title: Highly selective fluorescent OFF-ON thiol probes based on dyads of BODIPY and potent intramolecular electron sink 2,4-dinitrobenzenesulfonyl subunits.
abstract: Two highly selective OFF-ON green emitting fluorescent thiol probes (1 and 2) with intense absorption in the visible spectrum (molar extinction coefficient ε is up to 73 800 M(-1) cm(-1) at 509 nm) based on dyads of BODIPY (as electron donor of the photo-induced electron transfer, i.e.PET) and 2,4-dinitrobenzenesulfonyl (DNBS) (as electron acceptor of the PET process) were devised. The single crystal structures of the two probes were determined. The distance between the electron donor (BODIPY fluorophore) and the electron acceptor (DNBS) of probe 2 is larger than that of probe 1, as a result the contrast ratio (or the PET efficiency) of probe 2 is smaller than that of probe 1. However, fluorescence OFF-ON switching effects were observed for both probe 1 and probe 2 in the presence of cysteine (the emission enhancement is 300-fold for probe 1 and 54-fold for probe 2). The fluorescence OFF-ON sensing mechanism is rationalized by DFT/TDDFT calculations. We demonstrated with DFT calculations that DNBS is ca. 0.76 eV more potent to accept electrons than the maleimide moiety. The probes were used for fluorescent imaging of cellular thiols.
authors.affiliation: State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian, P R China. guohm@dlut.edu.cn
authors.forename: Huimin
authors.initials: H
authors.lastname: Guo
authors.forename: Yingying
authors.initials: Y
authors.lastname: Jing
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Yuan
authors.forename: Shaomin
authors.initials: S
authors.lastname: Ji
authors.forename: Jianzhang
authors.initials: J
authors.lastname: Zhao
authors.forename: Xiaohuan
authors.initials: X
authors.lastname: Li
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Kan
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D002460:Cell Line; D018360:Crystallography, X-Ray; D003624:Darkness; D004139:Dinitrofluorobenzene / Q000031:analogs & derivatives / Q000737:chemistry; D004579:Electron Transport / Q000528:radiation effects; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory; D013050:Spectrometry, Fluorescence; D013438:Sulfhydryl Compounds / Q000032:analysis* / Q000737:chemistry; D013449:Sulfonamides / Q000737:chemistry*
chemical_list: C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; D001896:Boron Compounds; D005456:Fluorescent Dyes; D013438:Sulfhydryl Compounds; D013449:Sulfonamides; C045305:2,4-dinitrofluorobenzene sulfonic acid; D004139:Dinitrofluorobenzene