Novel Inorganic (Carbon-Free) Chelate Rings: Tris(chelate) Compounds of [N-(Diphenylphosphinoselenoyl)-P,P-diphenylphosphinoselenoic amidato-Se, Se′] with MIII (M = Sb, Bi, In)

The [(SePPh2)2N]− ligand 1c forms stable tris(chelates) with the SbIII, BiIII, and InIII 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 SbIII and BiIII compounds the arrangement around the metals suggests a stereochemically nonactive electron lone pair.