Single crystal, spectral and electronic transition studies on (E)-N-(3-methoxy-4-hydroxybenzylidene)-4-nitrobenzohydrazide monohydrate

The single crystal of (E)-N-(3-Methoxy-4-hydroxybenzylidene)-4-nitrobenzohydrazide monohydrate (MHBNB) was grown by a slow evaporation method. The crystal structure was determined by single crystal X-ray diffraction method. The electron density, Hirshfeld surface and fingerprint analysis reveals that the crystal packing is governed by several weak OH⋯C, OH⋯O and OH⋯N intermolecular interactions. The analysis of bond critical points (BCP) and topology of the crystalline form of MHBNB were done. The intrusion of H2O molecule does not affect the aromaticity of the pheyl rings but marginally disturbs the aromaticity of hydrazide link. The FT-IR (4000-400 cm−1) and FT-Raman (3500-50 cm−1) spectra were recorded to study the vibrational behavior of MHBNB molecule. To explore the electronic transition of MHBNB, the UV absorbance spectrum was recorded in the range of 200–800 nm. Furthermore, the Density functional theory (DFT) and Time-dependent DFT (TD-DFT) calculations were performed to investigate the molecular geometry, vibrational behavior, electronic excitation and inter-intramolecular charge transfers within the molecule. The singlet (S) and Triplet (T) electronic excited states (n state = 6) of MHBNB were examined, in which, the electron spin density (s), excitation energy (ΔE1-6), oscillator strength (f) and electric dipole moment (μ) were examined. The frontier molecular orbitals (FMOs) were studied to find the band gap of FMOs. The natural atomic orbitals (NAO) and natural localized molecular orbitals (NLMO) of MHBNB were analyzed. The density of states (DOS) and Total density of states (TDOS) of functional groups in MHBNB molecule were also evaluated. This compound has very good first order hyperpolarizability (β0) coefficient.