Jump to main content
Jump to site search


A Highly Selective Fluorescence Turn–On Chemosensor for Zn2+, its Application in Live Cell Imaging, and a Colorimetric Sensor for Co2+: Experimental and TD-DFT Calculations

Abstract

A small fluorogenic molecule Hbpq, N-(quinoline-8-yl)pyridine-2-carboxamide, for monitoring Zn(II) ions in vitro has been synthesized. Hbpq, prepared by a facile eco-friendly one-pot synthesis under mild reaction conditions with high efficiency, selectively exhibits a ∼120-fold increase in fluorescence intensity upon addition of half equivalent of Zn2+. The chemoselective response of Hbpq to the Zn2+ ion in the presence of interfering ions in acetonitrile has also been examined. The results of the Job's plot experiment, the fluorescence and UV–vis titration, and ESI-MS, indicate that the binding stoichiometric ratio between Hbpq and Zn2+ in acetonitrile is 2:1. Single crystal X-ray structure determination of the zinc complex, synthesized independently, also confirms the formation of mononuclear Zn(bpq)2. In addition, Hbpq acts as a sensitive optical chemosensor for Co2+ ion in acetonitrile. The association constant (Ka) and limit of detection (LOD) for Zn2+ and Co2+ complexes are also calculated. The cytotoxicity of Hbpq has been examined, and its applicability for visualizing intracellular Zn2+ has been demonstrated. Importantly, the MTT assay and cell imaging experiments show that Hbpq exhibits low cytotoxicity, good cell membrane permeability, and high potential for monitoring Zn2+ ions in vitro. The weak emission of Hbpq in MeCN solution is highly sensitive to the presence of water being almost quenched, however this sensor behaves like a molecular light switch after entering the living cell and being surrounded by a hydrophobic environment. DFT/TD-DFT calculations have also been employed to support the binding mode and photophysical properties of Hbpq towards Zn2+ and the enhancement of its fluorescence by Zn2+ in living cells.

Back to tab navigation

Supplementary files

Publication details

The article was received on 31 Mar 2018, accepted on 07 Jun 2018 and first published on 07 Jun 2018


Article type: Paper
DOI: 10.1039/C8NJ01580E
Citation: New J. Chem., 2018, Accepted Manuscript
  •   Request permissions

    A Highly Selective Fluorescence Turn–On Chemosensor for Zn2+, its Application in Live Cell Imaging, and a Colorimetric Sensor for Co2+: Experimental and TD-DFT Calculations

    M. Sohrabi, M. Amirnasr, S. Meghdadi, M. Lutz, M. Bikhof Torbati and H. Farrokhpour, New J. Chem., 2018, Accepted Manuscript , DOI: 10.1039/C8NJ01580E

Search articles by author

Spotlight

Advertisements