RUI: Aromatic Diimide-Stabilized Acenes, Biradicals, and Radical Ions

Macalester College, Saint Paul MN

Investigators

Abstract

In this project, funded by the Chemical Structure, Dynamic & Mechanism-B Program of the Chemistry Division, Professor Dennis Cao of the Chemistry Department at Macalester College is developing a new approach toward stabilizing molecular structures. These structures display promising organic materials properties but are limited by instabilities that prevent their industrial and medical applications. With these stabilized species, it will be possible to develop new carbon-based materials for use in wearable electronics as well as imaging agents for medical diagnosis. The project, which lies at the interface of organic and materials chemistry. will further provide authentic research experiences to undergraduate students in both classroom and research laboratory settings. The research program will take place at Macalester College, an exclusively undergraduate institution, and closely involve undergraduate students in all aspects of the scientific process, ranging from hypothesis testing to the dissemination of results. The creation of research modules for introductory organic laboratory courses will engage many Macalester undergraduates who otherwise could not participate in a chemistry research experience. This project seeks to exploit an ortho-aromatic diimide, known as mellophanic diimide, to provide stabilizing effects to three classes of unstable target motifs: linear (aza)acenes, open-shell biradical species, and radical ions. The electron withdrawing effect of the imide functional group is expected to prevent oxidative degradation that normally takes place in long (aza)acenes. These modifications will enable future investigations into their semiconducting properties. The incorporation of imides onto Clar sextet engineered aromatic compounds is anticipated to enhance their open-shell character, a feature that can be exploited in the development of two-photon absorbers and near-IR dyes. Cationic groups will be leveraged to increase the stability of the reduced states of the electron accepting mellophanic diimide under ambient conditions, setting the stage for paramagnetic and low-energy, radical-radical interaction investigations. The experimental work in the project spans organic synthesis and spectroscopic characterization and will be further supported by computations. It is expected that the findings of this project will facilitate the discovery of new organic optical and electronic materials. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.