Dual-Function Metal-Organic Framework as Efficient Turn-Off Sensor for Water and Unusual Turn-On Sensor for Ag+

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 mu M, 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+.

Automated summary

A dual-function fluorescent sensor was synthesized in this work, which can sensitively detect trace water in ethanol and Ag+ in aqueous solution. The detection limits of this sensor are much lower than the international standards, showing potential applications in environmental monitoring and energy utilization.