间甲基苯胺和邻甲基苯胺恒电位电化学聚合行为的比较研究  

Comparative Study on Electrocopolymerization of m-Toluidine and o-Toluidine

作　　者：张贵荣[1] 赵学如[1] 徐晓明[1] 何丽[1] 吴靓[1] 陆嘉星[1] 

机构地区：[1]华东师范大学化学系、上海市绿色化学与化学工程绿色化重点实验室,上海200062

出　　处：《化学学报》2012年第11期1271-1277,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.20973065;21173085);物理化学上海市重点学科(No.B409)资助项目~~

摘　　要：在0.5 mol·L-1H2SO4水溶液中,以ITO导电玻璃为工作电极,用原位紫外-可见光谱进行跟踪恒电位电聚合间甲基苯胺和邻甲基苯胺.结果表明邻甲基苯胺的电化学聚合要比间甲基苯胺快.在0.9 V(vs.饱和Ag/AgCl)恒电位电解时的电流-时间响应曲线表明聚间甲基苯胺和聚邻甲基苯胺在导电玻璃上的沉积方式是不同的,在电解初期两者均可能以时间累积成核方式沉积,但随着电解的进行,邻甲基苯胺电化学聚合发生支链化,而间甲基苯胺的电化学聚合反应却变慢.扫描电镜图表明聚邻甲基苯胺具有多孔颗粒状的表面形貌,而聚间甲基苯胺却具有致密的表面形貌.量子化学从头计算(6-31**/B3LYP)表明,半氧化态的间甲基苯胺四聚体发生了明显的卷曲而与此对应的邻甲基苯胺四聚体却没有明显的卷曲;这说明尽管聚邻甲基苯胺和聚间甲基苯胺在化学结构上是类似的,但它们的空间结构可能存在明显的不同,导致其聚合和在电极沉积的方式可能产生较大的差别.The in situ UV-Vis spectra of electropolymerization of m-toluidine and o-toluidine on indium tin oxide （ITO） conducting glass electrode by potentiostatic method in sulfuric acid of 0.5 moloL 1 show that the electropolymerization of o-toluidine is faster than that of m-toluidine under the same condition. The current transient curves of electrolyzing m-toluidine and o-toluidine at potential 0.9 V （vs saturated Ag/AgCl） indicate that both poly（m-toluidine） and poly（o-toluidine） are deposited on ITO electrode in three-dimensional progressive nucleation （3DPN） at the beginning of electropolymerization; then the electropolymerization of o-toluidine keeps in branch chain reaction and the electopolymerization of m-toluidine becomes slow greatly. Due to the difference of the electropolymerization of them, the scan electron microscope morphol- ogy of poly（o-toluidine） is granulous and porous and that of poly（m-toluidine） is compact and slightly smooth. DFT geometry optimization using B3LYP/6-31G＊＊ basis set for the tetramer of o-toluidine and m-toluidine demonstrates that the emeraldine base （EB） for tetramer of m-toluidine has curly structure but EB for tetramer of o-toluidine not, which implies that the conformation difference between poly（m-toluidine） and poly（o-toluidine） might be main cause of the difference of their electropolymerization.

关 键 词：邻甲基苯胺 间甲基苯胺 电化学共聚 紫外-可见光谱 

分 类 号：O633.2[理学—高分子化学]