6 0 S Se and Te By J. D. WOOLLINS Department of Chemistry Imperial College London SW7 2A Y UK This review deals with developments in late 1991 and 1992over a broad range of Group 16 chemistry but does not make any attempt to include solid state materials such as oxides or sulfides which are dealt with elsewhere. There have been useful reviews on C-S1 ,Se-N/Te-N '-' and organodisulfide complexe~.~ Oxidants and mechanisms continue to provoke interest. The mechanism of the formation of singlet oxygen from the singlet and triplet states of 9,lO-dicyanoan- thracene (DCA) has been shown' to proceed by quenching of 30,by 'DCA. It was proposed that oxygen quenching of the benzophenone triplet state involves exciplex formation6 on the basis of variable temperature studies.The oxidation of ferrous ions by ozone (pH 0-2) has been studied' by stopped flow spectrophotometry and it was suggested that one of the intermediates is the ferry1 ion Fe02 + . Related to this a new blue paramagnetic p-0,-dirhodium(trispyridine) complex has been postulated on the basis of ESR UV/Vis spectrometry and its reaction chemistry.8 Pathways for water oxidation catalysed by [(bpy),Ru(OH,)],04+ have been prop~sed.~ The symmetric Ru-0-Ru stretch in this complex (as well as the other dimers containing ruthenium in higher oxidation states) was observed by resonance Raman for normal and l80 labelled material which allowed the Ru-0-Ru angle to be estimated. Other labelling experiments suggest that one pathway of the oxidation involves transfer of oxygen from an aqua ligand.An overall mechanism was proposed; the bridging oxygen is believed to be especially influential in controlling/activating the reactant water molecules via hydrogen bond formation. Kinetic studies of the MnO /RuO water oxidation system have also been reported;" the solid RuO behaves as microelectrodes for electron transfer between the two highly irreversible processes i.e. oxidation of 0 to water and reduction of MnO to Mn". Related to the above work is the report" of the spontaneous fixation of CO in air according to equation 1 ' 'The Chemistry of Inorganic Ring Systems' ed. Ralf Steudel Elsevier Amsterdam 1992. M. Bjoergvinsson and H. W. Roesky Pollhedron 1991 10 2353. P. F. Kelly A.M. Z. Slawin D. J. Williams and J.D. Woollins Chem. Soc. Rec.. 1992 21 245. D. Carrillo Coord. Chem. Rev. 1992 119 137. R.C. Kanner and C. S. Foote J. Am. Chem. Soc. 1992 114 678; 682. ' A. J. McLean and M. A. Rodgers. J. Am. Chem. Soc. 1992 114 3145. ' T. Logager J. Holcman K. Sehested and T. Pedersen Inory. Chem. 1992 31 3523. ' R.D. Gillard Polyhedron 1992 11 1737. J.K. Hurst J. Zhou and Y. Lei Inorg. Cliem. 1992 31 1010. A. Mills P. Douglas and T. Russel J. Chem. Soc.. Dalton Truns.. 1992. 1059. l1 T.Tanase S. Nitta S. Yoshikawa K. Kobayashi T. Sakurai. and S. Yano. Inory. Chem. 1992.31 1058. 73 J. D.Woollins [N,N-Me,en = N,N-dimethylethylene diamine]. The X-ray crystal structure of (1 ) reveals all three nickels to be in octahedral environments with the carbonate behaving as a bidentate ligand surrounded by an unusual planar hydrogen bonding network that may be responsible for the fixation of CO in this case; for related complexes containing bidentate en derivates no similar fixation was seen.Ruthenium compounds are still being developed as synthetic reagents. Thus [Ru(edta)NO)] was prepared and + characterized crystallographically. ' It contains five coordinate EDTA linear NO and catalyses the oxidation of hex-1-ene to hexan-2-one and cyclic olefins to epoxides without the need for a co-catalyst. 0x0-complexes particularly those containing bridging oxygen atoms have been studied by a number of groups. For example the structures of [TiCI(p-O)(12- crown-4),][SbC1,],~2CH2C12 (2)' and [Ti(THPED)] (3)14 (THPED = N,N'-tetrakis-(2-hydroxypropyl)ethylenediamine)both contain Ti,O cores (Ti-0-Ti 100.3(2) 112.2(2) and 0-Ti-0 79.7(2) 67.8( 1 ) ' in (2) and (3) respectively).0x0-bridged complexes are also important in biological systems and an example that may be relevant in this context has been described.' Ba{[(Fe(nta)(H2O)],0)~4H2O (H,nta = N(CH,C0,H)3) comprises from X-ray crystallographic studies octahedral iron centres with tetradentate nta3- ligands (viathe nitrogen and three oxygen atoms) and with the coordination being completed by water molecules and the bridging 0x0 ligand (Fe-0-Fe angle 153.2(6) "). A detailed spectroscopic study of a cobalt peroxo complex has also been reported.I6 A number of interesting spectroscopic and structural problems have been addressed.For example the ESR spectrum of OSOF (in WF, Freon 133a (F,CH,Cl) and SO,) was investigated.I7 Hyperfine coupling to the four axial fluorine atoms but not to the equatorial atom was observed. Multielement NMR studies into isopolytungstate solutions (pH 1.5-8) have shown that [W70,4]6- and [H,W,,04,]'o- are the initial products of acidification. Six metatungstates with Keggin ion type structures were also observed at low pH.'