The synthesis of nitrosyl-thiocarbonyl complexes of osmium

Abstract

Two procedures for the conversion of coordinated CS 2 into CS ligands are described involving the intermediacy of either η 2-carbonsulphide-telluride or hydridodithiomethoxycarbonyl complexes. The CS 2 ligand in OsCl(NO)(CS 2)(PPh 3) 2 is readily methylated to provide cationic dithiomethoxycarbonyl-containing complexes, which upon reduction with sodium hydrotelluride and sodium tetrahydroborate give OsX(NO)(CS)(PPh 3) 2 (X = Cl, I) and OsH 2 (CS 2Me)(NO)(PPh 3) 2, respectively. The latter reacts with electrophilic reagents (HCl, HI, I 2) to give OsX(NO)(CS)(PPh 3) 2, the halide of which is labile and is easily extracted by silver salts, allowing coordination of neutral ligands and providing the cations [Os(NO)(CS)(PPh 3) 2L] + (L = CO, PPh 3). OsH 2(CS 2Me)(NO)(PPh 3) 2 and OsI(NO)(CS)(PPh 3) 2 react with an excess of I 2 to give the ionic product [OsI 2(NO)(CS)(PPh 3) 2] +I 3 −.