Theoretical investigation on the spectroscopic properties of cyclometallated iridium (III) complexes and the deprotonation influence on them in solution

Abstract

Electronic structures and spectroscopic properties of mixed-ligand cyclometallated iridium complexes with general formula [Ir(NˆC) 2 (NˆN)] + (NˆC = 2-phenylpyridine, NˆN = Hcmbpy = 4-carboxyl-4 -methyl-2, 2 -bipyridine, 1; H 2 dcbpy = 4, 4 -dicarboxyl-2, 2 -bipyridine, 2) were studied theoretically. The geometries of the complexes in ground and excited state were optimized at B3LYP and CIS levels, respectively. The absorption and emission of the complexes in CH 3 CN solutions were calculated by time-dependent density functional theory (TD-DFT) with the PCM solvent model. The calculated absorptions and emissions of the complexes are in good agreement with the measured results. The deprotonation influence on the electronic structure and the optical properties of 2 was also investigated. The results indicate that the deprotonation which occurs on the COOH groups influences the geometries of the complexes in ground and excited state slightly but leads to significant blue-shifts in low energy absorption and emission maximum.

Spin–orbit coupling analyses of phosphorescent processes in Ir(Zppy)3 (Z = NH2, NO2 and CN)

“…At these stationary geometries, the molecular orbitals were optimized using the MCSCF method 58 together with the stateaveraging technique. The MCSCF active space includes six electrons and six orbitals, three of the orbitals mainly having an Ir d character and the remaining three orbitals having ligands' p character (principally anti-bonding) [MCSCF(6e, 6)]. The electronic density was averaged among the lowest ten singlet and nine triplet states during MCSCF iterations.…”

Theoretical Studies on the Electronic Structures and Spectral Properties of Two Iridium(III) Complexes with Tetraphenylimidodiphosphinate Ligand

“…In recent years, phosphorescent heavy metal complexes are of great interest to researchers as electrophosphorescent materials to fabricate highly efficient organic light-emitting devices (OLEDs) [1][2][3]. Recently, researchers have paid extensively attention to the phosphorescent transition-metal iridium(III) complexes because of their high thermal stability, short lifetime in excited states, and strong spin-orbit coupling effect of heavy metal [4][5][6]. In order to investigate the structure-property relationships and improve the design of OLEDs, we theoretically investigated the electronic structure, absorption and emission properties of two iridium(III) complexes using density functional theory (DFT) and time-dependent density functional theory (TDDFT).…”