Theoretical studies on the structure and excited states of oxophosphorus triazatetrabenzcorrole

Abstract

The geometrical optimization of Oxophosphorus triazatetrabenzcorrole (POTBC) has been studied at Density Functional Theory (DFT) level using various basis sets. The results at Hartree–Fock (HF) level were used for comparison. The results calculated at the HF and B3LYP levels are very different. The geometry at B3LYP level has C s structure while at HF level it has no symmetry. The structure at the DFT level is reliable because DFT includes an electron correlation correction. The HOMO-1 of POTBC is separated from HOMO-2 by a large gap. As a result the excited states of POTBC can be interpreted by the Gouterman's four-orbital model. It has been proved by TDDFT calculations of the excited states of POTBC. It can be concluded that the structure of POTBC is similar to that of phthalocyanine (Pc), while its orbital energies are similar to porphyrin's