Radical cations from diarylamino-substituted fluorenones

Chemical oxidation of diarylamino-substituted fluorenones gives highly persistent radical cations, some of which can be stored in the solid state for months. Solution UV-vis-NIR spectra show strong monoradical cation absorption bands in the 750-1700 nm range, with minimum energy about 0.73 eV. 2,7-Bis(dianisylamino)fluorenone exhibits strong absorptions at 1670 (monocation) and 873 nm (dication). Fast intervalence electron transfer behavior between amine sites in the monocation is indicated by EPR spectroscopic and absorption spectral Hush analyses.

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