Synthesis, Structure, and Bonding of a Xe^IV Transition-Metal Coordination Complex, F₃ XeF_b - - -WOF₄

The coordination complex, F₃ XeF_b - - -WOF₄ , was synthesized in CFCl₃ solvent by reaction of the weak fluoride-ion donor and strong oxidative fluorinating agent, XeF₄ , with the moderate-strength fluoride-ion acceptor, WOF₄ . 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 WOF₄ coordinate trans to the W=O bond through a W- - -F_b bond. The XeF₃ moiety of F₃ XeF_b - - -WOF₄ acquires a degree of [XeF₃ ]⁺ character upon coordination that is reflected by its Xe-F stretching frequencies which are intermediate with respect to those of XeF₄ and [XeF₃ ]⁺ . 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 F₃ XeF_b - - -MOF₄ (M=Cr, Mo) are less stable than their W analogue, consistent with failed attempts to synthesize F₃ XeF_b - - -MoOF₄ .