Complexes of Tris(N-piperidinomethyl)phosphine Oxide with Zinc and Cadmium

Abstract

A number of compounds which can by their stoichiometry be classified into several groups have been prepared by reaction of tris(N-piperidinomethyl)phosphine oxide (tppo) with Zn(II) and Cd(II) salts. The structure of two Zn(II) complexes differing by their Zn : tppo ratio and of one Cd(II) complex has been determined by the X-ray diffraction technique. The results show that in all the cases tppo is bound as divalent chelate N,O-donor, but the geometry of coordination sphere of M(II) decisively affects the steric arrangement of the five-membered chelate ring. Structures of the compounds studied are entirely different from those of Zn(II) complexes of sterically less demanding P,P-dimethyl-P-aminomethylphosphine oxide (dmao). On the other hand, the way of coordination of tppo is the same as that found in the case of the Co(II) complex of tris(N,N-dimethylaminomethyl)phosphine oxide.