[VCL3(NPPH3)(OPPH3)], A PHOSPHORANE IMINATO COMPLEX OF VANADIUM(IV)

The title compound has been prepared from vanadium tetrachloride and M e3SiNPPh3 in the presence of OPPh3 in CCl4 solution, forming orange-re d, moisture sensitive crystals, which were characterized by an X-ray s tructure determination. Space group Cc, Z = 4, 2 560 observed unique r eflections, R = 0.049. Lattice dimensions at 0-degrees-C: a = 1018(1), b = 1826(2), c = 1859(2) pm, beta = 93.65(9)-degrees [VCl3(NPPh3)(OPP h3)] forms monomeric molecules, in which the vanadium atom is coordina ted in a distorted square pyramidal fashion with the (NPPh3)- ligand i n apical position. The three chlorine atoms and the oxygen atom of the OPPh3 molecule occupy the basal positions. The phosphorane iminato gr oup V=N=PPh3 is nearly linear (bond angle VNP 161.4-degrees), the bond lengths VN (169 pm) and PN (162 pm) correspond with double bonds.