Preparation and structure of organoantimony(III) derivatives containing potentially dibentate ligands. Antimony-carbon cleavage upon complex formatio

Abstract

Organoantimony(III) derivatives of the tyes RSbX 2 and R 2SbX in which X represents a N, N-diethyldithiocarbamate, N, N-diethylcarbamate, oximate or tropolonate ligand have been synthesized and investigated by spectroscopic (IR, UV) methods. In the RsbX 2 compounds (R = phenyl, alkyl) the ligand X appears to be bidentate both in the solid state and in solution making the antimony pentacoordinate. The compounds RSbOx 2 are exceptional in that dissolution in benzene or chloroform causes rupture of the weak coordinate Sb bond. Compounds R 2SbX, in which R = alky, spontaneously disproportionate into a 1/1 mixture of R 3SbX 2 is connected with the much reduced electrophilic reactivity of RSbX 2 as a result of pentacoordination. In contrast, componds of the typ Ph 2SbX appear to be stable. A four-coordinate structure is observed in the solid state, but three-coordination appears to be preferred in solution.