Theoretical study on electronic structures, spectra, and charge transporting properties of two Pt(II) complexes with triazenido ligands

Abstract

Two compounds 1-[(2-carboxymethyl)benzene]-3-[2-pyridine]triazene (HL) and 1-[(2-carboxymethyl) benzene]-3-[o-aminobenzoic acid]triazene (H₂L') and two corresponding Pt(II) complexes, Pt(PPh₃)₂(L)Cl (1) and Pt(PPh₃)₂(L') (2), are theoretically studied by the density functional theory and time-dependent density functional theory. The geometric structure of complex 1 is optimized by B3LYP, PBE0, and M06 methods with the same mixed 6-31G(d)-LANL2DZ basis set. The absorption spectrum of complex 1 is simulated by the above method. As compared with the experimental data, the combination of M06/6-31G(d)-LANL2DZ and TD-M06/6-31G(d)-LANL2DZ is chosen for all other calculations including optimization of the ground-state and the lowest triplet excited state geometries, and the absorption and emission spectra. The detailed electronic transitions are analyzed to understand deeply the properties of spectra. Mobility of holes and electrons in 2 are studied computationally based on the Marcus theory. The ionization potential and electron affinity of complex 2 are calculated to evaluate qualitatively the hole- and electron-injection properties, respectively. Its potential as a dopant for phosphorescent OLEDs is explored.