Electronic structure and molecular properties of the [Mo6X8L6]2−; X = Cl, Br, I; L = F, Cl, Br, I clusters

Relativistic time-dependent density functional (TDDFT) calculations including spin orbit interactions via the zero order regular approximation (ZORA) and solvent effects were carried out on the [Mo6X8L6]2− X = Cl, Br, I; L = F, Cl, Br, I clusters. These calculations indicate that the closely spaced lowest excited states are largely centered on the cubic [Mo6X8]4+ core. The active molecular orbitals involved in the higher intensity transitions of each cluster are very much alike. Thus, our calculations and the electronic similarities with the strongly luminescent [Mo6Cl8Cl6]2−, [Mo6Br8Br6]2− and [Mo6I8I6]2− clusters, suggest that the clusters [Mo6Cl8F6]2−, [Mo6Br8F6]2−, [Mo6I8F6]2−, [Mo6I8Cl6]2− and [Mo6I8Br6]2− studied here might be also luminescent. The calculated bond energies and reactivity indexes indicate that the most labile clusters are those with axial iodide ligands.