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A series of tetranuclear lanthanide clusters supported by organic ligands ([Ln4L6(NO3)4]·4(MeCN), Ln = La, Nd, Sm) has been synthesized and characterized. The Lewis acidic Ln3+ sites were investigated as highly efficient catalysts regarding CO2 activation. The clusters showed significant thermal stability after 4 reaction cycles of CO2 insertion into epoxides to form cyclic carbonates, with TOF up to 6700 h−1. The catalytic system also displays a wide substrate scope and high catalytic activity. Unfortunately, the catalytic efficiency of the catalysts for some sterically hindered reaction substrates is not very satisfactory. [ABSTRACT FROM AUTHOR]

Lanthanide MOFs (Ln-MOFs), {[Ln2(L)2(H2O)2]·5H2O·6DMAC}n, [Ln‖‖‖ = Eu(1) and Tb(2); H3L = 4,4′-(((5-carboxy-1,3-phenylene)bis(azanediyl))bis(carbonyl)) dibenzoic acid, DMAC = N,N′-dimethylacetamide], with a new topology type have been isolated. Single crystal X-ray diffraction indicates that complexes 1 and 2 are isostructural with binuclear [Eu2(COO)7]n secondary building units as 7-connected nodes and H3L ligands as 3-connected nodes and can be viewed as a (5,7)-connected 3D framework with a new topological point symbol of {32·44·54} {34·46·56·65}. Complexes 1 and 2 exhibit an excellent luminescence sensing response to inorganic ions Fe3+, Cr2O72−, MnO4− and 4-nitrophenol, with a low detection limit and high Ksv value. Interestingly, when the MnO4− ions are detected, the color of the solid sample is observed to change from yellow to brown, visually indicating luminescence induction, which makes the process of detecting MnO4− ions simpler and more practical. Moreover, by using time-resolved photoluminescence techniques, complex 1 can effectively eliminate background fluorescence interference during detection and improve detection accuracy. Solvent luminescence studies, pH stability and PXRD data indicate that complexes 1 and 2 can be used as excellent water-stable multi-response luminescent sensors for detecting a wide variety of toxic substances. In addition, the mechanism of selective detection is explained by the energy competition between the excitation of complexes 1 and 2 and the ultraviolet absorption of the responsive substance. [ABSTRACT FROM AUTHOR]

A trifunctional aromatic building block (H2L) containing three different types of functional groups (carboxyl C(=O)OH, aldehyde C(=O)H, and O-ether) was applied for the hydrothermal synthesis of two novel lanthanide 2D coordination polymers [Ln(μ-HL)(μ3-L)(phen)]n {Ln = Tb (1) and Eu (2); H2L = 5-methoxy-(4-benzaldehyde)-1,3-benzene dicarboxylic acid; phen = 1,10-phenanthroline}. Both compounds 1 and 2 are isostructural and reveal very complicated 2D metal–organic double layers with the 3,4L27 topology. The presence of free aldehyde groups positioned outside of the double layers opens up a possibility of using them as functional groups toward sensing amines and small organic molecules. The fluorescence measurements for the Tb derivative 1 reveal that it acts as an efficient fluorescence sensor for p-phenylenediamine, benzidine and acetone molecules via a luminescence quenching effect. A similar sensing behavior was observed for the Eu compound 2. Moreover, thin-films of 1-PEG on glass (1-PEG-glass thin-film material) were fabricated and investigated for the detection of amine vapors. [ABSTRACT FROM AUTHOR]

