Three-dimensional Lanthanide Coordination Polymers Research Articles

Synthesis, structure and photoluminescence of 3D lanthanide coordination polymers based on 2-(3,5-dicarboxybenzyloxy) benzoic acid

A series of novel three-dimensional lanthanide coordination polymers with the building block [Ln2(dcob)6(DMF)2(H2O)2], [Ln(dcob)(DMF)(H2O)]n [Ln = Pr (1), Nd (2), Sm (3), Eu (4), Gd (5), Tb (6), Dy (7), Er (8), H3dcob = 2-(3,5-dicarboxybenzyloxy) benzoic acid, DMF = N,N-dimethylformamide], were prepared under hydrothermal conditions and characterized by X-ray single-crystal diffraction, infrared spectroscopy, elemental analysis and thermogravimetric analysis. 3, 4, 6 and 7 show luminescence of the trivalent lanthanides.

Temperature-dependent structure of three-dimensional lanthanide coordination polymers

Temperature-dependent structure of three-dimensional lanthanide coordination polymers

Syntheses, structures and properties of four 3D microporous lanthanide coordination polymers based on 3,5-pyrazoledicarboxylate and oxalate ligands

Four three-dimensional lanthanide coordination polymers with reversible structural interconversions, [Ln2(Hpdc)2(C2O4)(H2O)4]n·2nH2O [Ln=Sm (1), Eu (2), Tb (3) and Dy (4)], have been synthesized by hydrothermal reactions of lanthanide nitrates with 3,5-pyrazoledicarboxylic (H3pdc) and oxalic acids. It is noteworthy that there is an in situ reaction in 1, in which H3pdc was decomposed into (ox)2− with Cu(II)–Sm(III) synergistic effect under hydrothermal conditions. These compounds are isostructural and crystallized in the monoclinic P21/c space group. The Ln(III) ions are eight-coordinated with dodecahedron coordination geometry. These polyhedra are linked by oxalate groups to form 1D zigzag chain, which are further connected by 3,5-pyrazoledicarboxylate to extend similar 3D frameworks with channels along c-axis in 1–4. These coordination polymers display the characteristic emission bands of the Ln(III) ions in the solid state and possess good thermal stabilities.

Three-dimensional lanthanide coordination polymers with p-phenylenediacrylates: Syntheses, structures, and properties

Three three-dimensional lanthanide coordination polymers [Ln2(pda)2(HCOO)(OH)(H2O)]n (Ln=Dy, 1; Tb, 2; Ho, 3; H2pda=p-phenylenediacrylic acid) have been solvothermally synthesized and their structures have been determined using either X-ray powder or single-crystal diffraction data. They are isostructural and possess a 3D architecture with the pcu (α-Po) net topology based on the parallel 1D lanthanide–oxygen rod-shaped secondary building units, each of which is connected to four other rods by the pda ligands. The photoluminescent properties of 1–3 have been investigated. Complexes 1–3 all display the intense blue emission in the solid state at room temperature. Especially, compared with the free H2pda ligands, 1 shows the strong fluorescence enhancement due to the complexation.

Syntheses, structures and properties of three-dimensional lanthanide frameworks constructed with a trigonal anti-prismatic lanthanide cluster

Two three-dimensional lanthanide coordination polymers, [Ln9(HNA)12(O2H)]·6H2O (Ln = Gd (1), Eu (2); HNA = 2-hydroxylnicotinic anion), were obtained from the reactions of Ln2O3 with 2-mercaptonicotinic acid (MNA) under hydrothermal conditions, in which HNA was generated from in situsubstitution reactions of MNA. Single-crystal X-ray diffraction analysis reveals that 1 and 2 are isomorphous and crystallize in trigonal space group Rc. The structure features an ideal trigonal anti-prismatic hexanuclear cluster and a unique [O2H]3−group encapsulated in the cluster center, which represents the first example involving the lanthanide complexes. The hexanuclear cluster further forms a three-dimensional cubic network by bridging six outer lanthanide ions. Compound 2 displays the characteristic EuIII emission bands upon excitation at 395 nm. The magnetic properties of compounds 1 and 2 have also been investigated.