* Although only just within the scope of this review it is worth noting that the controversy over bond-stretch isomerism continues with regard to the MoOCI,(PR,) sy~tems.l'*~~ Although a number of groups believe that this phenom- ena is not yet proven (and may indeed be due to impurities) Gibson and co-workers continue to pursue the topic.The structure of Xe(OTeF,) (4) has been described,' with the xenon atom shown to adopt square planar geometry. Another oxide of xenon (5)was also prepared (equation 2) and characterized by X-ray diffraction studies. l2 M. M. Taqui Khan. K. Venkatasubramanian Z. Shirin. and M. M. Bhadbhade. J. Chem. Soc.. Dalton Trans.. 1992 103. l3 G. R. Willey. J. Palin and N. W. Alcock. J. Chem. Soc.. Dalton Trans. 1992 I 117. D. F. Evans J. Parr S. Raliman. A.M. Z. Slawin D.J. Williams. C.Y. Wong and J. D. Woollins. Polyhedron 1993 11. 337. I5 S. L. Heath A. K. Powell H. L. Utting. and M. Helliwell. J. Chem. Soc. Dalton Trans.. 1992 305. l6 F. Tuczek and E. I. Aolomon. Inorg. Chem.. 1992. 31 944. I' J. H. Holloway E.G. Hope J. B.Raynor and P.T. Townsen J. Chem. Soc. Dalton Trans. 1992 1131. J. J. Hastings and 0.W. Howarth J. Chrm. Soc. Dalton Trans. 1992 209. l9 A. P. Bashall S.W. A. Bligh A. J. Edwards. V.C. Gibson M. McPartlin. and 0.B. Robinson. Angew. Chrm. In[. Ed. Enyl. 1992 31 1607. V. C. Gibson and M. McPartlin. J. Chrm. Soc. Dalton Trans.. 1992. 9. 21 L. Turowsky and K. Seppelt Z. Anory. Allq. Chem. 1992. 609. 153. 0 S Se and Te Interestingly VSEPR rules fail to rationalize the observed distorted tetrahed-ral/pseudo trigonal bipyramidal geometry of (5). The related cations F,Xe(OTeF,)~- and OXeF,(OTeF,)~- have been studied2 in solution by lZ9Xe and 19FNMR the novel 0,XeOTeF cation was observed in SbF solution. Other simple telluriuni-oxygen species which have been studied include [H,0,]Te,CI,-4HZ0 (6) and [H,0,]TeCI,0H~5HZ0 (7) which were obtainedZ3" from reaction of TeCl in conc.and dil. HCI respectively and characterized by X-ray crystallography and Raman spectroscopy (6)has a novel polymeric structure made up of [Te,Cl,]:- chains whilst the anion in (7) is square pyramidal with oxygen in the ' apical site. Cyclic [Te,Mo 2060]- which can be considered to represent the unknown cyclic [TeO(OH),16 was crystallized from aqueous solution.23h Simple sulfur-oxygen compounds still provide significant problems. Thus for example although H2S,0 is very important commercially (in the Claus process i.e. H,S + SO + HZS20Z), and although complexes of S,02 are known the free acid has never been characterized. Ionization of diisopropoxy disulfide (and deuterated analogues) by 70 eV electron impact gives24 H2S,0f + (and deuterated analogues) which as deduced from its collisional activation and neutralization-reionization mass spectrum has a chain HO-S-S-OH that is stable to isomerism for ca.10-s. Although H2S0 (8) (Caro's acid) has been known since 1812 it has not been possible to crystallize it until recently when it was obtained, from H,SO,/H,SO,. The important bond lengths and angles obtained from a crystal structure determinati~n,~ at -130"C are given in Figure 1. The molecules pack into layers linked by almost linear 0-H.. . .O hydrogen bonds. Simple coordination compounds of oxygen-containing ligands/anions have been the subject of numerous studies. For example the reactions of [OSO,(S~O,),]~- with a range of inorganic and organic ligands were investigated;26 the X-ray structure of [NBu~][Os(H,O)(S,O,)(PMe,Ph),] reveals an octahedral geometry about the osmium with the truns S-bonded thiosulfate anions being syn and hydrogen bonded to the axial aqua ligand.26 Phosphorus-oxygen ligands that have been studied include the first structurally characterized example of a complexZ7 containing the phosphinate ligand [Mn{ OPPh,(OPh)),(NCS),]C,H,Me (9) as well as phosphinite complexes obtained28 by selenium elimination from a selenophosphinate (equation 3) PtCI,(PR,) + 4PH,PSeOH -+ [Pt{(Ph,PO),HJ ((Ph2PSeO),H)] + 2HCl + 2SePR (3) Mixed 0,S donor complexes were also studied; a trinuclear example (Figure 2) 22 R.G.Syvret K. M. Mitchell J. C. P. Sanders and G.J. Schrobilgen. Inorg. Chem.. 1992 31. 