Interaction of atenolol with iodine: a novel structural formula of charge transfer complexes

Abstract

Interaction of atenolol (ATE), as an electron donor, with iodine (I2), as a typical σ-electron acceptor, has been studied. This interaction occurs in several remarkable steps. The first step is the initial formation of the ATE–I2 outer charge transfer (CT) complex, meanwhile this interaction ends with the formation of the solid CT complex which has the stoichiometric ratio 4:2 (ATE:I2). The synthesized solid CT complex has a novel and amazing structural formula in which hydrogen bonds exist side by side with the CT binding. Formation constants, molar absorption coefficients, and thermodynamic properties, ΔH, ΔS, and ΔG, of this ATE/I2 interaction have been determined and discussed. The different structural forms of the ATE/I2 complexes which occur in each of the different formation steps, involving their stoichiometric ratios, have been determined and confirmed. Several techniques involving UV/Visible, FT-IR, 1H NMR, and Mass spectra have been used in this study. In addition, morphology of the synthesized solid complex has been investigated by the scanning electron microscope. The charge transfer (CT) interaction between atenolol (ATE) and iodine (I2) occurs in several remarkable steps starting with an initial formation of the ATE–I2 outer CT complex and ending by formation of the solid CT complex having the stoichiometric ratio 4:2 (ATE:I2). The synthesized solid CT complex has a novel and amazing structural formula in which hydrogen bonds exist side by side with the CT binding. Several techniques involving UV/Visible, FT-IR, 1H NMR, and Mass spectra have been used in this study. In addition, morphology of the synthesized solid complex has been investigated by the scanning electron microscope (SEM).