Crystal structure, Hirshfeld surface analysis and interaction energy and DFT studies of 5,5-diphenyl-1,3-bis(prop-2-yn-1-yl)imidazolidine-2,4-dione

The title compound, C21H16N₂O₂, consists of an imidazolidine unit linked to two phenyl rings and two prop-2-yn-1-yl moieties. The imidazolidine ring is oriented at dihedral angles of 79.10 (5) and 82.61 (5)° with respect to the phenyl rings, while the dihedral angle between the two phenyl rings is 62.06 (5)°. In the crystal, intermolecular C - HProp⋯OImdzln (Prop = prop-2-yn-1-yl and Imdzln = imidazolidine) hydrogen bonds link the molecules into infinite chains along the b-axis direction. Two weak C - HPhen⋯π interactions are also observed. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (43.3%), H⋯C/C⋯H (37.8%) and H⋯O/O⋯H (18.0%) interactions. Hydrogen bonding and van der Waals interactions are the dominant interactions in the crystal packing. Computational chemistry indicates that the C - HProp⋯OImdzln hydrogen-bond energy in the crystal is -40.7 kJ mol^-1. Density functional theory (DFT) optimized structures at the B3LYP/6-311G(d,p) level are compared with the experimentally determined molecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap.