Hydrogen-bonded salt cocrystals of xenon difluoride and protonated perfluoroamides

Abstract

The hydrogen-bonding ability of XeF₂ is an important factor influencing its chemical properties and reactivity, yet structurally characterised examples of hydrogen-bonded xenon fluorides remain rare. In this work, three salt cocrystals containing hydrogen-bonded xenon difluoride and hexafluoridoarsenate salts of protonated perfluoroamides—CF₃C(OH)NH₂[AsF₆]·XeF₂, C₂F₅C(OH)NH₂[AsF₆]·XeF₂, and C₃F₇C(OH)NH₂[AsF₆]·XeF₂—were synthesised and structurally characterised. Diverse hydrogen-bonding motifs were observed, and the first crystallographically characterised examples of N–H⋯FXeF hydrogen bonds are presented. In total, eleven new crystal structures are reported, including two perfluoroamides, three protonated and two hemiprotonated perfluoroamides, and one salt cocrystal containing an oxonium ion. The XeF₂-containing cocrystals demonstrate that XeF₂ reliably functions as a hydrogen-bond acceptor and readily forms hydrogen-bonded cocrystals. These findings broaden the scope of noble-gas chemistry and highlight the potential of noble-gas fluorides for cocrystal formation.