Insight into polymorphism in weakly polar systems using favorable connection motifs

Abstract

We explore the polymorphism of a weakly polar molecule, dibenzoylmethane, in which the intramolecular hydrogen-bonded enol “chelated” form is favoured. A simple geometric method on the basis of interatomic distance to visualize and count favourable connections between non-hydrogen atoms was constructed to judge the strength of intermolecular interactions in polymorphs of this kind of weakly polar molecule. The number of total favourable connections mirrored with resonance-assisted hydrogen bonds (RAHB) and aromatic interactions in DBM polymorphs increases from forms I to III, in agreement with the order of their equivalent interaction energies, proving that it is feasible for this geometric approach to be used in this weakly polar system.