1035. 268 M. S. Ram A. H. Martin and E. S. Gould Inorg. Chem. 1983 22 1103. 269 P.B. Abdulla and C. B. Monk J. Chem. SOC.,Dalton Trans. 1983 1175. 270 W. L. Purcell Inorg. Chem. 1983 22 1205. 27I H. Cohen E. S. Gould D. Meyerstein M. Nutkovich and C. A. Radlowski Inorg. Chem. 1983,22 1374. 272 R. J. Balahura W. C. Kupferschmidt and W. L. Purcell Inorg. Chem. 1983,22 1456. 273 C. Poon T. Lau C. Wong and Y. Kan J. Chem.SOC.,Dalton Trans. 1983 1641. 274 S. Balt H.J. A. M. Kuipers and W. E. Renkema J. Chem. SOC.,Dalton Trans. 1983 1739. 275 K. Miyoshi N. Katoda and H. koneda Inorg. Chem. 1983 22 1839. 276 W. L. Reynolds M.Glavas and E. Dzelilovic Inorg. Chem. 1983 22 1946. 277 P. M. Coddington and K. E. Hyde Inorg. Chem. 1983 22 2211. 278 P. A. Lay A. W. H. Mau W. H. F. Sasse I. I. Creaser L. R. Gahan and A. M.Sargeson Inorg. Chem. 1983 22 2347. 279 S. Balt H.J. GameIkoorn and W. E. Renkema 1. Chem. SOC.,Dalton Trans. 1983 2415. 280 R. V. Dubs L. R. Gahan and A. M. Sargeson Inorg. Chem. 1983 22 2523. 28I P. M. Balasubramanian and E. S. Gould Inorg. Chem. 1983 22 2635. t82 M. F. Hoq,C. R. Johnson S.Paden and R. E. Shepherd Inorg. Chem. 1983 22 2693.Fe Co Ni 239 Table 4 Complex Reaction Ref [Co"(nta) (H2 0121 Periodate oxidation 260 [CO(NH~)S~~CRI Aquation 261 [so3Co(NH3),I+ Electron transfer 262 [Fc0(NH3>,12' Reduction 263 [salCo( NH,),]" Hydrolysis 264 Cleavage 265 [~~,CO(RSS)(CH~)~NH~]~+ [Co(NH3)5XIn+ Hydrolysis 266 truns-[CoCI Py,]+ Solvol ysis 267 [CO( NH,) (02 cWl2+ Reduction( Ti3+) 268 [Co(NH,) (02CR)I2+ Aquation 269 [WNH3),(tet)l2' Linkage isomerism 270 [Co( NH3),O2CR7+ Reduction( R- ) 27 1 + [Co(NH,),NCR] Reduction( C8+) 272 [Co en,AX]+ Ligand substitution 273 [Co( NH3),0N0I2+ Linkage isomerism 274 [Co( NH3),ON0l2+ Linkage isomerism 275 [Co( NH,),Cl]'+ Aquation 276 [CO en2(CO3)2I3- Decarboxylation 277 [CO( cage)13 Electron transfer 278 + + Solvolysis ~~u~~-[CO(NH,),('~NH~)X]~~'~ 279 + [CO( age)]^+/^ Self-exchange 280 Cobalimine Reduction 28 1 [Co( NH3),meimidI3+ Isomerism 282 trans-[Co( NH3),C12]+ Ammoniation 283 [Co(NH,),NCRI3+ Reduction( C8') 284 [Co( NH,) ,imidazoleI3+ Reduction 285 [Co sep13 + Electron transfer 286 [CO sep13+ Electron transfer 287 [Co(NH3),NCNMe213+ Hydration 288 [Co en3I3+ Reduction 289 nta = nitriloacetete; sal = salicylato; ox = oxalato; tet = tetrazolato; meimid = 4-methylimidazole; cage = 1-methyl-3,13,16-trithia-6,8,10,19-tetra-azabicyclo[6.6.6]eicosane(one of a large group of cage ligands used by these worker see this and earlier papers for full details).sep = 1,3,6,8,10,13,16,19-octa-azabicyclo[6.6.6]eicosane 3 Nickel Low Oxidation States of Nickel.