Synthesis, optical and electrochemical properties of arylenevinylene‐based π‐conjugated polymers with imidazolium units in the main chain
Synthesis, optical and electrochemical properties of arylenevinylene‐based π‐conjugated polymers with imidazolium units in the main chain
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DOI：
10.1002/pola.24618
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发表时间：
2011-04
期刊：
影响因子：
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通讯作者：
Masaya Toba;T. Nakashima;T. Kawai
中科院分区：
文献类型：
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作者：
Masaya Toba;T. Nakashima;T. Kawai
合成了主链含咪唑阳离子单元的芳撑乙烯基π共轭聚合物及其模型化合物，并对其光学和电化学性质进行了表征。引入9，9-双辛基芴、2，5-双十二烷氧基苯和3-十二烷基噻吩作为具有不同给体特征的亚芳基单元，以评估对最高占据分子轨道-最低未占分子轨道（HOMO-LUMO）带隙能的影响。阳离子聚合物和模型化合物的紫外-维斯光谱和荧光光谱与母体中性分子相比均发生了明显的蓝移。X-射线单晶分析表明，阳离子模型化合物的有效π共轭长度较中性模型化合物减小，这是由于咪唑鎓的N-甲基与相邻芳基单元之间的CH-π相互作用导致的扭曲构象.循环伏安测试表明，咪唑转化为咪唑鎓时，LUMO能级负移，表明咪唑鎓阳离子单元具有吸电子特性。
Arylenevinylene-based π-conjugated polymers containing imidazolium cationic units in the main chain and their model compounds were synthesized and characterized in terms of optical and electrochemical properties. 9,9-Bisoctylfluorene, 2,5-bisdodecyloxybenzene, and 3-dodecylthiophene were introduced as arylene units with different donor characteristics to evaluate the effect on the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap energy. The UV―vis and fluorescence spectra of cationic polymers and model compounds with iodide counter anion exhibited a significant blue shift with respect to the parent neutral molecules. X-ray single crystal analysis for model compounds revealed that the effective π-conjugation length of cationic model compounds decreased compared to the neutral model compounds by means of twisted conformation directed by CH-π interactions between N-methyl groups of imidazolium and neighboring aryl units. The cyclic voltammetry measurement suggested the negative shift of LUMO levels by the conversion of imidazole to imidazolium, indicating the electron-accepting characteristics of cationic imidazolium unit.