5 O,S,Se,Te By F. J. BERRY Department of Chemistry University of Birmingham P.O. Box 363 Birmingham 815 2TT 1 Introduction Several spectroscopic studies involving the Group VI series of elements have been reported. For example the polyatomic cations S42+and Se42+ in oleum of Te42+ in sulphuric acid and of Te4[Al2Cl7I2 have been investigated' by Raman and resonance Raman (r.R.) spectroscopy. The data from the r.R. spectra were used to evaluate harmonic wavenumbers anharmonicity constants and stretching force constants. Data from the v1 band excitation profiles together with measurements on the Raman band polarizations at resonance indicated that the assignment of the lowest allowed transition of each ion is 7~*(6~~) e v(eR),'E e 'AlR.In another study,* the (T~-benzene) chromium(0) chalcocarbonyl complexes (7'-C6H6)Cr(C0)2(CX), (X =0,S Se) were investigated both as solids and in various organic solvents by infrared and Raman spectroscopy.Vibrational assignments were proposed for most of the fundamental modes. Variations between the primary cx and Cr(CX) potential constants of the (76-C6H6)Cr(Co),(CX) complexes and those of the related Cr(CO),(CX) derivatives were associated with 'charge buffering' of CS and CSe and in further agreement with previous studies on transition-metal chalcocarbonyls the net v-acceptorlo-donor capacity of the CX ligands was found to increase in the order CO <CS <CSe. Although no evidence was observed for appreciable mixing between the v(C0) and v(CS) or v(CSe) modes extensive mixing between v(CX) and the corresponding v[Cr(CX)] mode particularly in the selenocarbonyl complex was observed.Products from the thermal decomposition of open-chain dialkyl-sulphides -disulphides and -diselenides of the type RSR RSSR and RSeSeR [R =CH3 CH2CH3 CH2CH2CH3 CH(CH3)* and C(CH3),] have been analysed by photoelec- tron ~pectroscopy.~ Whereas pyrolysis at high temperatures >1000 K gave mix- tures of thermodynamically favoured final products such as H2 CH4 CS2 and HCCH lower temperature thermolysis produced olefins H2S sulphur alkaneselenol H2Se and selenium. The decolnposition temperatures were found to increase from RSeSeR towards RSSR and RSR and also with decreasing size of the alkyl groups. The likely course of the thermal decompositions were discussed.'R. J. H. Clark T. J. Dines and L. T. H. Ferris J. Chem. SOC., Dalton Trans. 1982 2237. A. M. English K. R. Plowman and I. S. Butler Znorg. Chem. 1982,21 338. T. Hirabayashi S. Mohmand and H. Bock Chem. Ber. 1982,115,483. 121 122 F. J. Berry Molecular orbital and band structure calculations have been applied4 to the geometry of the Chevrel phases MMkX,- (M = Pb Sn Bay Ag Ln; M' = Ru Mo Rh; X = S Se Te; y = 0-2). The structures were described and the bearing of the results on phenomena such as high temperature superconductivity considered. Other types of structural studies involving materials containing Group VI elements have been reported. These have included dynamic n.m.r. investigations5 of the barriers to ring inversion of the six-membered rings formed by bridging the 1-and 8-positions of naphthalene with a CH2-X-CH2 chain (X = 0,S Se or Te) and which were found to increase along the series 0 < S < Se < Te in marked contrast to the corresponding pentamethylene heterocycles and indicative of the influence of bond angle strain during inversion.It is interesting to note the renewal of interest6 in salts of Fe2(pS)z(N0)42-which were first synthesized in 1858 by Roussin. Some studies of Fe2(pX),(N0)42-(X = S Se Te) and related compounds have shown that in comparison with Fe2(p- S)2(CO)62- Roussin's nitrosyl anion is considerably more stable and reactive towards a narrower range of electrophiles. Another interesting feature of the work involved the synthetic utility of Fe2(p- 1)2(N0)4 which permits the preparation of anhydrous solutions of F~,(P-X),(NO)~~-and allows the in situ assembly of organochalcogenide ligands thereby obviating the need for noxious and unstable ligand precursors.2 Oxygen Chemical and electrochemical measurements7 of the reduction of oxygen in liquid ammonia at a platinum electrode have shown that the first reduction of 0 is a one-electron process producing 0;-which is a stable species in liquid ammonia and precipitates as KO in the presence of K'. Measurements of the solubility of O2in liquid ammonia between -60 and -40 "C were used in an evaluation of the diffusion coefficient of 0 in the solvent. E.s.r. has shown' the formation of the superoxide radical in the Os0,-catalysed decomposition of hydrogen peroxide.A mechanism was suggested involving the formation of a peroxo-osmic acid anion which decomposes into superoxide and osmium(vI1) radicals the latter being oxidized by hydrogen peroxide at pH C 9 but reduced by the peroxide anion at higher pH. Other studies have showng that in contrast to the reaction in dimethylformamide the superoxide ion reacts with chloroform in benzene and gives rise to the formation of dichlorocarbene. The study illustrates the attention which must be given to the solvent during superoxide ion reactions. An interesting study'' of oxygen atom transfer in low temperature matrices has shown that ultraviolet photolysis of ozone isolated in a noble-gas matrix in the presence of phosphorus- or arsenic-trifluoride results in the formation of the J.K. Biirdett and J. H. Lin Inorg. Chem. 1982,21 5. J. E. Anderson F. S. Jorgensen and T. Thomsen J. Chem. SOC.,Chem. Commun. 1982,333. T. B. Rauchfuss and T. D. Weatherill Inorg. Chem. 1982,21 827. 'F. A. Uribe and A. J. Bard Inorg. Chem. 1982 21 3160. * L. Nagy Z. M. Galbacs L. J. Csanyi and L. Horvath J. Chem. SOC.,Dalton Trans. 1982,859. S. T. Purrington and G. B. Kenion J. Chem. SOC.,Chem. Commun. 1982,731. lo A. I. Downs G. P. Gaskill and S. B. Saville Inorg. Chem. 1982,21 3385. 0,S Se Te 123 corresponding trifluoride oxide OMF,. The infrared data recorded from l6O-and O-substituted OsAsF were consistent with the expected C3"symmetry. Several structural studies of compounds with oxygen-transition metal bonds have been reported with molybdenum-containing materials receiving significant atten- tion.For example the crystal and molecular structure" of an intermediate in the reaction between Mo2(OPr') and molecular oxygen which yields [MOO~(OP~~)~],, has been found to contain a serpentine chain of molybdenum atoms connected by bridging oxo- and alkoxy-ligands and semi-bridging alkoxy ligands. In another report12 the preparation and structural characterization of two trinuclear molybdenum(1v) cluster compounds with capping oxygen atoms were described. The compound [Mo,O2(OAc),(H2O),]Br2-H20, formed from the reac- tion of Mo(CO) with acetic acid under oxygen was shown to contain [Mo,O2(O2CCH3),(H2o),12'ions (Figure 1) on crystallographic positions of C, symmetry but having effectively D3hsymmetry.The metal atoms form an equilateral ow Figure 1 View of the [M0~0~(02CCH3)6(H20)3]~+ cution (Reproducedby permission from Inorg. Chem. 1982 21,1912) triangle capped above and below by oxygen atoms with edges bridged by two acetate ions. A water molecule is co-ordinated to each metal atom with the Mo-OH2 bond direction intersecting the centre of the opposite Mo-Mo bond. The bromide ions and the additional water molecule are disordered over several positions in the rhombohedra1 cell. The other trinuclear molybdenum(1v) cluster compound,'2 [Mo,O~(O~CC~H,),(H~~)~](~F~S~~)~(~~~~~~H)(H~~)~, pre-pared by reaction of Mo,(02CCH3) with a mixture of propionic acid and propionic anhydride followed by cation column chromatography using CF,SO,H eluant l1 M.H. Chisholm K. Folting J. C. Huffman and C. C. Kirkpatrick I. Chem. Soc. Chem. Commun. 1982,189. l2 M. Ardon A. Bino F. A. Cotton Z. Dori M. Kaftory and G. Reisner Znorg. Chem. 1982,21 1912. 