Bonding and electronic structures in W@Au(12)AE complexes (AE= NO+, CO, BF, CN-, or BO-): analogies among ligands isoelectronic to carbon monoxide
A theoretical study on the geometries and electronic structures of W@Au(12)AE (AE=NO+, BF, CN-, or BO-) was carried out to gain insight into interactions between W@Au-12 and ligands isoelectronic with CO. The best configuration for the adsorption site is on-top type for all five complexes. After complexing with boron ligands (BF or BO-), the axial Au-W bond distance in W@Au-12 is lengthened notably, but NO+ has the opposite effect on the axial Au-W bond. A charge transfer and energy decomposition analysis shows that the metal-ligand bonds have enhanced sigma-donation strength from NO+ to BO-. Furthermore, the A-E bond strength in the complexes becomes weaker with stronger pi-back-donation interactions. Finally, W@Au12CO has the largest HOMO-LUMO gap, making it the most stable in terms of kinetic stability.
density functional gold cluster closed-shell back donation