Pentamethylcyclopentadienyl-Vanadium Complexes Containing Halogeno- and Oxo-Ligands
AbstractA simple and high-yield preparation of the pentamethylcyclopentadienyl vanadium(IV) trihalides Cp*VX3 (X = CL, Br, I) from Cp*V(CO)4 as well as their conversion into the oxo-vanadium(V) compounds Cp*VOX2 (X = CL, Br) and [Cp*VOX]2(μ-O) (X = CL, Br, I) are described. The equilibrium between the two fluoride species Cp*VOF2 and [Cp*VOF]2(μ-O) has also been investigated. The complexes are characterized by their NMR (51V, l3C, 1H), IR, and mass spectra. The crystal structure of the binuclear chloro-oxo complex [Cp*VOCl]2(μ-O) has been determined by X-ray diffraction. The molecules contain two [Cp*VOCl] units combined via a bent oxo bridge (V-O-V angle of 142.2(2)°). The vanadium-oxygen bond lengths are 157.6(8) and 179.4(1) pm for the terminal and the bridging oxo ligands, respectively, corresponding to double and single bonds.