3381. 23 (a)B. Krebs. S. Bonmann and K. Gretenkord Z. Naturforsch. Teil B 1992. 47. 93; (h)C. Rohl and M. Frost J. Chem. Soc. Chem. Commun. 1992 248. H. Schmidt R. Steudel D. Sulzle and H. Schwarz Inorg. Chem. 1992. 31. 941. 25 W. Frank and B. Bertsch-Frank Angew. Chem.. Int. Ed. Engl. 1992 31 436. *" C. F. Edwards W. P. Griffith and D. J. Williams J. Chem. Soc. Dalton Truns. 1992 145. 27 S. Abbas B. Beagley S.M. Godfrey. D.G. Kelly C.A. McAuliffe and R.G. Pritchard J. Chem. Soc. Dulron Truns.. 1992 1915. 2x M.J. Pilkington A. M.Z. Slawin D. J. Williams and J. D. Woollins J. Chem. Soc,. Ddon Truns. 1992 2425. J. D.Woollins om 1.602(2) 1.464(3) Bond angles (") O( l)-S(1)-0(2) 1O6.8( 1) O(l)-S(l jO(3) 112.9(1) 0(2)-S( 1)-0(3) O( 1)-S(1)-0(4) 121.4(2) I 04.O( 1) 0(2)-S(l)-0(4) 109.3(1) 0(3tS(1)-0(4) 101.0(1) S(l)-0(4)-0(5) 108.7(2) FI(l)-O(l)-S(l) 112(2) II(2)-0W-0(4) 9V3) Figure 1 The X-ray structure25 uf H,SO illustrating the hard and soft characteristics of 0 and S respectively has been isolated29 from the reaction of PtCl,(PMe,) with Zn{ OSP(OPr'),},.The electronic properties associated with the Pt-Pt bonding in Pt"' complexes containing the 'pop' ligand (P,O,H;-) continues to be of intere~t.~' The coordination of phosphorus by oxygen and sulfur has been ~tudied;~' reaction of phenols with the cyclic eight- Figure 2 The X-ray ~trucrure~~ ofthe core of [(Me,P)PtC1(SOP(OPri),)l,Zn~CH,C1 with the Pr' and the Me groups omitted for clarity 29 J.C.Poat. A. M.Z. Slawin D.J. Williams and J. D. Woollins Polyhedron 1992 11 2125. 30 C. M. Che M.C. Cheung Y. Wang and H. B. Gray Inorg. Chim. Actu 1992 191 7. 31 T.K. Prakasha R.O. Day and R. R. Holmes Inorg. Chern.. 1992 31 3391. 0,S Sc. and Te membered [(But),C ,,H,SO ,]POCH 2CF gives [(But ),C H,SO P( 0)OCH ,CF and the pentaoxyphosphorane [(Bu'),C 2H,S0,]P(C 2H,0,)OCH,CF3 which has a pseudooctahedral structure. There has been a large volume of work on metal oxides and as mentioned above no effort to review this area has been made. Nonetheless it is worth noting the preparation of some charge transfer salts of molybdates and tungstates. Tetrathiafulvane (and other organic-metal cations) form3 semiconducting solids with [M6Ol9I2- (M = Mo W) whilst the formation of salts of ,5'-[M0,0,,]~- with N,N,N',N'-tetramethyl-p-phenylenediamine has also been studied., Roesky advanced his work on the formation of M-P-N-P complexes by describing some cyclophosphazene metal oxides.34 Characterization of simple species containing selenium has also been important in 1992.For example HSe- and Se2- were studied by NMR35(x = 3-6) which has enabled the conditions for the formation of these anions in protic and aprotic solvents to be established. Interestingly no Se:- species with x > 6 were observed although the spirocyclic anion [Se(Se5),I2- was studied. The IR and Raman spectra of solid H,Se have been rep~rted.,~ Studies of sulfur-selenium melts by 77Se NMR3 methods showed that the most common eight membered Se- S ring is SeS, with 1,2-Se,S6 being formed in increasing amounts with increasing selenium content of the melt.Sele- nium-sulfur halides were also studied both by NMR38.39 and Raman spectroscopy. SeSX (X = C1 Br) were observed to have chain structures S-Cl and Se-Br bonds being preferred over S-Br and Se-CI and the ,'Se NMR chemical shifts correlate with the electronegativities of the directly bonded neighb~ur.~' The exchange processes in this system were studied by 77Se 2D EXSY meas~rements.,~ A number of selenium iodides were claimed,' to be formed from the reaction of selenium and iodine in CS and 77Se chemical shifts were correlated with structure for bis-chelates with 1,2-' .,dichalcogenates Theoretical investigations that merit discussion include a pseudopotential ab initio study4 of the influence of the phosphine co-ligands in Ni(PR,),(SO,) upon the q'-coordination of SO,.Sulfur-nitrogen chemistry continues to be a subject in need of rationalization and one paper, relates the sulfur-nitrogen enthalpy term to the S-N bond length for a series of S-N compounds; a surprisingly good linear fit was observed. The structures of Te:' and Te,Si+ were also investigated the ore tic all^.