Fluorescence sensing of H2O in alcohols solvents based on instability of the by-product from synthesis of metal-organic framework

Abstract In this work, a novel composite FS@ZIF-9/Co-formate was successfully prepared for fluorescent sensing of H2O. Characterizations indicate that fluorescent FS molecules (fluorescein sodium) were incorporated into the composite composed of ZIF-9 and the impurity (Co-formate) derived from synthesis process of ZIF-9. Based on the great instability of Co-formate towards H2O, Co-formate can be quickly dissolved in H2O, which can further induce the release of fluorescent FS molecules. Interestingly, similar phenomenon cannot be found in the cases of other common organic solvents. Further, the material can detect H2O in various organic solvents including methanol, ethanol, and propanol. To the best of our knowledge, this is the first example for effective use of the impurity/by-products derived from MOFs synthesis in the field of sensing.