The effect of the linking topology on the electrochemical and spectroelectrochemical properties of carbazolyl substituted perylene bisimides

We report on electrochemical and spectroelectrochemical characteristics of two isomeric, carbazolyl substituted perylene bisimides and their polymers. Investigations were carried out in order to determine the effect of the linking topology on their properties. Cyclic voltammetry (CV) measurements of the investigated monomers showed typical two-step reduction of the perylene diimide moiety. The electrochemical oxidation of the studied compounds gave the corresponding polymer, which was deposited on the electrode. The resulting films were also examined by cyclic voltammetry. Investigation indicated both: n-type and p-type doping of polymers. Analysis of redox process of the monomers and polymers was carried out using UV-Vis and EPR spectroscopy. Our studies point to differences in the kinetics of the reduction process, depending on the substitution of the carbazole moiety. Although both monomers easily undergo of electrochemical polymerization, an effect of the linking topology of carbazolyl substituted perylene bisimides on the polymerization process was evidently noticed. Monomer PE2 as well as PE3 led to stable polymers, but polymer based on PE3 displays the conjugation in a longer extend than that based on PE2, where carabazole is linked to perylene diimide at less favorable position 2.