-The new dinitrogen complex [Ni(CO) N2] can be generated in a pressure cell by U.V.photolysis of tetracarbonylnickel in liquid krypton. The decomposition of this complex was followed over the temperature range I 12-1 27 K and a value of the Ni- N2bond dissociation energy determined.290 Two classes of Ni-CS2 co-ordination compound have been prepared by reaction of CS2 with Nio phosphine complexes and the molecular structure of an example 283 S. Balt H. J. Gamelkoorn H. J. A. M.Kuipers and W.E. Renkema Znorg. Chem 1983 22 3072. 284 R.A. Balhura and A. J. Johnston Znorg. Chem. 1983 22 3309. 285 H.A. Boucher G. A. Lawrance A. M.Sargeson and D. F. Sangster Znorg. Chem. 1983 22 3482. 286 J. F. Endicott G. R. Brubaker T. Ramasami K.Kumar K. Dwarakanath J. Cassel and D. Johnson Znorg. Chem. 1983,22 3754. 287 I. F.Creaser A. M.Sargeson and A. W. Zanella Znorg. Chem. 1983,22,4022. 288 N.E.Dixon D. P. Fairlie W. G. Jackson and A. M. Sargeson Znorg. Chem. 1983 22 4038. 289 M.Kanesato M.Ebihara Y. Saseki and K. Saito J. Am. Chem. SOC. 1983 105 571 1. 290 J. J. Turner M. 9. Simpson M. Poliakoff and W. B. Maier J. Am. Chem. Soc. 1983,105,3898. B. W. Fitzsimmons (73) of one class established.291 Fourier-transform mass spectrometry has been used to study the structures of NiC,H2,+ complexes generated by reaction of’Nif with a range of hydrocarbons.292 Bis( q3-allyl)nickel(o) and bis( q5-pentadienyl)iron( 11) have been used as starting materials in the preparation of [Ni(PF3)J Ni(PF2H),] /s, Me P -C-N i-PMe, I I s ,s C II S (73) and [Fe( PF3)5].293 The gas-phase U.V.photoelectron spectra of a range of Ni-alkyne complexes have been recorded spectral features related to ionizations from molecular orbitals involved in nickel-alkyne back-bonding have been established.294 Tertiary phosphines co-ordinated to truns-[NiRXL2] or trans-[NiXL,’] (R = CC1=CC12 or C,H,Me3-2,4,6; X = halide pseudohalide or CECR’) have been shown to exchange in benzene.295 The dinuclear complex [(tppme)Ni(p-CS3) Ni(tppme)]BPh,(tppme = 1,1,1-tris(dipheny1phosphinomethyl)ethane) has together with related compounds been synthesized and ~haracterized.~~ Nickel(r1) Compounds.-Potentiometrically determined stability constants of tetra-azacycloalkane complexes of Ni” have been obtained.297 Some trans-octahedral- [Ni( N4S2)] complexes [NiL2I2+ (L = 1-thia-4,7-diazacyclononane)have been pre- pared and structurally ~haracterized.~~~ trans-Tetramminedinitritonickel(I1)has been closely examined with a view to clarifying the nature of the bonding.An X-ray diffraction study conducted at 110 K reveals an aspherical electron distribution about the and the results of a polarized neutron diffraction study were shown to complement one another in establishing a bonding A series of macrocyclic ligands have been prepared with the aim of designing one in which co-ordination is impossible unless ligand folding takes place.301 The ligands (74) (74) X = CN or CH,NH 29 1 M. G. Mason P. N. Swepston and J.A. Ibers Inorg. Chem. 1983 22 41 1. 292 D. B. Jacobson and B. S. Freiser J. Am. Chern. Soc. 1983 105 736. 293 S. J. Severson T. H. Cymbaluk R. D. Ernst J. M. Higashi and R. W. Parry Inorg. Chem. 1983,22,3833. 