A Homoleptic KrF₂ Complex, [Hg(KrF₂)₈][AsF₆]₂⋅2 HF

Abstract

The reaction of Hg(AsF6)2 with a large molar excess of KrF2 in anhydrous HF has afforded the first homoleptic KrF2 coordination complex of a metal cation, [Hg(KrF2)8][AsF6]2⋅2 HF. The [Hg(KrF2)8]2+ dication is well‐isolated in the low‐temperature crystal structure of its HF‐solvated [AsF6]− salt, and consists of eight KrF2 molecules that are terminally coordinated to Hg2+ by means of Hg−F(KrF) bonds to form a slightly distorted, square‐antiprismatic coordination sphere around mercury. The Raman spectrum of [Hg(KrF2)8]2+ was assigned with the aid of calculated gas‐phase vibrational frequencies. Computational studies indicate that both electrostatic and orbital interactions are important for metal–ligand bonding and provide insight into the geometry of the [Hg(KrF2)8]2+ cation and the nature of noble‐gas difluoride ligand bonding.