Phosphine and diphosphine complexes of tungsten(VI) oxide tetrafluoride

The reaction of [WOF4(MeCN)] with the diphosphines, Me2PCH2CH2PMe2 or o-C6H4(PMe2)2, in anhydrous Et2O produced high yields of [WOF4(diphosphine)], the X-ray crystal structures of which reveal seven-coordinate pentagonal bipyramidal molecules with axial O/F. In contrast, the reaction of [WOF4(MeCN)] and PMe3 forms the six-coordinate [WOF4(PMe3)]. These unusual W(VI) complexes have been characterised by microanalysis, IR, 1H, 19F{1H} and 31P{1H} NMR spectroscopy. The second-order 19F{1H} and 31P{1H} NMR spectra of the [WOF4(diphosphine)] have been analysed. Similar complexes do not form with the other o-phenylene-linked bidentate ligands, o-C6H4(PPh2)2, o-C6H4(AsMe2)2 or o-C6H4(SMe)2.