A {Ni7} cluster-containing sandwich-type phosphotungstate functionalized by organic bisphosphonate ligands and its two-dimensional supramolecular structure

A {Ni₇} cluster-substituted sandwich-type phosphotungstate Na₁₀（NH₄）₄[{(B-a-PW₉O₃₄)Ni₃ （OH）（H₂O）₂（HAIe）}₂Ni]·22H₂O（1） was syntliesized using the conventional aqueous solution method. Compound 1 represents the first nickel-containing sandwich-type polyoxometalate functionalized by bisphosphonate ligands.Fuither,the sandwich-type polyoxoanions aggregated via the H-bonding interactions into a two-dimensional（2D） supramolecular framework.     

Synthesis,Characterization, and Properties of Supported Tungstozincate Bridged by Co（Ⅱ） Complex Fragment

[Co^11（phen）3]2[{（ZnW12O40）Co^11（phen）2（H2O）}2Co^11（trien）2（NaH2O）2]·3H2O was synthesized via hydrothermal technique and characterized with elemental analyses, IR spectroscopy, TGA-DTA, and variable temperature magnetic susceptibility. The compound crystallized in the monoclinic system with the space group P21/n, a=1.8210 nm, b=2.3592 nm, c=2.2932 nm, β=110.31°, V=9.239 nm^3, Z=2, R1=0.0827. The compound consists of two coordination cations, three lattice water molecules, and a macroanion [{（ZnW12O40）Co（phen）2（H2O）}2Co（C6H18N4）2·（NaH2O）2]^4- in which each supported Keggin anion [（ZnW12O40Co^11（phen）2（H2O）]^4- acts as a ligand to coordinate to central bridging Co^2＋ ion via a terminal oxygen atom. Hydrogen bonds are responsible for the construction of 3D architecture of the compound. The compound is paramagnetic with a weak antiferromagnetic interaction（0=-46.796 K）.     

Heterometallic iodoplumbates modified by copper(I) or silver(I) with viologens

Cu/Ag(I) were introduced into iodoplumbate systems to produce two new heterometallic iodoplumbates with viologen as templates, i.e. (PV)₂(Pb₂Cu₂I₁₀) (1) and [(BV)(Pb₂AgI₇)]_n (2) (PV²⁺ = propyl viologen, BV²⁺ = benzyl viologen), in which the common connection of PbI₆ units have been remarkably altered. In (PV)₂(Pb₂Cu₂I₁₀) (1), two PbI₆ octahedra are bridged by two CuI₄ tetrahedra via face-sharing to give a (Pb₂Cu₂I₁₀)^4? cluster, but the ternary one-dimensional polymeric (Pb₂AgI₇)_n^2n? of [(BV)(Pb₂AgI₇)]_n (2) is assembled from edge-sharing AgI₄ tetrahedra and PbI₆ octahedra. Their optical band gaps and fluorescence were also discussed. The absorption edges of haloplumbates could be engineered by introduction of suitable conjugated molecules as templates.     

A new 1-D chain based on the trivacant monocapped Keggin arsenomolybdate and the copper complex linker: synthesis,crystal structure,and ESI-MS analyses

A new organic–inorganic hybrid (H₂en)₂[[Cu(en)₂]As^IIIAs^VMo^VI₉O₃₄]·6H₂O (1), containing a 1-D helical chain based on the trivacant monocapped Keggin arsenomolybdate and the copper complex linker {[Cu(en)₂][As^IIIAs^VMo^VI₉O₃₄]}_n^4n? (en = ethylenediamine), has been synthesized and characterized by IR spectra, TG analyses, single-crystal X-ray diffraction, and high-resolution electrospray ionization mass spectrometry (ESI-MS). Large voids are observed and a 1-D chain containing repeated (H₂O)₈ water units from lattice water molecules is formed along the a axis in the crystal structure. The high-resolution ESI-MS shows that the intact framework [Cu(en)₂][As^IIIAs^VMo^VI₉O₃₄]^4? exists in solution.     

