Crystal structure, Hirshfeld surface analysis and DFT calculations of (E)-3-[1-(2-hy-droxy-phenyl-anilino)ethyl-idene]-6-methyl-pyran-2,4-dione.

The asymmetric unit of the title compound, C14H13NO4, contains three independent mol-ecules, which differ slightly in conformation. Each contains an intra-molecular N-H⋯O hydrogen bond. In the crystal, O-H⋯O hydrogen bonds form chains of mol-ecules, which are linked into corrugated sheets parallel to (03) plane by C-H⋯O hydrogen bonds together with π inter-actions between the carbonyl groups and the 2-hy-droxy-phenyl rings. The layers are linked by further C-H⋯O hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (49.0%), H⋯O/O⋯H (28.3%) and H⋯C/C⋯H (10.9%) inter-actions. van der Waals inter-actions are the dominant inter-actions in the crystal packing. Moreover, density functional theory (DFT) optimized structures at the B3LYP/ 6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behavior was elucidated to determine the energy gap of 4.53 eV.