Crystal structure, spectroscopic and third-order nonlinear optical susceptibility of linear fused ring dichloro-substituent chalcone isomers

Two new anthracenyl chalcone isomers namely (E)-1-(anthracen-9-yl)-3-(2,4-dichlorophenyl)prop-2-en-1-one and (E)-1-(anhracen-9-yl)-3(2,6-dichlorophenyl)prop-2-en-1-one were successfully synthesized using Claisen Schmidt condensation method. The compounds were then characterized by using IR, 1H and 13C NMR and UV–Vis methods. The dichloro anthracene chalcone isomers have been solved and refined using X-ray single crystal diffraction data and optimized at the ground state using density functional theory (DFT) method with B3LYP/6-311G++(d,p) level. The experimental spectroscopic data were compared with the calculated TD-DFT spectra, where the values are in good agreement. The most stable conformer of the chalcones is identified from the computational results. Both compounds also show a good HOMO-LUMO energy gap values of 2.96 and 3.14 eV. The dipole moment at the different ortho-para and ortho-ortho position are 2.71D and 4.58D, respectively. The difference in orientation of the ortho-para and ortho- ortho position results affect the dipole moments and NLO properties response of the compounds. The analyses of nonlinear optical (NLO) properties were performed by calculating the third-order nonlinear polarizabilities. Both compounds show reasonably good NLO responds with the magnitude and sign of the third order optical susceptibility was determined. Based on the measured nonlinear susceptibility χ3 both structures offers great potential in applications such as optical switching and other optoelectronics devices