Crystal Structure, Hirshfeld Surface Analysis And Dft Study Of (2Z)-2-(2,4-Di­Chloro­Benzyl­Idene)-4-[2-(2-Oxo-1,3-Oxazolidin-3-Yl)Eth­Yl]-3,4-Di­Hydro-2H-1,4-Benzo­Thia­Zin-3-One

Abstract

In the title compound, the heterocyclic portion of the di­hydro­benzo­thia­zine unit adopts a flattened-boat conformation, while the oxazolidine ring adopts an envelope conformation. The 2-carbon link to the oxazole ring is perpendicular to the best plane through the di­hydro­benzo­thia­zine unit. In the crystal, the mol­ecules form stacks extending along the normal to (104) through π-stacking inter­actions between the two carbonyl groups and inversion-related oxazole rings. Aromatic rings from neighbouring stacks inter­calate to form an overall layer structure., The title compound, C20H16Cl2N2O3S, is built up from a di­hydro­benzo­thia­zine moiety linked by –CH– and –C2H4– units to 2,4-di­chloro­phenyl and 2-oxo-1,3-oxazolidine substituents, where the oxazole ring and the heterocyclic portion of the di­hydro­benzo­thia­zine unit adopt envelope and flattened-boat conformations, respectively. The 2-carbon link to the oxazole ring is nearly perpendicular to the mean plane of the di­hydro­benzo­thia­zine unit. In the crystal, the mol­ecules form stacks extending along the normal to (104) with the aromatic rings from neighbouring stacks inter­calating to form an overall layer structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (28.4%), H⋯Cl/Cl⋯H (19.3%), H⋯O/O⋯H (17.0%), H⋯C/C⋯H (14.5%) and C⋯C (8.2%) inter­actions. Weak hydrogen-bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Density functional theory (DFT) optimized structures at the B3LYP/ 6–311 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.