Isostructural Lanthanide-organic Frameworks Research Articles

Syntheses, crystal structures and properties of a series of isostructural lanthanide organic frameworks

We have successfully constructed nine isostructural Ln-MOFs with the formula Ln(L)1.5(H2O)2·H2O (1-Ce, 2-Dy, 3-Eu, 4-Gd, 5-Ho, 6-Nd, 7-Pr, 8-Sm, and 9-Tb) wherein the dihydroxy groups did not participate in coordination.

Two luminescent lanthanide–organic frameworks containing bithiophene groups for the selective detection of nitrobenzene and Fe3+

Two isostructural lanthanide–organic frameworks containing bithiophene groups can be used as fast-response fluorescent probes for the sensitive detection of nitrobenzene and Fe3+ ions through fluorescence quenching.

Two water-stable lanthanide metal-organic frameworks with oxygen-rich channels for fluorescence sensing of Fe(iii) ions in aqueous solution.

The development of metal-organic framework sensors with excellent stability under harsh physical and chemical conditions is of great significance in practical applications. Two isostructural lanthanide-organic frameworks, Ln-MOF ({Ln(L)(H2O)(DMA)}n, {FJU-13-Ln, Ln = Eu, Tb } (H3L = 3,5-(4-carboxybenzyloxy)benzoic acid)), were found to display exceptional stability, not only being stable in both acidic and basic aqueous solutions (pH 3-11), but also maintaining good robustness in boiling water and after activation. Furthermore, the plentiful oxygen atoms in the oxygen-rich channels of FJU-13-Eu and FJU-13-Tb acted as Lewis base sites for sensing metal ions, exhibiting high sensitivity (Stern-Volmer constant, KSV = 2.03 × 104 M-1 for FJU-13a-Eu and KSV = 2.11 × 104 M-1 for FJU-13a-Tb) and low detection limits (1.41 μM for FJU-13a-Eu and 1.01 μM for FJU-13a-Tb) for Fe3+ ions. This suggests that the two Ln-MOFs are promising fluorescent sensors for Fe3+ ion detection.

Visible‐Light Excited Luminescent Thermometer Based on Single Lanthanide Organic Frameworks

Isostructural lanthanide organic frameworks (Me2NH2)3[Ln3(FDC)4(NO3)4]·4H2O (Ln = Eu (1), Gd (2), Tb (3), H2FDC = 9‐fluorenone‐2,7‐dicarboxylic acid), synthesized under solvothermal conditions, feature a Ln‐O‐C rod‐packing 3D framework. Time‐resolved luminescence studies show that in 1 the energy difference between the H2FDC triplet excited state (17794 cm−1) and the 5D0 Eu3+ level (17241 cm−1) is small enough to allow a strong thermally activated ion‐to‐ligand back energy transfer. Whereas the emission of the ligand is essentially constant the 5D0→7F2 intensity is quenched when the temperature increases from 12 to 320 K, rendering 1 the first single‐lanthanide organic framework ratiometric luminescent thermometer based on ion‐to‐ligand back energy transfer. More importantly, this material is also the first example of a metal organic framework thermometer operative over a wide temperature range including the physiological (12‐320 K), upon excitation with visible light (450 nm).

Four new lanthanide-organic frameworks: selective luminescent sensing and magnetic properties.

Four new isostructural lanthanide-organic frameworks, [Ln(L)(H2O)2]·H2O·CH3CN (1-Ln) (Ln = Eu, Tb, Dy, and Gd), have been successfully synthesized via solvothermal reactions with a semi-rigid V-shaped multicarboxylate ligand 2-(2',4'-dicarboxylphenoxy) benzoic acid (H3L) and Ln(NO3)3·6H2O. 1-Ln shows 2D layer-by-layer frameworks with interlayer channels decorated by carboxylate groups. 1-Eu exhibits excellent luminescence properties, and therefore, is chosen as a probe for sensing different metal ions and anions. Consequently, 1-Eu displays high selectivity and sensitivity for Fe(3+) and Cr(6+) ions, simultaneously, through the luminescence quenching effect, and thus, should be an excellent candidate for probing these pollutant metal ions. In addition, antiferromagnetic exchange interactions also exist between the Dy(3+) ions in 1-Dy.