124 F.J. Berry contained a similar cation with virtually identical dimensions. Other species with bridging oxide species have been identified during investigation~~~ of uranyl com- plexes of p -polyketonates including a mononuclear uranyl 1,3,5-triketonate and a novel trinuclear uranyl 1,3,5-triketonate which has a trigonal planar bridging oxide. It is also relevant to note recent of the dioxygen complexes of ruthenium(II1) with EDTA and HEDTA in aqueous solution.The spectroscopic examination of compounds similar to those described in the foregoing has been found to be informative. For example e.s.r. has been used" to study the molecular oxygen adducts formed by the cobalt(I1) chelate of salicyl- adazine and related systems with the effect of substituent groups on the ligands and the influences of the various bases on magnetic and structural parameters being successfully determined. In a study16 of molecular oxygen adducts of [NN'-(acacen)ethylenebis(acetylacetoniminato)] cobalt(I1) some infrared spectra were measured using matrix isolation co-condensation techniques and resonance Rarnan spectra were recorded at low temperatures in CH2C12 solutions containing various base ligands. Oxygen-17n.m.r. has been found to be a versatile and potentially powerful means of investigation.The technique has been used17 to examine specifically labelled nitropentamminecobalt(III) CO(NH,),(ONO)~' and has shown that spon- taneous intramolecular oxygen- to oxygen-exchange in the nitrite ligand occurs at a comparable rate to that of the spontaneous oxygen- to nitrogen-isomerization. Oxygen-17n.m.r. spectroscopy has also been used in a study" of two series of metal carbonyl derivatives [MnR(CO)S] (R = H Me and Br) and [MM'(CO),,]"- (n= 0 for M = M' = Mn; n = 1 for M = Mn M' = Cr Mo and W; yt = 2 for M = M' = Cr Mo and W) at natural I7O abundance. The 170 n.m.r. chemical shifts for mononuclear [MnR(CO)S] were related to substituent electronegativity and paramagnetic shielding which increases with decreasing charge density at the oxygen 2p orbitals.For the dinuclear metal carbonyls the subtle changes in I7O resonance frequencies were related to diamagnetic shielding effects due to the metal-metal bond. It is also pertinent to record the use of 170 n.m.r. to monitor reactions such as the hydrolysis'9 of 2-acetyl[ '70]oxyethyl(pyridine)cobaloximeand the hydration of [170] formylmethyl(pyridine). In yet another example of the versatility of 170 n.m.r. the technique complimented by mass spectrometry was used to showz0 that 6-(~-a -amino[ 1,l ,6-'70/'80]-adipyl)-L-cysteinyl-D-valinewas converted into isopenicillin N in cell-free extracts of Cephalosporium acremonium with no loss of 170/180 label and that incubation of unlabelled tripeptide in a cell-free system containing 170/ 180-enriched water produced isopenicillin N without incorporation of 170/180.The relevance of the work is vested in both its l3 R. L. Lintvedt M. J. Heeg N. Ahmad and M. D. Glick Inorg. Chem. 1982 21 2350. l4 M. M. Taqui Khan and G. Ramachaudraiah Znorg. Chem. 1982,21,2109. '' T. D. Smith I. M. Ruzic S. Tirant and J. R. Pilbrow J. Chem. SOC.,Dalton Trans. 1982 363. l6 M. W. Urban Y. Nonaka and K. Nakamoto Inorg. Chem. 1982,21 1046. 17 W. G. Jackson G. A. Lawrence P. A. Lay and A. M. Sargeson J. Chem. SOC.,Chem. Commun. 1982 70. S. Onaka T. Sugawara Y. Kawada and H. Iwamura J. Chem. SOC.,Dalton Trans. 1982 257. l9 E. H. Curzon B. T. Golding and Ah Kee Wong J. Chem. SOC.,Chem. Commun. 1982,63. '"R.M. Adlington R. T. Aplin J. E. Baldwin L. D. Field E. M. M. John E. P. Abraham and R. L. White J. Chem. SOC.,Chem. Commun. 1982 137. 0,S Se Te 125 illustration of the use of ”0 n.m.r. and the current interest in the inorganic chemistry of biological systems a subject which will receive amplification in subsequent sections of this Chapter. In this respect it is pertinent to cite some semi-empirical MO calculations” describing the stability and bonding in FeO Fe02 and OFeO as a function of charge and geometry. The continued interest in the interaction of oxygen with iron atoms reflects contemporary awareness of the importance of fundamental chemistry in topics such as oxygen transport in living systems as well as on a distinctly different front the corrosion of structural metals.In terms of the former matter it is relevant to note the report22 of newly synthesized iron(I1) ‘hanging base’ porphyrins which indicate that polar groups on the distal side of the haem can stabilize the oxygenated complexes by reducing the rate constant for the dissociation of dioxygen. The increasing awareness of the importance of oxygenation of the iron(I1) form of haemoglobin and myoglobin in the physiological transport and storage of molecular oxygen is reflected in two e.s.r. studies. In an investigationz3 of the molecular oxygen adducts of the apomyoglobin complexes of cobalt(I1) protoporphyrin IX and cobalt(I1) 3,10,17,24-tetrasulphonated phthalocyanine the protein was described as providing the appropriate conditions for oxygenation of the cobalt(I1) tetrasulphonated phthalocyanine.In the other of some working haem analogues the reversible dioxygenation of Mn(PR,)X2 (R = n-butyl n-pentyl; X = C1 Br I) in solution to give ‘Mn(PR,)(02)X2’ were examined. Studies of related systems have included investigation~~~ of a new macrocyclic pentadentate ligand a pyridyl-containing 16-membered pentaamine (L’) which stabilizes a violet-pink coloured oxygenated species of iron(I1) in aqueous solutions at room temperature. Measurements of oxygen uptake and pH suggested a (FeL”)’- 0 adduct in which the violet-pink colour could be attributed to 0’ -+Fe charge- transfer and the Fe(I1)-L‘ complex used as a model of haemerythrin. A parallel autoxidation reaction was also measured with cobalt(I1)-L‘ which yields a stable brown (COL”)~-O~ adduct with a slightly larger oxygenation constant.Comparative kinetic studies of the autoxidation of the iron and cobalt complexes showed a common rate law. It is also relevant to record the reportz6 of the reaction of thermally unstable [Fe’(cp)(C6Me5NH2)] in which cp = q5-C5H5 with a mol of 0 at -10 “C in toluene to give [Fe”(cp)(q5-C6Me5NH) the N-H being activated by 0 and consistent with an O2+ 0;-electron transfer mechanism. The latter complex was reported to react with carbon dioxide under mild conditions (20 “C 1atm) to give an amino-acid zwitterion Fe+(cp)(q 6-Me5NHC02-). Developments in the synthesis and characterization of reversible dioxygen complexes of metals which have important implications in relation to oxygen carriers in bio-organisms and catalytic oxidation are illustrated in a report2’ of the first Moz-O2 complex chemically fixed on a silica surface which provides an example of a new class of ” G.Blyholder T. Head and F. Ruette Inorg. Chem. 1982 21 1539. ’’ M. Momenteau and D. Lavalette J. Chem. SOC.,Chem. Commun. 1982 341. 23 I. M. Ruzic T. D. Smith and J. R. Pilbrow. J. Chem. Soc.. Dalton Trans. 1982 373. 24 C. A. McAuliffe M. G. Little and J. B. Raynor J. Chem. SOC.,Chem. Commun. 1982 68. ’’ E. Kimura M. Kodama R. Machida and K. Ishizu Inorg. Chem. 1982 21 595. 26 P. Michaud and D. Astruc J. Chem. SOC.,Chem. Commun. 1982,416. 27 Y. Iwasawa M. Yamagishi and S. Ogasawara J. Chem. Soc. Chem. Commun. 1982 246.126 F. J. Berry oxygen carrier. Other interest in this area is demonstrated in the investigation28 of a number of quadridentate salicylaldimine cobalt(I1) complexes which were found to behave as reversible oxygen carriers similar to other models of biologically significant oxygen carriers. The preparative aspect of the work which involved the formation of water soluble sodium salts of cobalt(I1) complexes of a series of NN-substituted bis-salicylaldiminesulphonic acids were discussed in terms of the synthesis of organometallic compounds containing cobalt(I1) similar to vitamin B 12. Studies of the kinetics and mechanism of oxidation processes have also been reported For example the effect of chloride ions on the rate of the copper-catalysed oxidation of ascorbic acid by dissolved oxygen has been examined29 over the pH range 2.0 to 3.5 and with chloride concentrations up to 0.2 mol dm-3.A mechanism based on the involvement of copper(1) rather than copper(II1) was suggested. 