A new series of five lanthanide(iii) metal–organic frameworks with a general formula of [Ln3(bcpb)4(μ-HCOO)(μ-H2O)(H2O)2(DEF)]n (1–5) was generated by solvothermal reactions from Ln(NO3)3·6H2O {Ln = Eu (1), Tb (2), Gd (3), Dy (4), and Sm (5)} and 3,5-bis(3-carboxyphenyl)pyridine (H2bcpb) in an aqueous N,N-diethylformamide (DEF) medium. The obtained products were characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis (TGA), and powder and single crystal X-ray diffraction. The latter reveals that all compounds (1–5) are isostructural and feature very intricate 2D metal–organic frameworks. These were topologically analyzed, revealing a very complex hexanodal underlying net that can be simplified further to a binodal 3,5-connected layer with the 3,5L52 topology. Solid-state photoluminescence properties of 1–5 were studied in detail. Compound 1 exhibits a strong red luminescence upon excitation at 338 nm and its lifetime is 532 μs. Compound 2 shows an intense green luminescence upon excitation at 336 and its lifetime is 981 μs. The triplet state (3ππ*) of bcpb2− studied by using the Gd(iii) derivative 3 demonstrated that the ligand effectively populates Tb(iii) emission (Φ = 70.96%), whereas the corresponding Eu(iii) derivative 1 shows a weak luminescence efficiency (Φ = 15.81%) as the triplet state of bcpb2− has a poor match with the 5D0 energy level of Eu(iii). A notable feature of 1 is its remarkable sensing ability for Cu2+ ions and 2,4,6-trinitrophenol (TNP). Besides, a series of heterobimetallic Tb-based MOFs, [Tb3(1−x)Eu3x(bcpb)4(μ-HCOO)(μ-H2O)(H2O)2(DEF)]n {x = 0.001, 0.002, 0.003, 0.01, 0.02, 0.03, 0.04, 0.10, 0.15, 0.20} (compounds 2a–2j, respectively), was prepared. The luminescence studies reveal that the simultaneous presence of the characteristic sharp emission bands of Eu3+ and Tb3+ allows the tuning of the photoluminescence colors of such materials by adjusting the doping concentration of the Eu3+ ions. [ABSTRACT FROM AUTHOR]

An erbium(iii) salen “square prism” and a supramolecular aggregate of exo-erbium(iii) salen “double-decker” cations wrapped by an anionic cuprous cyanide network were prepared from N,N′-ethylene bis[4-(diethylamino)salicylideneimine. Both erbium(iii) edifices show fine-structure near-infrared (NIR) luminescence under the excitation in the visible light area. Here we provide a novel and efficient method for stabilizing non-isolable lanthanide edifices in the solid state. [ABSTRACT FROM AUTHOR]

A series of lanthanide metal–organic frameworks, namely [Ln(bpdc-NO2)1.5(DMF)(H2O)]·0.5DMF [Ln = Eu (1), Gd (2), Nd (3), La (4), Ce (5), Pr (6), Sm (7) and Tb (8)] have been prepared solvothermally by reacting 2-nitrobiphenyl-4,4′-dicarboxylic acid (H2bpdc-NO2) with related lanthanide(iii) nitrates in a mixed solution of DMF, EtOH and H2O. Single-crystal X-ray analyses reveal that complexes 1–8 are isostructural and crystallize in the P1̅ space group. They have the same three-dimensional (3D) architectures, consisting of bpdc-NO22− ligands and inorganic chains of {[Ln2(–COO)6(DMF)2(H2O)2]}n. Within the chain, each Ln(iii) ion is coordinated with eight oxygen atoms. The two neighbouring Ln(iii) ions are bridged by four μ2-monodentate carboxylate groups to form a [Ln2(–COO)4(DMF)2(H2O)2] dinuclear unit. The dimers are further linked together by the other two μ2-monodentate O–C–O bridges to generate an inorganic chain running along the a axis. Topological analyses suggest that these frameworks possess the 3D tfz-d net with Schläfli symbol of (43)2(4661884). Solid-state photoluminescent investigations at room temperature reveal that complex 1 exhibits strong red luminescence upon excitation at 466 nm, which arises from the characteristic emissions of the Eu(iii) ions, and its lifetime is 622 μs. For complex 3, the strongest emission band of 1055 nm is found in the near-infrared region upon excitation at 582 nm, and its lifetime is 12 μs. Magnetic susceptibility measurements suggest that the magnetic properties of 1 and 3 are mainly originated from the large spin–orbital coupling of Eu(iii) and Nd(iii) ions, respectively. For Gd(iii) complex 2, weak antiferromagnetic interactions mediated between the Gd(iii) centers are observed. [ABSTRACT FROM AUTHOR]

