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Chiral Near‐Infrared Fluorophores by Self‐Promoted Oxidative Coupling of Cationic Helicenes with Amines/Enamines
Author(s) -
Bosson Johann,
Labrador Geraldine M.,
Besnard Céline,
Jacquemin Denis,
Lacour Jérôme
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202016643
Subject(s) - helicene , chemistry , cationic polymerization , chromophore , electrophile , photochemistry , oxidative coupling of methane , alkyl , fluorescence , acceptor , organic chemistry , molecule , catalysis , physics , quantum mechanics , condensed matter physics
In one pot, tertiary alkyl amines are oxidized to enamines by cationic dioxa[6]helicene, which further reacts as electrophile and oxidant to form mono or bis donor‐π‐acceptor coupling products. This original and convergent synthetic approach provides a strong extension of conjugation yielding chromophores that absorb intensively in far‐red or NIR domains ( λ max up to 791 nm) and fluoresce in the NIR as well ( λ max up to 887 nm). Intense ECD properties around 790 nm with a |Δ ϵ | value up to 60 M −1 cm −1 are observed.