Crystal structure, Hirshfeld surface analysis and DFT study of 1-ethyl-3-phenyl-1,2-di-hydro-quinoxalin-2-one

Gamal Al Ati; Karim Chkirate; Ashraf Mashrai; Joel T Mague; Youssef Ramli; Redouane Achour; El Mokhtar Essassi

doi:10.1107/S2056989020015819

Crystal structure, Hirshfeld surface analysis and DFT study of 1-ethyl-3-phenyl-1,2-di-hydro-quinoxalin-2-one

Acta Crystallogr E Crystallogr Commun. 2021 Jan 1;77(Pt 1):18-22. doi: 10.1107/S2056989020015819.

Authors

Gamal Al Ati¹, Karim Chkirate¹, Ashraf Mashrai², Joel T Mague³, Youssef Ramli⁴, Redouane Achour¹, El Mokhtar Essassi¹

Affiliations

¹ Laboratory of Heterocyclic Organic Chemistry URAC 21, Pharmacochemistry Competence Center, Av. Ibn Battouta, BP 1014, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
² Department of Pharmacy, University of Science and Technology, Ibb Branch, Ibb, Yemen.
³ Department of Chemistry, Tulane University, New Orleans, LA 70118, USA.
⁴ Laboratory of Medicinal Chemistry, Drug Sciences Research Center, Faculty of Medicine and Pharmacy, Mohammed V University in Rabat, Morocco.

Abstract

In the title mol-ecule, C₁₆H₁₄N₂O, the di-hydro-quinoxaline moiety is not planar as there is a dihedral angle of 4.51 (5)° between the constituent rings. In the crystal, C-H⋯O hydrogen bonds form helical chains about the crystallographic 2₁ screw axis in the b-axis direction. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (51.7%), H⋯C/C⋯H (26%) and H⋯O/O⋯H (8.5%) inter-actions. The optimized structure calculated using density functional theory (DFT) at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined structure in the solid state. The calculated HOMO-LUMO energy gap is 3.8918 eV.

Keywords: crystal structure; dihydroquinoxaline; hydrogen bond.

Grants and funding

This work was funded by Tulane University grant .