Synthesis, crystal structure, Hirshfeld surface, nonlinear optical properties and computational studies of (E)-4-bromo-N'-(3,4-dimethoxybenzylidene)benzohydrazide single crystal for nonlinear optical applications

Abstract

(E)-4-bromo-N'-(3,4-dimethoxybenzylidene)benzohydrazide (DMBH) single crystals were synthesized by Schiff base method. The crystal structure of DMBH single crystal was determined using single crystal X-ray diffraction technique. The proton 1H and carbon 13C NMR spectral analysis were studied to identify the molecular structure of the crystal. From UV–Vis spectral analysis the maximum absorption for the DMBH molecule was observed around 338 nm and it reveals the presence of π-π* transition. The different functional group properties were studied via Fourier transform infrared (FTIR) analysis. Density functional theory (DFT) method was used to investigate the HOMO and LUMO energies and their energies were interrelated with the UV spectral analysis. Inter and intra molecular interactions with the assistance of colour coding were discussed using Hirshfeld surface analysis. The intramolecular stabilization by donor-acceptor interactions was investigated with the aid of natural bond orbital (NBO) analysis. In addition, the reactivity of the title compound was calculated by molecular electrostatic potential (MEP) analysis. For DMBH crystal, the first order hyperpolarizability value β0 = 5.0786 × 10−30 esu was obtained and is around 14 times greater than that of urea (0.3728 × 10−30 esu). The third order nonlinear optical (NLO) properties were studied through Z-scan method.