Synthesis, Structure, and Bonding of a Xe IV Transition-Metal Coordination Complex, F 3 XeF b - - -WOF 4 .

The coordination complex, F 3 XeF b - - -WOF 4 , was synthesized in CFCl 3 solvent by reaction of the weak fluoride-ion donor and strong oxidative fluorinating agent, XeF 4 , with the moderate-strength fluoride-ion acceptor, WOF 4 . The compound is the only transition-metal coordination complex of Xe IV and was characterized at low temperatures by single-crystal X-ray diffraction and Raman spectroscopy. Xenon tetrafluoride and WOF 4 coordinate trans to the W=O bond through a W- - -F b bond. The XeF 3 moiety of F 3 XeF b - - -WOF 4 acquires a degree of [XeF 3 ] + character upon coordination that is reflected by its Xe-F stretching frequencies which are intermediate with respect to those of XeF 4 and [XeF 3 ] + . Calculations show W- - -F b is predominantly an electrostatic, σ-hole bond with a significant orbital contribution that accounts for the bent Xe-F b - - -W angle. The calculations show F 3 XeF b - - -MOF 4 (M=Cr, Mo) are less stable than their W analogue, consistent with failed attempts to synthesize F 3 XeF b - - -MoOF 4 .