Ratiometric fluorescent Zn2+ chemosensor constructed by appending a pair of carboxamidoquinoline on 1,2-diaminocyclohexane scaffold

Xiaobo Zhou, Yunguo Lu, Jian Fa Zhu, Wing Hong CHAN*, Albert W M LEE, Pui Shan Chan, Ricky N S WONG, Nai Ki MAK

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


By appending a pair of carboxamidoquinoline pendants onto 1,2-diaminocyclohexane scaffold via N-alkylation, multifunctionalized ACAQ was designed and synthesized as a water soluble fluorescent ratiometric chemosensor for Zn2+. In 50% aqueous methanol buffer pH 7.4 solution, upon excitation at 316 nm, ACAQ (5 μM) displayed a selective ratiometric fluorescence changes with a shift from 410 to 490 nm in response to the interaction with Zn2+. After binding with 1 equiv of Zn2+, ACAQ exhibited a 12-fold enhancement in I490/I410 characterized by a clear isoemissive point at 440 nm. The metal sensor binding mode was established by Job's plot and the combined fluorescence and 1H NMR spectroscopic method. The selectivity of the probe toward biological relevant cations and transition metal ions was proven to be good. In addition, the interference caused by Cu2+ and Cd2+ in the quantitation of Zn2+ can be completely eliminated by the use of diethyldithiocarbamate as the screening agent. Exploitation of ACAQ as the sensing probe, ratiometric determination of Zn2+ with the limit of detection (LOD) at 28.3 nm can be realized. In addition, the unique responsive properties of the probe toward Fe3+ and Zn2+ were used to construct a fluorescent switch. The membrane permeability of ACAQ to living cells and bio-imaging of Zn2+ were demonstrated.

Original languageEnglish
Pages (from-to)3412-3419
Number of pages8
Issue number19
Publication statusPublished - 13 May 2011

Scopus Subject Areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

User-Defined Keywords

  • Cell imaging
  • Fluorescence
  • Molecular switch
  • Ratiometric
  • Zinc chemosensor


Dive into the research topics of 'Ratiometric fluorescent Zn<sup>2+</sup> chemosensor constructed by appending a pair of carboxamidoquinoline on 1,2-diaminocyclohexane scaffold'. Together they form a unique fingerprint.

Cite this