Chung Emily, Shepherd Jeff L, Bizzotto Dan, Wolf Michael O
Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
Langmuir. 2004 Sep 14;20(19):8270-8. doi: 10.1021/la0485024.
The study of heterodentate molecules adsorbed on metal electrodes provides an opportunity to expand the functionality of modified surfaces while offering insights into the surface and intramolecular electronic interactions of organic adsorbates. The adsorption of 2-(2'-thienyl)pyridine, a molecule containing both pyridine and thiophene moieties, on a Au(111) electrode is reported. Adsorption was characterized by electrochemistry in neutral and basic aqueous electrolyte and was compared to that of pyridine. The aqueous electrochemistry of thiophene on Au(111) was also characterized for comparison purposes. At negative potentials, in the presence of 2-(2'-thienyl)pyridine, a diffuse, pi-bonded monolayer was formed, and a phase transition to a close-packed N- and/or S-bonded configuration was observed near -0.4 V in a 1 mM solution of adsorbate, similar to that seen in pyridine on Au(111). The thiophene-like oxidative dimerization of the molecule was confirmed at positive potentials using in situ fluorescence microscopy by comparison with the spectrum of the chemically synthesized dimer.
对吸附在金属电极上的异齿配体分子的研究，为扩展修饰表面的功能提供了契机，同时也有助于深入了解有机吸附质的表面及分子内电子相互作用。本文报道了2-(2'-噻吩基)吡啶（一种同时含有吡啶和噻吩部分的分子）在Au(111)电极上的吸附情况。通过在中性和碱性水性电解质中的电化学方法对吸附进行了表征，并与吡啶的吸附情况进行了比较。为作比较，还对噻吩在Au(111)上的水性电化学进行了表征。在负电位下，在2-(2'-噻吩基)吡啶存在的情况下，形成了一个扩散的π键合单层，并且在1 mM吸附质溶液中，在-0.4 V附近观察到向紧密堆积的N键合和/或S键合构型的相变，这与在Au(111)上的吡啶的情况类似。通过与化学合成二聚体的光谱进行比较，利用原位荧光显微镜在正电位下证实了该分子的类似噻吩的氧化二聚作用。
