Structural effects of dibromocarbazoles on direct arylation polycondensation with 3,4-ethylenedioxythiophene
Structural effects of dibromocarbazoles on direct arylation polycondensation with 3,4-ethylenedioxythiophene
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DOI：
10.1039/c6py00381h
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发表时间：
2016-01-01
影响因子：
4.6
通讯作者：
Michinobu, Tsuyoshi
中科院分区：
文献类型：
--
作者：
Li, Wei;Michinobu, Tsuyoshi
C-H键与芳香卤化物的直接芳基化反应已被用作制备共轭聚合物的新型环境友好聚合方法。采用微波辅助无膦直接芳基化缩聚法合成了3，4-乙撑二氧噻吩（EDOT）与一系列二溴咔唑（Cbzs）的共聚物。与常规加热相比，微波加热显著缩短了反应时间。在优化条件下，成功合成了数均分子量（M-n）为5600、多分散指数（M-w/M-n）为1.9的可溶液加工的线型聚合物3，6-Cbz-EDOT。相反，具有不同取代模式的其它二溴咔唑单体，即，2，7-Cbz和1，8-Cbz分别由于发生不希望的交联和由空间位阻或不合适的催化剂引起的差的反应性而不能提供相应的可溶性线性聚合物。研究了3，6-Cbz-EDOT的电致变色性能。聚合物薄膜的颜色随电位的增加呈现两步变化。第一颜色变化是高度可逆的，着色和漂白过程的切换时间分别为3.2和2.0 s。
The direct arylation reaction of a C-H bond with aromatic halides has been employed as a novel environmentally-friendly polymerization method for producing conjugated polymers. In this article, 3,4-ethyle-nedioxythiophene (EDOT) was copolymerized with a series of dibromocarbazoles (Cbzs) by the phosphine-free and microwave-assisted direct arylation polycondensation. The microwave heating dramatically shortened the reaction time compared to conventional heating. Under optimal conditions, a solution processable linear polymer, 3,6-Cbz-EDOT, with the number-average molecular weight (M-n) of 5600 and polydispersity index (M-w/M-n) of 1.9 was successfully synthesized. In contrast, the other dibro-mocarbazole monomers with different substitution patterns, i.e., 2,7-Cbz and 1,8-Cbz, did not afford the corresponding soluble linear polymers due to the occurrence of undesired crosslinking and the poor reactivity caused by steric hindrance or unsuitable catalysts, respectively. The electrochromic properties of 3,6-Cbz-EDOT were investigated. The thin polymer film displayed two-step color changes with the increasing potentials. The first color change was highly reversible with the switching times of the coloring and bleaching processes being 3.2 and 2.0 s, respectively.