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Sensors 2017, 17(11), 2517;

A Ratiometric Fluorescent Sensor for Cd2+ Based on Internal Charge Transfer

Chemical Engineering College, Qinghai University, Xining 810016, China
Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84108, USA
These authors contributed equally to this work.
Authors to whom correspondence should be addressed.
Received: 9 October 2017 / Revised: 26 October 2017 / Accepted: 31 October 2017 / Published: 2 November 2017
(This article belongs to the Special Issue Fluorescent Probes and Sensors)
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This work reports on a novel fluorescent sensor 1 for Cd2+ ion based on the fluorophore of tetramethyl substituted bis(difluoroboron)-1,2-bis[(1H-pyrrol-2-yl)methylene]hydrazine (Me4BOPHY), which is modified with an electron donor moiety of N,N-bis(pyridin-2-ylmethyl)benzenamine. Sensor 1 has absorption and emission in visible region, at 550 nm and 675 nm, respectively. The long wavelength spectral response makes it easier to fabricate the fluorescence detector. The sensor mechanism is based on the tunable internal charge transfer (ICT) transition of molecule 1. Binding of Cd2+ ion quenches the ICT transition, but turns on the π − π transition of the fluorophore, thus enabling ratiometric fluorescence sensing. The limit of detection (LOD) was projected down to 0.77 ppb, which is far below the safety value (3 ppb) set for drinking water by World Health Organization. The sensor also demonstrates a high selectivity towards Cd2+ in comparison to other interferent metal ions. View Full-Text
Keywords: ratiometric fluorescent sensor; Me4BOPHY; Cd2+ ion; ICT ratiometric fluorescent sensor; Me4BOPHY; Cd2+ ion; ICT

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Cheng, D.; Liu, X.; Xie, Y.; Lv, H.; Wang, Z.; Yang, H.; Han, A.; Yang, X.; Zang, L. A Ratiometric Fluorescent Sensor for Cd2+ Based on Internal Charge Transfer. Sensors 2017, 17, 2517.

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