3 Sulphur The extended Huckel MO approach and the Jahn-Teller theorem have been applied3' to a consideration of the structures of a number of ions including The synthesis and structure of sulphur anions with triple co-ordination have been rep~rted.~**~~ The largest interest in inorganic compounds containing sulphur has been in those containing sulphur-nitrogen bonds. Indeed although poly(su1phur nitride) has been intensively studied in recent years and has been incorporated in various potentially useful materials it has always been prepared by essentially the same route.It is therefore pertinent to record the report33 of the synthesis of good quality poly(su1- phur nitride) (SN), in 65% yield by the reaction of excess of SiMe3N3 with S3N3C13 S3N2C12,or S3N2Cl at -15 "C in acetonitrile solution. Preparations from the reaction of S3N3C13 and excess of NaN3 or from CsN and S,NAsF6 in SO at -20 "C were also described but these appeared to be less facile routes. The analogous reactions involving selenium gave blue black explosive solids. Some new compounds with high sulphur and nitrogen contents have been repor- ted. For example a of formula S6N504with separately stacked cyclic radical cations S3N2+,and cyclic anions S3N304- has been described and other studies have that the 1 1reaction of S4N4Cl with trimethylsilyl-substituted sulphodiimides gives derivatives of pentasulphur hexanitride.Studies of the reac- tions of tetrasulphur tetranitride have continued with for example the compound 28 K. J. Berry F. Moya K. S. Murray A. M. B. van den Bergen and B. 0.West J. Chem. SOC.,Dalton Trans. 1982 109. 29 R. J. Jameson and N. J. Blackburn J. Chem. SOC.,Dalton Trans. 1982,9. 30 R. C. Burns R. J. Gillespie J. A. Barnes and M. J. McGlinchey Inorg. Chem. 1982,21,799. 31 H. W. Roesky W. Schrnieder W. Isenberg W. S. Sheldrick and G. M. Sheldrick Chem. Ber. 1982 115,2714. 32 H. W. Roesky W. Schmieder W. Isenberg D. Bohler and G. M. Sheldrick Angew. Chern. Suppl. 1982,269-282. 33 F. A. Kennett G. K. MacLean J. Passmore and N.N. Sudeheendra Rao J. Chem. SOC.,Dalton Trans. 1982 851. 34 H. W. Roesky M. Witt J. Schinkowiak M. Schmidt M. Noltemeyer and G. M. Sheldrick Angew. Chem. Suppl. 1982 1273-1280. 35 H. W. Roesky C. Pelz B. Krebs and G. Henkel Chem. Ber. 1982,115 1448. 0,S Se Te 127 l,l-dimethyl-l-phospha-3,5-dithia-2,4,6-triazene,Me2PS2N3 being isolated36 from the reaction of Me2PPMe2 with S4N4 and reported to undergo a ring expansion at ambient temperature to give 1,133-tetramethylbicyclo[3.3 .O]-1,5 -diphospha-3,7-dithia-2,4,6,8-tetrazene, Me2P(NSN)2PMe2. The crystal and molecular struc- ture (Figure 2)of Me2P(NSN)2PMe2 revealed a folded eight-membered butterfly- type ring with a cross-ring S-S contact. The 'H and I3Cn.m.r. spectra were Figure 2 Structure of Me2P(NSN)2PMe2 (Reproduced by permission from Inorg.Chern. 1982 21,982) consistent with non-equivalent pairs of methyl groups indicative of the maintenance of the folded structure in solution. Another study3' showed that the production of a S4N3Br and S4N3Br3 mixture from the reaction between S4N4 and bromine in carbon tetrachloride at ambient temperature whilst the additional formation of CS3N2Br2 and CS3N2Br4 was observed when the reaction was performed in carbon disulphide. The structure of the latter product formulated as [CS3N2Br]+Br3- was described in terms of a cation containing an almost flat CS2N2 five-membered ring with an S-Br group bonded exocyclically to the carbon atom. Other studies of tetrasulphur tetranitride have involved38 its reaction with some tin(@ and tin(Iv) compounds.Magnetic circular dichroism spectroscopy has been to study the thiotrithiazyl cation S4N3+. The results revealed the presence of four low-energy electronic transitions which were attributed to T*"TT*excitations in a cyclic ten-.rr- electron system. In other magnetic circular dichroism studies4' of cyclic m-electron systems the spectra of the [NP(C,H,),] and [NAs(C6H5),] derivatives of the ten-.rr- electron six-atom S3N3- anion were discussed. Other recent spectroscopic investiga- tion~~~ have involved the use of Raman spectroscopy to identify the S,N- and S3-ions in blue solutions of sulphur in liquid ammonia. 36 N. Burford T. Chivers P. W. Codding and R. T. Oakley Inorg. Chem. 1982 21,982. 37 G.Wolmershauser C. Kruger and Y. H. Tsay Chem.Ber. 1982,115 1126. M. K. Das J. W. Bibber and J. J. Zuckerman Inorg. Chem.,1982,21,2864. 39 J. W. Waluk and J. Michl Inorg. Chem. 1982,21 556. 40 J. W. Waluk T. Chivers R. T. Oakley and J. Michl Inorg. Chem. 1982 21 832. 41 T. Chivers and C. Lau Znorg. Chem. 1982,21,453. 128 F. J. Berry The syntheses and structures of other types of compounds containing sulphur and nitrogen have been reported. For example S&02 has been found42 to react with sulphur dioxide under mild conditions to give (S3N304),S which is a new bicyclic system composed of two six-membered sulphur-nitrogen rings bridged by a sulphur atom. The bond-lengths and -angles were found to be consistent with the presence of localized sulphur-diimide (-N=S=N-) units the remaining S-N bonds being essentially single bonds.The structure and mechanism of formation of the dithiozole zanthane hydride C2H2N2S3 has also been described.43 The crystal of 2,2,4,4,6-pentafluoro-6-[N-(1,2,4,3,5- trithiadiazol-1 -ylidene)- amino] cyclotriphosphazene S3N2NP3N3FS (Figure 3) is worthy of note since it consists of a cyclotriphosphazene ring bonded through a bridging nitrogen atom to an S3N2 ring. The nature of the bonding in the sulphur-nitrogen portion of the molecule was related to the properties of the five-membered ring. Figure 3 Structure of S3N2NP3N3FS (Reproduced from J. Chern. Soc. Dalton Truns. 1982 883) Investigations of compounds based on S2N2 have continued; indeed a facile synthesis of S2N2itself from the reaction of S4N4 with S,N2.2AlC13 at 80 "Cin high vacuum has been rep~rted.~' The low temperature of the reaction compared with the preparation by direct pyrolysis of S4N4at 300 "C is a distinct advantage.The crystal and molecular of the hydrazido(2-) and diazenido derivatives [MoO(N,Ph,)L] and [MO(N,C,H~OCH~)~L], where L is an N2Sz ligand have revealed the sterically strained configurations associated with this tetradentate ligand. The study also related the electrochemistry of a series of complexes of the type [MO(N&H~X)~L] to the geometry of the diazenido ligands. 42 H. W. Roesky W. Clegg J. Schinkowiak M. Schmidt M. Witt and G. M. Sheldrick J. Chem. SOC. Dalton Trans. 1982.21 17. 43 A. R. Butler and C.Glidewell J. Chem. Res. (S) 1982 65. 44 I. Rayment H. M. M. Shearer and H. W. Roesky J. Chem. Soc. Dalton Trans. 1982 883. 45 H. W. Roesky and J. Anhaus Chem. Ber. 1982,115,3682. 46 P. L. Dahlstrom J. R. Dilworth P. Shulman and J. Zubieta Znorg. Chem. 1982 21 933. 