Syntheses and structures of the chalcocarbonyl complexes OsCl2(CO)(CE)(PPh3)2 (E=S, Se, Te).

Article abstract of DOI:10.1016/0022-328X(88)80012-3

The Group VI nucleophiles HE^- (E=O, S, Se, Te) react with the electrophilic dichlorocarbene ligand in the complex OsCl2(=CCl2)(CO)(PPh3)2 to form the corresponding chalcocarbonyl derivatives OsCl2(CO)(CE)(PPh3)2, OsCl2(CO)(CTe)(PPh3)2 is the first reported tellurocarbonyl complex, and the compounds OsCl2(CO)(CE)(PPh3)2 constitute the first complete series of chalcocarbonyl complexes.H2O, H2S and H2Se also react with the dichlorocarbene complex to yield the corresponding chalcocarbonyl derivatives OsCl2(CO)(CE)(PPh3)2, although OsCl2(CO)(CTe)(PPh3)2 cannot be formed this way.The thiocarbonyl, dichlorocarbene complex OsCl2(=CCl2)(CS)(PPh3)2 gives tractable products with H2O, H2S and H2Se, and in this way the mixed chalcocarbonyl compounds OsCl2(CS)(CE)(PPh3)2 can be isolated.X-ray crystal structure determinations have been carried out on the complexes OsCl2(CO)(CS)(PPh3)2, OsCl2(CO)(CSe)(PPh3)2 and OsCl2(CO)(CTe)(PPh3)2.The CS and CSe complexes are isostructural and crystallise in space group P1^-, with two molecules in unit cells of dimensions: CS a 12.837(1), b 14.302(1), c 10.452(1) Angstroem, α 92.45(1), β 97.42(1), γ 99.86(1) deg; CSe a 12.846(3), b 14.341(3), c 10.462(4) Angstroem, α 92.26(2), β 97.67(2), γ 99.76(1) deg.The CTe complex crystallises in space group P2₁/n, with four molecules in a cell of dimensioms a 14.211(3), b 18.084(4), c 14.857(3) Angstroem, β 113.29(2) deg.The coordinated CTe ligand in OsCl2(CO)(CTe)(PPh3)2 displays similar overall structural features to the other coordinated chalcocarbonyl ligands in that the Os-C-Te angle is ca. 180 deg and the Os-CTe and C-Te bonds are very short.For each of the complexes the Os-CE bond length is shorter than the Os-CO bond length in the same molecule, although only for the thiocarbonyl complex is the difference significant.The trans-influence of the chalcocarbonyl ligands increases in the order CO