Synthesis and characterization of a three-dimensional framework built up of paradodecatungstate-B clusters and transition metals as linkers

A novel paradodecatungstate compound, namely [Na₂(H₂O)₁₀][Cu₄(H₂O)₁₂(H₂W₁₂O₄₂)]·15H₂O (1) has been synthesized by convenient aqueous solution method and structurally characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis, and differential thermal analysis. Single-crystal X-ray diffraction reveals that in compound 1, the [H₂W₁₂O₄₂]^10? anions are connected via divalent copper cation as purely inorganic linker to form a three-dimensional structural network. In addition, compound 1 exhibits strong photoluminescent emission at room temperature.     

Synthesis, crystal structure, and property of one- and two-dimensional complexes based on paradodecatungstate-B cluster

Three polyoxotungstates, Na₈[Cu(H₂O)₂(H₂W₁₂O₄₂)]·30H₂O (1), Na₈[Cd(H₂O)₂(H₂W₁₂O₄₂)]·20H₂O (2), and Na_7.4[Cd_1.3(H₂O)₂(H₂W₁₂O₄₂)]·24H₂O (3), were synthesized and characterized by elemental and thermogravimetric (TG)analysis, infrared spectroscopy and X-ray single-crystal analysis. Both complexes 1 and 2 exhibit one-dimensional structure with two neighboring paradodecatungstate-B clusters, [H₂W₁₂O₄₂]¹⁰⁻, linked by [Cu(H₂O)₂]²⁺ or [Cd(H₂O)₂]²⁺ units, while complex 3 displays a two-dimensional network structure. The electrochemical behaviors of complexes 1 and 3 were investigated in the buffer solution of pH 4.8. The results of electrocatalysis reveal that the reduced species of complexes 1 and 3 are electrocatalytically active for the reduction of nitrite. Complex 1 exhibits the electrocatalytic activity for the reduction of nitrate as well. The surface photovoltage spectroscopy (SPS) and electric field-induced SPS (EFISPS) measurements show that the surface photovoltage behavior of complex 1 is complicated while complex 3 bears the property of n-type semiconductor.     

手性金属簇合物的合成、结构表征及其反应

用潜手性羰基簇合物 ( μ3 S)RuCo2 (CO) 9( 1 )与阴离子金属交换试剂Na[M (CO) 3C5 H4C(O)R][R =H ,CH3,C6 H5 ,C6 H4C(O)OCH3;M =Mo ,W ]在四氢呋喃中回流反应 ,生成一系列新的由四个不同原子组成的不对称四面体簇合物 ( μ3 S)RuCoM (CO ) 8CpCOR .研究了簇合物 ( μ3 S)RuCoMo(CO) 8CpCOCH3的还原反应 .对合成的所有化合物进行了IR、1HNMR、C/H元素分析 ,测定了簇合物( μ3 S)RuCoMo(CO) 8CpCOC6 H5 的单晶结构 .     

Self-assembly of four new extended architectures based on reduced polyoxometalate clusters and cadmium complexes

