Analysis of charge-transfer complexes caused by the interaction of the antihypertensive drug valsartan with several acceptors in CH2Cl2 and CHCl3 solvents and correlations between their spectroscopic parameters

The charge-transfer (CT) interaction of the widely used antihypertensive drug valsartan (Val) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), tetrafluoro-1,4-benzoquinone (TFQ), and 7,7,8,8-tetracya noquinodimethane (TCNQ) resulted in new CT complexes [(Val)(DDQ)], [(Val)(TFQ)], and [(Val)(TCNQ)] that were characterized by Fourier transform infrared (FTIR) and ultraviolet-visible (UV/Vis) spectroscopies. The CT complexes were prepared in two non-polar solvents: dichloromethane (CH2Cl2) and trichloromethane (CHCl3) at room temperature. Val reacted with the acceptors via a 1:1 M ratio by donation electrons from Val's biphenyl rings to the aromatic ring of the acceptor (pi ->pi* interaction). Spectral results and the Benesi-Hildebrand approach were used to estimate the following spectroscopic parameters for the newly generated CT complexes: molar absorptivity (epsilon(max)), association constant (K-CT), energies parameters [ionization potential (I-P), interaction energy (E-CT), standard free energy change (Delta G degrees), and resonance energy (R-N)], transition dipole moment (mu), and oscillator strength (f). Statistical analyses indicated a strong correlation among several of these spectroscopic parameters. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the charge-transfer interaction between the widely used antihypertensive drug valsartan and three acceptors (DDQ, TFQ, and TCNQ) and characterized the generated CT complexes using spectroscopic methods. The analysis revealed correlations among these spectroscopic parameters.