Department of Chemistry, Joint Laboratory of Green Synthetic Chemistry, University of Science and Technology of China, Hefei 230026, PR China.
Chem Asian J. 2012 Nov;7(11):2696-702. doi: 10.1002/asia.201200594. Epub 2012 Sep 11.
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 nM 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.
一种新型的硫酚荧光探针，6HQM-DNP 和 7HQM-DNP，含有 6-或 7-羟基喹啉鎓作为荧光团和 2,4-二硝基苯氧基（DNP）作为亲核识别单元。作为醚，这些非荧光探针分子可以通过硫酚的硫阴离子通过芳香亲核取代（S（N）Ar）释放相应的荧光喹啉鎓（6HQM 和 7HQM）。在中性条件下（pH 7.3），该传感反应对硫酚具有高灵敏度（7HQM-DNP 的检测限为 8 nM）和高选择性，对硫酚比对脂肪硫醇和其他亲核试剂具有高选择性。探针对硫酚的响应迅速，7HQM-DNP 的二级速率常数 k=45 M(-1) s(-1)，6HQM-DNP 的二级速率常数 k=24 M(-1) s(-1)。此外，通过共聚焦荧光成像证明了 7HQM-DNP 对活细胞中硫酚的选择性检测。此外，这些喹啉鎓盐表现出良好的化学和热稳定性。总之，这种类型的探针可能在环境样品和生物系统中检测硫酚方面有应用。