Solid complexes of lanthanide picrates with N,N-dibenzyl-2-{2′-[(dibenzylcarbamoyl)-methoxy]-[1,1′]binaphthalenyl-2-yloxy}-acetamide (L), [Ln(pic)3L] (Ln=La, Nd, Eu, Gd, Tb, Dy, Y), have been prepared and characterized by elemental analysis, IR, 1H NMR, UV-Vis spectra and conductivity measurements. The fluorescence property of the europium complex in solid state and in CHCl3, acetone, AcOEt and DMF was studied. [Copyright &y& Elsevier]

Solid complexes of lanthanide picrates with N-Ethyl-2-{2′-[(ethyl-phenyl-carbamoyl)-methoxy]-[1,1′]binaphthalenyl-2-yloxy}-N-phenyl-acetamide (L), [Ln(pic)3L] (Ln=La, Tb, Y), have been prepared and characterized by elemental analysis, IR and 1H NMR spectra. The molecular structure of [Tb(pic)3L] shows that the Tb(III) ion is nine-coordinated by four oxygen atoms from the L and five from two bidentate and one unidentate picrates. The complex forms a 1D supramolecular structure along z-axis. [Copyright &y& Elsevier]

Abstract: A new tetrapodal ligand 1,1,1-tetrakis{[(2′-(2-furfurylaminoformyl))phenoxyl]methyl}methane (L) has been prepared and their coordination chemistry with Ln III ions has been investigated. The structure of {[Ln 4L3(NO3)12]·H2O}∞ (Ln=Nd, Eu)] shows the binodal 4,3-connected three-dimensional interpenetration coordination polymers with topology of a (86)3(83)4 notation. [DyL(NO3)3(H2O)2]·0.5CH3OH and [ErL(NO3)3(H2O) (CH3OH)]·CH3COCH3 is a 1:1 mononuclear complex with interesting supramolecular features. The structure of [NdL(H2O)6]·3ClO4·3H2O is a 2:1 mononuclear complex which further self-assembled through hydrogen bond to form a three-dimensional supramolecular structures. The result presented here indicates that both subtle variation of the terminal group and counter anions can be applied in the modulation of the overall molecular structures of lanthanide complex of salicylamide derivatives due to the structure specialties of this type of ligand. The luminescence properties of the EuIII complex are also studied in detail. [Copyright &y& Elsevier]

Abstract: Solid complexes of lanthanide nitrates with a new unsymmetrical tripodal ligand, bis[(2′-benzylaminoformyl)phenoxyl)ethyl](ethyl)amine (L) have been synthesized and characterized by elemental analysis, infrared spectra and molar conductivity measurements. At the same time, the luminescent properties of the Sm(III), Eu(III), Tb(III) and Dy(III) nitrate complexes in solid state were also investigated. Under the excitation of UV light, these complexes exhibited characteristic emission of central metal ions. [Copyright &y& Elsevier]

Abstract: The new ligand N-benzyl-2-{2′-[(benzyl-ethyl-carbamoyl)-methoxy]-biphenyl-2-yloxy}-N-ethyl-acetamide (L) and its complexes of rare earth picrates were synthesized. The complexes were characterized by elemental analysis, IR, UV–vis spectra and conductivity measurements. The fluorescence properties of the europium complex in solid state and in CHCl3, ethyl acetate, acetone, acetonitrile and DMF were investigated. Under the excitation, the europium complex exhibited characteristic emissions of europium. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. [Copyright &y& Elsevier]

