Crystallographic and computational investigations of structural properties in phenyl and methoxy‑phenyl substituted 1,4 dihydropyridine derivatives

Abstract

Single crystal preparation of two 1,4-dihydropyridine (1,4-DHP) derivative molecules, namely, (i) 2,6-dimethyl-4-phenyl-1, 4-dihydro-pyridine-3, 5-dicarboxylic acid diethyl ester and (ii) 4-(4‑methoxy-phenyl)-2,6-dimethyl-1, 4-dihydro-pyridine-3, 5-dicarboxylic acid diethyl ester was done. Crystal structure solution and refinement of final R values converged to 0.0478 and 0.0466. Hirshfeld surface analysis mapped dnorm surfaces, shape index, curvedness and hydrogen bonding present in the molecules. These calculations established the relative contributions of the various intermolecular contacts to the total Hirshfeld surface area. Both the molecular structures were optimized and confirmed by Density Functional Theory (DFT) simulations in an implicit aqueous solvation environment. The molecular electrostatic potential (MEP) analysis elucidated the electrophilic and nucleophilic regions in the molecules to be the hydrogen attached to the nitrogen and the carboxyl oxygen atoms. Frontier molecular orbital analysis indicated the stability of these molecules while they appeared to be electrophilic in nature from the reactivity descriptors analysis.