Substituent effect in unsymmetrical lutetium bisphthalocyanines: a DFT analysis

DFT calculations have been carried out on a series of unsymmetrical bisphthalocyanine lutetium complexes in which one of the ligands is substituted by 8 or 16 chlorine atoms. It is shown that their unpaired electron is predominantly localized on the non-substituted ligand. An orbital explanation is provided to rationalize this effect. A good agreement is found between the computed and experimental ionization potentials and electroaffinities and the redox potentials of a closely related series, as well as between their TDDFT-computed and experimental UV-visible transitions which are analysed.