Constructing porous lanthanide coordination polymers of 4,4′-bipyridine- N,N ′-dioxide templated by single- and double-Keggin anions

Three porous coordination polymers, {[Nd(dpdo)₂(H₂O)₅(CH₃OH)₂](PMo₁₂O₄₀)(CH₃OH)-(H₂O)₅} _n (1), {[Tb(dpdo)₄(H₂O)₃](PMo₁₂O₄₀)(H₂O)₂CH₃CN} _n (2) and {[Tb(dpdo)₄(H₂O)₃]H(SiMo₁₂O₄₀)(dpdo)_0.5(CH₃CN)_0.5(H₂O)₄} _n (3) (where dpdo is 4,4′-bipyridine-N,N′-dioxide), templated by single- or double-Keggin polyanions were synthesized and characterized by single crystal X-ray diffraction. The compounds exhibit three different 3D non-interwoven frameworks with large cavities occupied by the single- or double-Keggin-type anions. Thermogravimetric analyses suggest different stability for the three metal-organic frameworks. The SHG (second harmonic generation) efficiency of 1 confirms its noncentric framework.     

Variation in coordination modes of aromatic N-oxides in lanthanum(III) coordination polymers

Two new coordination polymers of lanthanum(III) benzoate having pyridine N-oxide and 4,4′-bipyridyl-N,N′-dioxide as ancillary ligands are synthesized and characterized. Different binding modes of the N-oxide are demonstrated; pyridine N-oxide binds as a bridging ligand, whereas 4,4′-bipyridyl-N,N′-dioxide is monodentate.     

Syntheses,structures, and fluorescent properties of four Co(II) coordination polymers based on 5-hydroxyisophthalic acid and structurally related bis(benzimidazole) ligands

Four cobalt(II) coordination polymers, {[Co(HO-BDC)(bbp)]}_n (1), {[Co(HO-BDC)(bmbp)₂]·(H₂O)₂}_n (2), {[Co(HO-BDC)(bbb)]}_n (3), and {[Co₂(HO-BDC)₂(bmbb)₂]·(H₂O)₃}_n (4), where HO-H₂BDC?=?5-hydroxyisophthalic acid, bbp = 1,3-bis(benzimidazol-1-yl)propane, bmbp = 1,3-bis(2-methyl-benzimidazol-1-yl)propane, bbb = 1,4-bis(benzimidazol-1-yl)butane, and bmbb = 1,4-bis(2-methyl-benzimidazol-1-yl)butane, have been synthesized and characterized by elemental analyses, IR spectra, single-crystal X-ray diffraction, thermogravimetric analyses, and fluorescence properties. Compounds 1 and 3 are 4-connected 2-D networks with (4⁴·6²) topology. Compound 2 is a 1-D chain, while 4 features a 1-D ladder. These 1-D and 2-D complexes are further connected by hydrogen bonds to form 3-D supramolecular architectures. Complexes 1–4 showed very strong yellow luminescence emission.     

Assembly of lanthanide coordination polymers with one dimensional channels

Three new Lanthanide 2-aminoterephthalate coordination polymers: [Pr₂(C₈H₅NO₄)₃·(H₂O)₅]·2H₂O 1, [Tb(C₈H₅NO₄)_1.5(H₂O)₂]·2H₂O 2 and [Eu(C₈H₅NO₄)_1.5(H₂O)₂]·2H₂O 3, were obtained by the hydrothermal synthesis. Crystal data: Complex 1. Triclinic, space group P-1, a=10.391(1), b=15.056(1), c=10.121(1) Å. α=101.363(4), β=101.115(3), γ=105.737(3)°, Complex 2. Triclinic, space group P-1, a=10.137(1), b=10.353(1), c=9.469(1) Å. α=95.443(3), β=110.649(4), γ=110.547(4)°. Complex 3. Triclinic, space group P-1, a=10.174(1), b=10.388(1), c=9.480(1) Å. α=95.443(6), β=110.732(3), γ=110.287(5)°. These carboxyl groups link Ln³⁺ via the chelating or bridging bond construct one-dimension channels in which pendant function groups can further connect with guest water molecules in channels through hydrogen bond.     

