Reactions of Laser-Ablated Gold with Nitric Oxide: Infrared Spectra and DFT Calculations of AuNO and Au(NO)2 in Solid Argon and Neon

Abstract

Laser-ablated gold reacts with nitric oxide in excess argon and neon, yielding the neutral nitrosyl complexes AuNO and Au(NO)2 as the main products. The N−O and Au−N stretching modes of AuNO are observed at 1701.9 and 517.6 cm-1 in solid argon and at 1710.4 and 523.8 cm-1 in solid neon. Both BPW91 and B3LYP density functionals predict 1A‘ state frequencies in very good agreement. An NBO analysis suggests more d orbital involvement in the bonding in AuNO than in the copper and silver nitrosyls. The dinitrosyl Au(NO)2 is observed at 1510.7 and 3183.2 cm-1 in solid argon and at 1528.2 and 3204.1 cm-1 in solid neon, which are in good agreement with DFT quartet state fundamental and combination frequencies: Au(NO)2 shows evidence for increased charge transfer and sd hybridization compared to AuNO. The cation nitrosyls Au(NO)1,2+ are minor products.