New preparative methods for the halides of titanium(II) and vanadium(II): Reduction of titanium(IV) halides with sodium and oxidation of Bis(mesitylene)vanadium(0)

Abstract

TiCl4(THF)2 reacts with two equivalents of sodium in THF to afford the soluble TiCl2(THF)n (1), which has been characterized analytically and by spectroscopic and magnetic measurements. By redox reactions, TiCl2(THF)n gives TiCl2(9, 10-C10H8O2) (2), or TiCl2(benzoate)2 (3), with 9,10-phenanthrenequinone or dibenzoylperoxide in toluene, respectively. By operating in 1,2-dimethoxyethane (DME), Na(DME)1.5[TiCl4(DME)] (4), or NaTiCl3(DME)2 have been isolated from the reaction of TiCl4(DME) with one or two equivalents of sodium, respectively. From 4, by cation exchange, PPN[TiCl4(DME)] [PPN = bis(triphenylphosphine)iminium] (5), has been obtained and characterized analytically, spectroscopically and by X-ray diffraction methods. Crystal data: C40H40Cl4NO2P2Ti, MW = 818.4, space group: Pna21 (No 33), a = 14.445(2), b = 15.690(2), c = 17.544(2) Å, V = 3976(2) Å3, Z = 4, F(000) = 1692, R = 0.041, Rw = 0.0420. The titanium(III) atom in the anion has the expected cis-octahedral, slightly distorted, geometry. By reaction of TiBr4(DME)0.5 with sodium in DME, TiBr3(DME)1.5, 1.5 DME (7), is the product. Bis(mesitylene)vanadium(0), Vmes2, reacts with two equivalents of CPh3Cl in DME, to give VCl2(DME)n.