Two fluorescent coordination polymers constructed from mixed rigid and flexible carboxylate ligands: Formation of cross-linking helical and zigzag chains

Two 3D coordination polymers with different structure motifs, [Zn₂(PCPA)₂(IN)₂]_n (1) and [Co(PCPA)(IN)]_n (2) (PCPA=p-chlorophenoxyacetate, IN=isonicotinate), first constructed from mixed rigid and flexible carboxylate ligands, have been obtained under hydrothermal condition and characterized by elemental analyses, IR spectra, thermogravimetric analysis, fluorescent spectra and single crystal X-ray diffraction analysis. The most intriguing structural feature is that each complex exhibits both infinite helical Zn(μ₂-carboxylate) or Co(μ₃-carboxylates) chain units with 2₁ helices and zigzag M₂(IN)₂ (M=zinc and cobalt) chain units by reason of two different carboxylate ligands coordinating to metal centers. Additionally, compounds 1 and 2 show similar blue fluorescence in the solid state at room temperature.     

A porous Cu(II)-MOF containing [PW12O40]3− and a large protonated water cluster: synthesis,structure, and proton conductivity

A proton-conducting metal–organic framework (MOF), {[Cu₄(dpdo)₁₂][H(H₂O)₂₇(CH₃CN)₁₂][PW₁₂O₄₀]₃}_n (where dpdo is 4,4′-bipyridine-N,N′-dioxide) (1), was synthesized by the reaction of CuHPW₁₂O₄₀·nH₂O and dpdo at room temperature. Single-crystal X-ray diffraction analysis at 293?K revealed that 1 crystallized in the cubic space group Im-3 and presented a non-interwoven 3-D framework with cubic cavities and guest molecules. A large ionic water cluster H⁺(H₂O)₂₇, consisting of a water shell (H₂O)₂₆ and an encaged H⁺(H₂O) as a center core, was trapped in the cubic cavity of the MOF {[Cu₄(dpdo)₁₂(PW₁₂O₄₀)₃]^?}_∞. Thermogravimetric analysis suggests that 1 has high thermal stability, indicating that such a non-interwoven 3-D framework with cubic cavities is a suitable host for researching protonated water clusters. Its water vapor adsorption isotherm at room temperature and pressure shows that the water vapor adsorbed in it was 65.1 cm^3?g^?1 at the maximum allowable humidity. It exhibits good proton conductivities of 10^?5–10^?4?S^?cm^?1 at 100 °C in the relative humidity range 35–98%.     

Synthesis and structure of a nickel coordination polymer with channels hosting polyanion chains

A porous coordination polymer, {[Ni(Dpdo)₄(H₂O)₂][H(H₂O)_6.5](PMo₁₂O₄₀)} _n (I), where Dpdo is 4,4′-ipyridine-N,N′-hoxide, templated by polyanion chains has been synthesized through the self-assembly of Ni²⁺ ions and Dpdo ligands in acetonitrile-water solutions and characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. The structure of compound I constructed from the polyanion [PMo₁₂O₄₀]³⁻ and the coordinated cation [Ni(Dpdo)₄(H₂O)₂]²⁺ exhibits a 3D non-interwoven frameworks with large channels occupied by the poly-Keggin anion chains as guests.     

