ABSTRACT
The asymmetric unit of the title compound, C14H13NO4, contains three independent mol-ecules, which differ slightly in conformation. Each contains an intra-molecular N-Hâ¯O hydrogen bond. In the crystal, O-Hâ¯O hydrogen bonds form chains of mol-ecules, which are linked into corrugated sheets parallel to (03) plane by C-Hâ¯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-Hâ¯O hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from Hâ¯H (49.0%), Hâ¯O/Oâ¯H (28.3%) and Hâ¯C/Câ¯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/ 6-311â 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 4.53â eV.