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

• Applicant: Dr. Daniel Trawny
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2014 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 260166975

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.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Privatdozent Dr. Jason J. Davis