0,S Se Te 129 The attention which has been given to the synthesis and characterization of molybdenum-sulphur complexes reflects interest in the role of molybdenum as a cofactor for a number of redox-active enzymes. In investigations4’ of the co- ordination chemistry of molybdenum with tetradentate ligands possessing N2S2 donor sets the preparation characterization and electrochemical properties of the molybdenum(Iv) (v) and (VI) -ox0 complexes were reported and in another study48 the crystal and molecular structures of complexes of the type MoOZY,where Yz- is a linear tetradentate ligand containing nitrogen and sulphur donor atoms and of molybdenum complexes with NS donor sets have been described.Compounds containing nitrogen sulphur and fluorine have also received atten- tion. The ground state potential surface of thiazyl fluoride (NSF) has been calcu- lated49 by using ab initio Hartree-Fock methods. In a study5’ of novel sulphur- nitrogen-fluorine compounds pentafluoro(fluorochloroamido)sulphur SF5NFC1 was synthesized from NSF by low temperature reaction with ClF followed by reaction with fluorine. Reduction of SF5NClF with mercury in trifluoroacetic acid gave (fluoroimido)pentafluorosulphur SF,NHF which was dehydrofluorinated by KF to give (fluoroimido)tetrafluorosulphur,FN=SF4.The imine was described as an unusual pentaco-ordinate molecule which according to 19Fn.m.r. does not undergo positional exchange of the sulphur fluorines. Vibrational analysis of FN=SF4 showed good agreement with the related OSF4 CHz=SF4 and SF4 molecules. The gas-phase structure determined from electron diffraction and microwave spectroscopic data showed a relatively long S=N bond a short N-F bond and a large difference in the non-equivalent axial S-F bonds. The reactivity of CIF with sulphur-nitrogen compounds has been considered in another study51 where its addition to the SN triple bond in NSF was achieved by use of the Cl2-HgFZ system. Other interesting reports involve5’ reaction of S,N,F and S3N3C13 with Lewis acids such as SbCl, AsF, SbF5 and SO in solvents such as SOz CHzClz and SOCl,.Compounds of formula (S,N,)(SbCl,) and S4N4.SbC15 were characterized by X-ray crystallography and the geometry of the planar pentathiazyl cation S5N5+ found to be intermediate between the previously described ‘azulene- like’ and ‘heart-shaped’ structures. Studies5 of reactions of [(pentafluorosul-phanyl)imino] difluorosulphane SF5N=SFz with TiC14 SnC14 and SbC1 have described four routes to the formation of SF,N=SCl and [(pentafluorosul- phanyl)imino] chlorofluorosulphane SF5N=SClF reported to be the first example of a mixed halide of the type SF5N=SXY. It is also pertinent to note the new54 synthesis of dithionitronium hexafluoroarsenate(v) SzNAsF6 from sulphur tetrasulphur tetranitride and arsenic pentafluoride in sulphur dioxide and which 47 C.Pickett S. Kumar P. A. Vella and J. Zubieta Inorg. Chem. 1982,21 908. 48 A. Bruce J. L.Corbin P. L. Dahlstrom J. R. Hyde M. Minelli El Stiefel J. T. Spence and J. Zubieta Inorg. Chem. 1982 21 917. 49 R. Seeger U. Seeger R. Bartetzko and R. Gleiter Znorg. Chem. 1982,21,3473. 5n D. D. DesMarteau H. H. Eysel H. Oberhamrner and H. Gunter Inorg. Chem. 1982,21 1607. ’*A. Waterfeld and R. Mews J. Chem. SOC.,Chem. Commun. 1982,839. ’* R. J. Gillespie J. F. Sawyer D. R. Slim and J. D. Tyrer Inorg. Chem. 1982 21 1296. ‘3 J. S. Thrasher N. S. Hosmane D. E. Maurer and A. F. Clifford Inorg. Chem. 1982 21 2506. s4 A. J. Banister R. G. Hey G. K. MacLean and J. Passmore Inorg.Chem. 1982 21 1679. 130 F. J. Berry occurs more rapidly in the presence of bromine. The SzN+ cation was identified as a potentially useful component in sulphur-nitrogen chemistry and a precursor to a variety of new compounds. The combined power of electron diffraction and microwave spectroscopy for the investigation of the structural properties of gaseous species has been further illus- trated in a of distorted trigonal bipyramidal CH3N=SF4 in which the bond angles around the sulphur atom were correlated with the electronic structure of the S=NT bond. Optimized yields56 of N-pentafluorosulphanyl amides by the acylation of pentafluorosulphanylamine SF5NHz have been obtained from reactions of acyl halides containing electron-deficient carbonyls.The N-and cy -halogeno-derivatives of S-aryl-S-[1,2-benzisoxazo1-3-y1] sulphoximides have been shown5' to undergo base-induced rearrangements to give corresponding N-sulphinylimines by reactions which seem to involve an intermediate composed of a three-membered cyclic sulphoximide with an endocyclic S=N moiety. Two crystal structures of other sulphur-nitrogen compounds are worthy of note. Bis(diphenylmethyleneamin0)monosulphide S(N=CPhz)2 has been shown" to be largely coplanar with the two phenyl groups twisted out of the central CNSNC plane. The bonding was described in terms of sulphur-nitrogen single bonds with the structural description giving no evidence of significant delocalization of the nitrogen lone pair. In another investigation the firsts9 single crystal X-ray diffraction study of a symmetrical dialkylsulphamide (~-BuNH)~SO~ containing sulphur- nitrogen bonds was described.Inorganic ring systems containing sulphur and either boron or phosphorus have also received attention. For example the rr-electronic structure of the B8SI6 molecule containing 32 n-electrons which is composed of four five-membered BzS3 rings linked through boron atoms by sulphur atom bridges to form a macrocycle (Figure 4) has been compared6" with that of structurally related porphine containing Figure 4 Representation of the B8Sl6molecule (Reproduced by permission from Inorg. Chem. 1982 21,21) " H. Gunter H. Oberhammer R. Mews and I. Stahl Inorg. Chem. 1982 21 1872. 56 J. S. Thrasher J. L.Howell and A. F. Clifford Inorg. Chem. 1982. 21 1616. '' T. Yoshida S. Naruto H. Uno and H. Nishirnura J. Chem. Soc. Chem. Commwn. 1982 106. '' M.-T. Averbuch-Pouchot A. Durif A. J. Banister J. A. Durrant and J. Halfpenny J. Chem. Soc. Dalton Trans. 1982 221. '9 J. L. Atwood A. H. Cowley W. E. Hunter and S. K. Mehrotra Inorg. Chem. 1982 21 435. ti0 B. N. Gimarc and N. Trinajstic Inorg. Chem. 1982 21 21. 0,S Se Te 131 26 T-electrons. Calculations of Huckel T-electron densities showed the atomic arrangements in these macrocycles to be topologically determined. The larger Huckel HOMO-LUMO gap (T-T* transition energy) in white B& compared with that in porphine was associated with the intense colour of the porphyrins. The extra electrons in BsS16 were envisaged as occupying predominantly antibonding molecular orbitals such that the molecule has smaller T delocalization -and topological resonance -energies than porphine.In phosphorus-sulphur systems n.m.r. has been used6' to identify P4Ss a new species of limited stability as the primary product of the desulphuration of P4S9 by Ph3P and tertiary phosphine sulphides have been reported62 to react with cobalt(I1) halides to give pseudo- tetrahedral compounds. Much interest has persisted in compounds containing sulphur-metal bonds. A MO treatment based on the extended Huckel method has been applied63 to the collinear M-S-M bridged linkages in dinuclear thiometal complexes in an attempt to investigate orbital interactions and the role of sulphur d orbitals in the metal- sulphur bonding.However more attention has been specifically given to compounds containing molybdenum and sulphur and the interest presumably reflects the biological significance of such materials. A number of structural studies of these compounds has been reported including that of a novelb4 highly symmetric poly- nuclear complex of formula [Mo4(NO),(S2),0]'- with two 'handle-shaped' and four 'roof-shaped' co-ordinated S2'-bridging ligands at a tetragonal Mo dispheroid. Other compounds such as the [Mo,S,(NO),(CN),]~-species,65 and the [Mo,"'S,(CN),,]~- cluster66 have been investigated and described in terms of highly charged anions containing cubane like units. [(S4)2M~0]2- and (Mo~S,~)~-The [(S4)2M~S]2- (MO~S~~)~- anions have been examined6' during investigations of the reaction of the MoSd2- anion with elemental sulphur and 'active' sulphur reagents such as organic trisulphides or ammonium sulphides.The successful isolation of these sulphides which appear to be components of a complex equilibrium system depends on the solvent system and the nature of the counterions in solution. The molybdenum(1v) in [(S4)2M~S]2-and [(S4)2M~0]2- was found to be co-ordinated by two bidentate S42-chelates and a terminal sulphur or oxygen atom in a distorted square pyramidal arrangement above the basal sulphur plane. The Mo2SlO2- and M02S122- anions have the (M02SJ2+ core which contains two (Mo"=S)~+ units bridged asymmetrically by two sulphide ligands in the syn configuration attached to one molybdenum with the other metal atom being co-ordinated by either a persulphido or a tetrasulphido group.All the structures contain an alternation of the S-S bond lengths in the S4'-chelate rings and the Mo-S ring adopts the puckered configuration such that the sulphur atoms '' J.