A highly fluorescent metal organic framework probe for 2,4,6-trinitrophenol detection via post-synthetic modification of UIO-66-NH2

Metal organic frameworks (MOFs) have been hotly concerned due to their unique structure and properties. A new highly fluorescent MOF was developed via post-synthesis of UIO-66-NH2 through an efficient click reaction with 1-ethynylpyrene for the 2,4,6-trinitrophenol (PA) detection which named UIO-66-Py. It exhibited a significantly enhanced fluorescence intensity than UIO-66-NH2 and showed excellent selectivity and sensitivity for sensing PA in solution via the fluorescence quenching mechanism. The UIO-66-Py showed an 85% fluorescence quenching efficiency with 0.203 mM PA and the detection limit was 4.5 x 10(-7) M. The excellent selectivity of the probe was ascribed to the hydrogen bond interaction between UIO-66-Py and PA as evidenced by FT-IR. The hydrogen bond interaction promoted the photo-induced electron transfer (PET) between UIO-66-Py and PA which leading to the better selectivity of UIO-66-Py for PA detection over TNT. This post-synthetic modification idea provided a strategy for the development of MOFs with multifunctional sensing.