The first example of "turn-off" red fluorescence photoswitching for the representatives of nitrile-rich negative photochromes

Representatives of negative photochromes containing a nitro-substituted 2-vinylphenolic fragment and a tricyanofuran (TCF) acceptor were synthesized. An efficient "turn-off" fluorescence photoswitching with full reversibility was shown for these compounds due to the negative photochromic transformation under irradiation by visible light. The obtained result reveals a new direction in the investigation of fluorescence photoswitching because of the great potential for structural variability of insufficiently studied nitrile-rich photochromes. The first example of reversible fluorescence photoswitching by visible light was shown for the representatives of negative photochromes containing a nitrile-rich acceptor.