Lanthanide contraction effects on the structures, thermostabilities, and CO2 adsorption and separation behaviors of isostructural lanthanide–organic frameworks

A systematic investigation of the CO2 adsorption and separation behaviours of fourteen isostructural lanthanide–organic frameworks of lanthanide benzenetricarboxylate is executed.

Four super water-stable lanthanide-organic frameworks with active uncoordinated carboxylic and pyridyl groups for selective luminescence sensing of Fe(3.).

Four super water-stable isostructural lanthanide-organic frameworks, [Ln(HL)(H2O)2]n·2H2O (1-Ln) (Ln = Eu, Tb, Nd and Sm), have been successfully synthesized under hydrothermal conditions with 3,5-di(2,4-dicarboxylphenyl)pyridine (H4L) and Ln(NO3)3·6H2O. 1-Ln shows a novel 2D layered structure with uncoordinated carboxylic and pyridyl groups pointing to the interior of interlayer channels. The luminescent properties of 1-Eu in the solid state and one steeped in aqueous solution have been measured, which show excellent luminescence and good luminescent stability in water. Next 1-Eu was chosen as a probe for sensing different metal ions. Consequently, 1-Eu exhibits a highly selective response to Fe(3+) through the luminescence quenching effect in aqueous solutions. The probable mechanisms of the quenching effects have been investigated in detail.

White light emission by a lanthanide doped Sm(iii) framework constructed from 4-sulfobenzoate and 1H-imidazo[4,5-f][1,10]-phenanthroline

The 2D isostructural lanthanide-organic frameworks [Ln(4-SBA)(IP)OH] · 1.5H2O (Ln = Sm 1, Eu, 2 Gd3 and Tb 4 ; 4-SBA = 4-sulfobenzoate and IP = 1H-imidazo[4,5-f][1,10]-phenanthroline) display different luminescent behavior. White light emission was realized by introducing single dopant Eu(III) and codopants Eu(III)/Gd(III) or Eu(III)/Tb(III) into the Sm(III) framework for the first time.

Construction of Lanthanide–Organic Frameworks from 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylate and Oxalate

Three novel isostructural lanthanide organic frameworks, |(H2O)(H3O)|[Ln(HPyImDC)(OX)0.5Cl] (Ln = Pr (1), Nd (2), and Sm (3), H3PyImDC = 2-(pyridine-3-yl)-1H-4,5-imidazoledicarboxylic acid, H2OX = oxalic acid) have been prepared under hydrothermal conditions and characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, and thermogravimetric analysis. The results of crystal structural analysis indicate that three compounds are isomorphous 3D frameworks, which are constructed by lanthanide polyhedral {LnNClO6}, 4-connected HPyImDC2– ligand and bridging OX2– ligand. The HPyImDC2– ligand offering its four oxygen atoms and one nitrogen atom of the pyridyl group, and the OX2– ligand offering all its four oxygen atoms coordinate with the lanthanide ions, which is a key essential for constructing the 3D frameworks. Topological analysis reveals that the 3D framework can be simplified into a 5-connected network with the lanthanide ion as a unique node, possessing the rare sqp topology. Mean...

