Reactivity of Pyridine-2,4,6-tricarboxylic Acid toward Zn(II) Salts under Different Reaction Conditions

A novel crystalline nanoporous iron phosphonate based metal–organic framework as an efficient anode material for lithium ion batteries

A new Fe-MOF prepared by using a tetraphosphonic acid as a ligand is reported and it showed high specific capacity and excellent recycling efficiency in lithium-ion batteries.

Architectures varying from discrete molecular units to 2-dimensional coordination polymers and photoluminescence behavior of zinc and cadmium comprising an anionic zwitterion of rigid 4,5-dicarboxy-1,3-dimethyl-1H-imidazolium iodide

A rigid ligand, 4,5-dicarboxy-1,3-dimethyl-1H-imidazolium iodide (H₂DDII) and crystallized as zwitterion (1) and employed in the synthesis of anionic zwitterion complexes or coordination polymers (CPs)2–6of Zn(ii) and Cd(ii).

Structural variation from heterometallic heptanuclear or heptanuclear to cubane clusters based on 2-hydroxy-3-ethoxy-benzaldehyde: effects of pH and temperature

Five novel clusters were reported, with results showing that pH and reaction temperatures have a key role in the self-assembly process.

Bis[μ-2,5-bis-(pyridin-2-yl)-1,3,4-thia-diazole-κ(4) N (2),N (3):N (4),N (5)]bis-[(nitrato-κO)silver(I)] tetra-hydrate

The self-assembly of an angular 2,5-bis-(pyridin-2-yl)-1,3,4-thia-diazole ligand (L) with silver nitrate (AgNO3) produced a new dinuclear silver(I) coordination complex, [Ag2(C12H8N4S)2(NO3)2]·4H2O, which crystallizes with two Ag atoms bridged by two L ligands. The Ag atom is surrounded by four N atoms of L and by one O from the nitrate anion defining a distorted square pyramid. The atoms comprising the dication are nearly coplanar, with an r.m.s. deviation of 0.1997 Å. Mol-ecules are linked by C-H⋯O and O-H⋯O hydrogen bonds through nitrate anions and water mol-ecules, forming a two-dimensional porous network. The overall structure involves stacking of Ag complex layers along the b axis. The cohesion in the three-dimensional architecture is ensured by O⋯Ag inter-actions.

Organic-inorganic hybrid supermicroporous iron(III) phosphonate nanoparticles as an efficient catalyst for the synthesis of biofuels

Here we report a novel family of crystalline, supermicroporous iron(III) phosphonate nanomaterials (HFeP-1-3, HFeP-1-2, and HFeP-1-4) with different Fe(III)-to-organophosphonate ligand mole ratios. The materials were synthesized by using a hydrothermal reaction between benzene-1,3,5-triphosphonic acid and iron(III) chloride under acidic conditions (pH ≈ 4.0). Powder X-ray diffraction, N2 sorption, transmission and scanning electron microscopy (TEM and SEM) image analysis, thermogravimetric and differential thermal analysis (TGA-DTA), and FTIR spectroscopic tools were used to characterize the materials. The triclinic crystal phase [P1(2) space group] of the hybrid iron phosphonate was established by a Rietveld refinement of the PXRD analysis of HFeP-1-3 by using the MAUD program. The unit cell parameters are a = 8.749(1), b = 8.578(1), c = 17.725(3) Å; α = 104.47(3), β = 97.64(1), γ = 113.56(3)°; and V = 1013.41 Å(3). With these crystal parameters, we proposed an 24-membered-ring open framework structure for HFeP-1. Compound HFeP-1-3, with an starting Fe/ligand molar ratio of 3.0, shows the highest Brunauer-Emmett-Telller (BET) surface area of 556 m(2) g(-1) and uniform supermicropores of approximately 1.1 nm. The acidic surface of the porous iron(III) phosphonate nanoparticles was used in a highly efficient and recyclable catalytic transesterification reaction for the synthesis of biofuels under mild reaction conditions.

A dinuclear zinc complex containing a diamond-core geometry: [Zn2(μ2-GueO)2(GueO)2(py)2]·0.5(toluene) (GueOH is guethol)

The title zinc alkoxide, bis(μ-2-ethoxyphenolato)-κ(3)O(1),O(2):O(1);κ(3)O(1):O(1),O(2)-bis[(2-ethoxyphenolato-κ(2)O(1),O(2))(pyridine-κN)zinc(II)] toluene hemisolvate, [Zn2(C8H9O2)4(C5H5N)2]·0.5C7H8, crystallizes with two independent complex molecules located on inversion centres and one independent toluene solvent molecule disordered about an inversion centre. The Zn(II) atoms are six-coordinated in distorted octahedral geometries with O5N donor sets. The Zn(II) ions and bridging alkoxide groups are arranged in a diamond Zn2O2 core structure. The guetholate (2-ethoxyphenolate) ligands adopt two different coordination modes, viz. peripheral chelating and μ2-bridging. Preliminary investigations of the catalytic activity of the compound in the ring-opening polymerization of L-lactide demonstrate rapid and efficient generation of polylactide.

catena-Poly[[bis(N,N-dimethylformamide-κO)zinc]-μ2-oxalato-κ4O1,O2:O1′,O2′]

In the crystal structure of the title compound, [Zn(C₂O₄)(C₃H₇NO)₂]_n, the Zn^II ion is situated on a twofold rotation axis and has a distorted octa­hedral coordination geometry defined by the O atoms of two dimethyl­formamide mol­ecules and four O atoms of two bidentate oxalate ligands. The oxalate anion is located on an inversion centre and bridges two metal ions, resulting in a polymeric structure with infinite zigzag chains extending parallel to [010].

