REACTIONS OF HYDRIDOVANADIUM COMPLEXES - THE FORMATION OF 7-COORDINATED SIGMA-ALKYLVANADIUM(I) COMPLEXES BY HYDROVANADATION OF ALKENES, ANDTHE MOLECULAR-STRUCTURE OF TRANS-[V(CO)(2)(DPPE)(2)]CENTER-DOT-3C(6)D(6)

sigma-Alkyl complexes of V-(I) of the general composition (alkyl)V(CO) (6-n)p(m) have been prepared by W-induced insertion of alkenes into th e V-H bond of HV(CO)(6-n)p(m.) p(m) is an oligophosphine coordinating through n phosphorus functions. Spectroscopic characteristics (IR and multinuclear NMR) suggest that the structure in solution is a face-cap ped octahedron, as for the hydride complexes. Many new hydride complex es and their anionic ([V(CO)(6-n)p(m)](-)) precursor compounds are als o described. The crystal and molecular structures of trans-[V(CO)(2)(d ppe)(2)], which forms as a byproduct in a side reaction of the photo-i nduced hydride transfer, have been determined. The compound crystalliz es in the orthorhombic space group P22(1)2(1) with the following cell parameters: a = 1220.4(2), b = 1421.5(3) and c = 1758.1(3) pm.