^^ The biological significance of Group 16 coordination chemistry has been further investigated. Manganese and iron cubane-like and dimer systems containing cat- echolate ligands i.e. M,(dbcat),(py) (M = Mn Fe); M,(dbcat),(py) (M = Mn '' S.Triki. J. F. Halet 0.Pena J. Padiou. D. Grandjean. C. Garrigou-Lagranpe and P. D. Elhaes J. Chrm. SOL... Dalton Trans. 1992 1217. 33 D. Attanasio M. Bonamico V. Fares. and L. Suber J. Chern. Soc.. Dalton Trans. 1992. 2523. 34 R. Hasselbring H. W. Roesky and M. Noltemeyer. Angrw. Chern..,Int. Ed. Engl.. 1992. 31. 601. " J. Cusick and I. J. Dance. Polyhedron 1991. 10 2629. jh B. A. Paldus. S. A. Schlueter and A. Anderson. J. Roman. Sprctrosc. 1992. 23. 87. 37 T. Chivers. R. S. Latiinen. and K. J. Schmidt. Cun. J. Chern.. 1992 70 719. jH J.B. Milne Can. J. Chem. 1992. 70. 693. " J. Milne and A. J. Williams. Inory. Chrm. 1992. 31. 4534. 40 J. Milne Inorg. Chrm. 1992. 31 4530. 41 B. Olk and R. M. Olk Z. Anorg. Allg. Chew. 1991. 600. 89. 42 J.Reinhold. M. Schuler T. Hoffmann. and E. Wenchuh Inorg. Chew. 1992. 31 559. 4J S. Parsons and J. Passmore Inorq. Chem. 1992. 31 526. 44 P. D. Lyne D. M. P Mingos and T. Ziegler. J. Chm. Sot,.. Dulrnn Truns. 1992 2743. J. D. Woollins n = 6; M = Fe; n = 4,6; dbcat = 3,5-di-tert-butylcatecholate) were prepared and characterized ~rystallographically.~~ Macrocyclic ligands continue to be studied. For example mixed S-N macrocyclic systems were used to complex nickel4' (Figure 3) and copper.47 The conformational behaviour and selectivity of arene thiocrown ether (cyclophane) ligands towards silver was investigated by a combination of crystallogra- phy molecular dynamics calculations and data base interr~gation.,~" Nickel coordination by [15]aneS5 and [16]aneS4 revealed that although the [16]aneS4 gave a simple octahedral complex (with the axial ligands being water molecules) the [15]aneS5 complex is square pyramidal and forms octahedral complexes with MeCN pyridine and Figure 3 The X-ray structure4' of [NiL,]" (L = 8-uza-l,5-dithiac~~clodecane) A series of compounds of formula [Fe,S,(MeCp),][PF,] (y = 0-2) were prepared by reaction of [Fe(MeCp),(CO),] with excess sulfur in refluxing toluene;49 in a subsequent paper49 Fe,S,(MeCp),][PF,] was crystallographically characterized.A general synthetic route to [Fe"'(SR),] -complexes has been reported5' (Equation 4) [Fe(OPh),]-+ 4RSH +[Fe(SR),]-+ 4PhOH (41 The synthesis and X-ray structural analysis of these compounds included a spectro- 45 S.C.Shoner and P. P. Power. lnory. Chem.. 1992. 31 1001. 46 S. Chandrasekhar and A. McAuley Inory. Chem.. 1992 31. 2234. 47 M. M. Bernardo M. J. Heeg R. R. Schroeder L. A. Ochrymowycz and D. B. Rorabacher. lnory. Chem.. 1992. 31 191. 48 (a) J.C. Lockhart. D.P. Mousley. M.N.S. Hill N. P. Tomkinson F. Teixidor. M.P. Almajano L. Escriche J. F. Casabo R. Sillanpaa and R. Kivekas J. Chrm. Soc. Dulton Truns. 1992. 2889; (h)A. J. Blake M. A. Halcrow. and M. Schroder J. Chem. Soc.. Dulron Trans.. 1992. 2803. 49 H. L. Blonk J. Mesrnan J. G. M. van der Linden J. J. Steggerda J. M. M. Smits G. Reurskens. P. T. Beurskens C. Tonon and J. Jordanov. Inorg. Chem. 1992 31. 962 and see 957. 50 L. E. Maelia M. Millar. and S. A. Koch lnory. Chem.. 1992. 31 4594.0 S Se and Te 79 scopic comparison with the [Fe(Cys-S),] -centres which are important in proteins such as rubredoxin.” A range of cubane-like compounds have also been reported; MFe,S (M = Mo W),’l NiFe,Q (Q = S Se),’ and MoS,(CuCl) ’3 cores were all prepared. UVPES data were reported for V,S cluster^.'^ Models for the active site in [FeNiSe] hydrogenases” and [Fe,S2L,I2- for Rieske-type proteins were also scrutini~ed.~~ The first example of stable aldehyde and ketone complexes of zinc have also been rep~rted.’