Supramolecular photochirogenesis

Supramolecular photochirogenesis is a rapidly growing interdisciplinary area of science at the boundary of photochemistry, asymmetric synthesis and supramolecular chemistry. The major advantage of supramolecular photochirogenesis over the conventional molecular one is entropic in origin, being achieved by preorganizing substrate(s) in the ground state and manipulating subsequent photochemical transformation by weak but non-transient interactions in chiral supramolecular media. The chirality transfer often becomes more efficient through the cooperative non-covalent interactions and the confinement by host in both ground and excited states. Thus, all of the ground- and excited-state events, including complexation stoichiometry and affinity, chiroptical properties, photophysical behaviour and photochemical reactivity, jointly play pivotal roles in supramolecular photochirogenesis. This may appear to cause complication but in reality expands the range of manipulable factors and available experimental/theoretical tools for elucidating the mechanism and controlling photochirogenic processes both thermodynamically and kinetically, from which some new concepts/methodologies unique to supramolecular photochemistry, such as non-sensitizing catalytic photochirogenesis and wavelength-controlled photochirogenesis, have already been developed. In this review, we will discuss the recent progress and future perspective of supramolecular photochirogenesis.