New halogenated chalcones: Synthesis, crystal structure, spectroscopic and theoretical analyses for third-order nonlinear optical properties

Abstract

The halogen chalcones have been prepared by a simple condensation reaction of 4-bromoacetophenone with different substituted halogen benzaldehydes by presence of catalyst of sodium hydroxide. The proposed structures were solved and refined by single crystal X-ray diffraction analysis and the optimized molecular structure at the ground state were further performed using density functional theory (DFT) method with B3LYP/6-311G++(d,p) basis set level. The supramolecular C—H⋯O, C—H⋯Cl and C—H···π hydrogen bonds and halogen···halogen interactions observed stabilize and strengthen the crystal structure of the halogen chalcones. All the newly synthesized compounds were characterized by spectroscopic methods including, FT-IR, 1H and 13C NMR and UV-Visible. The experimental geometrical parameters were compared with the calculated TD-DFT, where the values are in good agreement. All compounds exhibiting a good HOMO-LUMO energy gap values in a range of 4.0 and 4.2 eV. Additionally, Hirshfeld surfaces analysis was used to quantify the intermolecular interactions and to analyze intercontacts in the crystal structure. Results revealed mono-substitution molecules with ortho position will give a high impact on electronic dipole moment, thus offering a better quality NLO properties of the compounds.