The good description of the relative stabilities of the Al 3+ complexes included in Table is not straightforward, as it has been already reported for aqueous media and [Al(H 2 O) 6 ] 3+ species. The inclusion of explicit solvent molecules describing up to the second solvation sphere of the complex was revealed necessary to properly describe Al 3+ -water interactions. Specifically, the explicit description of hydrogen-bond nets that solvent molecules and ligands form in aque- ous or hydroalcoholic media seems necessary to successfully determine the corresponding pKa values of these Al 3+ complexes and to properly estimate their relative energies between protonated and deprotonated forms. However, for practical reasons, we have not considered additional explicit solvation spheres here and the solvent is just described using the PCM approach. Then, redox potentials of hydroquinones and DPPH• Al 3+ complexes that lie within a ∆G confidence interval of 10 kcal/mol are analyzed.