Synthesis, X-ray crystallography, vibrational spectroscopy, thermal and DFT studies of (E)-6-(4-methylstyryl)-4,5-dihydropyridazin-3(2H)-one

• Novel pyridazin-3( 2H )-one derivative has been synthesized and characterized using FT-IR, UV–vis, 1 H- and 13 C NMR, and X-ray diffraction. • Quantum chemical calculations were carried out by DFT/B3LYP method. • The Hirshfeld and MEP surfaces analyses were investigated. • The thermal stability of the synthesized compound was also studied. A novel pyridazin-3(2H)-one derivative, ( E )-6-(4-methylstyryl)-4,5-dihydropyridazin-3( 2H )-one ( 3 ) has been synthesized and characterized by FT-IR, UV–vis, 1 H- and 13 C NMR, TGA/DTA thermal analysis and single-crystal X-ray diffraction. Furthermore, the molecular geometry, vibrational frequencies, electronic absorption spectra, chemical shift values, HOMO-LUMO analysis, frontier molecular orbital (FMO) and molecular electrostatic potential (MEP) surface map of the title compound were calculated using DFT/B3LYP method with 6–31+ G (d,p) basis set. A comparison among the experimental and calculated results indicates that the vibrational frequencies, maximum electronic absorption wavelengths and chemical shift values are in a good agreement with each other. The intermolecular interactions in the crystal structure were investigated using Hirshfeld surface analysis. TGA/DTA thermal analysis revealed that the title compound is thermostable to its melting point.