Abstract A series of poly(alkyl thiophene-3-carboxylates), herein referred to as poly(3-alkylesterthiophenes) (P3ET) (P1-P6) with high head-to-tail (HT) coupled regioregularity up to ∼92% were synthesized by a direct C H coupling polymerization (DCHCP). The substitutions with various alkyl ester side-chains on the 3-position of the thiophene ring were performed by changing the length and size of alkyl groups, with a view to investigate the role of the alkyl ester side chain on DCHCP reaction as well as on the crystallinity, optical and electrochemical properties of these resultant polymers. It was found that the longer and bigger size alkyl ester side chains on 3-position of thiophene monomers, the higher HT regioregularity of the corresponding polymer products. X-ray diffraction (XRD) measurements manifested that all polymers (P1-P6) existed in not highly ordered state in solid films especially in the π-stacking direction. Red shift of the UV–Vis absorption maxima of the resultant polymers in the film state confirmed more effective electron delocalization along the polymer chain than that in solution state. Cyclic voltammetry (CV) study indicated that the introduction of 3-alkyl ester side chain on the thiophene ring lowered the products' highest occupied molecular orbital (HOMO) energy level and enhanced their electrochemical band gaps significantly in comparison with the corresponding HT regioregular poly(3-alkylthiophenes).

中文翻译：

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不对称单体的直接 CH 偶联聚合：区域规整聚（烷基噻吩-3-羧酸盐）的合成与性能

摘要 一系列聚（烷基噻吩-3-羧酸酯），本文称为聚（3-烷基酯噻吩）（P3ET）（P1-P6），具有高达 92% 的高头对尾（HT）耦合区域规整性。由直接 CH 偶联聚合 (DCHCP) 合成。通过改变烷基的长度和大小，在噻吩环的3-位上进行各种烷基酯侧链的取代，以研究烷基酯侧链在DCHCP反应中的作用以及这些所得聚合物的结晶度、光学和电化学性能。发现噻吩单体3-位上的烷基酯侧链越长和越大，相应聚合物产物的HT区域规整性越高。X 射线衍射 (XRD) 测量表明，所有聚合物 (P1-P6) 都以非高度有序的状态存在于固体薄膜中，尤其是在 π 堆积方向。所得聚合物在薄膜状态下的 UV-Vis 吸收最大值的红移证实了沿聚合物链的电子离域比在溶液状态下更有效。循环伏安法 (CV) 研究表明，与相应的 HT 区域规整聚 (HT) 相比，噻吩环上 3-烷基酯侧链的引入降低了产物的最高占据分子轨道 (HOMO) 能级并显着提高了其电化学带隙。 3-烷基噻吩）。所得聚合物在薄膜状态下的 UV-Vis 吸收最大值的红移证实了沿聚合物链的电子离域比在溶液状态下更有效。循环伏安法 (CV) 研究表明，与相应的 HT 区域规整聚 (HT) 相比，噻吩环上 3-烷基酯侧链的引入降低了产物的最高占据分子轨道 (HOMO) 能级并显着提高了其电化学带隙。 3-烷基噻吩）。所得聚合物在薄膜状态下的 UV-Vis 吸收最大值的红移证实了沿聚合物链的电子离域比在溶液状态下更有效。循环伏安法 (CV) 研究表明，与相应的 HT 区域规整聚 (HT) 相比，噻吩环上 3-烷基酯侧链的引入降低了产物的最高占据分子轨道 (HOMO) 能级并显着提高了其电化学带隙。 3-烷基噻吩）。