Regioregular, head-to-tail coupled poly(3-alkylthiophenes) made easy by the GRIM method: Investigation of the reaction and the origin of regioselectivity
Regioregular, head-to-tail coupled poly(3-alkylthiophenes) made easy by the GRIM method: Investigation of the reaction and the origin of regioselectivity
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DOI：
10.1021/ma001677
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发表时间：
2001-06-19
期刊：
影响因子：
5.5
通讯作者：
McCullough, RD
中科院分区：
文献类型：
--
作者：
Loewe, RS;Ewbank, PC;McCullough, RD
研究了一种利用镁-卤素交换（格氏分解）合成区域规则、首尾耦合聚（3-烷基噻吩）的新合成方法——GRIM法。用各种烷基和乙烯基格氏试剂处理2,5-二溴-3-烷基基噻吩，得到两个金属化的区域化学异构体，即2-溴-3-烷基-5-溴镁基噻吩和2-溴镁基-3-烷基-5-溴基噻吩，比例为85:15。这个比率似乎与反应时间、温度和所用的格氏试剂无关。将催化量的Ni(dppp)Cl-2引入到这种异构体混合物中，得到的聚（3-烷基噻吩）含有95%以上的KT-HT偶联（通常看到98%的HT偶联）。在聚合物中发现的高度区域规则性可以用催化反应中发现的空间和电子效应引起的动力学和热力学效应的结合来解释。通过一系列的反应研究，对聚噻吩聚合反应中区域规则性的起源有了一般性的解释。这些反应包括动力学研究和竞争实验。
An investigation of the new synthetic method to synthesize regioregular, head-to-tail coupled poly(3-alkylthiophenes)using magnesium-halogen exchange (Grignard metathesis) called the GRIM method is described. Treatment of 2,5-dibromo-3-alkylthiophenes with a variety of alkyl and vinyl Grignard reagents resulted in two metalated, regiochemical isomers, namely, 2-bromo-3-alkyl-5-bromomagnesiothiophene and 2-bromomagnesio-3-alkyl-5-bromothiophene in an 85:15 ratio. This ratio appears to be independent of reaction time, temperature, and Grignard reagent employed. Introduction of a catalytic amount of Ni(dppp)Cl-2 to this isomeric mixture afforded poly(3-alkylthiophene) that contained greater than 95% KT-HT couplings (typically 98% HT couplings were seen). The high degree of regioregularity found in the polymer can be explained by a combination of kinetic and thermodynamic effects arising from steric and electronic effects found in the catalytic reaction. A series of reaction investigations led to a general explanation of the origin of regioregularity in polythiophene polymerization reactions. These reactions included kinetic studies and competition experiments.