A theoretical study on the electronic structures and photophysical properties of phosphorescent Iridium(iii) complexes with –CH3/H and t-Bu substituents. Issue 31 (21st July 2016)

• Record Type: Journal Article
• Authors: Si, Yanling; Qu, Nan; Cui, Liying; Gao, Bo; Wu, Zhijian
• Is Part Of: Dalton transactions. Volume 45:Issue 31(2016)
• Page Start: 12587
• Page End: 12593
• Publication Date: 2016-07-21
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt02198k
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : We present the electronic structures, absorption and emission spectra of a series of Ir(iii ) complexes to shed light on the effect of different substituents on the photophysical properties. Abstract : The electronic structures and photophysical properties of the recently reported Ir(iii ) cyclometallated complexes containing the 2-(1-phenoxy-4-phenyl)-5-methylpyridine ligand (1 ) were studied via density functional theory and time-dependent density functional theory calculations. To improve the performance and establish the structural–photophysical property relationships, a series of Ir(iii ) complexes2–6 with –CH3 /H and t -Bu substituents have been designed according to the experimental complex1 . The calculated results demonstrate that the different substituted ligands not only modify the absorption and emission bands, but also enhance the phosphorescent quantum efficiency. The t -Bu substituent increases the energy levels of the LUMO for complexes4, 5 and6 and broadens the HOMO–LUMO energy gaps. When compared with1, the emission wavelengths for3 and6 are red-shifted considerably, while they are slightly blue-shifted for4 and5 . In particular, the –CH3 and t -Bu substituents in2, 4 and5 lead to a relatively high quantum yield. Therefore, the designed complexes2, 4 and5 with –CH3 / t -Bu substituents are expected to be promising phosphorescence emitters with high quantum efficiency.