Crystallographic, dynamic and Hirshfeld surface studies of charge transfer complex of imidazole as a donor with 3,5-dinitrobenzoic acid as an acceptor: Determination of various physical parameters.

Abstract The peculiar charge (CT) complex is synthesized by mixing the 1:1 ratio of the donor, imidazole (IZ) and acceptor, 3,5-dinitrobenzoic acid (DNBA) in ethanol at room temperature. The stoichiometry of the 1:1 proton transfer complex is obtained by using the Benesi-Hildebrand equation, which is used to determine the molar extinction coefficient (ε CT), formation constant (K CT) and the other physical parameters. The CT complex was investigated using various spectral techniques, such as UV–visible, FTIR, 1HNMR and powder XRD that confirm the formation of N+–H...O- bond between donor and acceptor. The Numerous thermodynamics parameters such as energy (E CT), Ionization potential (I D), resonance energy (R N), free energy (ΔĞ), oscillator strength (f) and transition dipole strength (μ EN) have been determined by using UV–visible spectroscopy. Structure of the synthesized CT complex has also been investigated by using X-ray crystallography. The formation of CT complex occurred by transfer of lone pair of electrons from donor to the acceptor through N +_ H... O− type of hydrogen bond and structure of the CT complex has been found to be monolclinic [(IZ)+(DNBA)-] as investigated by X-ray crystallographic and other studies. The thermal decomposition and mass loss of the CT complex were analyzed by TGA-DTA studies. The Hirshfeld surfaces of the CT complex have been mapped over a d norm , shape_index and curvedness range of −0.79 to 1.7, −0.99 to 1.0 and −4.0 to 4.0 respectively. Graphical abstract Dynamics of charge transfer in complex of acceptor-donor, single crystallography, absorption spectra, Hirshfeld surface analyses and Benesi-Hildebrand plots of CT complex. Image Highlights • Dynamics of charge transfer in complex of acceptor-donor was discussed. • The Benesi-Hildebrand equation was used to determine the stoichiometry of charge transfer complex. • Hydrogen bonding network and structure of charge transfer complex were determined by X-ray crystallography. • The crystalline nature of CT complex was investigated by Powder-XRD. • The Hirshfeld surfaces analyses of the CT complex have also been carried out. [ABSTRACT FROM AUTHOR]