Impact of Intermolecular Noncovalent Interactions on the Structural Integrity and Aromaticity of Solvent Clusters: A Theoretical Study Involving 2‐Hydroxypyridine and 2‐Hydroxynicotinic Acid

ABSTRACT Bader's “Atoms in Molecules” formalism has been adopted to assess the noncovalent interactions present within the mono and di‐solvent (water and methanol) clusters of 2‐Hydroxypyridine and 2‐Hydroxynicotinic acid in their Closed and Open conformations and to critically analyze the characteristics and the energetics of the interaction lines toward the planarity of the structural skeletons. Nucleus independent chemical shift (NICS) descriptor has also been exploited to delineate the role of aromaticity in dictating the structures and the characteristics of the noncovalent interactions present within the studied compounds. Both electrostatic and partially covalent Hydrogen bonding interactions (HB) are found within the clusters. Furthermore, apart from the typical O–H····O and O–H····N HBs, a weak albeit unique C–H····O interaction line of purely electrostatic origin is observed. The covalency of the HBs as well as the structural constraints, are found to modulate the aromaticity of the associated pyridine nuclei.