Four new [P₄Mo₆] cluster-based extended structures containing cadmium complexes, [Cd₃(4,4′-Hbpy)₂(4,4′-bpy)₂(H₂O)₈][Cd(H₂PO₄)₂(HPO₄)₄(PO₄)₂(MoO₂)₁₂(OH)₆]·7H₂O 1, (4,4′-Hbpy)₂[Cd(4,4′-bpy)₃(H₂O)₃][Cd(4,4′-bpy)(H₂O)]₂[Cd(H₂PO₄)₂(HPO₄)₄ (PO₄)₂(MoO₂)₁₂(OH)₆]·H₂O 2, [Cd₄(phen)₂(H₂O)₄][Cd(phen)(H₂O)]₂[Cd(HPO₄)₄ (HPO₄)₄(MoO₂)₁₂(OH)₆]·5H₂O 3 and [Cd₄(2,2′-bpy)₂(H₂O)₄][Cd(2,2′-bpy)(H₂O)]₂ [Cd(HPO₄)₄(HPO₄)₄(MoO₂)₁₂(OH)₆]·3H₂O 4 (4,4′-bpy=4,4′-bpyridine, phen=1,10-phenanthroline, 2,2′-bpy=2,2′-bpyridine), have been synthesized and characterized by elemental analysis, IR, TG and single crystal X-ray diffraction. The structure of compound 1 is constructed from the Cd[P₄Mo₆]₂ dimers linked by [Cd₃(4,4′-Hbpy)₂(4,4′-bpy)₂(H₂O)₈] subunits to generate a plane layer. Compound 2 consists of the positive 2D sheets that constructed from Cd[P₄Mo₆]₂ dimers linked by [Cd(4,4′-bpy)(H₂O)] complexes, then the 2D sheets are further linked up together to form a 3D supramolecular framework via extensive hydrogen-bonding interactions among the [P₄Mo₆] clusters, free 4,4′-bpy molecules, dissociated [Cd(4,4′-bpy)₃(H₂O)₃]²⁺ complexes and water molecules. Compounds 3 and 4 show new 2D layered structure, with Cd[P₄Mo₆]₂ building blocks connected by tetra-nuclear [Cd₄{(phen)₂/(2,2′-bpy)₂}(H₂O)₄] clusters and [Cd(phen/2,2′-bpy)(H₂O)] complexes. The fluorescent activities of compounds 3 and 4 are reported.     

Synthesis, characterization and formation process of transition metal oxide nanotubes using carbon nanofibers as templates

Mono and binary transition metal oxide nanotubes could be synthesized by the immersion of carbon nanofiber templates into metal nitrate solutions and removal of the templates by heat treatment in air. The transition metal oxide nanotubes were composed of nano-crystallites of metal oxides. The functional groups on the carbon nanofiber templates were essential for the coating of these templates: they acted as adsorption sites for the metal nitrates, ensuring a uniform metal oxide coating. During the removal of the carbon nanofiber templates by calcination in air, the metal oxide coatings promoted the combustion reaction between the carbon nanofibers and oxygen.     

Synthesis,crystal structures,thermal properties,and DNA-binding studies of transition metal complexes with imidazole ligands

A new series of complexes of transition metal (Cu, Zn, Ni) perchlorate with imidazole have been synthesized and characterized by elemental analysis, infrared (IR), UV-Vis spectroscopy, and single-crystal X-ray diffraction. Based on elemental and spectral data, the complexes are M(C₃H₄N₂) _x (ClO₄)₂ (M?=?Cu, Zn, x?=?4; M?=?Ni, x?=?6; C₃H₄N₂?=?imidazole). The crystal structures of Cu(C₃H₄N₂)₄(ClO₄)₂ (1) and Zn(C₃H₄N₂)₄(ClO₄)₂ (2) show metals surrounded by four nitrogens of imidazole, while the nickel complex Ni(C₃H₄N₂)₆(ClO₄)₂ (3) has six nitrogens of imidazole. Intra- and inter-molecular hydrogen bonds exist between hydrogen of imidazole and oxygen of perchlorate. The thermal stabilities of 1, 2, and 3 at different heating rates (β?=?5°C?min^?1, 10°C?min^?1, and 15°C?min^?1) show that all the complexes exhibit two thermal decomposition stages; the sequence of thermal stability is 2?>?1?>?3. 1, 2, 3, and imidazole display DNA binding ability, ascertained by UV-Vis titration.     

Ionothermal synthesis and characterization of two new heteropolytungstates with 1-ethyl-3-methylimidazolium bromide ionic liquid as solvent

In this article, we have synthesized two new heteropolytungstate-based compounds [EMIM]₄[SiW₁₂O₄₀] (1) and [EMIM]₆[P₂W₁₈O₆₂] · 4H₂O (2) using the ionic liquid (IL) [EMIM]Br (EMIM = 1-ethyl-3-methylimidazolium) as a solvent and characterized them by infrared (IR) and ultraviolet (UV) spectra, thermogravimetric (TG) and elemental analyses, electrochemistry, and single-crystal X-ray analyses. Compound 1 is constructed from one [SiW₁₂O₄₀]^4? and four [EMIM]⁺. In the structure, [SiW₁₂O₄₀]^4? and [EMIM]⁺ are connected by hydrogen bonds with the surface oxygens of the polyoxoanion to form a 3-D supramolecular framework. The heteropolyanion of 2 is a classical Dawson-type structure [P₂W₁₈O₆₂]^6? and connected with six cations through hydrogen bonds. The structures of these two heteropolyanions are consistent with those synthesized by traditional methods, indicating that ionothermal synthesis is an effective method for the preparation of heteropolyoxometalates. The photocatalytic properties of these compounds have also been investigated.     

