Preparation of Eu0.075Tb0.925-Metal Organic Framework as a Fluorescent Probe and Application in the Detection of Fe3+ and Cr2O72

Luminescent Ln-MOFs (Eu0.075Tb0.925-MOF) were successfully synthesised through the solvothermal reaction of Tb(NO3)3·6H2O, Eu(NO3)3·6H2O, and the ligand pyromellitic acid. The product was characterised by X-ray diffraction (XRD), TG analysis, EM, X-ray photoelectron spectroscopy (XPS), and luminescence properties, and results show that the synthesised material Eu0.075Tb0.925-MOF has a selective ratio-based fluorescence response to Fe3+ or Cr2O72-. On the basis of the internal filtering effect, the fluorescence detection experiment shows that as the concentration of Fe3+ or Cr2O72- increases, the intensity of the characteristic emission peak at 544 nm of Tb3+ decreases, and the intensity of the characteristic emission peak at 653 nm of Eu3+ increases in Eu0.075Tb0.925-MOF. The fluorescence intensity ratio (I653/I544) has a good linear relationship with the target concentration. The detection linear range for Fe3+ or Cr2O72- is 10-100 μM/L, and the detection limits are 2.71 × 10-7 and 8.72 × 10-7 M, respectively. Compared with the sensor material with a single fluorescence emission, the synthesised material has a higher anti-interference ability. The synthesised Eu0.075Tb0.925-MOF can be used as a highly selective and recyclable sensing material for Fe3+ or Cr2O72-. This material should be an excellent candidate for multifunctional sensors.

Five water-stable luminescent CdII-based metal–organic frameworks as sensors for highly sensitive and selective detection of acetylacetone, Fe3+ and Cr2O72− ions

Five Cd^II-based MOFs with different topologies were prepared, in which 2 and 3 are rare examples which display excellent sensitivity, selectivity, recyclability and structural stability for detection of acac/Fe³⁺ and acac/Cr₂O₇²⁻, respectively.

Three water-stable luminescent two-dimensional CdII-based coordination polymers as sensors for highly sensitive and selective detection of Cr2O72− and CrO42− anions

Three 2D Cd^II-CPs with different topologies were prepared, in which 1 and 3 are rare examples which display excellent sensitivity, selectivity, recyclability and structural stabilities for the detection of Cr₂O₇²⁻/CrO₄²⁻.

Lanthanide contraction effect and white-emitting luminescence in a series of metal–organic frameworks based on 2,5-pyrazinedicarboxylic acid

A series of lanthanide and yttrium MOFs of two structural types [M₂(H₂O)₂(nmp)₂(pzc)₃] (1M) and [M₂(H₂O)₄(pzc)₃]·NMP·5H₂O (2M) (where M – lanthanide or yttrium cation, nmp – N-methyl-2-pyrrolidone, pzc²⁻ – 2,5-pyrazinedicarboxylate) was synthesized and characterized by single crystal and powder X-ray diffraction crystallography, TG, elemental analyses and IR-spectroscopy. The effect of lanthanide contraction has led to the fact that lanthanides at the beginning of the series (from lanthanum to gadolinium) have a structure different from the structure of lanthanides at the end of the series and yttrium (from terbium and beyond). According to PXRD patterns of the obtained samples mixed metal materials could be obtained not only as crystalline mixtures of two structure types but also as crystalline products of single structure type. Varying the ratio of lanthanides in the initial reaction mixture allowed us to obtain a wide color range of luminescence, including several near-white-light emitting samples.

Influence of the lanthanide contraction effect on the formation of a series of new MOFs and their wide colour range luminescence spectra.

Highly chemically and thermally stable lanthanide coordination polymers for luminescent probes and white light emitting diodes

A series of isomorphic of highly chemically and thermally stable lanthanide coordination polymers exhibit luminescent probe and warm white-light emission.

Multifunctional Ln-MOF Luminescent Probe for Efficient Sensing of Fe3+, Ce3+, and Acetone

A new series of five three-dimensional Ln(III) metal-organic frameworks (MOFs) formulated as [Ln₄(μ₆-L)₂(μ-HCOO)(μ₃-OH)₃(μ₃-O)(DMF)₂(H₂O)₄] _n {Ln³⁺ = Tb³⁺ (1), Eu³⁺ (2), Gd³⁺ (3), Dy³⁺ (4), and Er³⁺ (5)} was successfully obtained via a solvothermal reaction between the corresponding lanthanide(III) nitrates and 2-(6-carboxypyridin-3-yl)terephthalic acid (H₃L). All of the obtained compounds were fully characterized, and their structures were established by single-crystal X-ray diffraction. All products are isostructural and possess porous 3D networks of the fluorite topological type, which are driven by the cubane-like [Ln₄(μ₃-OH)₃(μ₃-O)(μ-HCOO)]⁶⁺ blocks and μ₆-L^3- spacers. Luminescent and sensing properties of 1-5 were investigated in detail, revealing a unique capability of Tb-MOF (1) for sensing acetone and metal(III) cations (Fe³⁺ or Ce³⁺) with high efficiency and selectivity. Apart from a facile recyclability after sensing experiments, the obtained Tb-MOF material features a remarkable stability in a diversity of environments such as common solvents, aqueous solutions of metal ions, and solutions with a broad pH range from 4 to 11. In addition, compound 1 represents a very rare example of the versatile Ln-MOF probe capable of sensing Ce³⁺ or Fe³⁺ cations or acetone molecules.

A multifunctional Eu-CP as a recyclable luminescent probe for the highly sensitive detection of Fe3+/Fe2+, Cr2O72−, and nitroaromatic explosives

A multifunctional Eu-CP (1) as a recyclable luminescent probe for the highly sensitive detection of Fe³⁺/Fe²⁺, Cr₂O₇²⁻, and nitroaromatic explosives.