Structural elucidation and various computational studies for quantitative investigation of intermolecular interactions in pyridine-2,6-dicarboxylic acid and its di-hydrate

Abstract

Crystals of pyridine-2,6-dicarboxylic acid (1) have been structurally characterized through single-crystal X-ray diffraction analysis and compared with pyridine-2,6-dicarboxylic acid dihydrate ((2) retrieved from CSD), and explore the solid-state networks. In the solid state, compound (1) exhibits both hydrogen bonding and π···π interactions, while the supramolecular network of compound (2) is stabilized only by hydrogen bonding interactions. The non-covalent interactions are characterized by various computational studies such as Hirshfeld surface analysis, Bader's ‘Atoms in Molecules’ (AIM) theory, and ‘Non-covalent interaction’ (NCI) plot analysis. Hirshfeld surfaces and corresponding 2D fingerprint plots reveal the contribution of non-covalent interactions involved in the structure. Lattice energy framework calculations also are carried out for both compounds. The topological parameters of the AIM analysis suggest the ‘closed-shell’ nature of the non-covalent interactions. Further, NCI plots and scatter graphs (RDG vs sign (λ2)ρ) characterize non-covalent interactions with a color scheme.