Synthesis,characterization, and crystal structures of cobalt(II), copper(II), and zinc(II) complexes of a bidentate iminophenol

A bidentate iminophenol (HL = 2-((4-methoxyphenylimino)methyl)-4,6-di-tert-butylphenol derived from condensation of 4-methoxyaniline and 3,5-di-tert-butyl-2-hydroxybenzaldehyde) was mixed with divalent metal salts to form the corresponding mononuclear metal complexes [M^II(L)₂] (M = Co (1), Cu (2), and Zn (3)). The complexes are characterized by different spectroscopic and analytical tools. X-ray crystal structures of the complexes revealed homoleptic mononuclear complexes with MN₂O₂ coordination. The cobalt(II) (1) and zinc(II) (3) complexes display a pseudo-tetrahedral coordination geometry, whereas the copper(II) complex (2) exhibits a distorted square-planar coordination. The zinc(II) complex (3) emits at 460 nm with a twofold enhancement of emission with respect to the free iminophenol.     

Recent catalytic syntheses of trifluoromethylthio-containing organic compounds by transition metals,chiral organocatalysts,and photocatalysts

This review summarizes the recent advances in the catalytic syntheses of CF_3S-containing organic molecules using various nucleophilic or electrophilic trifluoromethylthiolating reagents.C-halogen and C—H bonds in various molecules have been transformed to C—SCF_3 bonds by transition-metal-catalyzed reactions,such as cross-coupling of aryl halides.Enantioselective reactions controlled by chiral metal complexes or chiral organocatalysts have afforded many trifluoromethylthiolated chiral architectures,such as β-ketoesters and oxindoles.Very recently,visible-light-induced photoredox trifluoromethylthiolations have been developed,providing versatile CF_3S-containing structures efficiently.     

Evolution of lowest singlet and triplet excited states with transition metals in group 10-12 metallaynes containing biphenyl spacer

A new series of thermally stable group 10 platinum(II) and group 12 mercury(II) poly-yne polymers containing biphenyl spacer trans-[-Pt(PBu₃)₂CC(p-C₆H₄)₂CC-]_n and [HgCC(p-C₆H₄)₂CC-]_n were prepared in good yields by Hagihara’s dehydrohalogenation reaction of the corresponding metal chloride precursors with 4,4′-diethynylbiphenyl HCC(p-C₆H₄)₂CCH at room temperature. We report the optical spectroscopy of these polymetallaynes and compare the results with their bimetallic model complexes trans-[Pt(Ph)(PEt₃)₂CC(p-C₆H₄)₂CCPt(Ph)(PEt₃)₂] and [MeHgCC(p-C₆H₄)₂CCHgMe] as well as the group 11 gold(I) counterpart [(PPh₃)AuCC(p-C₆H₄)₂CCAu(PPh₃)]. The structural properties of all model complexes have been studied by X-ray crystallography. The influence of the heavy metal atom in these metal alkynyl systems on the intersystem crossing rate and the spatial extent of lowest singlet and triplet excitons is systematically characterized. Our investigations indicate that the organic triplet emissions can be harvested by the heavy-atom effect of group 10-12 transition metals (viz., Pt, Au, and Hg) which enables efficient intersystem crossing from the S₁ singlet excited state to the T₁ triplet excited state.     

