Light-controlled switchable complexation by a non-photoresponsive hydrogen-bonded amide macrocycle

A new photoswitchable host-guest system based on a non-photoresponsive hydrogen-bonded (H-bonded) amide macrocycle and pyridinium salts was developed. The host was found to be capable of forming stable complexes with the analyzed protonated pyridine derivatives. Particularly, the guest capture and release process could be reversibly controlled to a greater extent via proton transfer by light stimulus with protonated merocyanine 1-MEH. The present study offers a rare example of photo-responsive 2D shape-persistent H-bonded macrocyclic host-guest system, which may find applications in constructing interlocked molecular architecture.