Photoisomerization in Cyclic Dipeptide Derivatives: Photoswitchable Supramolecular Hydrogels and the Discovery of Hemipiperazine Photoswitches

Cyclic dipeptides (CDPs) are ubiquitous biological motifs and pharmacophores. Through their defined structure and rich hydrogen bonding network they are prone to forming a large variety of supramolecular systems in aqueous environment. The merger of CDPs with molecular photoswitches, described here, enables photocontrol over bioactivity, as well as the self-assembly and macroscopic properties. Such systems can find broad range of applications, from smart photoresponsive materials to photopharmacology and precise control of complex biological systems. In particular, we demonstrate here two concepts—CDP-based photoswitchable hydrogels, and our journey towards discovery of a novel CDP-derived photoswitchable motif—hemipiperazine—which complements established photoswitches in terms of biocompatibility and visible-light triggering.