A structure and magnetic properties of one-dimensional manganese/cobalt coordination polymers with 5-nitro-1,3-benzenedicarboxylic acid and imidazole

One-dimensional manganese(II) complex, [Mn₂(5-nbdc)₂(imH)₆] · 2H₂O (1) (5-nbdcH₂ = 5-nitro-1,3-benzenedicarboxylic acid and imH = imidazole), has been hydrothermally synthesized and structurally characterized by X-ray crystallography with the following data: orthorhombic, space group Pna2(1), M _r = 972.63 for Mn₂C₃₄H₃₄N₁₄O₁₄, a = 13.3391(12) Å, b = 16.4657(15) Å, c = 18.2177(16) Å; V = 4001.3(6) ų, Z = 4, D _calcd 1.615 g cm^?3, µ = 0.718 mm^?1, the final R = 0.0490 and wR = 0.1277 for 7278 observed reflections (I > 2σ(I)). Complex 1 exhibits very weak intra-chain ferromagnetic coupling (J k^?1 = 0.001 K) with g = 1.930. The magnetism of a one-dimensional cobalt(II) complex [Co(5-nbdc)₂(imH)₂] _n (2) indicates weak intra-chain anti-ferromagnetic coupling (J k^?1 = ?0.067 K) with g = 2.0791.     

Cobalt and nickel coordination polymers containing 3-pyridylnicotinamide and five-membered ring dicarboxylates

Cobalt and nickel coordination polymers containing the conformationally flexible 3-pyridylnicotinamide (3-pna) ligand and a five-membered ring-based dicarboxylate ligand have been prepared and structurally characterized via single-crystal X-ray diffraction. [Co(tpdc)(3-pna)]_n (1) was prepared using 2,5-thiophenedicarboxylic acid (H₂tpdc). This material shows a 2-D layer structure containing {Co₂(OCO)₂} dimers linked by tpdc and 3-pna ligands. Compound 1 manifests an underlying 3,5-connected (4²6)(4²6⁷8) 3,5L2 topology. The isostructural pair of solids [Co(D-cam)(3-pna)(H₂O)₂]_n (2) and [Ni(D-cam)(3-pna)(H₂O)₂]_n (3) was obtained from the chiral D-camphorate (D-cam) ligand. These two materials possess acentric ribbon coordination polymer motifs. Compound 1 manifests antiferromagnetic coupling concomitant with Kramers doublet formation. Thermal properties of these materials are also discussed.     

Syntheses and structures of three new coordination polymers with the flexible 1,4- bis (imidazol-1-yl)butane ligand

Three new coordination polymers [Co(bimb)₂(NCS)₂] _n (1), {[Co(bimb)₂(dca)₂]?·?CH₃CN} _n (2) and [Cu(bimb)₂(NO₃)₂] _n (3) (bimb?=?1,4-bis(imidazol-1-yl)butane, dca?=?dicyanamide) were synthesized and characterized. In 1, each Co(II) links two Co(II)'s by double bimb ligands and extends to form a one-dimensional chain containing the Co₂(bimb)₂ 22-membered metallocycle. 2 and 3 are two-dimensional (4, 4) networks linked by bimb bridges. The conformations of the bimb ligands in 1, 2 and 3 are analyzed.     

One-dimensional coordination polymers of Co(II) and Cd(II)-squarate with 2-methylimidazole and 4(5)-methylimidazole ligands

Two new mixed-ligand coordination polymers, {[Co(μ_1,3-sq)(H₂O)₂(2-Meim)₂]·2(2-Meim)}_n (1) and [Cd(μ_1,3-sq)(H₂O)₂(4(5)-Meim)₂]_n (2), (sq = squarate, 2-Meim = 2-methylimidazole, 4(5)-Meim = 5-methylimidazole) have been synthesized and structurally characterized by X-ray crystallography. The spectral (IR and UV–Vis) and thermal analyses are also reported. The Co(II) and Cd(II) ions are distorted octahedrally coordinated by four oxygen atoms of two O¹–O³-bridging squarate ligands and two trans-aqua ligands, and by two nitrogen atoms of the trans-imidazole (2-Meim or 4(5)-Meim) ligands. The structures of 1 and 2 consist of one-dimensional chains of μ-1,3-squarato bridged metal(II) complex units. These chains are held together by hydrogen bonding interactions, forming three-dimensional framework.     

