Synthesis, spectral characterisation, third-order nonlinear optical properties and quantum chemical studies on ( E )-4-bromo- N' -(2,4-dimethoxybenzylidene)benzohydrazide crystal for optoelectronics applications

Single crystals of (E)- 4-bromo- N'- (2,4-dimethoxybenzylidene)benzohydrazide (DMBB) have been grown by slow evaporation technique. The molecular structure of the grown crystal was confirmed by Single-crystal X-ray diffraction (SC-XRD) studies. The active functional groups present in the synthesised compound were identified by Fourier transform infrared (FTIR) spectroscopy. 13 C and 1 H-NMR chemical shift values are in good agreement with the theoretical results. The UV–Vis spectrum is used to examine the optical characteristics of the grown crystal. The HOMO and LUMO energies are predicted as − 5.8981 and − 1.7469 eV. The energy gap between HOMO and LUMO is 4.1511 eV. The natural bond orbital (NBO) analysis results state that the highest energy transfer occurs between the donor π(C14-C21) and acceptor π*(C15-C16). The first-order hyperpolarizability value of the synthesised compound is six times greater than that of urea. The Z-scan approach was used to investigate the nonlinear optical (NLO) behaviour and optical limiting characteristics.