Mechanistic insight into water exchange and aqua/fluoride ligand substitution reactions on aqueous species of Al, Ga and In

Two ligand substitution reactions on aqueous complexes of Al, Ga and In, water-exchange and aqua/fluoride substitution reactions, were investigated using density functional theory (DFT), and the preferred substituted mechanisms were estimated based on the activated energy barriers. A series of mechanistic changeovers were found and interpreted at the molecular level. Four factors influencing substitution mechanisms were summarized, i.e. the size of central metal ions, the volume of entering ligands, the charge of clusters, and structural rigidity. The present study provides an approach to probe the ligand substitution mechanism of some reactions inaccessible experimentally. [GRAPHICS]