A New Polynuclear Copper‐Complex‐Substituted Tungstoarsenate(V)

A new polynuclear copper‐complex‐substituted dimeric tungstoarsenate(V), H₂[{Cu(2,2′‐bpy)}₈(H₂O)₂(AsW₉O₃₄)₂] · 12H₂O ( 1 ) (2,2′‐bpy = 2,2′‐bipydine), was synthesized hydrothermally and its structure was determined by single‐crystal X‐ray diffraction. The title compound has Ci symmetry and consists of two trilacunary Keggin anions [α‐AsW₉O₃₄]^9– supported by eight copper complex cations. The compound was also characterized by IR and fluorescence spectroscopy, TG analysis, and magnetic measurements. The emission spectrum of the compound in solid‐state exhibits a redshift relative to those of Na₈[A‐HAsW₉O₃₄] · 11H₂O and the free ligand 2,2′‐bpy. Magnetic measurements of the compound indicate competing ferro‐ and antiferromagnetic intramolecular coupling among the Cu^II atoms in the cluster anion.     

A novel dimeric zinc(II) complex with a tripodal peptide ligand: a structure stabilized by ligand sharing

The crystal structure of a novel dimeric zinc(II) complex, [ZnL(H₂O)]₂(ClO₄)₂·4H₂O (L?=?N-(bis(2-pyridyl)methyl)-2-pyridinecarboxamide), has been determined by X-ray diffraction. In this complex each planar N_py–N_amido–N_py moiety of the ligand coordinates to one zinc ion and the pendant pyridine of one [ZnL] unit completes the coordination sphere of a [ZnL] neighbor. Units of the complex are connected in a two-dimensional network by intermolecular hydrogen bonds. The thermodynamic properties of the ligand with bivalent metal ions Co(II), Ni(II), Cu(II) and Zn(II) were studied by potentiometric titration and the order of the stability constants is in agreement with the Irving–Williams series. The dimeric complex is stabilized through ligand sharing, as confirmed by the crystal structure and thermodynamic properties.     

Contribution of the ligand to the electroreduction of CO2 catalyzed by a cobalt(II) macrocyclic complex

The electrochemical reduction of carbon dioxide using hexa-aza-macrocycles derived from the condensation of 1,10-phenanthroline and its Co(II) complex as an electrocatalyst dissolved in dimethylformamide has been studied by cyclic voltammetry and UV-visible spectroscopy. The ligand does not show catalytic activity and only generates hydrogen when it is reduced under carbon dioxide. The cobalt complex shows electrocatalytic activity toward the reduction of carbon dioxide, generating carbon monoxide and formic acid. Cyclic voltammetry and UV-visible spectroscopy show that the active site for the reduction is the metal center in oxidation state (I), although the reduced cobalt center alone is not enough to promote reduction of the carbon dioxide. Electrolysis at controlled potential shows that only at potentials corresponding to reduction of the ligand (second reduction) does carbon dioxide reduction occur. Cobalt(I) probably reacts with CO₂ forming a non-isolated intermediate which, when reduced, gives CO and formic acid. The second reduction that takes place on the ligand regenerates the catalyst and gives products, thus becoming the rate-determining step of the reaction.     

Hydrothermal synthesis and characterization of a novel supramolecular network compound of Co(NIA)2(H2O)4 with molecular ladder hydrogen bond chains (NIA=nicotinate)

By hydrothermal method, a novel supramolecular compound, Co(NIA)₂(H₂O)₄ was synthesized and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffractometer, indicating that it is a novel polyporous supramolecule with molecular ladder hydrogen-bonded chains. TGA curve shows its thermal stability up to 520 °C.     

Synthesis,crystal structure and magnetism of 1D cobalt(II) coordination polymer with thiocyanate as bridging ligand

A one-dimensional coordination polymer [Co(μ _1,3-NCS)₂(npdo)₂] _n (npdo?=?4-nitropyridine N-oxide) has been synthesized and structurally determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group of Pbcn with a?=?22.688(5)?Å, b?=?7.2636(17)?Å, c?=?10.299(2)?Å. Adjacent Co(II) ions are coordinated by two μ _1,3-SCN^? bridging ligands, forming a one-dimensional chain along the c axis and the npdo coordinates to Co(II) ion as a terminal ligand. The thermal variation of the magnetic moments of the complex reflects the antiferromagnetic interaction between the bridged Co(II) ions above 20?K and the ferromagnetic transition or the strong short-range spin interaction below 20?K.     

A V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl) benzylamine with its cobalt(II) complex: synthesis,crystal structure,DNA-binding properties,and antioxidant activity

A V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl)benzylamine (bmbb) and its cobalt complex, [Co(bmbb)₂](pic)₂ (pic?=?picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal X-ray revealed that the coordination sphere around Co(II) is distorted octahedral with an N₆ ligand set from two tridentate bmbb. The DNA-binding properties of bmbb and the Co(II) complex were investigated by spectrophotometric and viscosity measurements. The results suggest that bmbb and Co(II) complex both bind to DNA via intercalation, and the Co(II) complex binds to DNA more strongly than bmbb. The Co(II) complex also exhibited potential antioxidant properties in vitro studies.     

