Structure-property relationship of three 2-chloro-4-fluoro chalcone derivatives: A comprehensive study on linear and non-linear optical properties, structural characterizations and density functional theory

• Main Authors: Wong, Qin Ai, Quah, Ching Kheng, Wong, Xin Ai, Maidur, Shivaraj R., Kwong, Huey Chong, Win, Yip-Foo, Patil, Parutagouda Shankaragouda, Gummagol, Neelamma B.
• Format: Article
• Published: Elsevier 2022
• Subjects: QD Chemistry
• Online Access: http://eprints.um.edu.my/41432/
• Institution: Universiti Malaya

This work focused on the relationship between molecular structure and non-linear optical (NLO) property of the chalcone derivatives. The NLO property is well known increased by push-pull effect, therefore we have explored donor-acceptor substitutions on both rings to develop excellent NLO materials. Three new crystals of 2-chloro-4-fluorochalcone derivatives bearing various donor end groups were synthesized in order to evaluate the donor dependence of their second-order hyperpolarizability y. The grown crystals were spectroscopically confirmed and crystallographically analysed. Their intermolecular interactions were visualized by Hirshfeld surface analysis. The electronic absorption spectrums were investigated by experimental and theoretical methods, to discuss the intramolecular charge transfer and energy gap of solution sample, which defined significantly affected NLO properties. Theoretical electronic properties have been simulated with density functional theory (DFT) at B3LYP/6-311++G (d,p) level and compared with experimental results. Thermally-induced NLO parameters such as non-linear absorption (NLA) coefficient (alpha(2)similar to 10(-5) cmW(-1)), non-linear refractive (NLR) index (n(2) similar to 10(-9)cm(2)W(-1)), third-order susceptibility chi((3))(-omega;omega,omega,-omega) similar to 10(-8) esu] and gamma(-omega;omega,omega,-omega)similar to 10(-27) esu] were measured by Z-scan technique under continuous-wave laser excitation (532 nm). The solution samples exhibit two-photon assisted reverse saturable absorption and self-defocusing non-linear refraction, optical limiting and all-optical switching behaviours. We have determined that y depends on the strength of donor/acceptor substituents, which is the result of the two contributions: the energy gap and the transition dipole moment between the ground and first excited states. A large value of gamma was found for compound gamma which bearing strong donor hydroxy substituent, thus the hydroxychalcone derivatives as a potential material with excellent NLO performance. (C) 2022 Elsevier B.V. All rights reserved.