Synthesis, non-covalent interactions and chemical reactivity of 1-pen-tyl-3-phenylquinoxalin-2(1H)-one-Structural and computational studies

This contribution presents the synthesis of a new quinoxaline derivative, 1-pentyl-3-phenylquinoxalin-2(1H)-one with formula C19H20N2O, through an alkylation reaction, followed by a thorough structural characterization. Xray crystallography revealed that pi-stacking and unconventional C-H...O/pi hydrogen bonding play a significant role in the supramolecular solid-state framework. These interactions are further assisted by infrequent C--O...pi interactions and C-H...H-C dispersive contacts. These non-covalent interactions (NCIs) are analyzed in terms of geometrical criteria, and Hirshfeld surface analysis is used to demonstrate their individual contributions. The nature and strength of prevalent NCIs are thoroughly discussed via computational tools NCI, NBO, and QTAIM. Moreover, the application of Density Functional Theory (DFT) at the wB97X-D/cc-pVTZ level yields valuable insights into both the global and local chemical reactivity of studied compound, thereby enhancing our understanding of the chemistry involved in the synthesis of quinoxaline and its derivatives.