EPR AND CRYSTALLOGRAPHIC STUDIES OF SOME REACTION-PRODUCTS OF VCL4, NBCL4, AND TACL4 WITH TRIALKYLPHOSPHINES AND TRIARYLPHOSPHINES

Solutions containing, or at least made from, the MCl(4) (M = V, Nb, Ta) compounds and alkyl phosphines have been studied. It is concluded that no VCl4(PR(3))(2) species survive, the main reactions being to give various V-III species, such as [VCl4(PR(3))(2)](-) accompanied by varying amounts of VOCl2(PR(3))(2) species which are responsible for the observed EPR spectra. When the trans-MCl(4)(PEt(3))(2) molecules are introduced and the solutions are scrupulously protected from laboratory air, little or no EPR intensity can be recorded. The complexes VOCl2(PPh(3))(2) and [HPMe(2)Ph][VCl4(PMe(2)Ph)(OPMe(2)Ph)] have been structurally characterized: VOCl2(PPh(3))(2) forms monoclinic crystals in space group C2/c (No. 15) with a = 24.691(4) Angstrom, b = 9.518(1) Angstrom, c = 15.690(2) Angstrom, beta = 117.19(1)degrees, V = 3280(1) Angstrom(3), Z = 4 and [HPMe(2)Ph][VCl4(PMe(2)Ph)(OPMe(2)Ph)] forms orthorhombic crystals in space group Pbca (No. 61) with a = 17.262(11) Angstrom, b = 28.967(8) Angstrom, c = 12.056(7) Angstrom, V = 6028(5) Angstrom(3), Z = 8.