Halogen bonding synthon crossover in conformational polymorphism

Abstract

Two concomitant conformational polymorphs of N-(3-bromophenyl)-2-pyrazinecarboxamide have been discovered and characterized. The synthon crossover between Br⋯Br and Br⋯N “halogen bonding” on the formation of these polymorphs has been investigated by Hirshfeld surface analysis, halogen bonding interaction energy, lattice energy calculations and calorimetric analysis. From our results, it can be seen that different halogen bonding synthons, along with other intermolecular interactions, namely hydrogen bonding and π–π stacking interactions, result in the formation of different conformational polymorphs.