Excited-State Distortions of Cyclometalated Ir(III) Complexes Determined from the Vibronic Structure in Luminescence Spectra

Abstract

The luminescence spectra of [(tpy) 2 Ir(CN-t-Bu) 2 ](CF 3 SO 3 ) in methylcyclohexane glass and frozen n-nonane at 15 K reveal well-resolved vibronic fine structure. The vibronic peaks are assigned by comparison with the vibrational frequencies obtained from Raman and IR spectra and those obtained using DFT electronic structure calculations. The magnitudes of the distortions along the normal coordinates are calculated by fitting the emission spectra using the time-dependent theory of spectroscopy. Broadening effects and the MIME frequency observed at room temperature are interpreted. The most highly distorted normal modes involve atomic motions on the tpy ligand, consistent with the metal to ligand/ligand centered assignment of the electronic transition.

Jaguar: A high‐performance quantum chemistry software program with strengths in life and materials sciences

“…The active layer materials and emitters are selected with close attention to their redox properties, triplet energies, and electronic structure. Molecular orbital calculations using Jaguar have been carried out for a variety of OLED materials including a highly emissive phosphine‐Cu 2 (μ‐NAr 2 ) 2 complex, mixed light‐emitting layer host materials, and various phosphorescent cyclometalated Ir(III) complexes …”

Phosphorescent Ir(iii) complexes bearing double benzyldiphenylphosphine cyclometalates; strategic synthesis, fundamental and integration for white OLED fabrication

“…The appearance of vibronic emission feature in 4 manifests its great pp* contribution for the lowest lying transition. 26 In stark contrast, such a vibronic feature is nearly diminished for 5 perhaps due to its large geometry distortion occurring at both ground and excited states. Support of this viewpoint has been provided in the X-ray structural analysis of 5 (vide supra) and in the section of theoretical approach (vide infra).…”

28.4: Invited Paper: Development of Tetradentate Pt Complexes for Efficient, Stable, and High Color Purity Blue OLEDs

“…As has been reported previously for many cyclometalated Ir and Pt complexes, phosphorescent emission originates from ligand centered ( 3 LC) triplet states with varying degrees of mixing from metal to ligand charge transfer states ( 1,3 MLCT) [11]. For blue emission, high energy ligands such as phenyl-pyrazole, phenyl-imidazole, or phenyl-imidazole carbene are employed as emissive ligands.…”