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A Synthetic Molecule that can Walk down a Track!

Final Report Summary - MECHPROCMOLS (A Synthetic Molecule that can Walk down a Track!)

In this project, the synthesis and operation of an artificial molecular species - that could 'walk' along a molecular 'track' - was proposed. Synthetic efforts towards the components (molecular walking component and molecular-track component), in addition to characterization were to be undertaken. Attachment of the 'walker' component to the 'track' component would follow, resulting in the complete assembly of the target molecule. Once assembled, and successfully operated, these walker-track conjugates would be self-assembled on to surfaces such that their 'walking' progress could be monitored via AFM (atomic force microscopy).
During the first 12 months of the project significant strides were taken towards the targeted 'walker-track conjugate' design, however due to unforeseen difficulties in the assembly and purification of the final target, combined with decomposition issues of the related starting materials, a re-design of the desired targets was undertaken.
The re-design, involving a change of metal complexes in the walker component, would result in a walking sequence brought about by alternately switching between thermal and photochemical stimuli. Model studies were successfully undertaken to first elucidate the appropriate experimental conditions that would induce the photochemical switching of one "foot" without affecting the other one. Compartmental targets were identified and synthesized over a six month period, at which point designs for the final assembly of the 'walker' component to the 'track' component were finalized.
Attachment of the "walker" component to a portion of the "track" was successfully accomplished. The final month of the project was spent successfully assembling the two major components together to reach the final target product. Evaluation of the first 'stepping" motion of the 'molecular walker' were then undertaken. However, conditions previously simulated to model this 'first step' did not proceed as efficiently as expected and major fine-tuning of the walking conditions was required.
Once completed, the successful synthesis and operation (demonstration of sequential processivity in a synthetic molecular structure) using two different transition metals for the switching protocol will be a landmark accomplishment in nanotechnology, enabling a new direction for synthetic coordination chemistry and supramolecular chemistry to develop.
Applications may well then follow. Changing the properties of materials in response to stimuli is of relevance to numerous other technologies and applications including in the fields of: Medicine, Information Technology, Energy Production and Storage, as well as Security. This project has/will also contribute to research excellence in Europe by bringing together highly qualified researchers to participate in an interdisciplinary project, resulting in productive collaborations and the transnational exchange of researchers over the long term, which will serve to strengthen European research.