Crystal structure, Hirshfeld surface analysis and DFT studies of ethyl 2-{4-[(2-eth-oxy-2-oxoeth-yl)(phen-yl)carbamo-yl]-2-oxo-1,2-di-hydro-quinolin-1-yl}acetate

Abstract

The title com-pound, C₂₄H₂₄N₂O₆, consists of ethyl 2-(1,2,3,4-tetra-hydro-2-oxo-quinolin-1-yl)acetate and 4-[(2-eth-oxy-2-oxoeth-yl)(phen-yl)carbomoyl] units, where the oxo-quinoline unit is almost planar and the acetate substituent is nearly perpendicular to its mean plane. In the crystal, C-H_Oxqn⋯O_Ethx and C-H_Ph-yl⋯O_Carbx (Oxqn = oxoquinolin, Ethx = eth-oxy, Phyl = phenyl and Carbx = carboxyl-ate) weak hydrogen bonds link the mol-ecules into a three-dimensional network sturucture. A π-π inter-action between the constituent rings of the oxo-quinoline 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%) inter-actions. Weak inter-molecular hydrogen-bond inter-actions and van der Waals inter-actions are the dominant inter-actions in the crystal packing. Density functional theory (DFT) geometric optimized structures at the B3LYP/6-311G(d,p) level are com-pared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO mol-ecular orbital behaviour was elucidated to determine the energy gap.

Keywords: 2-oxo­quinoline; Hirshfeld surface; alkyne; crystal structure; weak inter­molecular inter­actions; π-stacking.

Figure 1

The mol­ecular structure of the title com­pound, showing the atom-numbering scheme and displacement ellipsoids drawn at the 50% probability level. For the sake of clarity, the minor com­ponent of disorder is not shown.

Figure 2

A partial packing diagram viewed along the b axis. Weak C—H_Oxqn⋯O_Ethx and C—H_Ph­yl⋯O_Carbx (Oxqn = oxoquinolin, Ethx = eth­oxy, Phyl = phenyl and Carbx = carboxyl­ate) inter­molecular hydrogen bonds are shown as dashed lines. The disorder is not shown.

Figure 3

A view of the three-dimensional Hirshfeld surface for the title com­pound, plotted over d _norm in the range −0.2380 to 1.5740 a.u.

Figure 4

A view of the three-dimensional Hirshfeld surface of the title com­pound, plotted over the electrostatic potential energy in the range −0.0500 to 0.0500 a.u. using the STO-3G basis set at the Hartree–Fock level of theory. Weak hydrogen-bond donor and acceptor inter­molecular inter­actions are shown as blue and red regions around the atoms corresponding to positive and negative potentials, respectively.

Figure 5

A view of the Hirshfeld surface for the title com­pound, plotted over the shape-index.

Figure 6

The full two-dimensional fingerprint plots for the title com­pound, showing (a) all inter­actions, and delineated into (b) H⋯H, (c) H⋯O/O⋯H, (d) H⋯C/C⋯H, (e) C⋯C and (f) O⋯C/C⋯O inter­actions. The d _i and d _e values are the closest inter­nal and external distances (in Å from given points on the Hirshfeld surface contacts.

Figure 7

The Hirshfeld surface representations with the function d _norm plotted onto the surface for (a) H⋯H, (b) H⋯O/O⋯H, (c) H⋯C/C⋯H and (d) C⋯C inter­actions.

Figure 8

The calculated energy band gap for the title com­pound.