Two Indium(III)-based Fluorescent Metal-Organic Frameworks for Highly Sensing Fe^(3+),2,4-DNP,and TNP

Two novel metal-organic frameworks(MOFs),JLU-MOF130([In(NH2−BDC)(Imi)(1H−Imi)]·DMF·H2O,NH2−H2BDC=2-aminobenzene-1,4-dicarboxylic acid,1H−Imi=1H-imidazole,DMF=N,N-dimethylformamide)and JLU-MOF131([In(1,4-NDC)(Imi)(1H−Imi)]·DMF0.5,1,4-H_(2)NDC=1,4-naphthalene-dicarboxylic acid),were synthesized.JLU-MOF130 features a three-dimensional(3D)architecture with a neb topology.JLU-MOF131 is characterized by a two-dimensional(2D)structure with an sql topology.JLU-MOF130 has excellent fluorescence detection performance towards Fe^(3+),2,4-dinitrophenol(2,4-DNP),and 2,4,6-trinitrophenol(TNP),but the fluorescence detection performance of JLU-MOF131 is further improved by converting NH2−H2BDC to more conjugated 1,4-H_(2)NDC.The Stern-Volmer(SV)quenching constant(KSV)values of JLU-MOF130 sensing 2,4-DNP,TNP,and Fe^(3+)are 5.24×10^(4),4.44×10^(4),and 4.73×10^(3) L/mol,respectively.The corresponding limit of detection(LOD)values are 1.17,1.36,and 14.59µmol/L.The KSV values for JLU-MOF131 are 1.26×10^(5),9.02×10^(4),and 8.48×103 L/mol,and the corresponding LOD values are 0.35,0.42,and 3.60µmol/L,respectively.interestingly,the emission wavelengths of the two MOFs obviously shift as the fluorescence emission intensities decrease upon the addition of 2,4-DNP and TNP,which can be applied in selective detection.