Deep Blue Phosphorescence of the Iridium(III) Complexes ContainingN-Heterocyclic Carbene Ligands
摘要:
Previously, the iridium complexes containing N-Heterocyclic carbene (NHC) ligands have caught attention because of their phosphorescence for organic light-emitting diodes (OLEDs). It was reported that the use of strong-field ligands such as carbenes should result in an increase of the blue phosphorescent efficiency of their metal complexes. In this study, the new NHC ligands, 1-(4-fluorophenyl)-3-methyl benzimidazolate (fpmb) and 1-naphthyl-3-methyl benzimidazolate (nmb), were introduced to the iridium complexes to develop phosphorescent dyes for OLED.We investigated photoabsorption and photoluminescence (PL) properties of the iridium complexes and studied their bandgaps with cyclic voltammetry (CV). Deep blue and green phosphorescence was observed with these complexes, and the bandgaps between their highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) were correlated with CV data. We also studied the electroluminescence (EL) properties of the new iridium complexes as possible phosphors for the application to OLED.
<i>N</i>,<i>O</i>-Bidentate ligand-tunable copper(<scp>ii</scp>) complexes as a catalyst for Chan–Lam coupling reactions of arylboronic acids with 1<i>H</i>-imidazole derivatives
作者:Xuefeng Jia、Pai Peng
DOI:10.1039/c8ob02254b
日期:——
An efficient procedure for Chan–Lam coupling reactions of arylboronic acids with 1H-imidazole derivatives using N,O-bidentate ligand-tunable copper(II) complexes as a catalyst under base-free conditions has been developed. This protocol features mild reaction conditions, high yields and compatibility with different functional groups, providing a direct and facile strategy for the construction of C–N
Domino <i>N</i>-/<i>C</i>- or <i>N</i>-/<i>N</i>-/<i>C</i>-arylation of imidazoles to yield polyaryl imidazolium salts <i>via</i> atom-economical use of diaryliodonium salts
作者:Shiqing Li、Hongxu Lv、Yu Yu、Xiuqing Ye、Baisong Li、Songming Yang、Yanru Mo、Xiangfei Kong
DOI:10.1039/c9cc05237b
日期:——
Herein, we disclose a Cu-mediated domino di-/triarylation reaction of imidazoles to efficiently access polyaryl imidazolium salts in a single step by using two aryls as well as an anion of a diaryliodonium salt. The diarylation shows high atom economy and excellent selectivity with unsymmetrical iodonium salts.
A class of cationicdiphosphaneligands combining phosphane and amidiniophosphane moieties is illustrated on the N-methyl,N-naphthylbenzimidazolium framework. The palladium(II) complexthereof is described and compared to the corresponding complex of the analogous neutral diphosphane. Contrary to first-level expectations, the N2C–P and N2CP–Pd bonds in the cationicdiphosphanecomplex are not longer
Atropochiral NHC-phosphonium ylides based on the naphthyl-benzimidazolyl core are targeted as strongly σ-donor C,C-chelating ligands of transition metals. The ligand core is shown to act in either a monodentate (through the carbene center) or bidentate (through the carbene and the ylide centers) fashion in seven palladium(II) complexes obtained by two sequential strategies. In particular, the enantiomerically
heterocycles by selective deprotonation and quenching with chlorophosphines. The novel ligands are easily tunable and show good to excellent performance in palladium-catalyzed Suzuki reactions and Buchwald–Hartwig aminations of aryl and heteroaryl chlorides.