Effect over the electronic structure by changing the core metals from Mo to W in a family of [Mo_6-nW_nCl₈F ₆]^2- (n = 0-6) clusters

A complete theoretical characterization of a family of [Mo _6-nW_nCl₈F₆]^2- clusters where n = 0-6, was performed. The calculated geometrical parameters show a very good agreement with the previously reported experimental data. The assessed reactivity indexes indicate that the less reactive cluster would be [W₆Cl₈F₆]^2- which is in concordance with the fact that is the most energetically stable cluster. Relativistic time-dependent density functional (TDDFT) calculations including spin-orbit interactions via the zeroth order regular approximation (ZORA) Hamiltonian and solvent effects were carried out for the cluster families. These calculations showed that the frontier molecular orbitals involved in the transitions are largely centered on the cubic [Mo_6-nW_nCl ₈]⁴⁺ core and all the molecular orbitals involved in the calculated transitions of each cluster are very much alike. More interestingly, the UV-Vis transitions are tuned and displaced to higher wavelength by the mixture of Mo and W atoms. Furthermore, our calculations and the electronic similarities with previously reported clusters, suggest that the clusters family [Mo_6-nW_nCl₈F₆] ^2- might show similar properties to those previously reported.