Sulfur complexes, osmium

Apparently, soft sulfur ligands alone cannot stabilize Ru or Os . The existing thioether, thiolato, and sulfide complexes of ruthenium(VI) and osmium(VI) are associated with either the 0x0 or the nitrido ligand and they have been discussed in the previous sections. 

Osmium tetroxide forms hahde complex ions, hexachloroosmates, such as [OsCle], [OsCle], and [OsCle] . The former ion [OsCle] is obtained by reaction of the tetroxide with sulfur dichloride and chlorine at ambient temperature ... 

Chemical Properties. Compound 2 is readily decarbonylated upon exposure to UV irradiation.5 Irradiated solutions of 2 readily yield addition products of sulfur containing small molecules such as COS, CS2, and H2S. In the absence of reagents it will form the hexanuclear compound Os6(CO)17(/r4-S)2. It reacts with other metal complexes to form higher nuclearity osmium clusters and heteronuclear metal cluster compounds.5,11,12... 

The complete series, thio-, seleno-, and telluroformaldehyde complexes of osmium [OsCl(NO)(r72-E=CH2)(PPh3)2] (E = S, Se, Te), was obtained by reaction of the carbene complex [OsCl(NO)(=CH2)(PPh3)2] with elemental sulfur, selenium, and tellurium, respectively.53... 

The reaction of an osmium carbene cluster containing the cyclic carbene ligand = C(CH=CH)2C(Ph)H which is side on bound to a nonacarbo-nyltriosmium unit with either elemental sulfur/NEt3 or cyclohexene sulfide also afforded a rf-thioketone complex.184... 

The kinetics of chromium(l 11 )-catalyscd oxidation of fonnic acid by Ce(TV) in aqueous H2SO4 can be rationalized in terms of initial formation of an outer-sphere complex involving oxidant, catalyst, and substrate (S), Ce(TV)(S)Cr(III), followed by an inner-sphere complex Ce(III)(S)Cr(IV). It is proposed that electron transfer occurs within this complex from substrate to Cr(TV) (with elimination of H+) followed by fast reaction to give CO2 (again with elimination of H+).54 In contrast, there was no kinetic evidence for the accumulation of a corresponding inner-sphere intermediate in the osmium(VIII)-catalysed Ce(TV) oxidation of DMSO to dimethyl sulfone here, the observed rate law was rationalized in terms of rate-determining bimolecular electron transfer from DMSO to Os(VHI) in an outer-sphere step.55 The kinetics of oxidation of 2-hydroxy-l-naphthalidene anil by cerium(IV) in aqueous sulfuric acid have been... 

A related process has been reported for the synthesis of osmium nitrido complexes with 1,2-benzenedithiolate ligands. Thus, the synthesis of 173 was effected by treatment of (Bu4N)[OsNC14] with deprotonated 1,2-benzenedithiol (Eq. (70)). Interestingly, when 173 is treated with Me3OBF4 alkylation is observed to occur on the sulfur this contrasts the reaction of 173 with Ph3CPF6, for which reaction at the terminal nitride is observed [93]. 

Vinylidene osmium(O) (187) (Section II,B,3,g) reacts with sulfur, selenium, or copper chloride to give complexes 233 via electrophilic addition to the osmium-carbon bond (116) (Scheme 18). Complex 187 also reacts with benzoylazide to form the five-membered metallacycle 234 (Z) which isomerizes 234 (E) on heating in benzene (141). 

Preparative routes involve sulfur abstraction by osmium(VI) nitrido complexes from S2C12 or SCN , though the mechanisms of these reactions are not clear reaction of halides with (NSC1)3 has also been used. 

Another example of sulfur abstraction by an osmium nitrido complex occurs in the reaction of [OsNC14]- with (PPh4)NCS to give (Ph4P)2[Os(NS)(NCS)3], in which the thiocyanate groups are thought to be bonded to the metal via nitrogen.265 For reactions of the complex see Scheme 10, p. 563. 

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