Reversibly Tunable Lower Critical Solution Temperature Behavior Induced by H-Bonded Aromatic Amide Macrocycle and Imidazolium Host-Guest Complexation.

A new supramolecular host-guest motif comprising an H-bonded aromatic amide macrocycle and imidazolium cation based ionic liquids was developed, which allows tunable binding affinity via altering N-substitution or counterions. This host-guest system exhibits lower critical solution temperature behavior that can be precisely controlled by adjusting concentration, competitive guest, and acid/base. The demonstrated separation of two organic dyes with the supramolecular complex holds promising applications in separation science.