~ Reaction ofZn(EC,H,(CMe,),) (E = S Se) with aryl aldehydes or ketones gives complexes which may be models for transient metal-substrate complexes in metalloenzymes such as liver alcohol dehydrogenase. Group 16 elements continue to be important in coordination chemistry and although many of the compounds will be discussed in other chapters it is relevant to mention some examples here.Iron(II1) chloride has been shown to react with ClOTeF to give Fe(OTeF,) which can be crystallized as a tris-S0,ClF adduct that has octahedral geometry.s8 The use of [B(OTeF,),] -as a weakly coordinating anion has been studieds9 by NMR IR and in the case of the silver(r) salt X-ray crystallography. TeF reacts6’ at -78 “C in CD,Cl with Rh(CO)X(PEt,) (X = C1 Br NCO) to give CRh(C0 )X(PEt )2(TeF3 11CTeF 51. Cluster chemistry has seen some new developments. The reaction of Se(SiMe,) with NiCl,L in THF gives61 clusters such as [Ni,Se,L,] [NisSe,Cl,L,] [Ni,Se,L,] and larger clusters (including [Ni,,Se,,L,“J).Reaction6 ofexcess M(CO) (M = Mo Cr W) with polytelluride solutions gibes a range of products including [M4(CO),8 Te,] - which contains a four-membered M,Te2 ring. Mixed-metal clusters [Fe,M(E),(CO),,] (M = Mo W) containing selenium or tellurium were prepared by reaction of Fe,(CO),(E,) with M(CO),(thf) at room temperat~re.~, The X-ray structure of the tungsten-tellurium compound shows it to have a square pyramidal Fe,Te,W core with the tungsten atom being in the axial site. An inorganic cryptand complex [NaAul,Se,l3- was obtained from AuCN Na,Se and [Et,N]Cl. The selenium atoms are located on the corners of a cube with gold atoms on each edge and the sodium atom at the centre.“ Reaction of the cubane cluster [(WS~,),(S~),(CUPP~,),~~-with Lt,Se gives rise to a new ‘pinwheel’ cluster,6s which can be described as two Cu triangles bridged by tridentate WSei- ligands and capped by two selenium atoms.A cluster containing an unusual geometry of the central sulfur atom Ag ,S(Etdtc) (Etdtc = ethyldithiocarbamate) has been reported; although 51 M. A. Greaney C. L. Coyle R. S. Pilato. and E. I. Steifel Inorg. Chim. Actci 1991 189 11. 52 S. Ciurli. P. K. Ross M. J. Scott S. B. Yu and R. H. Holm. J. Am. Chrm.Snc.. 1992 114 5415. ’’ S. Berneo F. Secheresse and Y. Jeannia Inorq. Chim. ACIN.1992. 191 11. s4 c.E. Davies J.C. Green. N. Kaltsoyannis. M. A. MacDonald J. Qin. T. B. Rauchfuss C. M. Redfern G. H. Stringer and M.G. Woodhouse. Inorg. Chem. 1992. 31 3779. ” N. Baidya. B.C. Noll M.M. Olmstead.;and P. D. Mascharak. Inorg. Chem.. 1992. 31 2999. 5h P. Beardwood and J. F. Gibson J. Chrrii. Soc.. Dulron Trrrns. 1992 2457. ” M. Bochrnann K. J. Webb. M. B. Hursthcwse. and M. Mazid J. Chem. Soc.. Chrm. Commun.. 1992. 1735. 5H T. Drews and K. Seppelt Z. Anorg. Allg. Chem.. 1991 606 201. 59 D. M. Van Seggen. P. K. Hurlbut. M. D. hoirot 0.P. Anderson. and S.H. Straws Inorg. Chrm.. 1992.31. 1423. b” E. A. V. Ebsworth J. H. Holloway and F’. G. Watson. J. Chem. Soc. Chem. Commun. 1992. 1443. 61 D. Fenske H. Krautscheid. and M. Mueller. Angew. Cheni.. Inr. Ed. Engl. 1992. 31. 321. 62 L. C. Roof W. T. Pennington and J. W. Kolis Inorg. Chem.. 1992 31. 2056. h3 P. Mathur D. Chakrabarty M. M.Hossain R. S. Rashid. V. Rugrnini and A. L. Rheingold Inorg.Chew. 1992 31 1106. h4 S. P. Huang and M.G. Kanatzidas Angq~rt-.Chem. Inr. Ed. Engl.. 1992. 31 787. 65 C.C. Christuk. M. A. Ansari. and J.A. Ibers. Angew. Chem. Int. Ed. Engl.. 1992. 31. 1477. 80 J. D. Woollins serendipitously obtained the structure is of interest; the central sulfur atom is coordinated by five sulfur atoms.,‘ A compound containing a twelve membered silver-zinc-sulfur ring was obtained67 according to equation 5. R I RR R /R I/ Me3Si / S \ A SiMe3 AgO,SCFJ c N-Zn 26 Zn-N / \I \4 \ Me,Si 1 ss SiMe II RR R’ ‘R R = 2,4,6-’Pr3C6H3 R The reaction of Ni(S,COEt) with either Li,Se/Se or Li,Te/Te gave a range of Ni,E containing clusters by spontaneous assembly of the oxidized NilV centres.68 The selenium and tellurium cases behave differently giving rise to different chain length bidentate E -exocyclic ligands.The single crystal ESR spectrum of [cO6(S)8(PEt3),] BPh was studied. Although ESR silent at room temperature a low temperature signal is attributed to localization of the unpaired electron on one cobalt; there appears to be a very weak magnetic interaction between the clusters in the solid state.69 The formation of low-dimensional solids is currently of interest. For example partially oxidized compounds such as [TTF],~7[Ni(C3S,)(C3S,)]70 (TTF = tet-rathiafulvalene) and intercalation compounds7 with other organic donors and FeOCl have been described. There have been numerous reports on methods for forming II/VI thin films. Typical is the formation7’ of zinc selenide by the reaction of diethylzinc with diethylselenium in a hydrogen atmosphere at 40G500 -C.New sources of selenium and sulfur utilizing SnSez and SnS for ultra-high vacuum preparation i5iu molecular beam epitaxy are much more convenient than use of the element^.'