Salt-Dependent Switching of Crystal Packing in Cucurbituril-Antidepressant Crystals

Abstract

Across the CB[8]–imipramine and CB[6]–amitriptyline systems, addition of KI or ZnCl2 as salt additives can change packing topology, crystal stoichiometry, and channel architecture, while preserving the underlying CB[n]–guest–CB[n] recognition motif. Structural and interaction-energy analyses show that robust local recognition is retained, whereas weaker secondary interactions drive the differences in crystal packing.