Theoretical analysis of the electronic properties in Zinc-porphyrins derivatives

Metallated porphyrin derivatives were synthesized and theoretically analysed in order to observe the effect of the Zn atom and the functional groups in the electronic properties. Porphyrins A4, trans-A2B2 and A3B bearing different chemical groups were theoretically analysed. For the geometry optimization was used the B3LYP hybrid functional in combination with the DZVP basis set, while for the calculation of the absorption spectra several functionals were applied (B3LYP, CAM-B3LYP, HSE06, LC-wPBE, M06-HF, M11, M06-2X and wB97XD) with DZVP basis set, using SMD as solvation model and chloroform as solvent. This analysis reveals that the HSE06/DZVP methodology exhibits the best approximation with the experimental data. The obtained results revealed that the inclusion of the Zn atom does not affect the geometrical structure; however, this atom may influence the electronic properties since the LUMOs orbitals are affected by the presence of the Zn atom. The charge transfer values were modified by the position of the functional group in the molecular structure since the reorganization energy is minor in A3B and A2B2 conformations.