Crystal structure, Hirshfeld surface analysis and DFT calculations of (E)-3-[1-(2-hydroxyphenyl-anilino)ethylidene]-6-methylpyran-2,4-dione

The asymmetric unit of the title compound, C14H13NO4, contains three independent molecules, which differ slightly in conformation. Each contains an intramolecular N-H center dot center dot center dot O hydrogen bond. In the crystal, O-H center dot center dot center dot O hydrogen bonds form chains of molecules, which are linked into corrugated sheets parallel to ((1) over bar 03) plane by C-H center dot center dot center dot O hydrogen bonds together with pi interactions between the carbonyl groups and the 2-hydroxyphenyl rings. The layers are linked by further C-H center dot center dot center dot O hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H center dot center dot center dot H (49.0%), H center dot center dot center dot O/O center dot center dot center dot H (28.3%) and H center dot center dot center dot C/C center dot center dot center dot H (10.9%) interactions. van der Waals interactions are the dominant interactions 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 molecular structure in the solid state. The HOMOLUMO behavior was elucidated to determine the energy gap of 4.53 eV.