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

Abstract

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-I 2 in several organic solvents of different polarities have performed clear charge transfer (CT) band(s). Formation constants ( K CT) and molar absorption coefficients ( ε CT) and thermodynamic properties, Δ H, Δ S, and Δ G, 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.