XeF 2 Coordination Complexes of the [BrO 2 ] + Cation, [O 2 Br(FXeF) n ][AsF 6 ] ( n = 1, 2) and [O 2 Br(FXeF) 2 ][SbF 6 ]; Their Syntheses and Structural Characterizations.

The syntheses and structural characterizations of the first XeF 2 coordination complexes of the [BrO 2 ] + cation are described. The reactions of [BrO 2 ][PnF 6 ] (Pn = As, Sb) with XeF 2 in anhydrous HF solvent yield the salts [O 2 Br(FXeF) n ][AsF 6 ] ( n = 1, 2) and [O 2 Br(FXeF) 2 ][SbF 6 ], which were characterized by low-temperature (LT) Raman spectroscopy and single-crystal X-ray diffraction (SCXRD). The XeF 2 ligands and [PnF 6 ] - coordinate to the Lewis acidic [BrO 2 ] + cation through primarily electrostatic Br V ---F Xe σ-hole bonds that result from coordination of the F atoms into regions of high positive electrostatic potential on the Br(V) atom and have bond trajectories that avoid the stereoactive valence electron lone-pair of Br(V). The complexes and their structural characterizations by LT Raman spectroscopy and SCXRD significantly extend the coordination chemistry of Br(V) and provide rare examples of a noble-gas difluoride coordinated to a strong oxidant main-group Lewis acid center.