Complexes of molybdenum(VI) oxide tetrafluoride and molybdenum(VI) dioxide difluoride with neutral N- and O-donor ligands

[MoOF4(MeCN)], prepared from reaction of MoF6 with (Me3Si)(2)O in anhydrous MeCN solution, reacts with the neutral O-donor ligands, thf, Ph3PO-, Me3PO, dmf and dmso, (L) in a 1:1 molar ratio under rigorously anhydrous conditions to form six -coordinate [MoOF4(L)], which have been characterised by microanalysis, IR, H-1, F-19{H-1}and Mo-95 NMR spectroscopy. In the presence of moisture the major products are [MoO2F2(L)21, which can be made directly by reaction of [MoOF4(L)] with a further equivalent of L and (Me3Si)(2)O. [MoOF4(MeCN)] and 2,2'-bipyridyl produce the insoluble [MoO-F-4(bipy)], which is probably 7-coordinate. Ph3AsO is quantitatively converted to Ph3AsF2 by [MoOF4(MeCN)], and soft ligands, including Me2S, Me3P and Me3As, reduce the oxide fluoride on contact. Unstable [MoO2F2(MeCN)(2)] has also been prepared and the X-ray structure of [MoO-F-2(2)(MeCN)(2)].MeCN is reported. X-ray crystal structures are reported for (MoO-F-4(Ph3PO-)), [MoO2F2(Ph3PO-)(2)], [MoO2F2(Me3PO)(H2O)] and [Mo2O-F-4(2)( mu-F)(2)(Me3PO)(2)]. Comparisons with the corresponding chemistries of WOF4 and WO-F-2(2) are described.