Light-driven ratcheted formation of diastereomeric host-guest systems

The ability to exploit an energy source to drive chemical reactions away from thermodynamic equilibrium is an essential feature of life and a grand challenge for the design of fuel-driven dynamic artificial nanosystems. Here, we investigate the effect of light irradiation on the formation of supramolecular complexes composed of azobenzene-type guests and a cyclodextrin (CD) host in water. Whereas previous studies on these complexes have focused on equilibrium properties, our work explores far-from-equilibrium distributions obtained by light-driven association. We demonstrate that the relative abundance of the two CD orientational diastereomeric complexes can be inverted upon photoirradiation and showcase a ratcheted approach, employing biocompatible macrocycles and harnessing visible light, to the spontaneous formation of high-energy CD complexes with broad applicability in aqueous environments. We foresee opportunities for the development of active materials, the design of artificial metabolic networks, and the engineering of molecular machines operating under physiological conditions.