Up-conversion properties of lanthanide-organic frameworks and how to track ammunitions using these materials

This manuscript reports the first example of up-conversion properties involving Yb3+ and Tb3+ ions in five isostructural Lanthanide-Organic Frameworks (LnOFs), herein designated as UCMarker-1 to UCMarker-5, respectively, and their application as optical probes for the identification of gunshot residues (GSRs) and the ammunition encryption procedure. The excitation of the Yb3+ 2F7/2 ↔ 2F5/2 transition (980 nm) at room temperature leads to visible up-conversion (UC) emission of Tb3+ 5D4 → 7FJ. The GSR and lead-free primer residues are easily identified upon UV radiation (λ = 254 nm). These results prove that the exploration of LnOFs to identify GSR is attractive for the identification of ammunition origins or caliber recognition.

Ultrasensitive sorption behavior of isostructural lanthanide–organic frameworks induced by lanthanide contraction

Reactions of lanthanide nitrate and the trigonal-planar ligand 1,3,5-benzenetrisbenzoic acid (H3BTB) gave rise to a family of lanthanide–organic frameworks (LOFs) formulated as Ln(BTB)(H2O), where Ln = Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Yb. Single-crystal X-ray diffraction (XRD) analysis of Pr-LOF reveals a three-dimensional network with an ultramicroporous structure. Powder XRD and thermogravimetric analyses show that these LOFs are isostructural and can firmly stabilize up to 550 °C. Influenced by the opposite effects of ionic radius and molecular weight from La(III)–Yb(III), the related LOFs with the highest uptake of CO2 and CH4 happen to be Nd-LOF and Sm-LOF, respectively. Moreover, the isotherms of N2 at 77 K and benzene vapor at 298 K further evidence that lanthanide contraction greatly affects the adsorption performance of the resulting materials, bringing about stepwise and hysteretic sorption behavior for La-LOF to Pr-LOF but type I isotherms for the rest of the LOFs. This work represents the first systematic study of a family of lanthanide-based metal–organic frameworks with ultrasensitive sorption behavior induced by the lanthanide contraction.

First lanthanide coordination polymers with N,N-dimethylformamide hydrolysis induced formate ligands

A series of isostructural lanthanide organic frameworks with composition [Ln(tpa)(fa)] (Ln=Eu, Gd, Tb; H2tpa=terephthalic acid, i.e. 1,4-benzenedicarboxylic acid; Hfa=formic acid, i.e. methanoic acid) has been synthesized through reaction of the corresponding lanthanide nitrates with H2tpa in DMF/H2O mixed solvent under solvothermal conditions (DMF=N,N-dimethylformamide). The formate ligand is in situ generated by hydrolysis of DMF. The dilanthanide-diformate subunits build two-dimensional layers which are shored up by terephthalates, leading to a three-dimensional pillar-layer network. These are the first examples of lanthanide complexes containing the formate ligand originated from hydrolysis of DMF. The dilanthanide-diformate subunit is also the first ever reported. The Eu and Tb complexes emit strong ligand sensitized f–f luminescence. Temperature variable magnetic susceptibility analysis reveals that the Gd(III) atoms are antiferromagnetically coupled (J=−0.0048cm−1, Ĥ=−2JŜGd1·ŜGd2).

Control over Interpenetration in Lanthanide−Organic Frameworks: Synthetic Strategy and Gas-Adsorption Properties

Two isostructural lanthanide-organic frameworks (1 and 2) with 2-fold interpenetrating nets have been synthesized based on 1,4-benzenedicarboxylic acid (H(2)BDC). By application of an organic ligand with hindrance groups and a terminal chelating ligand to replace BDC and coordinated solvates, interpenetration has been effectively controlled. The gas-sorption properties of the noninterpenetrating net have been studied.

Microporous Lanthanide-Organic Frameworks with Open Metal Sites: Unexpected Sorption Propensity and Multifunctional Properties

Isostructural lanthanide-organic frameworks were prepared by a solvothermal reaction of the corresponding metal ions and the phosphine-oxide-based tricarboxylate ligand. The gravimetric gas uptake was unexpectedly increased when going from Nd(3+) to Gd(3+), which is associated with the enhanced surface areas and electrostatic interactions between exposed metal ions and gas molecules with quadrupole moments.