Synthesis, Characterization, Properties and DFT Calculations of 2-(Benzo[b]thiophen-2-yl)pyridine-based Iridium(III) Complexes with Different Ancillary Ligands

Abstract

A series of new cyclometalated btp-based iridium(III) complexes with three different ancillary ligands, Ir(btp)2(bozp) (3a), Ir(btp)2(btzp) (3b) and Ir(btp)2(izp) (3c) (btp = 2-(benzo[b]thiophen-2-yl)pyridine, bozp =2-(benzo[d]oxazol-2-yl)phenol, btzp =2-(benzo[d]thiazol-2-yl)phenol, izp = 2-(2 H-indazol-2-yl)phenol), have been synthesized and fully characterized. The crystal structure of 3b has been determined by single crystal X-ray diffraction analysis. A comparative study has been carried out for complexes 3a - 3c by UV-vis absorption spectroscopy, photoluminescence spectroscopy, cyclic voltammetry and DFT calculations. This observation illustrates that the substitution of N or S in ancillary ligand can lead to a marked bathochromic shift of absorption and emission wavelengths. The spectroscopic characterisation of these complexes has been complemented by DFT and TD-DFT calculations, supporting the assignment of (3)MLCT/(3)LC to the lowest energy excited state.

Solvatochromism and Theoretical Studies of Dicyanobis(phenylpyridine)iridium(III) Complex Using Density Functional Theory

“…More precisely, Becke's three-parameter functional and the Lee-Yang-Parr functional (B3LYP) have been used throughout. In all calculations, an extensive basis set was used, consisting of 6-311G** [11][12][13][14] on all atoms (C, H, N, O) apart from iridium, which was described using a Stuttgart-Dresden pseudo-potential [15][16][17][18]. Besides, bulk solvent effects were treated via the polarizable continuum model (PCM) [19][20][21][22].…”

Synthesis and Performance in OLEDs of Selenium-Containing Phosphorescent Emitters with Red Emission Color Deeper Than the Corresponding NTSC Standard

“…In contrast to widely used 2-(2-thenyl)­pyridine derivatives as ligands in the preparation of Ir­(III) complexes for phosphorescent organic light-emitting diodes (PHOLEDs), − only two recent examples have been reported on the application of selenium-containing ligands in the synthesis of Ir­(III) complexes. , Both research groups claim that the introduction of selenium is a extremely promising research direction in terms of development of deep red PHOLEDs. Red phosphorescent emitters allow obtaining high device efficiency due to the theoretically possible 100% internal quantum efficiency, the long lifetime of PHOLEDs due to the low triplet energies of red emitters, high color purity with Commission Internationale de l’Eclairage (CIE 1931) chromaticity coordinates ( x , y ) close to the National Television System Committee (NTSC) red color standard of (0.67, 0.33), etc. − Novel deep red phosphorescence emitters may have effects not only on the development of PHOLEDs with broader CIE 1931 chromaticity coordinates in comparison to red color standards but also on the development of white OLEDs the with improved color rendering index (CRI) required for good color reproduction.…”