Quantum chemical calculations on the structure and stability of Mg 2+XH 3OH complexes in the gas phase (X = C, Si, and Ge)

Abstract

The structure and stability of Mg 2+XH 3OH complexes in gas phase (X = C, Si and Ge) have been studied using the B3LYP/6-31 + G(d) and CBS-QB3 levels of theory. Several dissociation pathways for Mg 2+XH 3OH complexes have been investigated. The complexes are thermodynamically stable with respect to the loss of H +, OH +, XH 3, XH 4, and XH 4 + but thermodynamically unstable toward the loss of XH 3 +, XH 3OH +, and XH 3O + ions. The presence of sizable kinetic energy barriers (25–81 kcal/mol) for unimolecular dissociation hinders the exothermic processes. This indicates that Mg 2+XH 3OH complexes can form metastable species and is likely observed under appropriate experimental conditions. On the other hand, endothermic channels are unlikely occurred under mild experimental conditions. Binding energies in the investigated complexes parallel charge transfer from ligands to the Mg 2+ ion. Comparison between B3LYP and CBS-QB3 results is also presented.