Crystal structure, Hirshfeld surface analysis and interaction energy, DFT and antibacterial activity studies of ethyl 2-[(2Z)-2-(2-chlorobenzylidene)-3-oxo-3,4-dihydro-2H-1,4-benzothiazin-4-yl]acetate

Abstract

The title compound, C19H16ClNO3S, consists of chlorophenyl methylidene and dihydrobenzothiazine units linked to an acetate moiety, where the thiazine ring adopts a screw-boat conformation. In the crystal, two sets of weak C-HPh..ODbt (Ph = phenyl and Dbt = dihydrobenzothiazine) hydrogen bonds form layers of molecules parallel to the bc plane. The layers stack along the a-axis direction with intercalation of the ester chains. The crystal studied was a two component twin with a refined BASF of 0.34961 14;(5). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H..H (37.5%), H..C/C..H (24.6%) and H..O/O..H (16.7%) interactions. Hydrogen-bonding and van der Waals interactions are the dominant interactions in the crystal packing. Computational chemistry indicates that in the crystal, C-HPh..ODbt hydrogen bond energies are 38.3 and 30.3 14;kJ 14;mol-1. Density functional theory (DFT) optimized structures at the B3LYP/6-311 14;G(d,p) level are compared with the experimentally determined molecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap. Moreover, the antibacterial activity of the title compound has been evaluated against gram-positive and gram-negative bacteria.