Investigation of Redox Dependent Host-Guest Interactions Using Redox Switching AFM-Based Single-Molecule Force Spectroscopy and the Development of a Single-Molecular Switch

近十年来，单分子力谱（SMFS）技术在定量研究分子间相互作用方面具有重要意义。二茂铁/环糊精系统以及葫芦烷/紫胶系统是研究分子相互作用的理想选择，但迄今为止还没有对主-客体系统的氧化还原开关SMFS实验进行描述。这个跨学科的研究计划将利用SMFS研究氧化还原依赖的解离过程。我们将探索所需化合物的合成和即将进行的原子力显微镜研究，并为分子机器和开关的开发提供可能性。这项工作的基本目标是在真正的单分子尺度上对可切换的超分子相互作用进行定量分析。在这种空间分辨率下对这种开关的分析与“分子机器”和响应开关的开发和利用高度相关。除了所需组分的合成外，还需要进行大量的SMFS实验。因此，必须改变一些参数，如负载率、表面覆盖率和化学环境（添加剂、溶剂），以便详细了解超分子相互作用。在SMFS实验中，将使用循环伏安法研究主-客体相互作用作为二茂铁氧化的函数。因此，破裂力会发生变化，这种结合会发生戏剧性的改变，也就是说，可以产生可逆的单分子开关。

In the last decade, single-molecule force spectroscopy (SMFS) techniques have increased in significance in order to quantify molecular interaction of single molecules. The ferrocene / cyclodextrin system as well as the cucurbiturile / viologen system is ideally suited to investigate molecular interactions but hitherto no redox-switching SMFS experiments with host-guest systems have been described.This interdisciplinary research proposal will investigate the redox-dependent dissociation process using SMFS. Both, the synthesis of the required compounds and the upcoming AFM studies will be explored and offer the possibility for the development of molecular machines and switches. The fundamental objective of this work consists of the quantitative analysis of switchable supramolecular interactions at truly single molecular scale. An analysis of this switching at this spatial resolution is highly relevant to the development and utilisation of "molecular machines" and responsive switches. Besides the synthesis of the required components it is necessary to perform numerous SMFS experiments. Therefore several parameters have to be varied such as loading rates, surface coverages and chemical environment (additives, solvents) in order to get a detailed insight into the supramolecular interactions. In particular experiments will be performed whereupon the host-guest interactions will be examined as a function of ferrocene oxidation using cyclic voltammetry during the SMFS experiments. As a consequent the rupture force changes and the association will dramatically switch, i.e. a reversible single-molecular switch can be created.