Understanding the bonding and aromaticity of [Au3{C4H4(X)4E}3]− (X = CF3, CN, BO; E = Si, Ge): trinuclear gold superhalogens.

Carbene and its analogous silylene and germylene ligated trinuclear gold complexes are well established due to their cationic stability, but the anionic stability of such complexes is still rare. Density functional theory calculations on recently synthesized [Au3{C4H4(SiMe3)4Si}3]− and [Au3{C4H4(SiMe3)4Ge}3]− prove that the Au3 core is electron rich and the calculated vertical detachment energy is close to that of halogens. Further proper ligand manipulation on these complexes makes them remarkably stable anions having electron binding energies higher than 5 eV and behaving like superhalogens. Magnetic response calculations based on the magnetically induced current densities and the induced magnetic field confirm the aromatic nature of these anionic Au3-complexes. A study of the gradient Laplacian of electron density and energy density at the bond critical point and electron localization function gives additional bonding information of these anionic complexes. [ABSTRACT FROM AUTHOR]