Molecular machines are complex nanometric structures able to perform specific tasks at the nanoscale when driven out-of-equilibrium by various stimuli (light, electricity, chemical fuel, …). Biological molecular machines are present in every living organism where they perform a range of crucial tasks. These natural machines have evolved to achieve formidable efficiency, as demonstrated by the motor-protein ATP synthase, which seamlessly produces an average of 40 kg of ATP daily in each human being.
Inspired by Nature, chemists have been developing artificial molecular machines for the last three decades. The design, preparation and study of artificial molecular devices is now a very active research field in chemistry, which has recently witnessed tremendous advances. Stimuli-responsive (often chiroptical) molecular switches have been successfully used for the conception of fatigue-resistant bistable molecular devices. Among a myriad of reported examples, such switches have been used for information storage, as logic operators or as sensors, opening the way to numerous possible applications and new technologies. More advanced systems such as molecular motors providing a unidirectional and controlled rotational motion upon stimulation have been synthesized and integrated into higher order systems allowing to obtain macroscopic outputs from controlled motion at the molecular scale.
Current research on molecular motors can be broadly divided into three main areas. The first area focuses on developing applications, for instance by integrating molecular motors into higher-order structures and materials to render these materials stimuli responsive. The second area involves tuning the properties of existing motors to enhance control over their motion, including aspects such as speed and directionality. The third area aims to increase the functionality of these motors by generating more complex movements beyond simple rotation. This project primarily concentrates on advancing the third area of research, thus focusing on improving the functionality of synthetic light-powered molecular motors.
By developing molecular motors fused with helicene fragments aiming to control the handedness of the helicene moiety thanks to the actuation/rotation of the motor, and oppositely to control the rotation of molecular motors thanks to helicity. Even though the main contribution of this project was expected to concern the increase in functionality of molecular motors, new molecular motors and machines derivatives contributing to the two other objectives were also designed, prepared and studied during the course of this project.
