电化学联用技术差分法研究二茂铁硫醇自组装膜氧化构型变化机制

摘要

采用电化学-表面等离子体激元共振技术和电化学-石英晶体微天平联用技术结合差分方法,研究11-二茂铁基十一烷基-1-硫醇自组装膜在氧化过程中的构型变化机制.研究结果表明:二茂铁硫醇自组装膜在氧化过程中同时发生了2种结构变化, 一是烷基链远离电极表面,即烷基链与电极表面的夹角增大；二是二茂铁上的2个平行的戊基环绕着二茂铁-碳轴发生旋转.伴随着结构变化,二茂铁硫醇自组装膜还发生2种溶剂化过程,一是氧化的二茂铁与溶液中的阴离子产生静电吸引而形成“离子对”；二是溶剂分子进入膜内形成水化膜.二茂铁硫醇氧化时烷基链的偏移和膜的溶剂化都是快速步骤,而戊基环的翻转是唯一的慢速步骤.%Conformational changes accompanying with the redox process of the ferrocenylundecanethiol SAMs were investigated by the electrochemical surface plasmon resonance (EC-SPR) and electrochemical quartz crystal microbalance (EQCM) with differential method. There are two mechanisms of conformational change for the redox of ferrocenylalkanethiol self-assembled monolayers (SAMs): the alkyl chain is away from the surface of the positive charged electrode and the angle between the gold electrode and the alkyl chain increases; the Fc group rotating from a tilted conformation to a position where the cyclopentyldiene rings (Cp) is more perpendicular to the electrode. The results demonstrate that both the migration of ferrocene mercaptan alkyl chain and the hydration of SAM are quick. The rotation of Cp is a slow process.