Rare Earth Ion Encapsulated Basket-like {Gd⊂P<sub>6</sub>Mo<sup>V</sup><sub>2</sub>Mo<sup>VI</sup><sub>16</sub>O<sub>73</sub>} Cage as Efficient Electrochemical Sensor and Fluorescent Probe for Cr(VI)
Jiaqi Niu, Yuan‐Yuan Ma, Xing Xin, Zhangang Han
Abstract
A rare basket-like Gd3+-encapsulated {Gd⊂P6MoV2MoVI16O73} cage has been successfully synthesized with the formula of (H2 bpp)6{GdMoV2MoVI16O49(HPO4)(PO4)5}2·11H2O (1) (bpp is 1,3-bi(4-pyridyl)propane). Crystal 1 displays electrochemically reversible redox behavior and fluorescent property, and can serve as a bifunctional electrochemical sensor and fluorescent probe for efficiently detecting chromium (Cr(VI)) in water. As electrochemical sensor, compound 1 showed good electrochemical activity for trace Cr(VI) with a high sensitivity of 0.151 μA·μM–1 and low detection limit of 0.202 μM (0.021 ppm). These parameters fully met the WHO standards. When using as fluorescence probe, the detection limit of compound 1 is as low as 8.7 μM for Cr(VI) in water.