SYNTHESIS AND STRUCTURES OF THE HALOGENATED TUNGSTEN(VI) PHOSPHORANIMINATE COMPLEXES WCL5(N=PCL3) AND WCL4(N=PCL2PH)2 AND THE WEAKLY COORDINATED ION-PAIR [WCL4(N=PCL3)][GACL4]

Halogen-substituted transition metal phosphoraniminate complexes have been synthesized via the reactions Of WCl6 with the phosphoranimines Cl2RP=NSiMe3 (R = Cl or Ph). The latter species were prepared from the reaction of the phosphoranes PCl4R with Li[N(SiMe3)2]. The reaction Of WCl6 With 1 equiv Of Cl3P=NSiMe3 yielded the perhalogenated (phosphoraniminato)tungsten(VI) Species WCl5(N=PCl3) (1), Whereas with 2 equiv of Cl3P=NSiMe3, a product was isolated that was tentatively identified as CiS-WCl4(N=PCl3)2 (2). The analogous reaction Of WCl6 with 2 equiv of Cl2PhP=NSiMe3 yielded cis-WCl4(N=PCl2Ph)2 (3). Compounds 1 and 3 were characterized by single-crystal X-ray diffraction. Attempts to abstract a chloride anion from 1 to yield a cationic tungsten(VI) phosphoraniminate complex via the reaction of this species with excess GaCl3 yielded [WCl4(N=PCl3)] [GaCl4] (4). An X-ray diffraction study of the latter species showed that the [GaCl4]- anion is weakly coordinated to the cationic tungsten center through a single chloride bridge. Crystals of 1 are orthorhombic, space group Pcmn, with a = 8.867(4) angstrom, b = 10.749(2) angstrom, c = 12.180(4) angstrom, alpha = beta = gamma = 90-degrees, V = 1160.9(6) angstrom3, and Z = 4. Crystals of 3 are triclinic, space group P1BAR, with a = 9.461(4) angstrom, b = 10.099(3) angstrom, c = 14.506(3) angstrom, alpha = 109.65(2)degrees, beta = 97.88(2)degrees, gamma = 94.86(3)degrees, V = 1280.2(7) angstrom3, and Z = 2. Crystals of 4 are monoclinic, space group C2/m, with a = 13.099(3) angstrom, b = 10.339(2) angstrom, c = 12.540(3) angstrom, beta = 114.68(3)degrees, V = 1543.2(6) angstrom3, and Z = 4.