Infrared spectra and DFT calculations for the gold hydrides AuH, (H2)AuH, and the AuH3 transition state stabilized in (H2)AuH3

Reactions of laser-ablated gold atoms with hydrogen (H-2, D-2, HD) in excess argon and neon and in pure deuterium produced AuH and the (H-2)AuH and (H-2)AuH3 complexes in increasing yields, respectively, in these matrix hosts. The diatomic molecule AuH absorbs at 2226.6 cm(-1) in solid argon, slightly blue shifted from the gas-phase value, and the stable (H-2)AuH complex appears at 2173.6 cm(-1) on annealing to allow diffusion and association of H-2 and AuH. The higher (H-2)AuH3 complex presents at 1642.0 cm(-1) on deposition. In neon (H-2)AuH and (H-2)AuH3 give weak bands at 2170 and 1684 cm(-1) with D-2 counterparts at 1559 and 1207 cm(-1), which become strong 1556.5 and 1198.6 cm(-1) absorptions in pure deuterium. DFT structure and frequency calculations confirm these assignments and show that the AuH, transition state with an imaginary b(1) bending frequency is stabilized in the (H-2)AuH3 complex with a real b(1) bending frequency observed at 457.0 cm(-1) for (D-2)AuD3.