Syntheses and Structures of Xenon Trioxide Alkylnitrile Adducts

The potent oxidizer and highly shock-sensitive binary noble-gas oxide XeO₃ interacts with CH₃ CN and CH₃ CH₂ CN to form O₃ XeNCCH₃ , O₃ Xe(NCCH₃ )₂ , O₃ XeNCCH₂ CH₃ , and O₃ Xe(NCCH₂ CH₃ )₂ . Their low-temperature single-crystal X-ray structures show that the xenon atoms are consistently coordinated to three donor atoms, which results in pseudo-octahedral environments around the xenon atoms. The adduct series provides the first examples of a neutral xenon oxide bound to nitrogen bases. Raman frequency shifts and Xe-N bond lengths are consistent with complex formation. Energy-minimized gas-phase geometries and vibrational frequencies were obtained for the model compounds O₃ Xe(NCCH₃ )_n (n=1-3) and O₃ Xe(NCCH₃ )_n ⋅[O₃ Xe(NCCH₃ )₂ ]₂ (n=1, 2). Natural bond orbital (NBO), quantum theory of atoms in molecules (QTAIM), electron localization function (ELF), and molecular electrostatic potential surface (MEPS) analyses were carried out to further probe the nature of the bonding in these adducts.