Experimental and spectroscopic studies of charge transfer reaction between sulfasalazine antibiotic drug with different types of acceptors.

The charge-transfer (CT) interactions between the electron donor sulfasalazine (SS) and the acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), p-chloranil (CHL), picric acid (PA) and iodine have been studied spectrophotometrically in CHCl(3) or CH(3) OH solutions. The formed solid CT complexes were also isolated and characterized through infrared, (1) H-NMR, mass spectra as well as elemental and thermal analysis. The CT complexes were discussed in terms of formation constant (K(CT) ), molar extinction coefficient (ε(CT) ), standard free energy (ΔG°), oscillator strength (f), transition dipole moment (µ), resonance energy (R(N) ) and ionization potential (I(D) ). The stoichiometry of these complexes was found to be 1:1 molar ratio and having the formulae [(SS)(DDQ)], [(SS)(CHL)], [(SS)(PA)] and [(SS)(2) I](+) · I(3) (-) , respectively. The charge transfer interaction was successfully applied to the determination of SS drug using mentioned σ and π-acceptors also, the results obtained herein are satisfactory for estimation of SS compound in the pharmaceutical form.