A novel inorganic-organic compound: Synthesis and structural characterization of tin(II) phenylbis(phosphonate), Sn2(PO3C6H4PO3)

A novel tin(II) phenylbis(phosphonate) compound has been synthesized hydrothermally and its structure has been determined by single crystal X-ray diffraction. The structure is monoclinic, space group P2₁/c (no. 14), a=4.8094(4), b=16.2871(13), ; β=106.292(6)°, , Z=2. The three-dimensional structure consists of 3-coordinated tin and 4-coordinated phosphorus double layers separated (pillared) by phenyl rings. These phenyl rings are placed 4.8 Å apart along the a-axis in the structure resulting in lower surface area (∼14 m²/g). The porosity has been increased by replacing phenyl groups by methyl groups (∼31 m²/g).     

Hybrid nanoflowers bearing tetraphenylporphyrin assembled on copper(II) or cobalt(II) inorganic material: A green efficient catalyst for hydrogenation of nitrobenzenes in water

Simple fabrication of organic–inorganic hybrid nanoflowers (TPP@CuhNfs and TPP@CohNfs) was achieved with tetraphenylporphyrin (TPP) as organic counterpart and Cu²⁺ or Co²⁺ ions as inorganic materials via a green route, with lower cost and controlled pH. The effect of pH levels and TPP concentrations on the morphology of the TPP@CuhNfs and TPP@CohNfs materials was examined by scanning electron microscopy (energy-dispersive X-ray [EDX]). The formation and chemical structures of TPP@CuhNfs and TPP@CohNfs were evaluated using Fourier transform infrared. Elemental analyses of these hybrid nanoflowers were carried out by EDX. The fabricated TPP@CuhNfs and TPP@CohNfs nanomaterials under optimum conditions act as effective reusable catalysts for the hydrogenation of nitroanilines in aqueous media at ambient temperature. The time-dependent hydrogenation can be easily monitored spectrophotometrically and verified by ¹H-nuclear magnetic resonance. These types of the catalytic reaction or system are recorded to be useful toward the hydrogenation of nitroanilines, regardless of the position and type of substrate. Moreover, TPP@CuhNfs and TPP@CohNfs catalysts demonstrated a type of metal ions-dependent catalytic efficiency toward hydrogenation of nitroanilines (organic pollutants), with TPP@CuhNfs found to be more effective than TPP@CohNfs. However, both catalysts containing Cu²⁺ and Co²⁺ ions showed good performance and can be reused at least five times without a significant decline in yield. The presented approach based on hybrid nanoflowers provides as a low cost and ecofriendly method (green route) for different catalytic hydrogenations.     

X-ray structure and vibrational spectroscopy of a cobalt(II) complex prepared with excess of 4-hydroxybenzhydrazide

A new cobalt(II) complex was obtained from CH₃OH/H₂O solution containing CoSO₄ and 4-hydroxybenzhydrazide (4hbah) in 1?:?3 molar ratio. The crystals are composed of polymer chains [Co(4hbah)₂(μ-SO₄)] _n accompanied by lattice H₂O and CH₃OH forming the 3-D network. The CH₃OH molecules are highly disordered. For the assignment of IR and Raman spectra, the O,N-deuterated compound was prepared and DFT calculations were carried out.     

Syntheses and crystal structures of 3-tert-butyl-4-cyano pyrazole and its complexes with cobalt(II), manganese(II), and copper(II)

A new pyrazole ligand, 3-tert-butyl-4-cyano pyrazole (Hpz^t-Bu,4CN), has been synthesized. The crystal structure of this pyrazole, along with the syntheses and crystal structures of Co, Cu, and Mn complexes of this ligand, are reported. The uncoordinated pyrazole shows the formation of a cyclic hydrogen-bound dimer. The Co complex is octahedral, with four coordinated pyrazoles and two coordinated waters. The Mn complex is octahedral, with two coordinated pyrazoles, two coordinated triflates and two coordinated waters. A hydrogen bonding network involving the triflates and waters results in a linear double chain of Mn complexes. The Cu complex has two coordinated pyrazoles and two coordinated chlorides in a slightly distorted square-planar geometry, with a long bond to the cyano N atom of a neighboring Cu complex, forming a pseudodimer.     