^ Polychalcogen anions have received substantial attention. The crystal structures of [NPr,],Se and [NEt,],[Se -.;Se;Se,] obtained by reaction of K,Se with selenium have been de~cribed;~ Se 1-is spirocyclic whilst the structure of Se is the first characterization of this ring. The hydrothermal reaction75 of PdCl with K,Se in the presence of KOH gives K,[Pd(SeIo)] which consists of interpenetrating networks of [Pd(Se,),]’-and [Pd(Se,),]’- anions. Se$- and Sei- anions are also coordinated in [Rb( 1 8-crown-6)],[Zn(Se4)(Se,)] which was obtained from the reaction of Zn(OAc) with Li,Se in DMF.76 An interesting main group cluster (Bu‘Ge),S6 not 6h Z.Huang. X. Lei M. Honp. and H. Liu. Inorg. Chem.. 1992. 31. 2990. 67 M. Steiner. H. CrutLmacher. L. Zolnai. and G. Huttner. J. Chem. So(,..Chem. Comrnun.. 1992. 689 ’* J. M. McConnachie. M.A. Ansari. and J. A. Ibers. Inory. Chim. Acru. 1992. 85. ’’)A. Benncini. S. Midollini. and C. Zanchini. ltiory. Chem.. 1992 31. 2132. 7(1 G. Matsubayashi S. Tanaka. and A. Yokoorawa. J. Chem. So(... Dulton Trans.. 1992 1827. ’I J. F. Bringley. J. M. Fabre. and B. A. Averill. Chem. Muter.. 1992. 4. 522. 72 T.L. Chu. S.S. Chu G. Chen J. Britt. C. Ferekides. and C.Q. Wu. J. Appl. Phys.. 1992. 71.3865. 73 T. Shimada. F. S. Ohuchi. and R.A. Parkinson J. Vuc. Sci. Techno/.. A. 1992. 10. 539. 74 J. Dietz U. Mueller. V. Mueller. and K. Dehnicke. Z. Nururfor.xh.. Tcil.B. 1991. 46. 1293. K. W. Kim and M. C. Kanatzidas. J. Am. Chem. Soc.. 1992. 114. 4878. i6 D. Fenske. S. Magull. and K. Dehnicke. Z. Noturforsc~h..7ki/. B. 1991. 46. 101I. 0,S Se and Te 81 having the adamantane structure has been described.77 The molecule consists of two Ge,S rings linked by Ge-S-Ge bridges. Although cluster compounds are under intense study mononuclear systems have also received attention. Solid state metathesis reactions between transition metal halides and alkali metal chalcogenides (tungsten molybdenum) were performed (usually in bombs) by initiating the reactions with heated filaments and once started were self pr~pagating.~~ MOO:-and W03+ react with aqueous S; -in the presence of bpy to give the isostructural mononuclear pentagonal bipyramidal complexes MO(S,),(bpy) with four sulfur atoms and one nitrogen atom in the equatorial plane.79 A binuclear molybdenum complex8' containing edge-on S; - bridging S; - and bridging doubly-end-on H,NNH coordination has been described; here again the molybdenum atoms are in pentagonal bipyramidal environments.Despite the difficulty of the work polychalcogenide cations have been studied by a number of groups. Sulfur reacts with an excess of AsF in liquid SO with a trace of halogen as a catalyst to give S,(AsF,) in quantitative yield.81 [H,Se][SbF,] which decomposes at room temperature has been preparedE2 by treating H,Se with HF and SbF at -78 "C.Crystalline [S,I,][AsF,] was preparedE3 by oxidation ofsulfur with iodine and arsenic pentafluoride (equation 6). $S + 21 + ~AsF,-+ [S,I,][AsF,] + AsF The cation has a distorted triangular prismatic structure with S-S and S-I distances of 1.843(6)and 2.5987(17)A corresponding to bond orders of 2.4 and 1.3 respectively; the distances are even shorter in the SbF salt. A bonding scheme based upon the S unit being bonded to each I; unit in two orthogonal four-electron four-centre 71 systems was proposed.83 A range of [S7X]' cations have been reported in which X = pseud~halogen.~~ The cations were prepared by analogy to the synthesis of [S,I] ;the thermal stabilities of the new cations appear to be a function of the Pearson + hardness of the pseudohalide (increasing hardness leading to decreasing ~tability).~~ The coordination of iodine by the OTeF has been studied.85 Binary (and ternary) compounds containing nitrogen have been the subject of rapid progress in the last year or two.Very unstable new S-N molecules have been observed in an argon matrix. Microwave discharge upon an argon/nitrogen/sulfur vapour gave NS NS, N,S and NSS which were characterized by IR spectroscopy on the normal and isotopically labelled molecules.86 Nitrogen NMR studies on a variety of S-N molecules and anions were reported.87 A method for preparing "N labelled Se,N suitable for mechanistic/NMR studies was described.88 The usefulness of silyl reagents in S/Se/Te-N chemistry has been amply illustrated by 77 W.Ando T. Kadowaki. Y. Kabe and M. Ishii Angew. Chem. Int. Ed. Engl. 1992 31 59. " P. R. Bonneau R. F. Jarvis Jr. and R. B. Kaner Inorg. Chem. 1992 31 2127. 