Polymeric charge-transfer complexes: a study by electronic absorption spectroscopy

Abstract

The charge-transfer complex formation between an electron donor polymer, namely poly(2-vinyl pyridine) and low molecular weight acceptors namely 7,7′,8,8′-tetracyanoquinodimethane and iodine has been investigated by measuring electronic absorption spectra in dichloroethane at 25°C. The formation of charge-transfer complexes of 2-picoline with the same set of acceptors has also been studied as models for comparison. An alternative method has been proposed to determine the molar ratio and equilibrium constant for charge-transfer complex formation by electronic spectroscopy. The equilibrium constant and molar absorptivity for the polymeric complexes are found to be higher than those for the analogous model complexes. The charge-transfer complexes undergo an irreversible reaction to give a final product. The charge-transfer complexes have been studied by electron spin resonance spectra.