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 R22(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 (Eele = −48.4 kJ mol−1), polarization (Epol = −9.7 kJ mol−1), dispersion (Edis = −186.9 kJ mol−1) and repulsion (Erep = 94.9 kJ mol−1) with a total interaction energy, Etot, of −162.4 kJ mol−1.

Keywords

• azanylylidene
• crystal structure
• electrostatic potential map
• energy frameworks
• hirshfeld
• methylbenzoate
• shape index
• curvedness