-J. Barieux and M. C. Demarcq J. Chem. SOC., Chem. Commun. 1982 176. h2 J.-C. Pierrard J. Rimbault and R. P. Hugel J. Chem. Res. (S),1982 52. 63 C. Mealli and L. Sacconi Znorg. Chem. 1982,21 2870. 64 A. Muller W. Eltzner H. Bogge and S. Sarkar Angew. Chem. Suppl. 1982 1167-1 176. 65 A. Muller W. Eltzner W. Clegg and G.M. Sheldrick Angew. Chem. Suppl. 1982 1177-1185. 66 A. Muller W. Eltzner H. Bogge and R. Jostes Angew. Chem. Suppl. 1982 1643-1661. h7 M. Draganjac E.Simhou L. T. Chan M. Kanatzidis N. C. Baenziger and D. Coucouvanis Inorg. Chem.. 1982.21 3321. 132 F. J. Berry are asymmetrically bound to the molybdenum. The MoS~ ring conformation and its influence on the Mo-S bonding were attributed to intraligand sulphur electron lone-pair repulsions. Other molybdenum-sulphur compounds have been subjected to structural investigation including that68 of bis(dimethy1amine)tetrakis(t-butyl mercaptido)di- p-sulphidodimolybdenum(1v) in which each molybdenum atom is in a distorted trigonal-bipyramidal environment with the two halves of the molecule being joined by a pair of sulphido bridges. The structure~~~ the p-0x0 complex of and of the p -dioxo complex [MO,O~(C~H~~N~S~)~] [Moz03(C8H18N2S2)] have been reported and compared to previously described species containing the Moz034+ and Moz042+cores.A study7" stemming from interest in copper-molybdenum antagonism in ruminants considered the structural properties of mixed d4-d1" bimetal compounds obtained from the reaction of Mo(SBu') or Mo(SBU')~ (CNBU')~ with CUB~(CNBU')~ and revealed the presence of a highly delocalized or P~(CNBU')~ MoS2Cu core in two conformational isomers of (Bu'NC),Mo(p- SBu'),CuBr. It is also pertinent to note that interest in molybdenum-sulphur compounds is not restricted to materials of biological significance and in this respect an inelastic neutron scattering study7' of a model molybdenum disulphide hydrodesulphuriz- ation catalyst at high pressure which identified the existence of two sites at which hydrogen may be sorbed is illustrative of another area of interest in these com- pounds.Given the variety of applications of sulphur-molybdenum compounds it is also relevant to refer to investigation^^^ by X-ray photoelectron spectroscopy and Auger electron spectroscopy of the room temperature oxidation of radio-frequency sputtered molybdenum disulphide films which are used as lubricants in spacecraft. The data were interpreted in terms of changes in surface sulphur and molybdenum concentrations and oxidation states and the degradation of lubricating properties. Studies of compounds containing sulphur and a Group VIA metal using a range of other techniques have also been reported. Variable temperature 'H n.m.r. studies73 of the mononuclear complexes [M(C0)5(Me3SiCH2EECHzSiMe,] M = Cr Mo and W; E = S and Se have established the occurrence of expected pyramidal inversion about the co-ordinated sulphur or selenium atom plus novel higher temperature 1,2-metal shifts between two ligand atoms of the disulphide or diselenide.In an electrochemical and e.s.r. cis-bis(NN-dialkyldithiocar-bamato) dinitrosyl-molybdenum and -tungsten complexes were found to undergo a reversible one electron reduction to give the radical anion M(R,dtc),(NO),- (R = Me Et Pr' Bun Bzl Pyr) in which the unpaired electron was delocalized over both nitrosyl groups. Evidence supporting a MO description of the anion in which the electron resides in a dinitrosyl-based MO possessing little metal d-orbital '' M.H. Chisholm J. F. Corning and J. C. Huffman Inorg. Chem. 1982 21,286. 69 P. L. Dahlstrom J. R. Hyde P. A. Vella and J. Zubieta Inorg. Chem. 1982 21 927. 7" S. Otsuka N. Okura and N. C. Payne J. Chem. SOC.,Chem. Commun. 1982,531. 7' S. Vasudevan J. M. Thomas C. J. Wright and C. Sampson J. Chem.SOC.,Chem. Commun. 1982,418. 72 T. B. Stewart and P. D. Fleischauer Inorg. Chem. 1982 21 2426. 73 E. W. Abel S. K. Bhargava P. K. Mittal K. G. Orrell and V. Sik J. Chem. SOC., Chem. Commun. 1982,535. 74 J. R. Budge J. A. Broomhead and P. D. W. Boyd Inorg. Chem. 1982 21 1031. 0,S Se Te 133 character and close to non-bonding was presented. An electrochemical study75 by cyclic voltammetry complemented by controlled potential coulometry and elec- tronic- and infrared-spectroscopy of molybdenum( ~v)-oxo complexes with oxygen nitrogen and sulphur ligands relevant to molybdenum enzymes has been reported.It provided evidence for oxidation to molybdenum( v)-oxo complexes and for one-electron reduction at a platinum electrode in DMF. In other studies of sulphur- Group VIA metal compounds the reactions of the double cubane clusters [Mo2Fe6s,(sEt),13- and [M2Fe7S,(SEt),,]3- (M = Mo W) with benzenethiol and acetyl chloride were in~estigated~~ to ascertain ligand substitution properties of thiolate ligands; di-p- tolyl disulphide derivatives of molybdenum and tungsten have been examined;77 studies of sulphur( IV) compounds as ligands7' have focused attention of the carbonyl-chromium -molybdenum and -tungsten complexes of sulphur dioxide.A number of specific studies of sulphur-tungsten compounds have been reported. The mononuclear complexes W(CO),L (L = MeSCH2SMe MeSeCH,SeMe and MeSCH,SeMe) were found' to possess a novel fluxional character which by dynamic n.m.r. were interpreted as 1,3-metal jumps between the ligand atoms and which were associated with relative strengths of the S +W and Se +W bonds. Gas-phase electron diffraction studies of tetrachlorosulphidotungsten(vI) WSC14 and the selenium analogue WSeC14 have shown" the molecules to be square- pyramidal structures with C4usymmetry in which the tungsten atom is slightly above the plane of the four chlorine atoms. It is also relevant to record the synthesis and structure of [P(C6H5)4]2W4S12, the first" tungsten complex with the w&'+ core and described as a diamagnetic mixed Wv-Wvl valence compound.Interest in sulphur-metal compounds has also developed in materials containing other transition metals especially iron. For example a novel hexanuclear bimetal- sulphur cluster [Fe3W3S,4]4+ with an Fe3(p3-S)2 centre has recently been reported" and another similar cluster [Fe&(S-t-C4H9)2]4- containing a [Fe6S9I2- core has been describedx3 as a new structural type in iron-sulphide-thiolate chemistry (Figure 5). All the iron atoms are present in tetrahedral FeS4 sites with the thiolates being terminally co-ordinated to two iron atoms at the exterior of the structure. Although the structure is mixed valence there are no localized Fe"."' sites.The [Fe6S,(S-t- Bu),I4- species contains three types of bridging sulphur atoms and undergoes chemically reversible redox reactions and ligand substitution with benzenethiol to give [Fe6S9(SPh),14- and in large excesses of the thiol degradation to [Fe4S4(SPh),12- and [Fe2S2(SPh)4]2-. The species [Fe6S9(SCH2C6H5)2]4- has also been describeds4 in terms of a hexanuclear iron-sulphur cluster anion with a central 75 I. W. Boyd and J. T. Spence Inorg. Chem. 1982 21 1603. 76 R. E. Palermo P. P. Power and R. H. Holm Inorg. Chem. 1982 21 173. 77 D. Condon G. Ferguson F. J. Lalor M. Parvez and T. Spalding Znorg. Chem. 1982 21 188. 7R W. A. Schenk and F. E. Baumann Chem. Ber. 1982,115,2615. 79 E. W. Abel S. K. Bhargava T. E. Mackenzie P. K. Mittal K.G. Orrell and V. Sik J. Chem. Soc. Chem. Commun. 1982,983. E. M. Page D. A. Rice K. Hagen L. Hedberg and K. Hedberg Inorg. Chem. 1982,21 3280. S. Secheresse J. Lefebvre J. C. Daran and Y. Jeannin Znorg. Chem. 1982 21 1311. 82 A. Muller W. Hellmann H. Bogge R. Jostes M. Romer and U. Schimanski Angew. Chem. Suppl. 