Abstract: Solid complexes of rare earth nitrates and picrates with a new aryl amide podand, 1,4-bis{[(2′-benzylamino-formyl)phenoxyl]methyl}-naphthaline (L) were synthesized. The complexes were characterized by elemental analysis, IR and molar conductivity measurements. At the same time, the fluorescent properties of the Eu(III) and Tb(III) nitrates and picrates complexes in solid state were also investigated. Under the excitation, these complexes exhibited characteristic emissions of europium and terbium ions. The counter anion factor influencing the fluorescent intensity was also discussed. [Copyright &y& Elsevier]

Abstract: A new aryl amide type bifunctional bridging ligand 4,4′-bis{[(2″-benzylaminoformyl)phenoxyl]methyl}-1,1′-biphenyl (L) and its complexes with lanthanide ions (Ln=Pr, Eu, Gd, Tb, Ho, Er) were synthesized and characterized by elemental analysis, infrared spectra, conductivity measurements and thermal analysis. At the same time, the luminescence properties of the Eu and Tb complexes in acetone solutions were investigated. Under the excitation of UV light, these two complexes exhibited characteristic emission of europium and terbium ions. And the lowest triplet state energy level T1 of this ligand matches better to the lowest resonance energy level of Tb(III) than to Eu(III) ion. [Copyright &y& Elsevier]

Abstract: Solid complexes of rare earth nitrates and picrates with a new hexapodal ligand, 1,2,3,4,5,6-hexa{[(2′-benzylamino-formyl)phenoxyl]methyl}-benzene (L) have been prepared. These complexes were characterized by elemental analysis, IR and molar conductivity. At the same time, the luminescence properties of the Eu(III) and Tb(III) nitrates and picrates complexes in solid state were also investigated. Under the excitation of UV light, these complexes exhibited characteristic emission of europium and terbium ions. The influence of the counter anion on the luminescent intensity was also discussed. [Copyright &y& Elsevier]

Solid complexes of lanthanide picrates with 2,2′-[1,2-phenylenebis(oxy)]-bis(N-methyl-N-phenyl(acetamide)) (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR, electronic and 1H NMR spectroscopies. The crystal structure of terbium complex shows a nona-coordination polyhedron in the form of a distorted mono-capped square anti-prism. The extractability of lanthanide ions by L has been investigated using multitracer technology. [Copyright &y& Elsevier]

Abstract: A new amide type bridging ligand, 1,5-bis{[(2′-(2-picolylaminoformyl))phenoxyl]methyl}naphthalene (L), and its complexes with lanthanide ions (Ln═Sm, Eu, Gd, Tb, and Dy) have been designed and assembled. The crystal structures of {[EuL(NO3)3(CH3OH)](H2O)}n and [TbL(NO3)3(CH3OH)]n display one-dimensional (1-D) zig-zag coordination polymeric chains. At the same time, the solid state luminescent properties of the Sm, Eu, Tb, and Dy complexes were investigated at room temperature. The complexes all exhibit characteristic luminescence emissions of the central metal ions under UV light excitation. The lowest triplet state energy level (T1) of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Tb(III) ion than other lanthanide ions. [Copyright &y& Elsevier]

Abstract: A new aryl amide type bridging ligand 1,4-bis{[(2′-benzylaminoformyl)phenoxyl]ethoxyl}benzene (L) and its complexes with lanthanide ions (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) were synthesized and characterized by elemental analysis, infrared spectra and electronic spectra. At the same time, the luminescent properties of the Sm, Eu, Tb and Dy complexes in solid state and the Tb complex in solvents were also investigated. At room temperature, these four complexes exhibited characteristic luminescence emissions of the central metal ions under UV light excitation and could be significant in the field of supramolecular photonic devices. [Copyright &y& Elsevier]

