The reaction of [Cp_2Ti(C≡CPh)_2], [Cp_2Zr(C≡CPh)_2]with vanadocene in toluene at room temperature gives heterodimetallic complexes [Cp_2V(μ-η~2:η~4-butadiyne)MCp_2] 1 (M = Ti), 2 (M = Zr), respectively. These compounds, which have been characterized by elemental analysis, mass spectrometry, IR and Raman spectroscopy, exhibit similar magnetic susceptibilities. According to an X-ray diffraction analysis of 2, the Cp_2V and Cp_2Zr metallocene moieties are bonded to butadiene (or butadiyne) framework via the two internal carbon atoms for Cp_2V, and via both the two internal carbon atoms and the two external carbon atoms for Cp_2Zr. 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.

Key words: TITANIUM COMPLEX, ZIRCONIUM COMPLEX, VANADIUM COMPLEX, ELEMENTAL ANALYSIS, IR, RAMAN SPECTROMETRY, CRYSTAL STRUCTURE, BUTADIENE, REACTION MECHANISM