1982 1757-1776. 83 G. Christou M. Sabat J. A. Ibers and R. H. Holm Znorg. Chem. 1982 21 3518. 84 G. Henkel H. Strasdeit and B. Krebs Angew. Chem. Suppl. 1982,489-498. 134 F. J. Berry C silo BU‘ C Figure 5 Right plane projection formula illustrating atom-labelling scheme and idealized C2 symmetry of [Fe&(s-t-B~)~]~-; Left structure of the anion (Reproduced by permission from Inorg. Chem. 1982,21 3518) square-pyramidal moiety.It has also been reportedsS that a synthetic Fe4S4 cluster can mediate the transfer of electrons from phenyl-lithium to protons from ben- zenethiol in a homogenous system producing hydrogen. The crystal structures6 of a compound of nominal composition ‘Ba2Fe4S5’ has been described in terms of an infinite two-dimensional array of FeS4 tetrahedra and a material of formula [Fe4(C0)12(C2S4)], formed” by reaction of [Fe,(CO)12] with excess carbon disul- phide shown to contain two Fe2(C0)6 units bridged by a C2S4 unit such that it may be regarded as a derivative of ethenetetrathiol. Other studies of sulphur-first row transition-metal compounds have included e.s.r. investigations” of eight-co-ordinated complexes of vanadium(1v) and niobium(1v) dithio- and diseleno-carbamates although more significant interest has been shown in cobalt compounds.The synthesis of [{MeC(CH2PPh2)3}CoP2S]BF4-C6H6 has been reporteds9 and its structure described 85 H. Inoue and M. Sata J. Chem. SOC.,Chem. Commun. 1982 1014. 86 J. S. Swinnea G. A. Eisman T. P. Peng N. Kirnizuka and H. Steinfink J. Solid State Chem. 1982 41 104. P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC. Chem. Commun. 1982,140. 88 D. Attanasio C. Bellitto A. Flamini and G. Pennesi Inorg. Chern. 1982 21 1461. 89 M. Di Vaira M. Peruzzini and P. Stoppioni J. Chem. SOC.,Chem. Commun. 1982 894. 0,S Se Te 135 in terms of a new cyclic triangular diphosphorus-sulphur unit linked to the metal as a trihapto ligand which acts as a four-electron donor.The control by alkali-metal cations of the reactivity of cobalt(I1) Schiff base complexes and the synthesis of a p-persulphido ligand from the reaction of S with a cobalt(I1) oxygen carrier compound has been described." Some trithiocarbamate complexesg1 of cobalt and nickel have been found to be highly activated towards electrophilic reagents. In other studies the synthesis and characterization of a seriesg2 of cobalt(II1) complexes containing symmetrical disulphides bonded to cobalt through one sulphur atom have been discussed and cobalt(Ir1) complexes containing S-bonded sulphenato ligands [Co-S(0)-R] have been consideredg3 in terms of the similar chemistries of non-co-ordinated -sulphenate anions [R-S(0)-1 and -sulphoxides [R-S(0)-R'].It is also relevant to note the use94 of a specially developed program for calculations of the electronic ground states of the nickel-sulphur compounds Ni(S2C2H2)2 and Ni(S2C3H3)2. Studies of compounds containing copper and sulphur have continued especially in areas relating to protein chemistry for example investigationsg5 of the electronic structures of copper(I1) complexes with N4and S4ligand fields including blue-copper proteins have involved MO calculations. Other studiesg6 of the structural properties and chemical reactivity of cubic clusters based on eight copper atoms with sulphur- containing ligands have been described while the cleavageg7 of the disulphide bond in a pyridine-containing disulphide in the presence of copper(r1) and dioxygen has been found to give a copper(I1) sulphonate complex in which the sulphonate oxygen ztom bridges two copper(I1) ions in a square-pyramidal environment.Attention has also been given to compounds containing sulphur and second- and third-row transition metals. The reactions of sulphur dioxide with [RhH(Co)- (PPh3)3] and [IrH(Co)(PPh,),] have been shown9* to give hydrido(su1phur dioxide) complexes [MH(Co)(SO,)(PPh,),] where M = Rh or Ir; and the structural in~estigation~~ of a dirhodium(I1) oxygen-bonded sulphoxide adduct has identified the first example in a transition-metal complex of a crystal packing modification solely effected by the substitution of deuterium for hydrogen. In other investiga- tions"' the u-S and q3-SCS co-ordination of sulphines to rhodium(1) has been considered and the influence of sulphine geometry on the formation of rhodium 90 S.Gambarotta M. L. Fiallo C. Floriani A. Chiesi-Villa and C. Guastini J. Chem. SOC., Chem. Commun. 1982,503. 91 C. Bianchini C. Mealli A. Meli and G. Scapacci J. Chem. SOC.,Dalton Trans. 1982 799. 92 J. D. Lydon R. C. Elder and E. Deutsch Inorg. Chem. 1982,21 3186. 93 J. D. Lydon and E. Deutsch Inorg. Chem. 1982 21 3180. 94 Z. S. Herman R. F. Kirchner G. H. Loew,U. T. Mueller-Westerhoff A. Nazzal and M. C. Zerner Inorg. Chem. 1982,21,46. 95 T. Yamabe K. Hori T. Minato K. Fukui and Y. Sugiura Inorg. Chem. 1982 21 2040. 96 S. Kanodia and D. Coucouvanis Inorg. Chem. 1982,21 469. 97 A. Odani T. Maruyama 0.Yamanuchi T. Fujiwara and K.Tomita J. Chem. SOC.,Chem. Commun. 1982,646. 98 L. K. Bell and D. M. P. Mingos J. Chem. SOC.,Dalton Trans. 1982 673. 99 F. A. Cotton and T. R. Felthouse Inorg. Chem. 1982,21,431. 100 J. W. Gosselink A. M. F. Brouwers G. van Koten and K. Vrieze J. Chem. SOC., Dalron Trans. 1982,397. 136 F. J. Berry complexes examined. The formation"' and structural properties of compounds of [OS,(CO)~S~], formula [OS,(CO)~(CS)S~] and [OS,(CO),~(CS)S] from the reaction of [Os,(CO), J with excess carbon disulphide have also been reported. Attention has been given to compounds containing sulphur and precious metals. Although compounds containing PtSs rings have been known for nearly a century the reportedlo2 crystal and molecular structure of [(C6H,),P],PtS4.CHC1 (Figure 6) is notable because it is the first structural study of a compound containing a PtS Figure 6 Structure of [(C6H5)3P]2PtS4CHC13 (Reproduced by permission from Inorg.Chem. 1982 21,3577) ring. In another study the six-membered ring inversion in the tris(pentasu1phane- 1,5-diyl)platinate(1v) anion was investigated" by 195Pt n.m.r. and two conforma- tions identified. Dynamic n.m.r. methods have also been used104 to investigate the energy barriers associated with pyramidal inversions of individual chalcogen atoms in mixed chalcogen ligand complexes of trimethylplatinum(1v) halides of the type [PtXMe,(MeSRSeMe)] where R = (CH2)Zor o-C6H4. It is also relevant to note the reported1O5 incorporation ofdimethylsulphoxide(DMSO)into molecular species such as [Pt(diamine)(DMS0)2]2+ to give water-soluble less toxic derivatives with equivalent chemotherapeutic activity to those of the parent chloro-complexes.Two structural studies of compounds containing silver to sulphur bonds are worthy of note. The existence'06 of a highly charged 1,l-dithiolate cluster anion lo' P. V. Broadhurst B. F. G. Johnson J. Lewis and P. R. Raithby J. Chem. SOC.,Dalton Trans. 1982 1641. D. Dudis and J. P. Fackler Inorg. Chem. 1982 21 3577. F. G. Riddell R. D. Gillard and F. L. Wimmer J. Gem. SOC.,Chem. Commun. 1982,332. E. W. Abel S. K. Bhargava K. Kite K. G. Orrell V. Sik and B. L. Williams J. Chem. SOC.,Dalton Trans. 1982 583. lo' N. Farrell J. Chem. SOC.,Chem. Commun. 1982 331. H. Dietrich W.Storck and G. Manecke J. Chem. SOC.,Chem. Commun. 1982 1036. 