294 M. Casein D. Ajo G. Granozzi E. Tondello and S. Aime J. Chem. SOC.,Dalton Trans. 1983 869. 295 M. Wada and K. Nishiwaki J. Chem. SOC.,Dalton Trans. 1983 1841. 296 C. Bianchini P. Innocenti and A. Meli J. Chem. SOC.,Dalton Trans. 1983 1777. 29’ M. Micheloni P. Paoletti and A. Sabatini J. Chem. SOC.,Dalton Trans. 1983 1189. 298 S. M. Hart J. C. A. Boeyens J. P. Michael and R. D. Hancock J. Chem. SOC.,Dalton Trans. 1983 1601. 299 B. N. Figgis P. A. Reynolds and S. Wright J. Am. Chem. SOC.,1983 105 434. 300 B. N. Figgis P. A. Reynolds and R.Mason J. Am. Chem. SOC.,1983 105,440. 301 K. R. Adam A. J. Leong L. F. Lindoy H. C. Lip B. W. Skelton and A. H. White J. Am. Chem. SOC. 1983 105 4645. Fe Co Ni 24I were prepared and complexation with Ni" under neutral conditions leads to high- spin five-co-ordinate species.302 The extraction rates of Ni" or Zn" with ethyl- dithiazone butyldithiazone or hexyldithiazone in CHC13 are found to be first-order in ligand or metal and inverse first-order in hydrogen-ion c~ncentration.~'~ Nickel phthalocyanin iodide [Ni( Pc)I] is found to exhibit metallic conductivity at low temperature^.^'^ [(5,10,15,20-Tetramethylporphinato)nickel(II)] partially oxidized with iodine contains the 13-anion and the material exhibits metallic-like conduc- ti~ity:~"the charge density over the parent compound has been investigated by low-temperature crystallography and the results compared with a calculated set of electron-density maps.306 Red-shifts are observed in the optical spectra of protonated nickel(11) p~rphyrins.~~' Muonium atoms in aqueous solutions were shown to interact differently with the two alternative spin-states of [nickel( ~~)cyclam]- (cyclam = I ,4,8,11 -tetra-azacyclotetradecane),spin-state switching being brought about by changing the ionic strength of the medium.308 The crystal structure of the complex (75) has been determined.309 A family of macrobicyclic ligands has been Et Et Et -Et (75) designed in which a substrate might be held close to a metal centre as a guest molecule in a clathrate.Some complexes of this design have been prepared?" In a further paper on this theme host-guest interactions have been investigated using n.m.r. methods.311 The square-planar complex (76) has been prepared and character- i~ed.~'~ The chemisorption of dioxygen carbon monoxide and other small molecules on clean (1 11) surfaces of Nisi has been studied using a wide range of techniques. Some (02,CO and C02 are observed to dissociate at 170K but neither H2 nor N2 absorbs.313 (76) 302 K. P. Wainwright J. Chem SOC.,Dalton Trans. 1983 1149. 303 H. Watarais and H. Freiser J. Am. Chem. SOC. 1983 105 189. 304 J. Martinsen R. L. Greene S.M. Palmer and B. M. Hoffman J. Am. Chem. SOC.,1983 105,677. 305 L. J. Pace J. Martinsen A.Ulman B. M.Hoffman and J. A. Ibers J. Am. Chem. SOC.,1983 105 2612. 