Mechanochemistry of small synthetic molecules by single-molecule techniques

Abstract:

Inspired by the great diversity and efficiency of functional biomolecules, chemists have pursuit the design of wholly synthetic molecular systems able to produce a useful work or to perform a specific task. Using atomic force microscopy (AFM)-based single-molecule force spectroscopy (SMFS), we investigate the mechanochemical properties of synthetic small molecules, i.e. we describe the relationship between the work of a single molecule and the chemical interactions supporting its conformation. The force spectroscopy experiments consist in trapping an individual molecule between a small AFM tip and a substrate and stretch it following a ramp of force. These experiments allow the observation of the molecule’s response under mechanical stress and can evidence characteristic processes as well as unprecedented insights into the behavior of functional synthetic molecules.

Here we present recent AFM-based single-molecule force spectroscopy investigations on synthetic small molecules, and further discuss on ongoing research in our group. We will first focus on the mechanical stretching of mechanically interlocked molecules in solution, such as rotaxanes, catenanes and molecular knots. Recently, we evidenced remarkable force performances and fast dynamics of such artificial molecules compared to their natural analogs.

Additionally, we will present single-interaction experiments. These experiments were essential in quantifying and modulating the mechanical strength of different noncovalent π-π interactions in solution, opening the way for the study of many other chemical interactions.

Short bio: 

Damien obtained his Ph.D. in 2017 at the University of Liege, under the supervision of Prof. Anne-Sophie Duwez. He then moved to Northwestern University as a Belgian American Educational Foundation (B.A.E.F.) fellow. He worked in the group of Prof. Fraser Stoddart focusing on the design and the single-molecule characterization of artificial molecular machines. In 2018, Damien obtained a “Chargé de Recherches” position (FNRS) to pursue his career in Liège, where he now holds a Lecturer position. His work focuses on the use of single-molecule techniques — AFM and Optical Tweezers— for the investigation of chemical interactions and synthetic molecular systems.

Damien is a fellow of the Foresight Institute (Class of 2018). He also received the Antonella Karlson prize (2019, FNRS) and the F. Swarts Prize (Royal Academy of Sciences and Art, 2021).