Insights into the anion effect on the self assembly of perylene bisimide diimidazolium salts

Abstract

We studied how changing the anion affects the self-assembly of three diimidazolium salts bearing a perylene bisimide spacer. In particular we used [BF4−] and [NTf2−] based salts together with a mixed salt bearing both [I−] and [BF4−] anions. Thermal as well as concentration and temperature dependent spectroscopic investigations revealed that changing the anion impacts on solid state and solution aggregation, leading to articulate thermotropic behaviors and contrasting solvent effects, respectively. We also studied the electrochemical behavior of the salts to verify if changing the anion alters the redox properties of the salts. Finally, different anions also lead to very different aggregate morphologies, as evidenced by SEM and TEM measurements.