Dual-Function Metal–Organic Framework as Efficient Turn-Off Sensor for Water and Unusual Turn-On Sensor for Ag<sup>+</sup>
Ting Zhou, Shuang Liu, Xianmin Guo, Qiang Wang, Lianshe Fu, Shengyong Mi, Pan Gao, Qijin Su, Huadong Guo
Abstract
Fluorescent sensors have been extensively employed in efficient energy utilization and environment protection. In this work, an amino-decorated metal–organic framework [Cd(3-NH2-pba)2]4·8DMF (3-NH2-Hpba = 3-amino-4-(pyridin-4-yl)benzoic acid) was synthesized as a dual-function fluorescent sensor through the distinctive interaction of amino moieties with analytes. This compound exhibits highly sensitive turn-off sensing of trace water in ethanol with a detection limit to 0.09%, much below the required values for hydrated ethyl alcohol fuel internationally. Meanwhile, it can also be developed as an unusual turn-on sensor for the probe of Ag+ in aqueous solution with the detection limit to 0.44 μM, lower than the maximum concentration of Ag+ in drinking water according to the standard of the U.S. Environmental Protection Agency. It is the first example of MOF-based fluorescent sensor for simultaneously detecting trace water and Ag+.