A coumarin-based near-infrared fluorescent probe with a large Stokes shift for the sequential recognition of Ni2+ and CN−: performance research and quantum calculation

Publication date: Available online 18 June 2019Source: Journal of Photochemistry and Photobiology A: ChemistryAuthor(s): Kai Wang, Chengxi Zhao, Shaohua Guo, Yunxiang Lu, Yongjia Shen, Chengyun WangAbstractThe design and synthesis of bifunctional probes have gradually become a new research focus in the field of fluorescent probes. In this work, a reversible colorimetric and NIR fluorescent probe (Ni−3) for the sequential detection of Ni2+ and CN− was developed based on 3-benzothiazolyl-7-hydroxycoumarin. This probe featured a large Stokes shift (145 nm) and excellent anti-fatigue performance for the sequential detection of Ni2+ and CN−. Ni−3 showed a highly colorimetric response to Ni2+ and the selectivity could be distinguished by naked eyes. Besides, Ni−3 also exhibited selective NIR fluorescence response toward Ni2+ due to the paramagnetic effect and the chelation-enhanced quenching (CHEQ) effect. Additionally, the in situ generated complex [2 Ni−3 + Ni2+] showed highly sensitive and selective sensing ability for CN− via Ni2+ displacement approach. The limit of detection toward CN− (1.29 μM) was lower than the maximum acceptable concentration level of cyanide in drinking water (1.9 μM) set by WHO. Furthermore, a “paralleled-coordination” mode between Ni−3 and Ni2+ was proposed and demonstrated with the aid of quantum calculations.Graphical AbstractA coumarin-based reversible colorimetric and near-infrared fluorescent probe (Ni−3) for the seq...

Source: Journal of Photochemistry and Photobiology A: Chemistry - June 18, 2019 Category: Chemistry Source Type: research