306 F. W. Kutzler P. W. Swepston 2.Beerkovitch-Yellin D. E. Ellis and J. A. Ibers J. Am. Chem. SOC. 1983 105 2996. 307 D. Ward P. M. Callahan R. Young G. T. Babcock and C. K. Chang J. Am. Chem. SOC.,1983,105,634. 308 J. M. Stadlbauer B. W. Ng,Y. C. Jean and D. C. Walker J. Am. Chem Soc. 1983 105 752. 309 P. W. Hitchcock J. Chem. SOC.,Dalton Trans. 1983 2127. 310 K. J. Takeuchi D. H. Busch and N. Alcock J. Am. Chem SOC.,1983 105 4261. 31 1 K. J. Takeuchi and D. H. Busch J. Am. Chem. SOC.,1983 105 6812. 3'2 J. L. Davidson P. N. Preston and M. V. Russo J. Chem. SOC.,Dalton Trans. 1983 783. 313 L. H. Dubois and R. G. Nuzzo J. Am. Chem. SOC.,1983 105 365. 242 B. W.Fitzsimrnons Reaction Kinetics of Nickel( zz) Complexes.Table 5 lists recent papers.31L324 Table 5 Reaction Rex Ni2+ + isoquinoline + complex 314 Ni2+ + 2-(2-pyridylazo)-1-naptho1 complex 315 [Ni en212+ + PO:-+ product 3 16 Ni2+ + C1-+ complex 317 Ni2+ + salicylate --* complex 318 [Ni'"cplx] + Fe2+ -+ reduced complex 319 Ni2+ + dicarboxylic acid -* 320 Ni2+ + hydroxy-acid -complex complex 321 planar Ni" complex + octahedral complex 322 Ni2+, + water exchange 323 [Ni ll/lllpeptide] -+ electron transfer 324 High Oxidation States of Nickel.-The molecular structure of the ion-radical salt bis(maleodithiolato)nickelate(111) has been solved and its electronic structure investigated.325 These higher oxidation states of nickel often involve five-co-ordina- tion as in the compounds (77) X-ray analysis of the iodo-derivative reveals essen- tially square-pyramidal Two products of chlorination of [Ni en2C12] have Me N -,N i X,+ N Me, Ill (77) X = CI Br or I been ~haracterized.~~' These are trans-[Ni"'en2CI2]C1 and a mixed-valence com- pound [Ni"en2Ni1Ven2C12]C14.Pulse radiolytic studies of [1,4,7,10,13-penta-aza-cyclohexadecane)nickel( II)] reveal oxidative processes yielding Ni"' Cluster Compounds of Iron Cobalt and Nickel.-Table 6 lists recent papers.329-354 314 K. Ishari S. Funahashi and M. Tanaka Inorg. Chem. 1983 22 2564. 315 R. L. Reeves G. S. Calabrese and S. A. Harkaway Inorg. Chem. 1983 22 3076. 316 R. A. Read and D. W. Margerum Inorg. Chem. 1983 22 3447 317 S. A. Cower H.W. Dodgen and J. P. Hunt Znorg. Chem. 1983 22 1952. 318 S. Chopra and R. B. Jordan Inorg. Chem. 1983 22 1708. 319 D. H. Macarthy and A. McAuley Inorg. Chem. 1983 22 2062. 320 T. Inoue K. Kojima and R. Shimozawa Inorg. Chem. 1983 22 3972. 321 T. Inoue K. Sughara K. Kojima and R. Shimozawa Inorg. Chem. 1983 22 3977. 322 A. F. Godfrey and J. K.Beattie Inorg. Chem. 1983 22 3794. 323 H. W. Dodgen and J. P. Hunt Znorg. Chem. 1983 22 1146. 324 C. K. Murray and D. W. Margerum Inorg. Chem. 1983 22 463. 325 B. L. Ramakrishna and P. T. Manoharan Inorg. Chem. 1983 22 21 13. 326 D. M. Grove G. van Koten R. Zoet N. W. Murrall and A. J. Welch J. Am. Chem. SOC.,1983,105,1379. 