Procainamide Charge Transfer Complexes with Chloranilic Acid and 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone: Experimental and Theoretical Study

Abstract

The formation of charge transfer (CT) complexes between bioactive molecules and/or organic molecules is an important aspect in order to understand ‘molecule-receptor’ interactions. Here, we have synthesized two new CT complexes, procainamide-chloranilic acid (PA-ChA) and procainamide-2,3-dichloro-5,6-dicyano-1,4-benzoquinone (PA-DDQ), from electron donor procainamide (PA), electron acceptor chloranilic acid (ChA), and 2, 3-dichloro 5, 6-dicyano-1,4-benzoquinone (DDQ). The structures of these two CT complexes were elucidated /characterized using FTIR, NMR, and many other spectroscopic methods. A stability study of each complex was conducted for the first time using various spectroscopic parameters (e.g., formation constant, molar extinction coefficient, ionization potential oscillator strength, dipole moment, and standard free energy). The formation of CT complexes in solution was confirmed by spectrophotometric determination. The molecular composition of each complex was determined using the spectrophotometric titration method and gave a 1:1 (donor: acceptor) ratio. In addition, the formation constant was determined using the Benesi–Hildebrand equation. To understand the noncovalent interactions of the complexes, density functional theory (DFT) calculations were performed using the ωB97XD/6-311++G(2d,p) level of theory. The DFT-computed interaction energies (ΔIEs) and the Gibbs free energies (ΔGs) were in the same order as observed experimentally. The DFT-calculated results strongly support our experimental results.

DFT Study of Charge Transfer Complexes Between Norfloxacin and Ciprofloxacin Drugs with Picric Acid and 3,5-Dinitrobenzoic Acid Acceptors

“…The variances in interaction energies between complexes [(cip)(PA)], [(nor)(PA)], and [(nor)(DNBA)] can be linked to the varying ability of the donor molecule to act as a donor, which can be directly correlated to the ionization potential values of the donors [20].…”

Special Issue: Synthesis, Application, and Biological Evaluation of Chemical Organic Compounds

“…In their article [8], Rahman and colleagues describe the development of charge transfer (CT) complexes between organic and/or bioactive compounds, which is a crucial component in understanding molecule-receptor interactions. They created two novel CT complexes, procainamide-chloranilic acid and procainamide-2,3-dichloro-5,6-dicyano-1,4benzoquinone, using the electron donor procainamide, electron acceptor chloranilic acid, and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.…”