This paper is focused on a combined experimental and theoretical study of 3-substituted coumarin derivative, the 2-oxo-2H-chromen-3-yl acetate (I). The compound was synthesized by reacting chroman-2,3-dione and acetic anhydride in dried diethyl ether in the presence of dried pyridine and crystallized in the orthorhombic crystal system with Pbca space group.
The lattice parameters of the structure are a=14.6770 (1), b=7.1079 (1), c=17.6767 (2) Å, α =β = γ =90° with 8 molecules per unit cell (Z=8). The compound has been characterized structurally by Spectroscopy utilizing 1H NMR, 13C NMR and IR techniques and by crystallography using the X-Ray diffraction (XRD) analysis. In the crystallographic study, the positions of the atoms were determined by direct methods and refined to a final R value of 0.038 for 1768 independent reflections. The stabilization of the structure is provided by intermolecular C-H•••O hydrogen bonds extending along [010] direction. Likewise, the presence and nature of intermolecular contacts are determined by the 3-D molecular Hirshfeld surface and 2-D fingerprint plot analysis which indicate the main contributions to the Hirshfeld surface, 38.7% for O ••• H and 28.7% for H •• H. Moreover, the molecular geometry of (I) was as well minimized utilizing density functional theory (DFT/RB3LYP), the frequency calculations with RB3LYP method, the basic ab initio model i.e the restricted Hartree-Fock (RHF) and the exchange component of Perdew and Wang’s 1991 functional B3PW91 methods with the 6-311++G(d, p) basis set in ground state. The derived structural parameters highlight very good correlation with the crystallographic results. Frontier molecular orbitals (HOMO-LUMO), their energy gap, the non-linear optical effects (NLO) and related reactive parameters were also computed to better apprehend the properties of the molecule.

3-substituted Coumarin Derivative, C—H…O Hydrogen Bonds, Hirshfeld Surface Analysis, Quantum Chemical Computations