Crystal Structure, Hirshfeld Surface Analysis And Inter­Action Energy And Dft Studies Of 3-{(2Z)-2-[(2,4-Di­Chloro­Phen­Yl)Methyl­Idene]-3-Oxo-3,4-Di­Hydro-2H-1,4-Benzo­Thia­Zin-4-Yl}Propane­Nitrile

Abstract

In the title compound, the di­hydro­benzo­thia­zine moiety is folded about the S1⋯N1 axis. In the crystal, inversion dimers, generated by C—HBnz⋯NPrpnit (Bnz = benzene, Prpnit = propane­nitrile) hydrogen bonds, are linked into stepped ribbons extending parallel to [110] by C—HPrpnit⋯OThz (Thz = thia­zine) hydrogen bonds. The ribbons are joined into pairs by inversion-related C=O⋯Cl inter­actions., The title compound, C18H12Cl2N2OS, consists of a di­hydro­benzo­thia­zine unit linked by a –CH group to a 2,4-di­chloro­phenyl substituent, and to a propane­nitrile unit is folded along the S⋯N axis and adopts a flattened-boat conformation. The propane­nitrile moiety is nearly perpendicular to the mean plane of the di­hydro­benzo­thia­zine unit. In the crystal, C—HBnz⋯NPrpnit and C—HPrpnit⋯OThz (Bnz = benzene, Prpnit = propane­nitrile and Thz = thia­zine) hydrogen bonds link the mol­ecules into inversion dimers, enclosing R 2 2(16) and R 2 2(12) ring motifs, which are linked into stepped ribbons extending along [110]. The ribbons are linked in pairs by complementary C=O⋯Cl inter­actions. π–π contacts between the benzene and phenyl rings, [centroid–centroid distance = 3.974 (1) Å] may further stabilize the structure. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (23.4%), H⋯Cl/Cl⋯H (19.5%), H⋯C/C⋯H (13.5%), H⋯N/N⋯H (13.3%), C⋯C (10.4%) and H⋯O/O⋯H (5.1%) inter­actions. Hydrogen bonding and van der Waals inter­actions are the dominant inter­actions in the crystal packing. Computational chemistry calculations indicate that the two independent C—HBnz⋯NPrpnit and C—HPrpnit⋯OThz hydrogen bonds in the crystal impart about the same energy (ca 43 kJ mol−1). 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.