Gelating-induced supramolecular chirality of achiral porphyrins: chiroptical switch between achiral molecules and chiral assemblies

Chiral low molecular weight organogelators which can gel nearly all kinds of common organic solvents were designed. The gelators could also form organogels with other functional compounds, which could not form the organogel themselves. Achiral porphyrins were employed as functional compounds to form the co-gel with the gelator in DMSO and interesting properties were found. Although no chirality was observed when the achiral porphyrin derivative containing a long alkyl chain was mixed with the gelator in hot DMSO solution, supramolecular chirality of the achiral porphyrin was induced when cooling to form an organogel. Based on the thermo- reversible property of the organogel, a thermo-driven supramolecular chiroptical switch was proposed through the switch between achiral molecule and chiral molecular assemblies.