Topological diversification of two new Cd(II) photoluminescent coordination polymers via auxiliary N-donor ligands

Two new cadmium(II) coordination polymers, [Cd₂(nda)₂(L₁)] _n (1) and [Cd(nda)(L₂)_0.5] _n (2), were hydrothermally synthesized with 1,4-naphthalenedicarboxylic acid (H₂nda) and auxiliary N-donor coligands [L₁?=?1,5-bis(2-methyl-imidazol-1-yl)pentane and L₂?=?4,4′-bis(2-methyl-imidazol-1-ylmethyl)biphenyl]. Single-crystal X-ray diffraction analyses showed that the topological networks are different when the N-donor ligands are changed. Compound 1 showed a (4¹⁶.6⁵) topology and 2 showed a twofold interpenetrating pcu topology.     

Syntheses,structures, photoluminescences of silver(I) coordination polymers with 2-aminopyrazine and varied dicarboxylate ligands

Four new silver(I) coordination polymers, namely [Ag(NH₂pyz)(ox)_0.5]_n (1), [Ag(NH₂pyz)(adp)_0.5·2H₂O]_n (2), [Ag₂(NH₂pyz)₂(bdc)·H₂O]_n (3) and [Ag₂(NH₂pyz)_2.5(ndc)]_n (4) [NH₂pyz = 2-aminopyrazine, ox = oxalate anion, adp = adipate anion, bdc = 1,4-benzenedicarboxylate anion, ndc = 1,4-naphthalenedicarboxylate anion] have been synthesized by solution phase ultrasonic reactions of Ag₂O with heterocyclic NH₂pyz and various dicarboxylates under ammoniacal conditions. The complexes were characterized by elemental analyses, IR spectra and single-crystal X-ray diffraction. Complex 1 is a three-dimensional (3D) framework with an α-ThSi₂ topology. Complex 2 features a 2D 4⁴-sql net involving infinite 1D double Ag-NH₂pyz chains and flexible adp anion spacers. Complex 3 is a 3D framework in which 1D single Ag-NH₂pyz chains are pillared by bdc anions to form a 2D 6³-hcb network, adjacent 2D networks are packed into a 3D framework through bridging O atoms of dbc anions. Complex 4 is a 2D structure built from infinite 1D stair-like chains containing finite Ag₄(NH₂pyz)₅ subunits. The results show that the structural diversity of the complexes result from the nature of the dicarboxylate ligands. The photoluminescence properties of the complexes were also investigated in the solid state at room temperature.     

Synthesis,crystal structure and magnetism of a two-dimensional Ni(II) coordination polymer with thiocyanate anion and dehydrogen-1,10-phenanthrolin-2-ol as bridging ligands

A two-dimensional coordination polymer [Ni(μ_1,3-SCN)(μ-Pheno)(CH₃OH)] _n (where Pheno = dehydrogen-1,10-phenanthrolin-2-ol) has been synthesized and its crystal structure determined by X-ray crystallography. Adjacent Ni(II) ions are coordinated by μ_1,3-SCN^? and μ-Pheno alternately forming a two-dimensional sheet structure. The fitting of the variable-temperature magnetic susceptibilities with a binuclear nickel(II) formula reveals that there is an anti-ferromagnetic interaction between the bridging Ni(II) ions with the magnetic coupling constant 2J = ?0.67 cm^?1.     

Syntheses and structural characterization of inifinite coordination polymers from bipyridyl ligands and zinc salts

The reaction of ZnSiF₆·6H₂O with 4,4′-dipyridyldisulfide (4-PDS) in CH₃OH afforded the complex [Zn(4-PDS)₂(SiF₆)·3CH₃OH] _n , 1, while the reaction of Zn(ClO₄)₂·6H₂O with l,2-bis(4-pyridyl)ethane (bpa) in CH₃OH gave the complex [Zn(bpa)₂(ClO₄)₂·CH₃OH] _n , 2. The 4-DPS ligand in 1 is coordinated to the metal centers through both nitrogen atoms to form a 3-D open channel and the distorted octahedral coordination geometry at each zinc center is completed by a pair of trans-F-bonded hexafluorosilicate molecule. Compound 2, the channel-type 1-D chains are interlinked through C–H···O interaction to form 3-D structure with large cavities that are occupied by the methanol molecules.     