327 D. A. Cooper S. J. Higgens and W. Levason J. Chem. SOC.,Dalton Trans.1983 2131. 328 L. Fabbrizzi H.Cohen and D. Meyerstein 1. Chem. Soc. Dalton Trans. 1983 2125. 329 F. Bottomley Inorg. Chem. 1983 22 2656. 330 A. F. Dyke S. A. R. Knox M. R. Morris and P. J. Naish 1. Chem. SOC.,Dalton Trans. 1983 1417. 33 I A. G. Orpen J. Chem. SOC.,Dalton Trans. 1983 1427. 332 G. K. Yang and R.G. Bergman J. Am. Chem. SOC.,1983 105 6045. Fe Co Ni Table 6 Cluster M2 Fe Fez CO cow Fe3 Fe3 Fe3 Fe3 Fe3 Co3 Fe (c03)2 FeRu Fe,W Few Fe W FeCo c03 c03 NiRu FeRu Fe pt2 CozHg, Fe Rh FeRh, FeRh Fez Rh Ni Nil Ligan ds CO NO RC co RzC CP CO CHCH, Cp CO (CH,),CHMe Cp co RC C6Me6 H CO H MeCO OMe CO CNBu' CO N S CO CMe C=CH, co,sco CO OH PPh3 CO CR Cp co CS, CP co s RC CP CPh Cp CO H RC Cp CO H (Me0)3P PPh, S NO R3 p CO Te Cp co CO PPh s R3P CO H ReJ 3 29 330 33 1 332 333 334 335 336 337 Cp 338 339 340 341 342 343 344 345 346 347 348 349 350 35 1 352 353 354 333 J.A. Abad L. W. Bateman J. C. Jeffrey K. A. Mead H. Razay F. G. A. Stone and P. Woodward J. Chem. SOC.,Dalton Trans. 1983 2075. 334 C. K. Chen and C. H. Cheng Inorg. Chem. 1983 22 3378. 335 W. Wong K. W. Chiu G. Wilkinson A. M. R. Galas M. Thornton-Pett and M. B. Hursthouse J. Chem. SOC.,Dalton Trans. 1983 1557. 336 M. I. Bruce T. W. Hambley and B. K. Nicholson J. Chem. SOC.,Dalton Trans.1983 2385. 337 K. H. Pannell A. J. Mayr and D. VanDerveer J. Am. Chem. SOC.,1983 105 6186. 338 P. Brun G. M. Dawkins M. Green R. M. Mills J.-Y. Salaiun F. G. A. Stone and P. Woodward J. Chem. SOC.,Dalton Trans. 1983 1357. 339 G. Gervais R. Rosetti P. L. Stanghellini and G. Bor J. Chem. SOC.,Dalton Trans. 1983 1613. 340 D. F. Jones P. H. Dixneuf A. Benoit J. LeMarouille Inorg. Chem. 1983 22 29. 34 I L. Busetto J. C. Jeffrey R. M. Mills F. G. A. Stone M. J. Went and P. Woodward J. Chem. Soc. Dalton Trans. 1983 101. 342 L. Busetto M. Monari A. Palazzi V. Albano and F. Demartin J. Chem. SOC.,Dalton Trans. 1983 849. J43 P. T. Cheskey and M. B. Hall Inorg. Chem. 1983 22 2102. 344 K. P. C. Vollhardt and E. C. Walborsky J. Am. Chem. SOC.,1983 105 5507.345 S. Enoki T. Kawamura and T. Yonezawa Inorg. Chem. 1983 22 3821. 346 A. J. Carty N. J. Taylor E. Sappa and A. Tiripicchio Inorg. Chem. 1983 22 1871. 347 H. W. Walker R. G. Pearson and P. C. Ford J. Am. Chem. SOC. 1983 105 1179. 348 A. M. Mazany J. P. Fackler M. K. Gallagher and D. Seyferth Inorg. Chem. 1983 22 2593. 3 49 F. Cecconi C. A. Ghilardi S. Midollini and S. Moneti J. Chem. SOC.,Dalton Trans. 1983 349. 350 D. A. Lesch and T. B. Rauchfuss Znorg. Chem. 1983 22 1854. 351 A. Ceriotti G. Longoni R. D. Pergola B. T. Heaton and D. 0. Smith J. Chem. SOC.,Dalton Trans. 1983 1433. 352 R. J. Haines N. D. C. T. Steen and R. B. English J. Chem. SOC.,Dalton Trans. 1983 1607. 353 F. Cecconi C. A. Ghilardi and S. Midollini Inorg.Chem. 1983 22 3802. 354 A. Ceriotti P. Chini R. D. Pergola and G. Longoni Inorg. Chem. 1983 22 1595.