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.

Detection of 2,4,6-trinitrophenol based on f-f transition of Eu^(2+)

In this paper,we designed Eu^(2+)-doped BaAlF_(5) and BaSiF_(6) downconversion nanophosphors with strong f-f transition emission to realize the quantitative detection of TNP.The surface of the as-prepared nanophosphors was modified by polyethylenimine(PEI) to increase the water solubility and to provide a pair of electrons to bind to the benzene ring in TNP,forming a Meisenheimer complex.The detection principle of TNP is based on luminescence resonance energy transfer(LRET) technology,where the PEI-functionalized BaAlF_(5):Eu^(2+) and BaSiF_(6):Eu^(2+) nanophosphors are used as energy donors and TNP is an energy acceptor.With increasing TNP concentrations,the luminescence intensity of the BaAlF5:Eu^(2+) and BaSiF6:Eu^(2+) nanophosphors at 359 nm [^(4)f_(7)(^(6)P_(7/2))→^(4)f_(7)(^(8)S_(7/2)) transition of Eu^(2+)] displays dramatic luminescent quenching.The BaAlF_(5):Eu^(2+)@PEI or BaSiF_(6):Eu^(2+)@PEI nanophosphor downconversion luminescent sensors show great sensitivity and selectivity and good linearity,and the detection limits of TNP are 0.57 and 2.82 ng/mL,respectively.

A Luminescent Metal-Organic Framework with LON Topology for Highly Effective Fluorescence Sensing of Fe^(3+) and TNP

A luminescent Ag-based metal-organic framework(compound 1)has been synthesized and its structure has been characterized.Compound 1 was fabricated using the Ag+and bbimb2−ligands and manifestes a rare LON topology.Compound 1 is selective not only in detecting traces of Fe^(3+)and 2,4,6-trinitrophenol(TNP)via luminescence quenching,but also demonstrates high selectivity in the presence of other competitors.Compound 1’s K sv values towards Fe^(3+)can reach as high as 9.3×l0^(3) L/mol,which is higher than those of several other MOF materials.It is also a recyclable luminous sensor with the potential to be utilized for detecting TNP.Hence,based on its characteristics,compound 1 can be regarded as a prospective luminescence sensor for detecting Fe^(3+)and TNP.