Controlled synthesis, structures and properties of one-, two-, and three-dimensional lanthanide coordination polymers based on (8-quinolyloxy)acetate

Hydrothermal reactions of Ln(NO3)3 and (8-quinolyloxy)acetic acid (HQOA) with auxiliary ligands resulted in a series of new one-, two- and three-dimensional (1D, 2D and 3D) coordination polymers, namely, [Ln(QOA)2 (H2O)2]·NO3·H2O [Ln = Eu (1), Gd (2)], [Ln2(QOA)4(ox)(H2O)]·3H2O [Ln = Pr (3), Er (4)], [Ln2(QOA)4(BDC) (H2O)]·4H2O [Ln = Sm (5)] and [Ln(QOA)(BDC)] [Ln = Sm (6), Eu (7)] [QOA = (8–quinolyloxy)acetate; ox = oxalate; BDC = 1, 4–benzenedicarboxylate], respectively. Compounds 1–2 possess 1D zigzag chains bridged by QOA anions and 3–4 contain 1D folded chains alternately bridged by oxalates and QOA anions. Complex 5 is an ordered (2,4)–connected 2D sheet-like structure. In compounds 6–7, four BDC anions bridge two adjacent metal atoms to form dinuclear lanthanide building blocks and these dinuclear blocks are further connected together to form an 8-connected 3D network. The progressive variation from 1D zigzag chains (1–2) to 1D folded chains (3–4) to a 2D layer network (5) and to 3D frameworks (6–7) is mainly attributed to the change of bridging ligands as well as the different coordination modes of organic carboxylic ligands. Moreover, the thermal stabilities and photoluminescent properties of these compounds show a remarkable difference due to the progressive variation of crystal structures.

Synthesis, crystal structures and properties of a series of three-dimensional lanthanide coordination polymers with the rigid and flexible mixed dicarboxylate ligands of 1,4-benzene dicarboxylic acid and succinic acid

A series of new lanthanide coordination polymers, with the formula [Ln(Suc) 0.5( p-BDC)] (Ln = Eu ( 1), Sm ( 2), Tb ( 3), Pr ( 4), Ho ( 5); H 2Suc = succinic acid; p-H 2BDC = 1,4-benzene dicarboxylic acid), have been synthesized under hydrothermal condition and all of them have been structurally characterized. X-ray diffraction analyses reveal that complexes 1– 5 are isostructural and crystallized in orthorhombic space group Pbca. One-dimensional infinite inorganic edge-sharing polyhedra chains formed by lanthanide ions and tetradentate carboxyl groups of succinic acid ligands, link to each other through the carbon atoms of succinic acid ligands and phenyl groups of the 1,4-benzene dicarboxylic acid ligands, to lead to a three-dimensional framework structure. In addition, the phase purities of the bulk samples were identified by X-ray powder diffraction. The photoluminescent properties of 1 and 3 were discussed in detail.

Syntheses, structures, and photoluminescence of three-dimensional lanthanide coordination polymers with 2,5-pyridinedicarboxylic acid

Four new open-framework coordination polymers of lanthanide 2,5-pyridinedicarboxylates, with the formulas Pr2(pydc) 3(H 2O) 2 ( 1), Ln(pydc)(Hpydc) ( Ln=Tb ( 2), Er ( 3), Eu ( 5)), and Gd(pydc)(nic)(H 2O) ( 4) (H 2pydc=2,5-pyridinedicarboxylic acid, Hnic=nicotinic acid), have been hydrothermally synthesized and four of them (except Eu ( 5)) have been structurally characterized. Complex 1 consists of two types of ligand-binding modes contributing to link the PrO 7N(H 2O) polyhedral chains to three-dimensional (3D) open-framework architecture. Complexes 2 and 3 are isostructural and feature unique 3D cage-like supramolecular frameworks remarkably different from that of 1, owing to the different ligand-bridging pattern. Complex 4, however, has the distinct 3D open-framework architecture due to the presence of unexpected nicotinate ligands, which may be derived from pydc ligands via in-situ decarboxylation under the hydrothermal condition.

