Theoretical Studies of Direct Exchange Couplings Between Transition Metal Ions II. Tetranuclear Transition Metal Systems

Abstract

The model clusters for the tetranucler transition metal complexes synthesized by Mashima et al. were investigated theoretically. The ab-initio UHF calculations were performed for the Ni-Cr(?)-Cr(II)-Ni and Pd-Mo(?)-Mo(?)-Pd systems to study the nature of the intermetallic bonds. The bond orders and the effective exchange integrals were calculated changing the intermetallic bond distances. It is shown that the tetranuclear dσ-bonds are formed in the cases: Ni(I) and Pd(I).