Among our accomplishments in the field of noble-gas chemistry are the X-ray crystallographic characterization of the first Xe-N bonded compound, FXeN(SO2F)2 first reported by Prof. Darryl D. DesMarteau. We were the first to provide a means of bonding organic moieties to noble gases. This was accomplished by showing that a number of oxidatively resistant organo- and fluoro-organo nitrogen bases (L) form stable FXeL+AsF6-; salts in which the Xe atom is N bonded to an organic moiety. This new area of organo-ligand noble-gas chemistry resulted in a considerable expansion of group 18 chemistry, providing numerous new examples of Xe-N bonded species; among which are a series of nitrile cations, e.g., HCNXeF+AsF6-, (CH3)3CCNXeF+AsF6-, and the first examples of a noble-gas atom functioning as an aromatic ring substituent, e.g. C5F5NXeF+AsF6-, s-C3F3N2NXeF+AsF6-, s-C3F3N2N- XeOTeF5+Sb(OTeF5)6-, 1,4-C4F4NNXeF+AsF6-, 1,3-C4F4NNXeF+AsF6-, and 1,2-C4F4NNXeF+AsF6-. We have extended these studies to Xe(II) Lewis acid adducts with inorganic bases such as F3SN and F5TeNH2 which has resulted in the characterization of the F3SNXeF+, F4S=N-Xe+, F5SN(H)Xe+ and F5TeN(H)Xe+ cations. Neutral adducts with high-valent xenon centres, namely, O3XeNCCH3, O2F2XeNCCH3 and OF4XeNCCH3, have also been characterized, providing the first examples of Xe(VI)-N bonds. Most recently, the first example of a Xe(IV)-N bond, OF2XeNCCH3, has been synthesized and fully characterized by X-ray crystallography.
Our research group has also synthesized the first compounds containing Kr-N bonds (RCN-KrF+, R = H, CF3, C2F5, n-C3F7). It should be noted that HCN-KrF+ is highly explosive as a solid at -60 oC, but was nevertheless fully characterized by use of 19F, 1H and 15N NMR spectroscopy. The existence of Kr-F and Kr-N bonded species underscored the anomalous apparent non-existence of a Kr-O bonded species and led Schrobilgen to synthesize the first example of a Kr-O bonded compound (Kr(OTeF5)2). Using low-temperature crystal mounting techniques devised in this laboratory, we have succeeded in characterizing several salts of the KrF+ and Kr2F3+ cations, among the most potent chemical oxidizers now known, by low-temperature X-ray crystallography. Most recently, the first example of a compound in which KrF2 function as a ligand, namely, BrOF2+.2KrF2AsF6- has been synthesized and structurally characterized.
Our research group has reopened chapters in noble-gas that had been closed for more than 30 years. The chemistry of Xe(VIII) had not progressed synthetically or structurally beyond the incomplete characterization of XeO3F2 by matrix-isolation infrared spectroscopy in 1968. The field had languished because of the extremely explosive nature of XeO4, the only known precursor to Xe(VIII) compounds other than perxenate, XeO64-. We have more fully characterized XeO3F2 and XeO4 by 129Xe and 19F NMR spectroscopy and have documented the formation of the novel fac-XeO3F3- anion and the first example of a Xe(VIII)-N bond, O4Xe-NCCH3. A 131Xe NMR study represents the first such study of a chemical compound.