Crystal structure, Hirshfeld surface analysis, crystal voids, interaction energy calculations and energy frameworks and DFT calculations of ethyl 2-cyano-3-(3-hydroxy-5-methyl-1H-pyrazol-4-yl)-3-phenylpropanoate

The title compound, C₁₆H₁₇N₃O₃, is racemic as it crystallizes in a centrosymmetric space group (P1), although the trans disposition of substituents about the central C—C bond is established. The five- and six-membered rings are oriented at a dihedral angle of 75.88 (8)^◦. In the crystal, N—H. . .N hydrogen bonds form chains of molecules extending along the c-axis direction that are connected by inversion-related pairs of O—H. . .N into ribbons. The ribbons are linked by C—H. . .π(ring) interactions, forming layers parallel to the ab plane. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H. . .H (45.9%), H. . .N/N. . .H (23.3%), H. . .C/C. . .H (16.2%) and H. . .O/O. . .H (12.3%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 100.94 ų and 13.20%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the electrostatic energy contributions in the title compound. 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.