Coordination of KrF to a Naked Metal Cation, Mg.

Examples of coordination compounds in which KrF functions as a ligand are very rare. In contrast, XeF provides a rich coordination chemistry with a variety of main-group and transition metal cations. The reactions of Mg(AsF ) and KrF in HF or BrF solvent have afforded [Mg(KrF ) (AsF ) ] and [Mg(KrF ) (AsF ) ]⋅2 BrF , respectively, the first examples of a metal cation ligated by KrF . Their X-ray crystal structures and Raman spectra show that the KrF ligands and [AsF ] anions are F-coordinated to a naked Mg cation. Quantum-chemical calculations are consistent with essentially non-covalent ligand-metal bonding. These compounds significantly extend the XeF -KrF analogy and the limited chemistry of krypton by introducing a new class of coordination compound in which KrF functions as a ligand towards a naked metal cation.