Poly[diimidazole-μ(4)-oxalato-μ(2)-oxalato-dicopper(II)]

The title compound, [Cu₂(C₂O₄)₂(C₃H₄N₂)₂]_n, was obtained as an unexpected product under hydro­thermal conditions. The Cu^II atom is in a Jahn–Teller-distorted octa­hedral environment formed by one imidazole N atom and five O atoms from three oxalate anions. The two independent oxalate anions are situated on centres of inversion and coordinate to the Cu^II atom in two different modes, viz. bidentate and monodentate. The bidentate anions bridge two Cu^II atoms, whereas the monodentate anions bridge four Cu^II atoms, leading to a layered arrangement parallel to (100). These layers are further linked into a final three-dimensional network structure via inter­molecular N—H⋯O hydrogen bonds. The title compound is isotypic with the Zn analogue.

(μ-Butane-1,2,3,4-tetra-carboxyl-ato)bis-[triaqua-(1,10-phenanthroline)nickel(II)] hexa-hydrate

The asymmetric unit of the title compound, [Ni₂(C₈H₆O₈)(C₁₂H₈N₂)₂(H₂O)₆]·6H₂O, contains a half of the centrosymmetric dinuclear complex mol­ecule and three uncoordinated water mol­ecules. In the dinuclear mol­ecule, two Ni^II cations are bridged by the butane-1,2,3,4-tetra­carboxyl­ate (BTC⁴⁻) anion. Each Ni^II atom is coordinated by two N atoms from the 1,10-phenanthroline ligand, one O atom from the BTC⁴⁻ anion and three aqua ligands in a distorted octa­hedral geometry. Inter­molecuar O—H⋯O hydrogen bonds and π–π stacking inter­ations [centroid–centroid distances = 3.646 (2), 3.781 (2) and 3.642 (2) Å] consolidate the crystal packing.

Poly[dimethyl-ammonium [aquadi-μ(2)-oxalato-dysprosate(III)] trihydrate]

The title compound, {(C₂H₈N)[Dy(C₂O₄)₂(H₂O)]·3H₂O}_n, was obtained as an unexpected product under hydro­thermal conditions. The Dy^III atom is chelated by four oxalate anions, two of which are situated on two different centres of inversion. The distorted tricapped trigonal-prismatic coordination sphere of the Dy^III atom is completed by a water mol­ecule. The bridging mode of the anions results in the formation of a three-dimensional network with cavities where the ammonium cations and the uncoordinated water mol­ecules reside. The structure is stabilized by numerous N—H⋯O and O—H⋯O hydrogen-bonding inter­actions.

Coordination polymers with pyridine-2,4,6-tricarboxylic acid and alkaline-earth/lanthanide/transition metals: synthesis and X-ray structures

Pyridine-2,4,6-tricarboxylic acid (ptcH(3)) reacts with Cd(II), Mn(II), Ni(II), Mg(II), Ca(II), Sr(II), Ba(II), Dy(III) salts forming different products depending on the reaction conditions. In the presence of pyridine at room temperature the acetate, chloride or nitrate salt of Cd(II) breaks the ligand to form an open framework structure with the empirical formula, {[Cd(Ox)(H(2)O)(2)]H(2)O}(n) (Ox = oxalate), 1. In the absence of pyridine, no crystalline compound could be isolated at room temperature (RT). However, under hydrothermal conditions and in the absence of pyridine, a discrete tetrameric complex with the formula, {[Cd(2)(cda)(2)(H(2)O)(4)](H(2)O)(3)}(2) (cdaH(2) = 4-hydroxypyridine-2,6-dicarboxylic acid), 2, is formed where the carboxylate group at the 4-position of the ligand is reduced to a hydroxyl group. When Ni(II), Mn(II), Mg(II), Ca(II), Sr(II), Ba(II), Dy(III) salts are used in place of Cd(II), no crystalline product could be isolated at RT. But under hydrothermal conditions, coordination polymers ({[Ni(1.5)(ptc)(pip)(0.5)(H(2)O)(4)].H(2)O}(n), (pip = piperazine), 3; {Mn(1.5)(ptc).2H(2)O}(n), 4; {Mg(3)(ptc)(2).8H(2)O}(n), 5; {[Mg(ptc)(H(2)O)(2)].1/2[Mg(H(2)O)(6)].H(2)O}(n), 6; {Ca(1.5)(ptc).2H(2)O}(n), 7; {Sr(1.5)(ptc).5H(2)O}(n), 8; {[Ba(ptc)(H(2)O)][Ba(ptcH(2))H(2)O]}(n), 9; {[Dy(ptc).3H(2)O].H(2)O}(n), 10) are formed. The structures exhibit different dimensionality depending on the nature of the metal ions. In 1 a discrete acyclic water hexamer is also identified. All the compounds are characterized in the solid state by X-ray crystallography, IR and elemental analysis.

Synthesis, Structure, and Photoluminescent Properties of Two New Microporous Eu(III) Coordination Polymers with 2,4,6-Pyridinetricarboxylate

Two new three-dimensional (3D) microporous Eu(iii) coordination polymers, [Eu5(pyta)5(H2O)7]·3.5H2O (1) and [Eu2(ox)1.5(pyta)(H2O)4]·4.5H2O (2) (H3pyta = 2,4,6-pyridinetricarboxylic acid, ox2– = oxalate), have been synthesized under hydrothermal conditions. The oxalate ligand in 2, generated in situ from the cleavage and chemical rearrangement of the H3pyta ligand, is incorporated to construct two kinds of 1D hydrophilic channels in 2. Both 1 and 2 show the characteristic photoluminescent properties of Eu(iii) compounds. Desolvated 2 shows interesting solvent-dependent photoluminescent properties.