Locality and strength of intermolecular interactions in organic crystals: using conceptual density functional theory (CDFT) to characterize a highly polymorphic system

Intermolecular interactions of seven polymorphs of a model organic compound were elucidated through electronic structure-based local descriptors, derived from conceptual density functional theory, and their correlations with interaction energies. Visual and statistical analyses were conducted to inspect the underlying connections between interacting modes and electronic properties. It was found that Fukui function and Fukui potential determine interactions especially where pi-pi stacking is predominant in a contacting motif. The overall large regions of negative and positive values of electronic properties on interacting motifs unveil the significant correlation of the local electronic properties with the intermolecular interactions. This study further confirmed our previous reports that local softness and hardness descriptors, such as Fukui functions, are capable of characterizing the locality and strength of intermolecular interactions.