Unequivocal Characterization of an Osmium Complex with a Terminal Sulfide Ligand and Its Transformation into Hydrosulfide and Methylsulfide.

Deprotonation of the thioamidate group of [OsH{κ 2 - N , S -[NHC(CH 3 )S]}(≡CPh)(IPr)(P i Pr 3 )]OTf [ 1 ; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolylidene; OTf = CF 3 SO 3 ] results in the release of acetonitrile and formation of the terminal sulfide complex OsH(S)(≡CPh)(IPr)(P i Pr 3 ) ( 2 ), which has been transformed into the hydrosulfide [OsH(SH)(≡CPh)(IPr)(P i Pr 3 )]OTf ( 3 ) and the methylsulfide [OsH(SMe)(≡CPh)(IPr)(P i Pr 3 )]OTf ( 4 ) through protonation and methylation reactions, respectively. The structure, spectroscopic characteristics, and reactivity of these compounds are compared. Reactions of 3 and 4 with 2-hydroxypyridine and 2-mercaptopyridine afford [OsH{κ 2 - X , N -[X-py]}(≡CPh)(IPr)(P i Pr 3 )]OTf [X = O ( 5 ), S( 6 )].