Crystal structure, Hirshfeld surface and crystal void analysis, inter­molecular inter­action energies, DFT calculations and energy frameworks of 2H-benzo[b][1,4]thia­zin-3(4H)-one 1,1-dioxide

In the title mol­ecule, C(8)H(7)NO(3)S, the nitro­gen atom has a planar environment, and the thia­zine ring exhibits a screw-boat conformation. In the crystal, corrugated layers of mol­ecules parallel to the ab plane are formed by N—H⋯O and C—H⋯O hydrogen bonds together with C—H⋯π(ring) and S=O⋯π(ring) inter­actions. The layers are connected by additional C—H⋯O hydrogen bonds and π-stacking inter­actions. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯O/O⋯H (49.4%), H⋯H (23.0%) and H⋯C/C⋯H (14.1%) inter­actions. The volume of the crystal voids and the percentage of free space were calculated as 75.4 Å(3) and 9.3%. Density functional theory (DFT) computations revealed N—H⋯O and C—H⋯O hydrogen-bonding energies of 43.3, 34.7 and 34.4 kJ mol(−1), respectively. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via the electrostatic energy contribution. Moreover, the DFT-optimized structure at the B3LYP/ 6–311 G(d,p) level is compared with the experimentally determined mol­ecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.