Novel inorganic (carbon-free) chelate rings: Tris(chelate) compounds of [N-(diphenylphosphinoselenoyl)-P,P-diphenylphosphinoselenoic amidato-Se,Se'] with M(III) (M=Sb,Bi,In)

The [(SePPh(2))(2)N](-) ligand 1c forms stable tris(chelates) with the Sb-III, Bi-III, and In-III ions. The crystal and molecular structures of the resulting compounds 3, 4, and 5 were determined by X-ray diffractometry. The coordination geometry around the metal centers can be described as a distorted octahedron. This feature and the results obtained by comparing the structures with their sulfur and oxygen analogs lead us to conclude that in both Sb-III and Bi-III compounds the arrangement around the metals suggests a stereochemically nonactive electron lone pair.