Interaction of 2-aminopyrimidine with σ- and π-acceptors involving chemical reactions via initial charge transfer complexation

Interaction of 2-aminopyrimidine (AP) with iodine as a typical σ-type acceptor and with a typical π-type acceptor, 2,3,5,6-tetrachloro-1,4-benzoquinone, p-chloranil (CHL) have been studied spectrophotometrically. Electronic absorption spectra of the system AP-I2 in several organic solvents of different polarities have performed clear charge transfer (CT) band(s). Formation constants (KCT) and molar absorption coefficients (εCT) and thermodynamic properties, ΔH, ΔS, and ΔG, of this system in various organic solvents were determined and discussed. Interaction of AP with the π-acceptor has shown unique behaviors. Chemical reaction has occurred via prior or initial formation of the outer-sphere CT complex followed by formation of the corresponding anion radicals, CHL−, as intermediates. UV–vis, 1H NMR, Mass, and FT-IR spectra in addition to the elemental analysis were used to confirm the proposed occurrence of the chemical reaction and to investigate the synthesized solid products.