Synthesis of Stable, High-SOMO Zwitterionic Radicals: Enabling Intermolecular Electron Transfer between Naphthalenediimides.

Synthesis to enhance the electron donor ability of organic radicals has not been attempted due to reactivity challenges. Herein, naphthalenediimide-based (NDI•±) zwitterionic radicals are synthesized and isolated bestowing SOMO levels up to -4.04 eV. As a result, reduction of the NDI is realized with NDI•± radicals in their ground states. Notably, reduction of the NDI unit applying a π-electron donor is unprecedented and has been limited to inorganic/organometallic reagents or by light-driven excited states.