0,S,Se Te 137 containing an Aga octahedron [Aa{S2C=C(CN)2}6]6- has been associated with Ag- Ag interactions and in another study lo' the structure of [Ag(Ss)2]AS3F6 pre- pared from the reaction of AgAsF6 with ss in liquid sulphur dioxide was described in terms of cyclo-octasulphur ligands with the silver atoms achieving distorted four-co-ordination by 1,3-linkages to two ss rings. The diversity of metals which have been used in reactions with sulphur-containing compounds is further illustrated by the synthesis1o8 and structural characterization of bis(di-n-propy1ammonium)disulphidobis(di-n-propy1thiocarbamato)dioxoura-nate(vI) a uranyl complex with a disulphide ligand. Although a number of solid-state studies have been cited in the foregoing several others somewhat different in nature warrant attention.The formation of metal sulphides for example'09 Tis& and' lo TaS and NbS (and their selenium analogues) are worthy of note since the tantalum and niobium trichalcogenides prepared under high pressure adopt the NbSe,-type structure and show a variety of electrical transport properties. Diffuse reflectance spectroscopy and four-probe electrical conductivity measurements"' of Na3Cu4S4 have shown the mixed valence S2-/S- solid to be a one-dimensional metal with the conductivity corresponding to pseudo- one-dimensional [CU~S~~-]~ columns parallel to the crystal needle axis. Another area of interest concerns materials containing both sulphur and selenium.Sulphur-selenium mixed crystals have been prepared' l2 by melting the elements in sealed tubes followed by Raman controlled fractional recrystallization of the products from benzene/carbon disulphide. Molecules containing Se-Se bonds were preferentially precipitated from the solvent while ss and molecules containing isolated selenium atoms were enriched in the solvent phase. In another study113 the structural properties and polytype phase transitions in the series Gasel- S,were investigated. Materials containing sulphur or selenium and a Group IV element have also been the subject of examination. The crystal and molecular structures of disilyl sulphide and disilyl selenide have shown' l4 Si-4(or Se) intermolecular interactions with each silicon atom adopting 4 + 1 co-ordination and the sulphur or selenium having 2 + 2 co-ordination.The situation contrasts with the crystalline SiH3-0-SiH species in which only one silicon atom is involved in an inter- molecular contact to oxygen. investigation^'^^ of the synthesis and characterization by 'H n.m.r. and l19Sn Mossbauer spectroscopy of novel penta- and hexa-co- ordinated sulphur-containing spirocyclic tin(1v) compounds have been interpreted in terms of the chemical and structural properties of the materials. It is also relevant to note the use116 of functional sulphur units as one-electron ligands in syntheses via trimethylstannylthio complexes of manganese and rhenium lo' H. W. Roesky M. Thomas J. Schimkowiak P. G. Jones W.Pinkert and G. M. Sheldrick J. Chem. SOC.,Chem. Commun. 1982,895. '08 D. L. Perry A. Zalkin H. Ruben and D. H. Templeton Inorg. Chem. 1982,21 237. Io9 M. Saeki and M. Onoda Bull. Chem. SOC.Jpn. 1982 55 113. 'Io S. Kikkawa N. Ogawa and M. Koizumi J. Solid State Chem. 1982,41 315. Z. Peplinski D. B. Brown T. Watt W. E. Hatfield and P. Day Inorg. Chem. 1982 21 1752. 11* V. R. Frey and H. H. Eysel 2. Anorg. Allg. Chem. 1982,489 173. 'I3 J. C. J. M. Terhill V. A. M. Brabers and G. E. van Egmond J. Solid State Chem. 1982,41,97. M. J. Barrow and E. A. V. Ebsworth J. Chem. SOC.,Dalton Trans. 1982,211. A. C. San R. R. Holmes K. C. Molloy and J. J. Zuckerman Inorg. Chem. 1982 21 1421. R. Kury and H. Vahrenkamp J. Chem. Res. (S),1982 31. 138 F. J.Berry Compounds containing sulphur and a Group V element have also received attention. Reactions"' between sulphur iodine and either antimony- or arsenic- pentafluoride to give compounds of the type [(S71),I](SbF6),.2AsF3 and (S71)4S4(A~F6)6 which contain the iodo-cyclo-heptasulphur (1+) and the -tetrasul- phur (2+) cations have been reported and their structures described. Melts containing sulphur bearing compounds have been the subject of examin- ation and in a Raman spectroscopic spectrophotometric and e.s.r. study118 the blue solutions produced by reaction between aluminium and sulphur in basic CsCl-AlC13 melts have been associated with the presence of S3-species. However the sulphur-chlorine system in molten NaC1-AlCI has,119 by use of the same techniques been shown to contain different cationic species S4+ Ss+ and possibly S1p+ and to be produced by anodic oxidation or by reaction between chlorine and elemental sulphur.Other work1*' has investigated complex formation in pyrosul- phate melts to elucidate the mechanism of the vanadium oxide catalysed oxidation of sulphur dioxide to sulphur trioxide which is an important aspect of the production of sulphuric acid by the contact process. Other recent studies of sulphur bearing compounds in solution have resulted"' in a proposed mechanism for the oxidation of peroxovanadium(v) V03+,by HSOS- whereas studies of the dimerization of bisulphite ion in aqueous solution to form S2OS2-have lead1" to the re-determination of the equilibrium quotient from Raman- and ultraviolet-spectroscopic measurements.Non-aqueous systems have also received attention. For example the novel reactions123of several metal oxides with the mixed non-aqueous system dimethylsul- phoxide-sulphur dioxide to give metal disulphates probably by direct conversion of oxide through sulphide have been reported and in contrast with the spontaneous reaction of metals with the system reported to proceed without the involvement of metal-S02- ion pairs. Other solvent-sulphur dioxide mixed systems are less reactive towards metal oxides and the DMSO-S02 system seems to be unique in its ability to convert sulphur(rv) to sulphur(vr) in the form of the disulphate ion. The reactivity and solvent properties of pure sulphur dioxide have also received attention.A new between sulphur dioxide and hexamethyldisilazane to give (Me3Si),0 Me3SiNS0 and NH,Me,SiOSO has been reported to involve the transfer of oxygen from sulphur dioxide to silicon and sulphur with partial retention of the Si-N bonding. The use'25 of liquid sulphur dioxide as a solvent in the new electrosynthesis of Hg,AsF6 and Hg3SbF6 illustrates its potential utility in other systems which require a non-reactive aprotic solvent offering high solubility to a large range of compounds. J. Passmore G. Sutherland and P. S. White Inorg. Chem. 1982,21,2717. R.Fehrmann S.von Wimbush G. N. Papatheodorou R. W. Berg and N. J. Bjerrum Inorg. Chem. 1982,21,3396. R.Fehrmann N.J. Bjerrum and E. Pedersen Inorg. Chem. 1982,21 1497. N.H.Nansen R. Fehrmann and N.J. Bjerrum Inorg. Chem. 1982,21,744. R.C. Thompson Inorg. Chem. 1982,21,859. ''' R. E. Connick T. M. Tam,and E. von Denster Inorg. Chem. 1982,21 103. 123 B. Jeffreys J. B. Gill and D. C. Goodall J. Chem. Soc. Chem. Commun. 1982,788. 124 D.W. Bennett and L. D. Spier Inorg. Chem. 1982,21,410. 12' G. E.Whitwell D. C. Miller and J. M. Burlitch Inorg. Gem. 1982 21 1692. 0,S,Se Te 139 4 Selenium Some investigations of selenium compounds have been cited in the section on sulphur but other studies which have been reported illustrate specific interests in the chemistry of this element. These have ranged from investigations of the separ- ation126 of selenide constituents from materials containing elemental selenium to studies of the synthesis and structures of species such as the diarsenichexaselenate anion As~S~~~- was reported during the isolation of large heteroatomic polyanions from Na- As-Se ternary alloys.Other structural descriptions have been related to properties of the compounds for example the structure128 of TIzMo6Se6 which consists of (M06Se62-) chains separated by columns of TI’ ions has been related to its metallic appearance and conductivity. New mixed of selenium and tellurium of composition Te3Se08 Te2Se209 and TeSe04 have been prepared by solid-state reactions between the corresponding elements and their oxides and the materials characterized by X-ray diffraction and infrared spectroscopy. Phase eq~ilibria’~’ in the Cu0-Se0,-H20 and Ag20-Se02-H20 systems have been investigated with the conditions for formation of CuSeO3.2HzO CuSe03.H2Se03 and Ag2Se03 being determined for the first time.In a of mercury(I1) selenolates the structure of polymeric Hg(SeMe)2 was described in terms of infinite one-dimensional chains with pseudo- tetrahedral mercury being bridged by pairs of