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Fluorogenic Sydnone-Modified Coumarins Switched-On by Copper-Free Click Chemistry
journal contribution
posted on 2018-07-11, 19:20 authored by Camille Favre, Frédéric FriscourtThe synthesis, photophysical
characterization, and biochemical
application of sydnone-modified coumarins, a novel class of fluorogenic
clickable reagents, are reported. The sydnone moiety, a stable aromatic
1,3-dipole, efficiently quenched the fluorescence of coumarin, which
could be restored, with a 132-fold enhancement, upon cycloadditions
with cyclooctynes, thereby expanding the fluorogenic click toolbox.
TD-DFT calculations suggest that the fluorescence quenching of the
sydnone-modified coumarins is likely due to the presence of an energetically
low-lying nonemissive charge-separated state.