Cationic Gold(I) Complexes of Xenon and of Ligands Containing the Donor Atoms Oxygen, Nitrogen, Phosphorus, and Sulfur

Ligation of atomic gold(I) cation Au + by various inorganic and organic ligands containing heteroatoms has been examined by experimental and theoretical means. The Au(Xe) + complex has been studied comprehensively by CCSD(T) calculations in order to provide a benchmark for a gold(I) cation affinity scale. The best theoretical estimate of the binding energy is D 0 (Au + −Xe) = 30.1 kcal/mol. This value is used to relate calculated and experimentally bracketed binding energies of Au(L) + complexes with a relative gold(I) cation affinity scale for heteroatom ligands L, i.e., Xe < C 6 F 6 < H 2 O < CO < H 2 S < CH 3 CN ≈ C 2 H 4 ≈ NH 3 ≈ CH 3 NC < CH 3 SCH 3 < PH 3 . In comparison to other transition metal cations, the gold(I) cation is unique in that the binding energies to several ligands are exceptionally large. Further, the covalent character of the Au + −L bonds as well as charge transfer from the ligand to gold are significant. Finally, the gas-phase behavior of Au + suggests some implications for possible new approaches to gold(I) chemistry in condensed matter.