Synthesis, growth, structural, spectroscopic, optical, thermal, DFT, HOMO–LUMO, MEP, NBO analysis and thermodynamic properties of vanillin isonicotinic hydrazide single crystal

Abstract

• The vanillin isonicotinic hydrazide (VINH), an organic single crystal • Single-crystal X-ray diffraction to determine the cell dimensions • Powder X-ray diffraction to evaluate the planes and phase purity of the crystal • Spectral, optical, and thermal properties were studied. • Further, DFT, HOMO–LUMO, MEP, HOMA, NBO analysis were studied • The dipole moment, linear polarizability, and first hyperpolarizabilities have been investigated as molecular parameters. The work is aimed to present the synthesis and physical analysis of vanillin isonicotinic hydrazide (VINH), an organic single crystal, produced by the method of slow evaporation at room temperature. The grown VINH crystal was subjected to (SXRD) single-crystal X-ray diffraction to determine the cell dimensions. The powder X-ray diffraction study was performed to evaluate the planes and phase purity of the crystal. The presence of functional groups were analyzed through FTIR spectroscopy. UV–Vis–NIR spectroscopy study was carried out to enumerate the cutoff wavelength. Thermogravimetric and differential thermal analysis (TGA/DTA) was done to identify the thermal properties of the grown crystal. Further, the density functional theory (DFT/B3LYP) methods with the 6-311++G(d,p) basis set were used to compute the optimized molecular structure, HOMO-LUMO, molecular electrostatic potential surfaces, and vibrational studies of VINH crystal. The low HOMO - LUMO energy gap shows that the charge transfer inside the molecule is possible. NBO analysis proved the presence of intermolecular ON...H hydrogen bonds caused by the interaction of the lone pair of oxygen with the anti-bonding orbital. The dipole moment, linear polarizability, and first hyperpolarizabilities have been investigated as molecular parameters.