2,2'-BIPYRIDYL FLUORO COMPLEXES OF TUNGSTEN(VI) - PREPARATION, CHARACTERIZATION AND CRYSTAL-STRUCTURE OF [WF4(BIPY)2]2+.2[WF7]-.WF6 AND [WF4(BIPY)2]2+.2[WF7]-.CH3CN - PREPARATION AND CHARACTERIZATION OF WF6.BIPY

The complex [WF4(bipy)2]2+ . 2[WF7]- . WF6 has been obtained by the reaction of excess WF6 with 2,2'-bipyridyl (bipy) in acetonitrile solution, and the complex [WF4(bipy)2]2+ . 2[WF7]- . CH3CN resulted from treatment of [WF4(bipy)2]2+ . 2[WF7]- . WF6 with CH3CN. The adduct WF6 . bipy, obtained from the reaction of WF6 with bipy in a 1:1 molar ratio in CH2Cl2 or CH3CN 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 WF6 . bipy, the two ionic complexes are very moisture-sensitive. They were characterized by elemental analysis, X-ray powder data, vibrational spectroscopy and F-19, C-13 and H-1 NMR spectroscopy in CD3CN solution. The crystal structures of [WF4(bipy)2]2+ . 2[WF7]- . WF6 and [WF4(bipy)2]2+ . 2[WF7]- . CH3CN 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 [WF7]- anion is a distorted monocapped trigonal prism. The fluorine atoms of the WF6 molecule in [WF4(bipy)2]2+ . 2[WF7]- . WF6 form a slightly elongated octahedron. In [WF4(bipy)2]2+ . 2[WF7]- . CH3CN, the WF6 molecules are replaced by CH3CN molecules although the crystal packing is virtually the same in the two complexes.