Alkyl- and aryl-substituted benzo[ghi]perylenetriimides: Synthesis, characterization and comparison of electrochemical and spectroscopic properties

Benzo[ghi]peryleneimides constitute a unique class of fluorescent perylene dyes which possesses great synthetic diversity due to the presence of a large number of reactive active sites (availability of third imide region). Taking advantage of this additional active site we synthesized a new series of benzo[ghi]perylenetriimides comprised of alkyl- and aryl-substituents in the third imide region. The core extension of perylene diimides was performed using a Diels-Alder reaction to afford diimido anhydride (3) which provided access to the various triimides with yields ranging from 58% to 69%. The combined spectroscopic and electrochemical studies revealed strong electron accepting properties of the triimides. Potential application of the synthesized triimides for various optoelectronic devices and as non-fullerene electron acceptors in photovoltaics is evident from this study.