Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Develop methods of shuttling/switching the positions of mechanically interlocked components

- Rotaxanes have been designed and synthesized in which the shuttling process can be monitored by means of fluorescence spectroscopy. This allowed us to observe shuttling in individual molecules and in thin films of rotaxanes.

- To be able to study the structural and dynamic properties of molecular motors under actual working conditions in solution, we performed studies in which we employed (femtosecond) two-dimensional (2D) vibrational spectroscopy to probe the conformation and conformational heterogeneity of a rotaxane composed of a benzylic amide-based ring hydrogen-bonded onto a succinamide-based thread. Both the ring and the thread contain carbonyl groups, and by determining the coupling between the stretching modes of these groups from the 2D-IR spectrum, the solution conformation of the ring-thread system have been investigated.

From the diagonal peaks in the 2D spectrum, we found that the carbonyl stretching bands of the thread were inhomogeneously broadened, which suggested that there existed a distribution of ring-thread hydrogen-bond lengths. From the position of the cross peak, we found evidence that the hydrogen-bond strength and the coupling strength were correlated. The results demonstrated the feasibility of a time-resolved 2D-IR experiment in which the motion in a molecular device was followed on a subpicosecond time scale. Molecular dynamics calculations in this respect formed an important input for the analysis.

Reported by

University of Edinburgh
Forbes Chair of Organic Chemistry West Main's Road
EH9 3JJ Edinburgh
United Kingdom
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