Structures of Nitrogen Oxides Attached to Anionic Gold Clusters Au<sub>4</sub><sup>–</sup> Revealed by Infrared Multiple Photon Dissociation Spectroscopy
Masato Yamaguchi, Yufei Zhang, Olga V. Lushchikova, Joost M. Bakker, Fumitaka Mafuné
Abstract
The adsorption forms of NO and NO2 on anionic Au4– clusters were investigated by a combination of IR multiple photon dissociation (IRMPD) spectroscopy and density functional theory (DFT) calculations. For all three species investigated (Au4NO–, Au4N2O2–, and Au4NO2–), the spectra were found to be consistent with a Y-shaped Au4– cluster with triangular Au3 and one Au atom sticking out, on which NO and NO2 molecules adsorb molecularly. These species are considered as intermediates of the Au4–-mediated disproportionation reaction of NO, Au4(NO)3– → Au4(NO2)(N2O)−. We discuss the reaction path on the basis of the found geometries and energies and conclude that the disproportionation reaction of NO can occur catalytically on the Au4– cluster.