Synthesis of Group IV (Zr, Hf)−Group VIII (Fe, Ru) Heterobimetallic Complexes Bearing Metallocenyl Diphosphine Moieties and Their Application to Catalytic Dehydrogenation of Amine−Boranes

A series of heterobimetallic complexes, including [M1Me(μ-η5:η1-C5H4PEt2)2M2Cp*] (5a, M1 = Zr, M2 = Ru; 5b, M1 = Hf, M2 = Ru; 5c, M1 = Zr, M2 = Fe) have been prepared and characterized by X-ray analyses. Dehydrogenation of Me2NH·BH3 takes place in the presence of a catalytic amount of these heterobimetallic complexes. Studies on the reaction pathway of the catalytic dehydrogenation of Me2NH·BH3 lead us to propose a catalytic cycle where two metal centers cooperatively participate in the catalysis. Here, heterobimetallic hydride species serve as key reaction intermediates.