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-l-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, H-1 and C-13 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 X-3 both structures offers great potential in applications such as optical switching and other optoelectronics devices.