Nano-Electro-Chemistry Group, Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086 CNRS, Paris, France.
J Am Chem Soc. 2012 Mar 28;134(12):5476-9. doi: 10.1021/ja300224c. Epub 2012 Mar 13.
This work describes the formation of a mixed organic layer covalently attached to a carbon electrode. The strategy adopted is based on two successive electrochemical reductions of diazonium salts. First, bithiophene phenyl (BTB) diazonium salt is reduced using host/guest complexation in a water/cyclodextrin (β-CD) solution. The resulting layer consists of grafted BTB oligomers and cyclodextrin that can be removed from the surface. The electrochemical response of several outer-sphere redox probes on such BTB/CD electrodes is close to that of a diode, thanks to the easily p-dopable oligo(BTB) moieties. When CD is removed from the surface, pinholes are created and this diode like behavior is lost. Following this, nitrophenyl (NP) diazonium is reduced to graft a second component. Electrochemical study shows that upon grafting NP insulating moieties, the diode-like behavior of the layer is restored which demonstrates that NP is grafted predominately in the empty spaces generated by β-CD desorption. As a result, a mixed BTB/NP organic layer covalently attached to a carbon electrode is obtained using a stepwise electrochemical reduction of two diazonium compounds.
这项工作描述了一种通过共价键将混合有机层附着在碳电极上的方法。所采用的策略基于两个相继的电化学还原反应。首先，在水/环糊精（β-CD）溶液中，通过主体/客体络合作用还原联噻吩苯（BTB）重氮盐。所得的层由接枝的 BTB 低聚物和环糊精组成，它们可以从表面去除。在这样的 BTB/CD 电极上，几种外层氧化还原探针的电化学响应类似于二极管，这要归功于易于 p 掺杂的寡聚（BTB）部分。当 CD 从表面去除时，会产生微孔，这种类似二极管的行为就会丢失。随后，将硝基苯（NP）重氮盐还原以接枝第二个组件。电化学研究表明，当接枝 NP 绝缘部分时，层的类似二极管的行为得以恢复，这表明 NP 主要接枝在β-CD 解吸产生的空穴中。因此，通过两步电化学还原两种重氮化合物，获得了共价键合在碳电极上的混合 BTB/NP 有机层。
