Enhancing probe's sensitivity for peroxynitrite through alkoxy modification of dicyanovinylchromene.

An intramolecular charge transfer (ICT)-based fluorescent probe P-ONOO - was synthesized to detect ONOO - . After responding to peroxynitrite, the dicyano-vinyl group of P-ONOO - generates the aldehyde group, emitting strong green fluorescence accompanied by quenching of the yellow fluorescence. According to the calculated Fukui function, the modification of the alkoxy group can enhance the f + of P-ONOO - , which can enhance the probe's nucleophilic addition reactivity with ONOO - . It has been experimentally verified that P-ONOO - shows fast response (within 30 s), excellent sensitivity (the detection limit = 10.4 nM), and good selectivity towards ONOO - . Additionally, the probe P-ONOO - has high membrane permeability and good biocompatibility, which can image endogenous ONOO - and exogenous ONOO - in HeLa cells.