Synthesis, Structure, and Bonding of a Xe~(IV) Transition-Metal Coordination Complex, F3XeFb- - -WOF4

摘要

The coordination complex, F3XeFb- - -WOF4, was synthesized in CFCl3 solvent by reaction of the weak fluoride-ion donor and strong oxidative fluorinat-ing 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---Fb bond. The XeF3 moiety of F3XeFb---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---Fb is predominantly an electrostatic, α-hole bond with a significant orbital contribution that accounts for the bent Xe-Fb---W angle. The calculations show F3XeFb---MOF4 (M = Cr, Mo) are less stable than their W analogue, consistent with failed attempts to synthesize F3XeFb- - -MoOF4.