Ambient Water-Stable Dianionic Electron Donors: Intramolecular Noncovalent Conduits Assist Charge Delocalization

Electron-rich π-conjugated dianions are known to be ambient unstable and their stabilization in ambient water is yet to be realized. We report the first example of an exceptionally stable naphthalenediimide-based dianion in ambient and hot water, forming one of the most stable redox-active dianion. The half-life (t_1/2 ) of dianion (1 a^2- ) is more than four months in ambient water. The dianionic state was confirmed by X-ray crystallography and by various spectroscopic methods. The noncovalent electronic conduits introduced for the first time in dianions, embrace n_O →π*_C≡N interactions and aid in delocalizing the dianionic charge as validated from theoretical studies. The dianions harness strong NIR absorption and electron donor ability to organic acceptors and metal ions, which make them suitable for potential green energy applications.