Decorated rutile net built on the six-connected Ln2 SBUs (secondary building units) and three-connected organic spacers

Three new three-dimensional Lanthanide coordination polymers, namely [Ln2(Ac)2(ip)2(H2O)4·H2O]n [LnGd(1), Sm(2), Nd(3)], where Ac=acetate, ip=isophthalate, have been synthesized in hydrothermal method and characterized by single-crystal X-ray diffraction. Compounds 1–3 are isostructural and crystallize in the monoclinic system, space group P2(1)/C. Thermogravimetry, infrared spectra, elemental analysis have also been used to characterize 1. From topological view, the compounds present the second lanthanide-based, non-interpenetrating, decorated rutile net with the (4×62)(42×610×83)2 topology notation. Notably, within them, (H2O)6 cluster formed by free and coordinated water molecules via H-bonds is observed; and based on the consideration of the average O⋯O distance and IR spectrums, it is similar to those of liquid water.

Novel open-framework architectures in lanthanide phosphonates

Two novel three-dimensional lanthanide coordination polymers have been prepared hydrothermally with the phosphonic acid N , N ′ -piperazine bis(methylenephosphonic acid), H 2O 3PCH 2N(C 2H 4) 2NCH 2PO 3H 2 ( LH 4). The structures of Gd 2( LH 2) 3⋅3H 2O (I) and Nd 2( LH 2) 3⋅9H 2O (II) have been characterised by single crystal X-ray techniques. One-dimensional ‘lanthanide-phosphate’ chains are a key feature in both structures, although there are major structural differences between the chains, with (I) displaying octahedral GdO 6 coordination and (II) showing eight-coordinate NdO 8 polyhedra. In each case, three-dimensional connectivity is completed by coordination of the phosphonate group resulting in open framework structures encapsulating loosely bound water molecules. Isostructural Y 3+ and Yb 3+ analogues of (I) have been prepared, suggesting that cation size is a key factor in controlling the differing reaction products. In the case of Y 2( LH 2) 3⋅5H 2O, isostructural to (I), it is shown that the extra-framework water molecules may be removed reversibly without framework collapse. Structural relationships to other known lanthanide phosphonates are discussed.

A Series of Three-Dimensional Lanthanide Coordination Polymers with Rutile and Unprecedented Rutile-Related Topologies

The complexes of formulas Ln(pydc)(Hpydc) (Ln = Sm (1), Eu (2), Gd (3); H2pydc = pyridine-2,5-dicarboxylic acid) and Ln(pydc)(bc)(H2O) (Ln = Sm (4), Gd (5); Hbc = benzenecarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG analysis, and single-crystal X-ray diffraction. Compounds 1-3 are isomorphous and crystallize in the orthorhombic system, space group Pbcn. Their final three-dimensional racemic frameworks can be considered as being constructed by helix-linked scalelike sheets. Compounds 4 and 5 are isostructural and crystallize in the monoclinic system, space group P2(1)/c. pydc ligands bridge dinuclear lanthanide centers to form the three-dimensional frameworks featuring hexagonal channels along the a-axis that are occupied by one-end-coordinated bc ligands. From the topological point of view, the five three-dimensional nets are binodal with six- and three-connected nodes, the former of which exhibit a rutile-related (4.6(2))(2)(4(2).6(9).8(4)) topology that is unprecedented within coordination frames, and the latter two species display a distorted rutile (4.6(2))(2)(4(2).6(10).8(3)) topology. Furthermore, the luminescent properties of 2 were studied.