Exploring ellagic acid as a building block in the design of organic semiconductors

Ellagic acid (H4EA), a natural polyphenol, is an ideal candidate in the search for sustainable materials for use in organic electronics due to its strong resemblance to other well-known polyaromatic hydrocarbons being employed in the field such as pyrene. The work presented herein focuses on the functionalization of H4EA with aryl moieties via SNAr reactions, thereby affording a facile two-step approach to tailor the optoelectronic properties of the resulting organic semiconductors. In particular, pyrazine and quinoxaline moieties were selected to due to the presence of additional nitrogen atoms along with the π-system afforded through their molecular frameworks. The results presented demonstrate that such functionalization of H4EA does in fact impact the finetuning of the photophysical and structural properties of the resulting materials. Although performance was less than ideal when implemented into thin-film transistors, this may be attributed to poor film morphology. Nonetheless, this work introduces new green materials to the field, through which facile functionalization can be realized.