title: Chiral-aminoquinoline-based fluorescent pH probe with large stokes shift for bioimaging.
abstract: The aminoquinoline derivatives, (R)- and (S)-2-phenyl-2-(quinolin-6-ylamino)ethan-1-ol (R-PEO and S-PEO), were synthesized by a tandem one-pot three-step CN coupling method where Smiles rearrangement was the key procedure. The selected compound R-PEO showed a significant fluorescence enhancement with a turn-on ratio over 98-fold and enabled the real time determination of proton concentration in acidic solution. The fluorescence intensity of R-PEO exhibited strong pH-dependent performance with a large Stokes shift (115nm) and responded linearly to minor pH change within the range of 3.8-6.0. With the help of1H NMR spectrum, we also confirmed the protonation of the quinoline unit should be the proposed reaction. Compared with the conjugated acid of N-hexylquinolin-6-amine (NQA), the conjugated acid of R-PEO shows significant planar intramolecular charge transfer (PICT) character. Furthermore, biological imaging proved that R-PEO probe can be used to monitor the pH change of S. cerevisiae in vivo.
authors.affiliation: The School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404100, China.
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Xie
authors.affiliation: The School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404100, China.
authors.forename: Xin-Ling
authors.initials: XL
authors.lastname: Zhang
authors.affiliation: The School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404100, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Xie
authors.affiliation: The School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404100, China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: The School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404100, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Wu
authors.affiliation: The School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing 404100, China. Electronic address: flyjd6400@163.com.
authors.forename: Jidong
authors.initials: J
authors.lastname: Yang
mesh_terms: D000634:Aminoquinolines / Q000138:chemical synthesis / Q000737:chemistry*; D016923:Cell Death; D049109:Cell Proliferation; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D021621:Imaging, Three-Dimensional; D066244:Proton Magnetic Resonance Spectroscopy; D011789:Quantum Theory; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000634:Aminoquinolines; D005456:Fluorescent Dyes
keywords: Bioimaging; CN coupling; Chiral aminoquinoline; Intramolecular charge transfer; Large Stokes shift; pH probe