79 P. K. Chakrabarty S. Bhattacharya C. G. Pierpont and R. Bhattacharyya Inorg. Chem. 1992,31,3573. HO Z. Nianyong D. Shaowu W. Xintao and L. Jiaxi Angew. Chem.. Int. Ed. Engl. 1992. 31 87. " M. P. Murchie. J. Passmore G. W. Sutherland. and R. Kapoor J. Chem. Soc.. Dalton Trans. 1992 503. H2 R. Minkwitz A. Kornath. and W. Sawodny Angew. Chem. Int. Ed. Engl. 1992 31 643. 83 M. P. Murchie J. P. Johnson J. Passmore,G. W. Sutherland M. Tajik T. K. Whidden P. S. White and F. Grein Inorg. Chem. 1992 31 273. 84 R. Minkwitz and J.Nowicki Z. Anorg. Allg. Chem. 1992 607 96. H5 L. Turowsky and K. Seppelt Z. Anorg. Allg. Chem. 1991. 602 79. 86 P. Hassanzadeh and L. Andrews J. Am. Chem. Soc. 1992 114 83. '' T. Chivers and K. J. Schmidt Can. J. Chem.. 1992 70. 710. '* V. C. Ginn P. F. Kelly and J. D. Woollins J. Chem. Sac. Dalton Trans. 1992 2129. J. D. Woollins several pieces of elegant work. The formation of poly(aryl/alkyloxothiazenes) by condensation of sulfonimidates has been described89 (equation 7). Me,SiN-S(0)ROR +[NSOR] (7) E[NCMe,(SiMe,)] (E = Se Te) have been prepared and characterized by X-ray crystallography and 77Se/'25Te NMR.90 Se(NSO) reacts with TeCI to give" the five-membered mixed-chalcogen ring system (Cl,Te)NSNSe and with XS0,H to form + . [Se,N,S]' The first tellurium(I1) radical-cation-containing compound [Te(N(SiMe,),),]'+ [AsF,] - formed by warming a mixture of Te[N(SiMe,),] and AgAsF from -78 "C to room temperature has been described;' The Te-N distance in the cation was reduced relative to the parent neutral molecule.The reaction of TeCl with (Me,SiN),S gives9 the novel tellurium-sulfur-nitride shown in Figure 4. Figure 4 The X-ray structure93 ofTe,S,F,N A number of cationic S/Se-N species have been reported. Reaction of tris(trimethylsily1)aminewith selenium tetrachloride gives Se,NCI which undergoes chloride abstraction when treated with gallium trichloride to give9 [ClSeNSeCl] [GaCl,] (Equation 8). Closely related to this it was noted that the reactiong5 of [SeCl,][AsF,] with N(SiMe,) gives [(Cl2Se)N(SeC1,)][AsF6].Dehnicke described XY A.K. Roy J. Am. Chem. Soc.. 1992 114 1530. 90 M. Bjoervinsson H. W. Roesky F. Pauer D. Stalke and G. M. Sheldrick Eur.J. SolidSrure Inory. Chem. 1992 29 759. 91 A. Haas J. Kasprowski. and M. Pryka. Chem. Ber. 1992. 125 789. 92 M. Bjoervinsson T. Heinze H. W. Roesky F. Pauer D. Stalke and G. M. Sheldrick Angew. Chem. Int. Ed. Engl. 1991 30 1677. 93 J. Munzenberg H. W. Roesky S. Besser R. Herbst-lrmer and G. M. Sheldrick Inory. Chem.. 1992 31 2986. 94 R. Wollert. A. Hollwarth G. Frenking D. Fenske H. Goesmann and K. Dehnicke. Angew. Chrm. In?.Ed. Engl. 1992 31 1251. 95 M. Broschag T. M. Klapotke 1. C. Tornieporth-Oetting. and P. S. White J. Chrm. Sor...Chem. Commun. 1992.1390. 0 S Sc. and Tc. the synthesis96 of [Se,N,CI][GaCl,] according to equation 9. The cation was characterized by both X-ray crystallography and vibrational spectroscopy. [C1SeNSeC1][GaC14] SbPh3 -t [Se,N,CI][GaCI,] (91 Following an earlier report by Dehnicke that the reaction of Me,SiN with SeCl gives Se,N, Chivers re-investigated the reaction9' and suggested that the original formulation is incorrect and that the product should be re-formulated as Se,N,CI,. This issue awaits final resolution. The preparation and structure of the mixed chalcogen [Se,N,S][AsF,] has also been reported.98 The preparation of a number oi' five-membered organo-S/Se-N radical cations which have potential in the study of organic metals has been studied. Hence an interesting solid-state rearrangement of 1,3,2,4-dithiadiazoles to their 1,2,3,5 ana- logues has been reported.99 The preparation"' of 5-(trifluoromethy1)-l ,2,3,4-trithiazolium hexafluoroarsenate ([CF,CNSSS][AsF,]) from the reaction of CF,CN with Ss+/Sz+ has been described.Preparation and structural details for (cy-anopheny1)dithia- and diselenadiazolyl radicals and related six-membered rings have lso been The preparation of P N-S and P-N-Se rings from R,PN,(SiMe,) has been described"3~"4 (equation 10). R I N.E.N NSiMe3 N.Se ii Ph PPh2 +-!