A New Model for Proposing Crystallization Mechanisms at the Molecular Level Based on Energetic and Topological Data of Supramolecular Interactions: An Application to Halogenated Anilines

In this work, a new model for proposing crystallization mechanisms at the molecular level was created, based mainly on theoretical energetic and topological data of intermolecular and supramolecular interactions. Initially, a supramolecular study was conducted on anilines substituted with halogens in the ortho or para positions. All of the compounds had a molecular coordination number equal to 14. In these structures, all the intermolecular interactions were checked and classified, and their robustness was evaluated in terms of energy using density functional theory and their contribution at each contact point using QTAIM theory. The substantial number of interactions considered weaker such as C–H···X, C–H···C, and N–H···C contribute more to stabilizing the cluster than the N–H···N interactions, considered stronger, which have a much smaller number of occurrences. In order to validate the energy data of the intermolecular interactions, lattice energy data (theoretical) and sublimation enthalpy data (experimental) were compared, which revealed an excellent correlation and a notable trend for most of the compounds. Finally, crystallization mechanisms were proposed, starting from the strongest interaction present in the first coordination sphere. Starting from the supramolecular chain (1D) formed, hypotheses were created to approximate these structures in order to determine which one brings greater stability to the system and suggest the formation of supramolecular layers (2D), until a structure with growth in three directions is achieved. All of the compounds required at least four stages to achieve a 3D structure.