Abstract: Solid complexes of lanthanide nitrate with 1,4-di(N,N-di-n-butyl-acetamido)-quinoxaline-2,3-dione (L), [Ln(NO3)3L·H2O] (Ln=La, Nd, Eu, Gd, Tb, Er), have been prepared and characterized by elemental analysis, IR, UV–vis spectra and conductivity measurements. The fluorescence property of the europium complex in solid state and in MeCN, acetone, AcOEt and THF was studied. Under the excitation, the europium complex exhibited characteristic emissions of europium. The result indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. [Copyright &y& Elsevier]

Abstract: A new amide-based 1,3,4-oxadiazole derivative ligand 2,5-bis[2-(N,N-diethyl-1′-oxopropylamide)phenyl]-1,3,4-oxadiazole (L) and its complexes, Ln(NO3)3L (Ln=La, Eu, Gd, Tb, Er), were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The lanthanide ions were coordinated by O atoms from Cuorescence properties of Eu(NO3)3L and Tb(NO3)3L in the solid state and in different solvents were investigated. Under the excitation of UV light, these complexes exhibit characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity were discussed. [Copyright &y& Elsevier]

Abstract: Solid complexes of lanthanide isothiocyanates with an amide-type tripodal ligand, 2,2′,2″-nitrilotris-(N-phenylmethyl)-acetamide (L) have been synthesized and characterized by elemental analysis, infrared spectra and molar conductivity measurements. At the same time, the luminescent properties of the Sm(III), Eu(III), Tb(III), Dy(III) isothiocyanate complexes in solid state and the Tb(III) complex in solvents were also investigated. [Copyright &y& Elsevier]

Abstract: A new amide-based ligand derived from biphenyl, N-benzyl-2-{2′-[(benzyl-methyl-carbamoyl)-methoxy]-biphenyl-2-yloxy}-N-methyl-aceamide (L) was synthesized. Solid complexes of lanthanide picrates with this new ligand were prepared and characterized by elemental analysis, conductivity measurements, IR and electronic spectroscopies. The molecular structure of [Eu(pic)3L] shows that the Eu(III) ion is nine-coordinated by four oxygen atoms from the L and five from two bidentate and one unidentate picrates. All the coordinate picrates and their adjacent equivalent picrates form intermolecular π–π stacking. Furthermore, the [Eu(pic)3L] complex units are linked by the π–π stacking to form a two-dimensional (2-D) netlike supramolecule. Under excitation, the europium complex exhibited characteristic emissions. The lifetime of the 5D0 level of the Eu(III) ion in the complex is 0.22ms. The quantum yield Φ of the europium complex was found to be 1.01×10−3 with quinine sulfate as reference. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. [Copyright &y& Elsevier]

Abstract: Solid complexes of lanthanide picrates with a new podand-type ligand, 2,2′-[(1,2-phenylene)bis(oxy)]bis(N-benzylacetamide) (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR, electronic and 1H NMR spectroscopies. The crystal and molecular structures of the complex NdL(Pic)3 have been determined by single-crystal X-ray diffraction. The crystal structure shows that the Nd(III) ion is coordinated with four oxygen atoms of the ligand L and six oxygen atoms of three bidentate picrates. Furthermore, the NdL(Pic)3 complex units are linked by the intermolecular hydrogen bonds to form a three-dimensional (3-D) netlike supermolecule. Under excitation, Eu complex exhibited characteristic emissions. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. [Copyright &y& Elsevier]

Abstract: Solid complexes of lanthanide picrates with a new amide type tripodal ligand, 2,2′,2″-nitrilotris-(N-phenylmethyl)-acetamide (L) have been prepared. The X-ray single-crystal diffraction analysis indicates that the ML2 type complexes [PrL 2(Pic)](Pic)2 and [NdL 2(Pic)](Pic)2 are isomorphous. And the ML2 complex units are hydrogen bonded to give infinite one-dimensional zigzag supramolecular chains which are further linked by the interchain hydrogen bonds and π–π interactions of the picrate groups to form two-dimensional layer. The luminescent property of the Eu (III) complex is described. [Copyright &y& Elsevier]