Synthesis and crystal structure of heterodimetallic complexes [Cp2V(μ-η2:η4-PhC4Ph)MCp2′](M=Ti, Zr; Cp′=C5H5, C5H4SiMe3)

The reaction of [CP2Ti(Cequivalent toCPh)(2)], [Cp2Zr(Cequivalent toCPh)(2)], [(C5H4SiMe3)(2)Zr(Cequivalent toCPh)(2)] and vanadocene in toluene was performed at room temperature and gave heterodimetallic complexes [Cp2V(mu-eta(2) : eta(4)-PhC4Ph) . MCp2'] (1, M=Ti, Cp'=C5H5; 2, M Zr, Cp' =C5H5; 3, M=Zr, Cp' C5H4SiMe3), respectively. These compounds, which have been characterized by elemental analysis mass spectrometry, H-1 NMR, IR and Raman spectroscopy, exhibit similar magnetic susceptibilities. According to an X-ray diffraction analysis of compound 3, the Cp2V and CP2'Zr metallocene moieties are bonded to a butadiene(or butadiyne) framework via the two internal carbon atoms for Cp2V, and via both the two internal carbon atoms and the two external carbon atoms for CP2'Zr. The distances and angles observed around the internal carbon atoms of the butadiene framework indicate that both internal carbon atoms of butadiene skeleton are planar and tetracoordinated.