Comprehensive study of the molecular structure and nonlinear optical response of two novel halogenated pyrenyl-chalcones

Herein, two novel pyrenyl-chalcone derivatives named PCh-1 and PCh-2 were synthesized by the Claisen-Schmidt reaction and successfully recrystallized in acetone to get single crystals. The crystals were spec-troscopically characterized via SCXRD and UV-Vis absorption. Quantum computational studies including NBO, MEP, FMO, and polarity were performed using DFT at B3LYP/6-311 ++ G (d,p). Intermolecular inter-actions were investigated using Hirshfield analysis while intramolecular interactions were discussed ex-perimentally (UV-Vis absorption spectroscopy) and theoretically using TD-DFT at CAM-B3LYP/6-311 ++ G (d,p). The presence of the intermolecular interactions of C -H...O, C -H...F, C -H...n, and n -n interactions stabilize both crystals in head-tail (PCh-1), zig-zag fashion (PCh-2), and face to face stacking. The hy-per conjugative interactions extracted from NBO analysis confirmed the high stability of both crystals. The UV-Vis and FMO studies show low bandgap energy of 3.012 eV (PCh-1) and 3.047 eV (PCh-2) and opaque in the visible range revealing strong ICT. The nonlinear behavior of the compounds was investi-gated using the Z-scan technique via CW laser working at 637 nm. An excellent NLO response in order of 10 -5 esu (PCh-1) & 10 -6 esu (PCh-2) and fast response in limiting optical signal at 1245.5 mW (PCh-1) & 1431.9 mW (PCh-2) are observed. The structure-property findings suggest the higher inter/intramolecular charge transfer in PCh-1 compared to PCh-2 is due to the strength of the EDG, planarity of the bone structure, and polarizability. The high NLO performance of the crystals suggests a promising application to use them as NLO material. (c) 2023 Elsevier B.V. All rights reserved.