Crystal structure and Hirshfeld surface analysis of dimethyl 3,3′-{[(1E,2E)-ethane-1,2-diylidene]bis(azanylylidene)}bis(4-methylbenzoate)

Abstract

The title Schiff base compound, C20H20N2O4, synthesized by the condensation reaction of methyl 3-amino-4-methylbenzoat and glyoxal in ethanol, crystallizes in the the monoclinic space group P21/n. The molecule is Z-shaped with the C—N—C—C torsion angle being 47.58 (18)°. In the crystal, pairs of molecules are linked via C—H...N hydrogen bonds, forming centrosymetric dimers with an R 2 2(8) ring motif; this connectivity leads to the formation of columns running along the a-axis direction. Hirshfeld surface analysis and two-dimensional fingerprint plots were used to explore the intermolecular interactions and revealed that the most significant contributions to the crystal packing are from H...H (49.4%), H...O/O...H (19.0%) and H...C/C...H (17.5%) contacts. Energy frameworks were constructed through different intermolecular interaction energies to investigate the stability of the compound. The net interaction energies for the title compound were found to be electrostatic (E ele = −48.4 kJ mol−1), polarization (E pol = −9.7 kJ mol−1), dispersion (E dis = −186.9 kJ mol−1) and repulsion (E rep = 94.9 kJ mol−1) with a total interaction energy, E tot, of −162.4 kJ mol−1.