Progress on ligands effects in porphyrin-based molecules in benzene solvent for photodynamic therapy applications

Density Functional Theory (DFT) calculations are carried out to investigate the ligands effects on porphyrin-based molecule in benzene solvent environment. Benzene solvent is modeled by PCM Tomasi. We are motivated to study the alternation of electronic and geometric structure of porphyrin-based molecule in the presence of ligands for achieving theoretical explanation about ligand porphyrin-based behaviours. We aim to investigate the ligands effect on the groundstate electronic structure of porphyrin-based molecules. This investigation will lead us in better understanding on characteristic of porphyrin-based molecule as photosensitizer in benzene solvent environment. We perform the electronic structure calculation of ZnP, ZnTPP, ZnTBP, H₂TPP and H₂TBP in the ground state. The results show that ligands distortion induces the point group symmetry of ZnTBP, ZnTPP, H₂TBP and H₂TPP belong to the trivial point group (C₁) in benzene environment. Tetrabenzo ligand distortions significantly change the Zn-N bond of ZnP. The energy difference between HOMO and HOMO-1 is increasing in the present of ligand. We also report that benzene solvent has only significant contribution to the alternation of E_Δ of porphyrin-based molecules.