Structure and interactions in benzamide molecular crystals

Abstract

In this study, we resolved discrepancies concerning the experimentally determined structure of benzamide molecular crystals from dispersion-corrected density functional calculations. A clear energy ranking was obtained for the two candidates of the stable (P1) modification of benzamide. This was rationalised by subtle differences of the molecular interactions in the molecular crystal. The potential energy of the different structures was dominated by the interplay of intermolecular attraction and molecular torsion/deformation to accommodate favourable hydrogen-bonded networks. Using suitable proxies arranged in pseudo-crystalline set-ups, we discriminated the contribution of electrostatics, π–π interactions and intra-molecular interactions to the lattice energies.

Keywords::

• crystal structure
• density-functional theory calculations
• molecular interactions
• polymorphism