From intermolecular forces, via crystal engineering, to mechanical flexibility in the organic solid-state

Abstract

To better understand the structural influence of competing hydrogen- and halogen-bond interactions, we have investigated the solid-state landscape of a family of amide-substituted pyridines, belonging to four series; (N-(pyridin-2-yl)benzamides (Bz), N-(pyridin-2-yl)picolinamides (2Pyr), N-(pyridin-2-yl)nicotinamides (3Pyr) and N-(pyridin-2-yl) isonicotinamides (4Pyr) functionalized with three different halogen atoms (chlorine, bromine and iodine). We analyzed crystal structures of these sixteen compounds and identified their primary intermolecular interactions. The calculated molecular electrostatic potential (MEP) of the halogen atoms increased in the order of chlorine< bromine