In this study, DFT(density functional theory) and TD-TDFT(time-dependent functional theory) calculations were employed to investigate the geometries, electronic structures, reorganization energy and photo-chemical properties of six cyclometalated Pt(II) complexes with tetra-dentate asymmetric ligands. The platinum complexes have the general structure [Pt(CzPy^O^ppz)] and [Pt(CzPy^O^pIz)], where a tetradentate cyclometalating ligand is consisting of CzPy (carbazolylpyridine), ppz (3,5-dimethyl-1-phenyl-pyrazole), pIz(3-methyl-1-phenyl-imidazole) components, and an oxygen bridging group. And Pt(II) complexes with several tetra-dentate ligands derivative form linked cyclohexyl and adamantly substituents. The geometric structures of the complexes in the ground and excited states were explored at the B3LYP and UB3LYP levels, respectively. The absorption and emission spectra of the complexes in CH2Cl2 solutions were calculated by time-dependent density functional theory (TD-DFT) with the PCM solvent model.
According to the results, Electrochemical analysis indicates that reduction process occurs mainly on the electron-accepting pyridyl group, and the irreversible oxidation process is primarily localized on the metal-phenyl portions. The studies of their photo-physical properties indicate that the lowest excited state of the platinum complexes is a ligand-centered 3π−π* state with minor to signiﬁcant 1MLCT/3MLCT character and are strongly dependent on the nature of the electron accepting pyridyl moiety.