Unravelling the structure and reactivity of N,O-heterocycles: a multifaceted quantum chemical approach using a benzoxazole derivative as a case study

Quantum chemistry provides valuable insights into the structure and reactivity of heterocyclic organic compounds, facilitating the rational design of novel molecules with targeted functionalities. In this paper, structural features and chemical properties of 2-(2-phenyl-1,3-benzoxazol-7-yl)benzaldehyde, a benzoxazole-based heterocycle, were investigated. This multifaceted study combines crystallographic and quantum chemical methods to elucidate molecular geometry, crystal packing, and chemical reactivity of mono and dimeric forms. A rich network of intermolecular interactions, including nonclassical hydrogen bonds (C-H<middle dot><middle dot><middle dot>O and C-H<middle dot><middle dot><middle dot>N), pi-stacking, and a unique C=O<middle dot><middle dot><middle dot>pi(ring) interaction, were found to govern the solid-state structure. Multi-approach quantum mechanics analysis using dispersion-corrected DFT (omega B97X-D/aug-cc-pVTZ) revealed the electronic features, energetics, and nature of these interactions. Furthermore, Conceptual DFT identified the molecule as a moderate electrophile and strong nucleophile in polar organic reactions, while Parr functions pinpointed favourable sites for electrophilic and nucleophilic attacks.Graphical abstractQuantum chemistry provides valuable insights into the structure and reactivity of heterocyclic organic compounds, facilitating the rational design of novel molecules with targeted functionalities. In this paper, a benzoxazole-based heterocycle was computationally investigated using dispersion-corrected density functional theory. The focus was on noncovalent interactions and chemical reactivity in both mono and dimeric forms. This work not only introduces the molecule for future study, but also emphasizes the capability of used theoretical approaches in elucidating structure and reactivity within heterocyclic compounds.