Synthesis,spectra, crystal structure and thermal properties of a polymeric 1-D cobalt(II) cyanato complex with hexamethylenetetramine

A new cobalt(II) cyanato complex, [Co(NCO)₂(H₂O)₂(hmt)] (I) where hmt is hexamethylenetetramine, has been synthesized and structurally characterized. The electronic spectra of the solid compound suggest octahedral cobalt and IR spectra revealed monodentate N-cyanato groups and aqua ligands, while hmt is a bridging N, N′-bidentate leading to a 1-D infinite polymeric chain. The structure has been confirmed from single crystal X-ray diffraction. Crystal data for I : Fw 319.20, a = 9.234(2), b = 11.252(2), c = 12.576(3) Å, β = 107.75(3)°, V = 1244.5(4) ų, Z = 4, T = 100 K. Crystal system : monoclinic, space group : C2/c. Hydrogen bonds of the type O–H ··· O and O–H ··· N between aqua molecules and O atom of the terminal N-cyanato groups or an N atom of hmt ligands consolidate and extend the structure to a 3-D network. The thermal properties of I are reported.     

Structure,spectroscopic, and magnetic properties of a new cobalt(II) complex with 5-sulfoisophthalic anion

A complex of [Co(H₂SIP)(Phen)(H₂O)₃] ? H₂O (H₂SIP = 5-sulfoisophthalic anion, Phen = 1,10-phenanthroline) has been synthesized by hydrothermal reaction. Crystal structure determination revealed that the complex crystallizes in the monoclinic space group P2(1)/c, in which Co(II) is distorted octahedral coordinating with one carboxylate sulfonate ligand, one phen, and three coordinated waters. Molecules of [Co(H₂SIP)(Phen)(H₂O)₃] ? H₂O are connected to form a 3-D structure by intermolecular hydrogen bonds and π–π stacking interactions. IR spectra, UV-Vis spectra, and magnetic susceptibilities have been analyzed to obtain values of the ligand field and magnetic parameters: Α = 1.33, λ = ?102.3 cm^?1, κ = 0.96, and Δ = 252.2 cm^?1.     

Synthesis and crystal structure of a 3-d polymeric cobalt(II) and sodium complex with pyrazine-2-carboxylate as a bridging ligand

A complex with a three-dimensional structure {[Na₃Co(pyz)₃(H₂O)₄(ClO₄)₂]} _n (pyz = pyrazine-2-carboxylate anion) has been synthesized and its crystal structure determined by X-ray crystallography. The complex crystallizes in a triclinic system with a space group Pī and a = 8.598(11), b = 11.382(15), c = 14.496(19)?Å, α = 87.79(2), β = 88.21(2), γ = 82.08(2)°. The Co(II) ion is located in a distorted octahedral environment with three oxygen atoms and three nitrogen atoms, from the three pyr ligands. Na(1) ion is coordinated by four oxygen atoms and two nitrogen atoms, in which O(1), O(2), O(2A), N(4A) and N(6A) come from ligand pyr while O(15) comes from H₂O. Na(2) and Na(3) ions are each coordinated by six oxygen atoms. Through coordination of the bridging ligand pyr with Co(II) and Na(I) a three-dimensional net structure is formed.     

新型化合物[Ni(en)3]2[Ni(en)2(H2O)2][As6V15O42]·4H2O晶体的水热合成与表征

金属氧酸盐因其在医药临床、工业催化、功能材料等方面的广泛应用而引起人们的关注[1～6], 其中, 有关钒化学的研究一直很活跃, 钒具有与钼、钨明显不同的结构特性, 钒可以采取VO4, VO5和VO6方式配位, 同时, 钒的价态可以是+3, +4和+5价. 由于钒可采取多种配位方式及多种价态, 与钼酸盐和钨酸盐相比, 钒酸盐更具有结构柔顺性, 同时易形成低价或混合价态物种.在以往的文献中, 有关P-V-O体系多金属氧酸盐的水热合成的研究已有大量的报道[7], 在常规溶液合成中, 人们已对As-V-O体系进行了相对深入的研究, 而有关水热合成的研究报道却很少, 已见报道的砷钒化合物有K6*6H2O[8,9], 4-[10], 6-[11](X=SO2-3, SO2-4, H2O). 为了探究水热条件下As-V-O体系的反应特性, 我们开展了这方面的研究工作, 并取得了突破性进展. 本文采用中温水热技术合成了含有机基团的砷矾超分子化合物2**4H2O, 探讨这类化合物的非线性光学性质、催化性质及其它功能特性将是一个非常有意义的研究领域.