Crystal structure, Hirshfeld surface analysis and DFT studies of ethyl 2-{4-[(2-ethoxy-2-oxoethyl)(phenyl)carbamoyl]-2-oxo-1,2-dihydroquinolin-1-yl}acetate

The title compound, C₂₄H₂₄N₂O₆, consists of ethyl 2-(1,2,3,4-tetrahydro-2-oxoquinolin-1-yl)acetate and 4-[(2-ethoxy-2-oxoethyl)(phenyl)carbomoyl] units, where the oxoquinoline unit is almost planar and the acetate substituent is nearly perpendicular to its mean plane. In the crystal, C-HOxqn..OEthx and C-HPhyl..OCarbx (Oxqn = oxoquinolin, Ethx = ethoxy, Phyl = phenyl and Carbx = carboxylate) weak hydrogen bonds link the molecules into a three-dimensional network sturucture. A π-π interaction between the constituent rings of the oxoquinoline unit, with a centroid-centroid distance of 3.675 (1) Å may further stabilize the structure. Both terminal ethyl groups are disordered over two sets of sites. The ratios of the refined occupanies are 0.821 (8):0.179 (8) and 0.651 (18):0.349 (18). The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H..H (53.9%), H..O/O..H (28.5%) and H..C/C..H (11.8%) interactions. Weak intermolecular hydrogen-bond interactions and van der Waals interactions are the dominant interactions in the crystal packing. Density functional theory (DFT) geometric 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 molecular orbital behaviour was elucidated to determine the energy gap.