2,2'-Bipyridyl fluoro complexes of tungsten(VI): preparation, characterization and crystal structure of [WF 4(bipy) 2] 2+ · 2[WF 7] − · WF 6 and [WF 4(bipy) 2] 2+ · 2[WF 7] − · CH 3CN; preparation and characterization of WF 6 bipy

Abstract

The complex [WF 4(bipy) 2] 2+·2[WF 7] −·WF 6 has been obtained by the reaction of excess WF 6 with 2,2'-bipyridyl (bipy) in acetonitrile solution, and the complex [WF 4(bipy) 2] 2+·2[WF 7] − CH 3N resulted from treatment of [WF 4(bipy) 2] 2+·2[WF 7] −·WF 6 with CH 3CN. The adduct WF 6 bipy, obtained from the reaction of WF 6·with bipy in a 1:1 molar ratio in CH 2Cl 2 or CH 3CN solution, is not moisture-sensitive at ambient temperature and is almost insoluble in the usual organic solvents. It was characterized by elemental analysis, X-ray powder data and infrared spectroscopy. In contrast to WF 6·bipy, the two ionic complexes are very moisture-sensitive. They were characterized by elemental analysis, X-ray powder data, vibrational spectroscopy and 19F, 13C and 1H NMR spectroscopy in CD 3CN solution. The crystal structures of [WF 4(bipy) 2] 2+·2[WF 7] −·WF 6 and [WF 4(bipy) 2] 2+·2[WF 7] −·CH 3CN have been determined from X-ray diffraction data. For both ionic complexes, the coordination polyhedron of the tungsten atom in the cation is a triangular dodecahedron and in the [WF 7] − anion is a distorted monocapped trigonal prism. The fluorine atoms of the WF 6 molecule in [WF 4(bipy) 2] 2+·2[WF 7] −·WF6 form a slightly elongated octahedron. In [WF 4(bipy) 2] 2+·2[WF 7] −CH 3CN, the WF 6 molecules are replaced by CH 3CN molecules although the crystal packing is virtually the same in the two complexes.