The substitution effect of heterocyclic rings to tune the optical and nonlinear optical properties of hybrid chalcones: A comparative study

The present study spotlights the hybrid chalcone derivatives consisting of coumarin moieties conjugated systematically with different heterocyclic rings. The heterocyclic rings including bifuran, bicyclopentane, bipyrrole and bithiophenes groups are used to design compounds 1, 2, 3 and 4, respectively. Different density functional theory (DFT) methods are used for optimization of designed compounds. The M06 functional shows reasonably good accuracy for calculations of geometrical and absorption spectra as compared with other methods and/or available experimental data. The calculated average third-order NLO polarizabilities (γ) for compounds 1, 2, 3 and 4 are found to be 526.22 × 10−36, 675.40 × 10−36, 939.58 × 10−36 and 1109.30 × 10−36 esu., respectively, at M06/6-311G** level of theory. The γ amplitudes of compounds 1, 2, 3 and 4 are reasonably enhanced, which are about 25, 27, 30 and 32 times larger to the γ amplitude of para nitroaniline (a prototype NLO molecule) at same M06/6-311G** level of theory. Furthermore, we highlight the structure-property relationship using TD-DFT calculations for absorption and emission spectra, frontier molecular orbitals and molecular electrostatic potential maps. Thus, the present study will evoke the interest of scientific community to develop the above title materials for efficient NLO applications.