Observation of the interaction between Au- and CO2 in Au(CO2)n- anions: Physisorption as the dominant mechanism.

In this study, we investigated the structure and bonding of Au(CO2)n- (n = 2, 3) using photoelectron spectroscopy analysis, quantum chemical calculations, and weak interaction analysis. Quantum chemical calculations revealed that the geometries of the physisorbed structures closely aligned with experimental data, suggesting that these configurations were the most stable under the experimental conditions. Conversely, while chemisorbed structures exhibit stronger interactions and considerable CO2 activation, they show less agreement with the observed spectroscopic data. Using the interaction region indicator method, our weak interaction analysis confirmed that van der Waals forces were the dominant interaction in the physisorbed structures. Our experimental results indicate that these physically adsorbed structures are more stable under the conditions of this study. These findings shed light on the interaction mechanisms of Au(CO2)n- (n = 2, 3) at the molecular level and provide new insights into the potential for transition metals to catalytically activate CO2.