Reactions of Schiff Base‐Substituted Diselenides and ‐tellurides with Ni(II), Pd(II) and Pt(II) Phosphine Complexes

Abstract

The salicylidene Schiff bases of bis(2‐aminophenyl)diselenide and ‐ditelluride react with [MIICl2(PPh3)2] (M = Ni, Pt) or [PdII(OAc)2(PPh3)2] with formation of square‐planar complexes with the general formulae [MII(LY)(PPh3)] (M = Ni, Pd, Pt, Y = Se, Te). The ligands coordinate to the metals as tridentate {O,N,Se/Te} chelates. The reduction of the dichalcogenides and the formation of the chalcogenolato ligands occurs in situ by released PPh3 ligands. A mechanism for such reactions has been derived from the experimental data with the aid of DFT calculations. It suggests a higher polarization of the dichalcogenide bond with partial charge separation upon coordination to a metal centre, which therefore facilitates the cleavage of the dichalcogenide bond with PPh3. In accordance with the proposed mechanism, best yields are obtained with a strict exclusion of oxygen, but in the presence of water.