A novel chemosensor for the distinguishable detections of Cu2+ and Hg2+ by off-on fluorescence and ratiometric UV-visible absorption

Huie Jiang; Danni Tang; Nihao Li; Junwei Li; Zhijian Li; Qingxin Han; Xinhua Liu; Xunjin Zhu

doi:10.1016/j.saa.2020.119365

A novel chemosensor for the distinguishable detections of Cu²⁺ and Hg²⁺ by off-on fluorescence and ratiometric UV-visible absorption

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Apr 5:250:119365. doi: 10.1016/j.saa.2020.119365. Epub 2021 Jan 5.

Authors

Huie Jiang¹, Danni Tang², Nihao Li², Junwei Li², Zhijian Li², Qingxin Han², Xinhua Liu², Xunjin Zhu³

Affiliations

¹ College of Bioresources Chemistry and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi'an 710021, China; Department of Chemistry, Hong Kong Baptist University, Hong Kong, China. Electronic address: jianghuie@sust.edu.cn.
² College of Bioresources Chemistry and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science and Technology, Xi'an 710021, China.
³ Department of Chemistry, Hong Kong Baptist University, Hong Kong, China. Electronic address: xjzhu@hkbu.edu.hk.

PMID: 33418474
DOI: 10.1016/j.saa.2020.119365

Abstract

A novel dual-functional chemosensor, derived from the conjugation of rhodamine B with a quinoline derivative (RHQ), was firstly synthesized with high efficiency and cost-effectiveness for the distinguishable detections of Cu²⁺ and Hg²⁺ via ring-opening and ring-forming mechanism. The chemosensor exhibits highly selective and distinguishable responses for Cu²⁺ and Hg²⁺ in CH₃CN-H₂O (4:1, v/v) with off-on fluorescence and ratiometric ultraviolet-visible (UV-Vis) absorption changes. Additionally, Cu²⁺ is identified by opening a rhodamine spirocycle with a UV-Vis absorption band, at around 560 nm and fluorescence turn-on. Interestingly, Hg²⁺ is discerned by opening the rhodamine spirocycle and by generating a new special cycle for the quinoline unit. Resultantly, there were two UV-Vis absorption bands at around 365 nm and 560 nm, which were accompanied by fluorescence turn-on. Moreover, the chemosensor can quantitatively detect Cu²⁺ and Hg²⁺ by off-on fluorescence and ratiometric UV-Vis absorption changes, respectively. Furthermore, the chemosensor with low cytotoxicity could be successfully administered to monitor Cu²⁺ and Hg²⁺ in living cells. This work may pay the way for the development of dual-functional chemosensor for quantificationally detecting metal ions in environmental and biological systems.

Keywords: Cytotoxicity; Fluorescent imaging; Heavy metal ions; Living cells; Naked-eyes.