selenium. The tetrameric pyridinates [{HgCl(py)(SeEt)},] and [{HgCl(py)o.5(SeBu‘)}4],have both been investigated and described131 in terms of their eight-membered (-Hg-SeR-)4 rings. Another new compound Ba(en)4(SbSe2)2 from the dissolution of Ba4Sb4Sel in ethylenediamine has been shown to contain [SbSe,-1 chains formed by distorted trigonal SbSe3 pyramids connected by common corners. A of charge transfer interactions involving the square-planar chalcogen cations M4” in the compounds (Se4”)(Sb2F4”)(SbzF5+) (SbFa-) (Te4’+)(SbF6-)2 and (Se4”) (A1C14-)2 has been reported.Cryoscopic of the Se03-H2Se04 system have indicated the existence of diselenic acid H2Sez07 at a maximum freezing point of 18.84 f 0.01 “C. Self dissociation in diselenic acid was discussed and the presence of triselenic acid predicted. Results from Fourier-transform heteronuclear triple resonance studies in complex spin systems acyclic ditertiary phosphines and their selenides have been related to factors affecting 77Se shielding. Other developments in selenium chemistry lZ6 Y. Tamari K. Hiraki and Y. Nishikawa Bull. Chem. SOC.Jpn. 1982,55 101. ”’C. H. E. Belin and M. M. Charbonnel,Znorg. Chem. 1982 21 2504. T. Highbanks and R.Hoffmann,Znorg. Chem. 1982,21,3578. lZ9 A. Castro A. Jerez C. Pico and M. L. Veigar J. Chem. SOC.,Dalton Trans. 1982,733. 130 V.T. Ojkova and G. Gospodinov Z. Anorg. Allg. Chem. 1982,484,235. 13’ A. P. Arnold A. J. Canty B. W. Skelton and A. H. White J. Chem. SOC.,Dalton Trans. 1982 607. 13* V. T. Konig B. Eisenmann and H. Schafer 2. Anorg. Allg. Chem. 1982,488 126. 133 G. Cardinal R. J. Gillespie J. F. Sawyer and J. E. Vekris J. Chem. SOC.,Dalton Trans. 1982 765. 134 M. A. Hussein G. M. Iskander M. M. Nur S. Wasif and M. M. Zeidan J. Chem. SOC.,Dalton Trans.,1982 1645. 13’ J. Colquhoun and W. McFarlane J. Chem. SOC.,Dalton Trans. 1982 1915. 140 F. J. Berry have included reports of the of vinyl selenides under phase-transfer conditions which may be applicable in other areas of organoselenium chemistry and the in situ preparati~n'~' of benzeneseldenyliodide from the reaction of diphenyl diselenide and iodine and its use in the formation of carbocyclic compounds from diolefins.It is also interesting to record the reaction138 of carbon diselenide under high pressure and the preparation and characterization of poly(carbon dis- elenide) as a highly conducting polymer stable to 300 "C in air. 5 Tellurium Studies of tellurium compounds have been included in reports cited in previous sections and in this respect it is relevant to refer to the application3' of the extended-Huckel MO approach and the Jahn-Teller theorem to a consideration of Group VI species which included Te4*+ Tee+ and Tet+.Mixed oxides of composition MTe206 have been prepared139 in the M02/Te02 (M = Ce,Th) systems and discussed in terms of a new type of fluorite superstructure. The infrared spectral4' of the phases A$*'B;VTe308 (A = Fe In Sc; B = Nb Ta) have been compared with those of MrVTe308 and the presence of uranyl groups confirmed in UTe309 which has a fluorite-type structure. A series'41 of OTeF compounds of tellurium iodine and xenon and their fluorine analogues have been studied by '*'Te and 129Xe n.m.r. and by 12'1 and 129Xe Mossbauer spectroscopy. The n.m.r. chemical shifts and Mossbauer quadruple splittings of the central xenon iodine and tellurium atoms were used to assess the relative electronegativities of fluorine and OTeF,. of OTeF compounds of several transition metals have also been reported and several definite products e.g.W(OTeF,), OMO(OT~F,)~ and 02Re(OTeFS) have been identified. Structural OOS(OT~F,)~ studies of O=Mo(OTeF,) and O=Os(OTeF,) revealed the central atom to have a square-pyramidal surrounding with the double bonded oxygens occupying the apical positions. In O=Os(OTeF,) a fluoride ion observed close to the sixth co-ordination position of osmium was considered as being donated by co-crystall- ized TeF4 which although forming as a chain adopted a different linkage as compared with that in pure TeF4. Several developments in organotellurium chemistry have been reported including several structure determinations. The crystal and molecular structure of diphenyl telluride has been to consist of Ph2Te=0 monomers linked by short tellurium-oxygen secondary bonds and longer tellurium-oxygen interactions between dimers (Figure 7).It is also relevant to record that the first definitely characterized tellurone bis( p-methoxyphenyl) tellurone has been prepared144 by 136 J. V. Comasseto and C. A. Brandt J. Chem. Res. (S) 1982 56. '37 A. Toshimitsu S. Uemura and M. Okano J. Chem. Soc. Chem. Commun. 1982,87. 'la Y. Okamoto and P. S. Wojcieckowski J Chem. SOC.,Chem. Commun. 1982,386. V. I. L. Botto and E. J. Baran 2.Anorg. Allg. Chem. 1982,484,215. 140 V. I. L. Botto and E. J. Baran 2. Anorg. Allg. Chem. 1982 484,210. 14' T. Birchall R. D. Myers D. de Waard and G. J. Schrobilgen Inorg. Chem. 1982,21 1068. 14* V. P. Huppmann H. Labischinski D.Lentz H. Pritzkow and K. Seppelt 2.Anorg. Allg. Chem. 1982,487 7. 143 N. W. Alcock and W. D. Harrison J. Chem. SOC.,Dalton Trans. 1982,709. 144 L. Engman and M. P. Cava J. Chem. SOC.,Chem. Commun. 1982,164. 0,S Se Te 141 Figure 7 View of diphenyl telluroxide showing the short secondary bond in outline and the dotted longer intermolecular association periodate oxidation of the corresponding telluroxide. Structural studies of aryltel-lurium(1v) halides'45 have reported diphenyltellurium dichloride (Figure 8) to contain tellurium in a trigonal bipyramidal site in which one of the equatorial positions remains vacant whereas phenyltellurium trichloride involves its two Figure 8 Structure of Ph2TeC12 (Reproduced from J. Chem. SOC. Dalton Trans.1982 251) 145 N.W.Alcock and W.D. Harrison I. Chem. Soc. Dalton Trans. 1982,251. 142 F. J. Berry independent tellurium atoms in square-based pyramidal geometry (Figure 9) which are bridged by chlorine atoms to give a chain structure. Both structures exhibit weak longer Te-.Cl interactions which are likely to be of negligible significance in PhTeC13. The crystal and molecular of p-0x0-bis[nitratodiphenyltel-luriurn(~~)]-diphenyltellurium(~v)hydroxide nitrate oxophenyltellurium(1v) nitrate and diphenyltellurium(1v) dinitrate have revealed th? presence in all compounds of four-co-ordinate pseudo-trigonal-bipyramidaltellurium atoms with equatorial lone pairs and weak secondary Te. -0bonds. Figure 9 Structure of PhTeCI3 showing two independent molecules and long Te...Cl contacts (Reproduced from J.Chem. Soc. Dalton Trans. 1982 251) In a of some organotellurium fluorides and carboxylates the factors influencing the formation and stability of covalent forms of telluronium salts were discussed. Carbon-13 n.m.r. data14* for a number of phenyl- and p-methoxyphenyl- tellurium compounds have been reported and the variations in chemical shifts and tellurium<arbon coupling constants discussed in terms of the polarity of the tellurium-carbon bond. Other149 solid-state high-resolution carbon-13 n.m.r. spectra of tellurium co-ordination complexes of the type [Te(S2CNEt2),] (n = 2 4);Te(S2COEt) and AsPh,[Te(S,COEt),] have been recorded using cross polariz- ation dipolar decoupling and magic-angle sample spinning techniques to investi- gate structural and intermolecular effects.146 N. W. Alcock and W. D. Harrison J. Chem. SOC.,Dalton Trans. 1982 1421. W. R. McWhinnie and J. Mallaki Polyhedron 1982,1 13. R. J. Chadha and J. M. Miller J. Chem. SOC.,Dalton Trans. 1982 117. 149 N. Zumbulyadis and H. J. Gysling Inorg. Chem. 1982 21 564. 14' 14' 0,S Se Te 143 The preparation”’ of dibenzotetratellurafulvalene (DBTTeF) by treatment of dilithiobenzene with elemental tellurium followed by tetrachloroethane and its investigation by cyclic voltammetry has been reported. K. Lerstrap D. Talham A. Bloch T. Poehler and D. Cowan J. Chem. Soc. Chem. Commun. 1982 336.