Synthesis of novel twisted carbazole–quinoxaline derivatives with 1,3,5-benzene core: bipolar molecules as hosts for phosphorescent OLEDs
摘要:
A series of carbazole/quinoxaline hybrids have been synthesized by classic Ullmann and Pd/Cu-catalyzed Sonogashira coupling reaction. Their photophysical, thermal, and electrochemical properties were investigated. The introduction of electron rich carbazole and electron deficient quinoxaline on to the 1,3,5-benzene center leads to twisted structure with good glass forming property and imparts bipolar character. The triplet energies in the range of 2.34-2.53 eV indicate them as potential host materials in phosphorescent OLEDs. (C) 2011 Elsevier Ltd. All rights reserved.
Synthesis and Photophysical Properties of Carbazole-Based Blue Light-Emitting Dendrimers
作者:Ravi M. Adhikari、Rajib Mondal、Bipin K. Shah、Douglas C. Neckers
DOI:10.1021/jo0703911
日期:2007.6.1
A new class of highly fluorescent and stable carbazole-based dendrimers (1−5) that contain the ethynylbenzene and diethynylbenzene cores has been synthesized and characterized. They show very high extinction coefficients of absorption (Amax ≈ 328−353 nm) and high quantum yields of fluorescence (λmax ≈ 386−437 nm; ΦF ≈ 0.72−0.89; τF ≈ 2.09−3.91 ns) in dichloromethane. The quantum yields of fluorescence
Visible-Light Copper Nanocluster Catalysis for the C–N Coupling of Aryl Chlorides at Room Temperature
作者:Arunachalam Sagadevan、Atanu Ghosh、Partha Maity、Omar F. Mohammed、Osman M. Bakr、Magnus Rueping
DOI:10.1021/jacs.2c02218
日期:2022.7.13
bond-forming reactions of aryl chlorides under visible-light irradiation at room temperature. A range of N-heterocyclic nucleophiles and electronically and sterically diverse aryl/hetero chlorides react in this new Cu61NC-catalyzed process to afford the C–Ncoupling products in good yields. Mechanistic studies indicate that a single-electron-transfer (SET) process between the photoexcited Cu61NC complex and aryl
在交叉偶联反应中活化芳基氯是有机合成中长期存在的挑战,工业界对此非常感兴趣。超小(<3 nm)、原子级精确的纳米团簇(NCs)由于其高表面积和不饱和的活性位点而被认为是最有前途的催化剂之一。在此,我们介绍了一种基于铜纳米团簇的催化剂 [Cu 61 (S t Bu) 26 S 6 Cl 6 H 14 ] (Cu 61 NC),它能够在可见光照射下使芳基氯化物发生 C-N 键形成反应。室内温度。范围为N-杂环亲核试剂和电子和空间上不同的芳基/杂氯化物在这种新的 Cu 61 NC 催化过程中反应,以良好的收率提供 C-N 偶联产物。机理研究表明,光激发的 Cu 61 NC 配合物和芳基卤化物之间的单电子转移 (SET) 过程能够实现 C-N-芳基化反应。
Site-Selective N-Arylation of Carbazoles with Halogenated Fluorobenzenes
作者:Ning Liu、Bin Dai、Lei Wang、Enhui Ji
DOI:10.1055/s-0035-1560386
日期:——
A method for the highly site-selective C-N bond-formation reaction of halogenated fluorobenzenes with carbazoles is described. The selectivity of iodine and fluorine atoms on the aromatic ring of fluorinated iodobenzenes was initially determined with a copper-N,N-diisopropylethylamine catalytic system. By changing the position of the iodine atom on the aromatic ring from the 3- or 4-position to the 2-position, the preferred coupling site was switched from the iodine atom to the fluorine atom. Steric hindrance of the fluorinated iodobenzenes is responsible for the selectivity switch. After elucidating the reaction mechanisms of these reaction processes, a metal-free method for the highly site-selective C-N bond-formation reaction of halogenated fluorobenzenes with carbazoles was revealed through C-F bond activation. The metal-free system is able to handle a range of halogenated groups. Thus, a broad range of chlorinated, brominated, and iodinated N-arylated carbazoles were generated, which are widely useful in organic chemistry.