Charge Transfer Interaction Dynamics between MHQ and DNP: Synthesis, Spectroscopic Characterization, DNA Binding and Density Functional Theory Studies

Abstract

Abstract The e-donor 2-methyl-8-hydroxyquinoline (MHQ) and the e-acceptor 2, 4-Dinitrophenol (DNP) were both involved in the synthesis of a new charge transfer (CT) complex, which was then characterized experimentally as well as theoretically. The CT complex has a 1:1 stoichiometry. Formation constant (KCT), Molar absorptivity (εCT) and other spectroscopic physical measurements can all be determined with the help of the Benesi-Hildebrand equation. Several spectroscopic techniques were used to analyze the produced solid compound. 1H NMR, FT-IR, P-XRD and SEM-EDX analyses all established the presence of charge in addition with proton transfer in the resulting complex. Analysis of the complex DNA binding capability was carried out via electron absorption spectroscopy; the CT complex binding mechanism was determined to be intercalative, and the intrinsic binding constant (Kb) value was determined to be 4.2 x 106 M-1. To corroborate the results of the experiments, theoretical calculations were performed using DFT with a basis set of CAM-B3LYP/6-31 G (d, p). In accordance with the experimental findings, we calculated and analyzed the electrostatic potential maps (MEPs), geometrical parameters and Mullikan charges. The presence of an H-bond also affects the stability of the complex, in addition to e-transfer. The experimental findings are in agreement with the DFT calculations.