Syntheses and electropolymerization of carboranyl-functionalized pyrroles and thiophenes
Syntheses and electropolymerization of carboranyl-functionalized pyrroles and thiophenes
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DOI：
10.1021/cm701935n
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发表时间：
2007-12-11
影响因子：
8.6
通讯作者：
Vicente, M. Graca H.
中科院分区：
文献类型：
--
作者：
Hao, Erhong;Fabre, Bruno;Vicente, M. Graca H.
通过吡咯硼酸和噻吩硼酸与碳硼烷基甲基苯基卤的偶联反应，或溴取代的吡咯与碳硼烷基甲基苯基硼酸的偶联反应，高产率地合成了一系列3-和3，4-取代的具有吸电子碳硼烷基甲基苯基的吡咯和噻吩.这些化合物中的一些在乙腈或二氯甲烷中有效地电聚合。在0.0-0.25 V（相对于Ag/A（+）10（-2）M）范围内对吡咯基聚合物进行了可逆p掺杂，在约100 V（相对于Ag/A（+）10（-2）M）范围内对吡咯基聚合物进行了p/n掺杂。0.60噻吩基聚合物为-1.90V。由于碳硼烷笼的存在，当施加高氧化电位（高达2.0 V）时，聚噻吩的电活性没有降低。相比之下，聚吡咯衍生物在类似条件下呈现完全电惰性。电生成聚合物的紫外-可见光谱分析表明，引入碳硼烷笼导致所得聚合物的平均共轭长度与参考苯基取代的聚吡咯和聚噻吩相比增强或稳定。此外，这些功能化材料在惰性气氛下，在高达500摄氏度的温度下，表现出不寻常的热稳定性，质量损失小于10%。
A series of 3- and 3,4-substituted pyrroles and thiophenes with electron-withdrawing carboranyl-methylphenyl groups has been synthesized in high yields via the coupling of either pyrrole- and thiopheneboronic acids with carborany1methylphenyl halides or brorno-functionalized pyrroles with carboranylmethylphenylboronic acid. Some of these compounds were efficiently electropolymerized in acetonitrile or dichloromethane. The resulting conducting polyrner films were reversibly p-doped in the range 0.0-0.25 V vs Ag/A(+) 10(-2) M for the pyrrole-based polymers and p-/n-doped at ca. 0.60 and -1.90 V for the thiophene-based polymers. As a consequence of the presence of the carborane cages, the electroactivity of the polythiophenes was not degraded when highly oxidizing potentials (up to 2.0 V) were applied. In contrast, the polypyrrole derivatives were rendered totally electroinactive under similar conditions. The UV-vis spectroscopy analysis of the electrogenerated polymers revealed that the introduction of carborane cages resulted in either an enhancement or a stabilization of the mean conjugation length of the resulting polymers in comparison with the reference phenyl-substituted polypyrrole and polythiophene. In addition, these functionalized materials show unusual thermal stability for conducting polymers with a mass loss less than 10% up to 500 degrees C, under an inert atmosphere.