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Quinolinium‐Based Fluorescent Probes for the Detection of Thiophenols in Environmental Samples and Living Cells
Author(s) -
Liu XiuLing,
Duan XueYou,
Du XiaoJiao,
Song QinHua
Publication year - 2012
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201200594
Subject(s) - fluorophore , fluorescence , nucleophile , chemistry , detection limit , nucleophilic substitution , photochemistry , molecule , combinatorial chemistry , organic chemistry , catalysis , chromatography , optics , physics
A new type of fluorescent probes for thiophenols, 6HQM‐DNP and 7HQM‐DNP, containing 6‐ or 7‐hydroxy quinonlinium as fluorophore and 2,4‐dinitrophenoxy (DNP) as nucleophilic recognition unit were constructed. As ethers, these non‐fluorescent probe molecules can release the corresponding fluorescent quinolinium (6HQM and 7HQM) through aromatic nucleophilic substitution (S N Ar) by thiolate anions from thiophenols. The sensing reaction is highly sensitive (detection limit of 8 n M for 7HQM‐DNP) and highly selective to thiophenols over aliphatic thiols and other nucleophiles under neutral conditions (pH 7.3). The probes respond rapidly to thiophenols, with second‐order rate constants k =45 M −1 s −1 for 7HQM‐DNP and 24 M −1 s −1 for 6HQM‐DNP. Furthermore, the selective detection of thiophenols in living cells by 7HQM‐DNP was demonstrated by confocal fluorescence imaging. In addition, these quinolinium salts show excellent chemical and thermal stability . In conclusion, this type of probes may find use in the detection of thiophenols in environmental samples and biosystems.