Structural elucidation and Z-scan investigation of NLO E-N’-(4-formylbenzylidene)furan-2-carbohydrazide hydrate crystal

Abstract

Substituted hydrazides have significant potential as nonlinear optical materials. In this contribution, synthesis and structural (X-ray crystallography, UV, IR, and Raman spectroscopy) characterization of a novel NLO material, E-N’-(4-formylbenzylidene)furan-2-carbohydrazide (4FBC), is presented. The Hirshfeld surface analysis allowed for the investigation of the intermolecular interactions within the crystal structure and the most significant contacts with the neighboring units were examined. The structural characterization is amended by quantum-chemical optimization employing several common functionals, and a comparison between crystallographic and predicted parameters determined the appropriate level of theory. The CAM-B3LYP/6–311++G(d,p) level of theory was used for further calculations, as the lowest differences in bond lengths and angles were obtained for the structure optimized at this level of theory. The vibrational and UV-VIS spectra were assigned, and the effects of different groups were discussed. The experimental electronic transition energy was well reproduced upon optimizing the excited state. The Quantum Theory of Atoms in Molecules (QTAIM) and Natural Bond Orbital (NBO) theory were used to quantify intramolecular stabilization interactions. The NLO properties of 4FBC were proven through the Z-scan experimental determination of the absorption coefficient and nonlinear refractive index.