Establishment of highly sensitive and selective fluorescent sensor for Fe3+ based on a post-synthetic modification of metal-organic framework

A post-synthetic modification method was developed to prepare fluorescent metal organic frameworks by the covalent interaction of ethoxycarbonyl isothiocyanate with amine functionalized UMCM-4. X-ray diffraction spectrometry , X-ray photoelectron spectrometry, elemental analysis , Fourier-transformed infrared spectroscopy, nuclear magnetic resonance spectrometry, thermogravimetric analysis/derivative thermogravimetry analysis, and nitrogen sorption isotherms were employed to characterize the modified metal organic frameworks. With high emission efficiency and excellent fluorescence stability, the sensing properties of Fe 3+ were studied. Possible mechanisms of energy and electron transfers between the target and the fluorescent probe were demonstrated. Effects of response time, Fe 3+ concentration, and other metal ions on the fluorescence intensity were also studied.