Synthesis,crystal structures,and characterization of two Co(II) coordination polymers with 3-pyrid-3-ylbenzoic acid

Two pyridinecarboxylato-bridged coordination polymers {[Co(pbc)₂(H₂O)] · H₂O} _n (1) and [Co(pbc)₂] _n (2) (Hpbc = 3-pyrid-3-ylbenzoic acid) have been synthesized by the hydrothermal method and characterized by X-ray single crystal diffraction. In 1, pbc^? ligands link two Co(II) centers as μ₂-N,O and μ₂-N,O,O. Co(II) is six coordinate, octahedral. In 2, Co(II) is coordinated by four oxygens and two nitrogens. The ligands are μ₂-N,O,O and μ₃-N,O,O. Through different pbc^? ligands, 2 generates a 3-D network composed of six-connected nodes. Compound 2 exhibits good photoluminescence, whereas 1 is nonemissive at room temperature.     

Three lanthanide coordination polymers with nitrilotriacetic acid: hydrothermal syntheses,crystal structures and fluorescent property

Hydrothermal reactions of Sm₂O₃, Gd(ClO₄)₃?·?6H₂O and Tb(ClO₄)₃?·?6H₂O with nitrilotriacetic acid, give rise to three lanthanide coordination polymers, {[Sm(NTA)(H₂O)₂]?·?H₂O} _n (1), {[Gd(NTA)(H₂O)]?·?H₂O} _n (2) and {[Tb(NTA)(H₂O)]?·?H₂O} _n (3). Their solid-state structures have been characterized by elemental analysis, and IR spectroscopy. X-ray single-crystal diffraction analyses indicated that 2 and 3 are isomorphous three-dimensional coordination polymers with eight-coordinate Gd(III) (or Tb(III)), while 1 forms a two-dimensional coordination polymer containing nine-coordinate Sm(III). The photophysical properties of 3 have been studied with excitation and emission spectra, which exhibit strong green emission.     

Structural and magnetic properties of one-dimensional polymeric Co complexes

Pyridine-2,6-dicarboxylic acid reacts as the first ligand under hydrothermal conditions with divalent cobalt ions to form three 1D polymeric complexes in the presence of 2,4′-bipyridine as well as its derivatives 5-phenyl-2,4′-bipyridine or 5-(4-bromophenyl)-2,4′-bipyridine as the second ligands. The structures and properties of these complexes are characterized by X-ray crystallography, variable temperature magnetic measurements, infrared and thermal gravimetric analyses. It was found that the antiferromagnetic interactions between the Co^II ions can be tuned by the substituent on the second ligand.     

Two cobalt coordination polymers with a highly undulated 2-D network and a 2-D (4,4) network

Two cobalt(II) coordination polymers [Co₃(ttmb)₂(H₂O)₆Cl₆] · 3H₂O (1) and Co(ttmb)₂(H₂O)₂](NO₃)₂ · 4H₂O (2) were synthesized by the reaction of 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (ttmb) and CoCl₂ or Co(NO₃)₂. In 1, each ttmb shows a tri-monodentate coordination mode and bonds three Co(II)s to form a highly undulated 2-D network. The Schläfla symbol for the 2-D network is 3²6². The highly undulated 2-D networks are not catenated, but interdigitate each other. In 2, each ttmb shows a two-monodentate coordination mode and connects two Co(II)s to extend a 2-D (4,4) network. The ttmb exhibits the cis,cis,cis-conformation in 1 and the cis,trans,trans-conformation in 2. The thermal stability of 1 was studied.