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. [ABSTRACT FROM AUTHOR]