Evaluating structure-property relationship in a new family of mechanically flexible co-crystals.

A structure-property analysis of ten compositionally and chemically similar co-crystals of -(pyridin-2-yl)alkylamides and carboxylic acids shows that three co-crystals of targets bearing a methyl chain were brittle, while the remaining co-crystals of targets bearing ethyl or propyl chains were flexible. Five of these displayed elastic deformation while two displayed plastic deformation. Compounds with different mechanical behaviour (brittle, plastic, and elastic deformation) in response to external mechanical stimuli could be organized into structurally similar groups based on the presence of specific intermolecular interactions and packing features in each crystal structure.