Crystal structure of an ordered [WOF5]- salt: (1,10-phen-H)[WOF5] (1,10-phen = 1,10-phenanthroline)

Crystals of 1,10-phenanthrolinium pentafluoridooxidotungstate(VI), (1,10-phen-H)[WOF5] (1,10-phen = 1,10-phenanthroline, C12H8N2), were obtained upon hydrolysis of WF6(1,10-phen) in CH3CN at 193 K. The (1,10-phen-H)[WOF5] salt contains a rare example of a [WOF5](-) anion in which the oxygen and fluorine atoms are ordered. This ordering was verified by bond-valence determinations and structural comparisons with [Xe2F11][WOF5] and Lewis acid-base adducts of WOF4 with main-group donor ligands. The crystal packing is controlled by N-H center dot center dot center dot F hydrogen bonding that is directed exclusively to the axial F atom as a result of its increased basicity caused by the trans influence of the oxido ligand.