Mixed Noble-Gas Compounds of Krypton(II) and Xenon(VI); [F5Xe(FKrF)AsF6] and [F5Xe(FKrF)2AsF6]

The coordination chemistry of KrF2 has been limited in contrast with that of XeF2, which exhibits a far richer coordination chemistry with main-group and transition-metal cations. In the present work, reactions of [XeF5][AsF6] with KrF2 in anhydrous HF solvent afforded [F5Xe(FKrF)AsF6] and [F5Xe(FKrF)(2)AsF6], the first mixed krypton/xenon compounds. X-ray crystal structures and Raman spectra show the KrF2 ligands and [AsF6](-) anions are F-coordinated to the xenon atoms of the [XeF5](+) cations. Quantum-chemical calculations are consistent with essentially noncovalent ligand-xenon bonds that may be described in terms of sigma-hole bonding. These complexes significantly extend the XeF2-KrF2 analogy and the limited chemistry of krypton by introducing a new class of coordination compound in which KrF2 functions as a ligand that coordinates to xenon(VI). The HF solvates, [F5Xe(FH)AsF6] and [F5Xe(FH)SbF6], are also characterized in this study and they provide rare examples of HF coordinated to xenon(VI).

Automated summary

The coordination chemistry of KrF2 is limited compared to XeF2, but in this study, new mixed krypton/xenon compounds were synthesized where KrF2 acts as a ligand coordinating to xenon atoms. This extends the XeF2-KrF2 analogy and introduces a new class of coordination compound.