-/ 'p\N. A.N/ Ph2qN(SiMe3)2 __f Ph2P Kse" N\ /pPh2 (10) I (i) E = S SCl, or SOCI E =SC +SeCh +t s%c12 R (ii) RSeC1 R = Me Et Ph Binary Group 15/16 compounds also merit some mention. Photochemical redis- tribution reactions of mi~tures''~ of sr-P,S31 and sr-P,Se,I in CS gave P,S,SeI and 'Ih R.Wollert. B. Neumuller. and K. Dehnicke Z. Anorg. A//q. Chem.. 1992 61 191. '-J. Siivari. T. Chivers. and R. Laitinen. Anyrn.. Chrm.. Int. Ed. EnqI. 1992 31. 1518. un E.G. Awere J. Passmore and P.S. White. J. Chem. Soc.. Dulton 7run.s.. 1992 1267. VQ C. Aherne A. J. Banister. A. W. Luke. J. M. Rawson and R. J. Whitehead. J. Cliem. So(... Dulfon 7tuns.. 1992 1277. '"O T. S. Cameron R.C. Haddon. S. M. Mattar. S. Parsons. J. Passmore. and A. P. Ramirez. /nor(/. Chcrn.. 1992 31. 2274. 101 A. W. Cordes. R.C. Haddon. R. G. Hicks. R.T. 0akley.and T.T. M. Palstra. Inorq. Chmi..1992.31. 1802. I('' K. Bestari. G. Ferguson. J. F. Gallagher. and R.T. Oakley.Inorq. Chem.. 1992 31. 442. T. Chivers S.S. Kumaravel. M. Parvez. and M.N. S. Rao. Inory. Cheni.. 1992 31 1274. I04 T. Chivers. M. Edwards. and M. Parvez. Inory. Chem.. 1992 31. 1861. l(14 R. Rlachnik. P. Loennecke. and B. W. T.Attershall. J. Chrm. Soc... Dulron Trum.. 1992. 3105. 84 J. D.Woollins P,S,SeI, which were studied by NMR. A number of As-S/Se systems have been st~died.'~~-'~~ [As,,Se,12-(n = 2,4)was obtained by treatment of As,Se with Se2- in DMF.'" The structure and bonding in a thio-arsenium system was discussed with particular interest in the degree of p-7c-bonding.'08 The reactions of As-Se anions with M(CO) (M = W Mo) have been investigated."' Phosphorus-selenium systems also form metal complexes. Thus reaction of P,Se with polyselenides gives P,Sei- which reacts' lo with Fe(CO) to give [Fe,(CO),- (PSe,),12 -.K[Ph,P(Se)NP(Se)Ph,] has been shown to react' "with ReOCl,(PPh,) with displacement of triphenyl phosphine and two chloride ions to give Re- OCl[Ph,P(Se)NP(Se)Ph,] which rapidly loses one selenium atom from each bidentate ligand to give ReOCl[Ph,PNP(Se)Ph,],. The formation of binuclear metal complexes by reactions' l2 between suitable silyl reagents with an M-Ph,PCl complex once again shows the utility of these reagents (equation 11). 2[(CO),Cr(Ph,PCI)J + (Me,Si),Se -+ [(CO),Cr(Ph,P)J,Se + 2Me3SiC1 (1 1) Finally M-S/Se-N and related areas continue to be fruitful. A detailed study of a technetium thionitrosyl system investigated the effect of the other ligand upon the N S coordination in this difficult system;'13 no reasons for the use of technetium were presented.The reaction of S,N with [M,X,I2- anions (M = Pd Pt; X = C1 Br I) has been studied. With palladium,' l4 binuclear Pd" compounds containing S,N or S,Ni -are obtained whereas with platinum Pt'" complexes containing thefac-S,Ni- ligand are formed."' The first reaction of S,N, to give [PdCl,(S,N,)]- has been described.' l6 The reaction of [WCl,(NSeCl)] with PPh,Cl has been shown to give [PPh,],[WCl,(NSeCI,)] which contains the NSeCli- ligand.' l7 The coordination chemistry of some of the eight-membered substituted thiazenes formed in equation 10 has been shown to be particularly including N-bonding q2-E,E' and p2-q3-N,S,S'coordination. Acknowledgements.I am grateful to A. M. Z. Slawin for preparing the crystal structure diagrams. B. Siewert and U. Mueller Z.Anorg. Allg. Chem.. 1992 609 77. lo7 M. A. Ansari J. A. Ibers S.C. O'Neal W.T. Pennington and J. W. Kolis Polyhedron 1992 11 1877. lo' N. Burford T. M. Parks B. W. Royan J. F. Richardson and P. S. White Can. J. Chem. 1992 70 703. Io9 S.C. O'Neal W.T. Pennington and J. W. Kolis Znorg. Chem. 1992 31 888. J. Zhao W.T. Pennington and J. W. Kolis Angew. Chem. Znt. Ed. Engl. 1992 31 265. ''I R. Rossi A. Marchi L. Marvelli M. Peruzzini U. Castellato. and R. Graziani. J. Chem. Soc. Dalton Trans. 1992 435. 'I2 K. Merzweiler and H. J. Kersten Z. Naturforsch. Teil B. 1991 46 1025. 'I3 J. Lu and M. J. Clarke J. Chem. Soc.. Dalton Trans. 1992 1243. V. C. Ginn P.F. Kelly A. M. Z. Slawin D. J. Williams and J. D. Woollins. J. Chem. Soc. Dalton Trans. 1992 963. P. S. Belton V.C. Ginn P. F. Kelly and J. D. Woollins J. Chem. Soc. Dalton Trans. 1992 1135. 1I6 P. F. Kelly A. M. Z. Slawin 13.J. Williams. and J. D. Woollins Angew. Chem.,In?.Ed. Engl. 1992,31,616. S. Volger and K. Dehnicke Z. Naturforsch. Teil B 1992. 47 301. 118 T. Chivers M. Edwards A. Meetsrna J. C. van de Grampel and A. van der Lee Inorg. Chem.. 1992.31 2156. T. Chivers R. W. Hilts I.H. Krouse A. W. Cordes R. Hallford and S.R. Scott Can. J. Chrm. 1992,70 2602. T. Chivers and R. W. Hillts Znorg. Chem. 1992. 31,5272.