title: α-Monoacylated and α,α'- and α,β'-diacylated dipyrrins as highly sensitive fluorescence "turn-on" Zn2+ probes.
abstract: With the purpose of developing readily synthesized CHEF (chelation-enhanced fluorescence) type Zn(2+) probes with relatively simple molecular structures and excellent sensing behavior, p-anisoyl chloride was used for the acylation of 5-(pentafluorophenyl)dipyrromethane. Interestingly, the α,β'-diacylated product PS2 with a unique substitution mode was obtained in high yield in addition to the normal α-substituted mono- and diacylated products PS1 and PS3. Further oxidation of PS1-PS3 afforded dipyrrins S1-S3. Crystal structure and (1)H NMR measurements of S2 demonstrate the existence of a pure tautomer, which is consistent with DFT calculations. S1-S3 show highly Zn(2+) selective "turn-on" fluorescence based on a CHEF mechanism by the formation of 2:1 (probe:metal) Zn(2+) complexes. The emission colors can be easily tuned from green to red by changing the dipyrrin substitution modes. Furthermore, these probes demonstrate fast responses and wide applicable pH ranges. Among them, S2 shows the highest Zn(2+) sensitivity, with a detection limit of 4.4 × 10(-8) M.
authors.affiliation: Key Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, People's Republic of China.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Ding
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Tong
authors.initials: T
authors.lastname: Li
authors.forename: Weihong
authors.initials: W
authors.lastname: Zhu
authors.forename: Yongshu
authors.initials: Y
authors.lastname: Xie
mesh_terms: D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D009942:Organometallic Compounds; D011725:Pyridines; D015032:Zinc