Optical nonlinearity of D-A-π-D and D-A-π-A type of new chalcones for potential applications in optical limiting and density functional theory studies

• Published in: Journal of molecular structure 2017-09, Vol.1143, p.306-317
• Main Authors: Chandra Shekhara Shetty, T., Chidan Kumar, C.S., Gagan Patel, K.N., Chia, Tze Shyang, Dharmaprakash, S.M., Ramasami, Ponnadurai, Umar, Yunusa, Chandraju, Siddegowda, Quah, Ching Kheng
• Format: Article
• Language: English
• Subjects: Chalcone; Crystal; Density functional theory (DFT); Nonlinear optical (NLO); Optical limiting; Z-scan
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2017.04.107

Two new chalcones namely, (2E)-1-(3-fluoro-4-methoxyphenyl)-3-(4-methoxyphenyl) prop-2-en-1-one and (2E)-3-(4-chlorophenyl)-1-(3-fluoro-4-methoxyphenyl)prop-2-en-1-one were synthesized and grown as single crystals by slow evaporation technique in methanol. The FTIR spectrum recorded confirms the presence of functional groups in these materials. The molecular conformation of the compounds was achieved by single crystal X-ray diffraction studies. The thermal stability of the crystals was determined from TGA/DSC curve. The third order optical nonlinearity of the chalcone compounds in DMF solution has been carried out using an Nd:YAG laser at 532 nm as the source of excitation. The nonlinear optical response was characterized by measuring the intensity dependent refractive index n2 of the medium using Z-scan technique. It is seen that the molecules exhibit a negative (defocusing) nonlinearity and large nonlinear refractive index of the order of −1.8 × 10−11 esu. The third-order nonlinearity of the studied chalcones is dominated by nonlinear refraction, which leads to strong optical limiting of laser. The result reveals that these two new chalcone molecules would be a promising material for optical limiting applications. In addition, the optimized molecular geometry, vibrational frequencies in gas, and the Molecular Electrostatic Potential (MEP) surface parameters of the two molecules were calculated using DFT/B3LYP method with 6–311++G(d,p) basis set in ground state. All the theoretical calculations were found in good agreement with experimental data. [Display omitted] •3D structure was confirmed by single crystal XRD data.•The experimental results were supported by computational studies by using DFT.•Theoretical calculations are in good agreement with the experimental results.•THG of chalcones dominated by nonlinear refraction, leading to strong optical limiting of laser.