紫精类化合物分子聚集体材料的界面组装

Interfacial Self-Assembly of Viologen-Functionalized Ultrathin Films and Molecular Aggregates

紫精类化合物具有良好的电化学活性,并且在发生氧化还原反应时伴有颜色的变化,在膜修饰电极、电致变色材料和分子器件的研制等方面受到广泛的关注。紫精中的烷基链非常易于进行化学修饰,因而比较适合于通过自下而上的分子自组装技术制备多功能的分子和纳米材料。本文综述了利用Langmuir-Blodgett法、自组装法和层层组装法制备紫精分子聚集体材料的研究进展,并讨论了分子聚集体薄膜中紫精的结构、电致变色、电化学氧化还原特性及其在研制超分子器件方面的应用。

Viologens are a group of electroactive organic electrolytes and generally change from colorless to blue or violet after the first reductive reaction, thus they have attracted much attention in the fields of chemically modified electrodes, electrochromic display and supramolecular devices. The alkyl substituents in the viologens are easily functionalized （oxosilane or thiol）, resulting in the as-prepared viologens suitable for potential candidates to construct well-defined thin films, multilayers or molecular aggregates by the bottom-up techniques, such as the Langmuir-Blodgett （LB） films, self-assembled monolayers （SAMs） and layer-by-layer （LBL） assembly. If the alkylated substituents contain a thiol or silane substituent, the viologens produced can form SAMs on the solid surfaces, while if they are long alkyl chains, the amphiphilic viologens can form stable insoluble monolayers at the air-water interface and be deposited on the substrate surfaces to form the LB films. The poly（viologen） derivatives can form LBL muhilayers with negatively charged polyelectrolytes or nanostructural materials including carbon nanotubes. This paper reviews recent developments in the design and assembly of viologen-functionalized supramolecular and nanoscale materials by the molecular assembling methods. The optical and electrochemical properties of viologens in the molecular assemblies are discussed together with their potential applications as electron mediators for the electron donors, light-harvesting units and proteins.