title: From nonconjugation to conjugation: novel meso-OH substituted dipyrromethanes as fluorescence turn-on Zn2+ probes.
abstract: Most reported Zn(2+) probes suffer from the interference of background fluorescence originated from the conjugated structures of commonly utilized fluorophores. In this work, three novel meso-hydroxyl group substituted dipyrromethanes DPMOH1-DPMOH3 were synthesized and found to be colourless and nonfluorescent due to the interruption of the conjugated π system by an sp(3) carbon between the two pyrrolic units. Interestingly, only the addition of Zn(2+) to the solutions of DPMOH1-DPMOH3 promoted their oxidation to dipyrrin forms, and bright fluorescence "turn on" was observed due to the formation of corresponding dipyrrin complexes with the dipyrrin : zinc stoichiometry of 2 : 1. Zn(2+) detection mechanism was investigated by UV-Vis, fluorescence, (1)H NMR and HRMS analyses, which can be ascribed to the CHEF type fluorescence enhancement, resulting from good rigidity of the dipyrrin complexes. Hence, DPMOH1-DPMOH3 can be used as fluorescence turn-on Zn(2+) probes with the advantage of no background fluorescence.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai, P. R. China.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Ding
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Weihong
authors.initials: W
authors.lastname: Zhu
authors.forename: Yongshu
authors.initials: Y
authors.lastname: Xie
mesh_terms: D002413:Cations, Divalent / Q000032:analysis; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011758:Pyrroles / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D015032:Zinc / Q000032:analysis*
chemical_list: D002413:Cations, Divalent; D005456:Fluorescent Dyes; D011758:Pyrroles; C512015:dipyrromethane; D015032:Zinc