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A coumarin based highly selective fluorescent chemosensor for sequential recognition of Cu2+ and PPi

Meng, Xianjiao, Cao, Duanlin, Hu, Zhiyong, Han, Xinghua, Li, Zhichun, Liang, Dong, Ma, Wenbing
Tetrahedron letters 2018 v.59 no.49 pp. 4299-4304
anions, chemical reactions, chemical structure, copper, coumarin, fluorescence, nuclear magnetic resonance spectroscopy, pH stability, phosphates, quinolones, receptors, stoichiometry
In this study, we have successfully synthesized a new coumarin based fluorescent chemosensor 1, in which tren and quinolone are introduced as receptors for sequential recognition of Cu2+ and PPi. The structure of chemosensor 1 was characterized by 1H NMR, 13C NMR and ESI-HR-MS. Sensor 1 showed an obvious “on-off” fluorescence quenching response toward Cu2+, and the quenching efficiency reached a maximum of 99.6% with the addition of 20 equiv. of Cu2+. The 1-Cu2+ complex showed an “off-on” fluorescence enhancement response toward PPi over many competitive anions, especially HPO42− and H2PO4−. The detection limit of sensor 1 was 1.9 × 10−6 M to Cu2+ and 5.96 × 10−8 M to PPi. In addition, sensor 1 showed a 1:1 binding stoichiometry to Cu2+ and sensor 1-Cu2+ showed a 2: 1 binding stoichiometry to PPi in CH3CN/HEPES buffer medium (9:1 v/v, pH = 7.4). The stable pH range of sensor 1 to Cu2+ and 1-Cu2+ to PPi was from 4 to 8.