title: Quinolinium-based fluorescent probes for the detection of thiophenols in environmental samples and living cells.
abstract: 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.
authors.affiliation: Department of Chemistry, Joint Laboratory of Green Synthetic Chemistry, University of Science and Technology of China, Hefei 230026, PR China.
authors.forename: Xiu-Ling
authors.initials: XL
authors.lastname: Liu
authors.forename: Xue-You
authors.initials: XY
authors.lastname: Duan
authors.forename: Xiao-Jiao
authors.initials: XJ
authors.lastname: Du
authors.forename: Qin-Hua
authors.initials: QH
authors.lastname: Song
mesh_terms: D045744:Cell Line, Tumor; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010636:Phenols / Q000032:analysis*; D011806:Quinolinium Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013438:Sulfhydryl Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D010636:Phenols; D011806:Quinolinium Compounds; D013438:Sulfhydryl Compounds; C042983:thiophenol