Syntheses,crystal structures,and properties of four new coordination compounds of transition metals and imidazoledicarboxylic acid derivatives

Four new transition metal coordination complexes, [Cd(H₂pimdc)₂(H₂O)₂]?·?4H₂O (1), [Zn(H₂pimdc)₂(H₂O)₂]₂?·?7H₂O (2), and [M(H₂pimdc)₂] (M?=?Cu (3) or Ni (4), H₂pimdc^??=?2-propyl-4,5-imidazoledicarboxylate), have been prepared by conventional synthesis and characterized by elemental analyses, IR, TG, and single-crystal X-ray diffraction. H₂pimdc^? is a bidentate chelating ligand in 1 and 2, leading to 3-D supramolecular structures through hydrogen bonds. However, H₂pimdc^? is a tridentate chelating-bridge ligand in 3 and 4, which exhibit 2-D layer structures. Thermal properties and photoluminescence spectra of 1–4 were measured.     

Interaction of Naproxen with transition metals: synthesis,characterization, anti-inflammatory activity and kinetic studies

Coordination complexes of transition metals (Co, Ni, Cu, Fe, Cr, Ru, Ir, Mn, and Zn) with 6-methoxy-α-methyl-2-naphthalene acetic acid (Naproxen) and triphenylphosphine have been synthesized and characterized by conductance, elemental analysis, UV-Vis, AAS, and FT-IR spectroscopy. The elemental analyses data reveal the presence of 1:1 (metal : ligand) stoichiometry and the IR data suggest that naproxen functions as a bidentate ligand in coordination with transition metals. The anti-inflammatory assays of these complexes have significant effect.     

Synthesis and biological evaluation of Cu(II), Zn(II), and Ni(II) 3-(4-nitrophenyl)acrylic acid complexes with diamines as potential urease inhibitors

Five new Cu(II), Zn(II), and Ni(II) 3-(4-nitrophenyl)acrylic acid complexes were synthesized and evaluated for inhibitory activity on jack bean urease. All five complexes were structurally determined by single crystal X-ray analysis. Compared with the positive reference acetohydroxamic acid (IC₅₀?=?13.25?μM), Cu(II) complexes 3 and 4 showed the strongest inhibitory activity against jack bean urease (IC₅₀?=?1.23 and 1.17?μM). Ni(II) and Zn(II) complexes also exhibited inhibitory activities (IC₅₀?=?10.09–13.10?μM).     

A 1-D ladder-like aggregate constructed from Preyssler anion and transition metal linkers

A 1-D ladder-like aggregate, K₂Na₆[Na(H₂O)Fe₂(H₂O)₈(P₅W₃₀O₁₁₀)] · 23.5H₂O (1; K₂Na₆[1a] · 23.5H₂O) has been obtained by conventional aqueous solution reaction. X-ray diffraction analysis reveals that 1 crystallizes in the monoclinic system, space group P 2 ₁ /m, a = 16.938(3) Å, b = 21.396(4) Å, c = 17.520(4) Å, β = 98.14(3)°, V = 6285(2) ų, and Z = 2. Polyoxoanion 1a shows a 1-D ladder-like chain, built up of Preyssler anion and Fe³⁺ linkers, which represents the first extended structure based on Preyssler anion and transition metal linkers. The 1-D chains in 1 are further connected into a 3-D open framework by potassium and sodium cations. Compound 1 displays electrocatalytic activity towards the reduction of nitrite.     

Synthesis and Structural Characterization of a Novel Sphere Compound of Mo_8V_2O_(28)·7H_2O

Polyoxometalates( POMs) are attractivebuilding blocks for functional materials withpotential application in electrocatalysis and thepreparations of molecular electronic,orelectrooptical devices[1,2 ] . With the recentdiscovery of giant nanoporous and spherePOMs[3— 6] ,it remains a great challenge tosynthesize rationally new nanoscale materialspossessing novel structures and desirableproperties.The present paper covers a novelstructure characterization of Mo8V2 O2 8· 7H2 O( abbreviated Mo…     

Hydrothermal syntheses, crystal structures of three new organic–inorganic hybrids constructed from Keggin-type [BW12O40] clusters and transition metal complexes

Three new organic–inorganic hybrid compounds constructed from Keggin-type polyanions and transition metal complexes, [Mn(2,2′-bipy)₃]_1.5[BW₁₂O₄₀Mn(2,2′-bipy)₂(H₂O)]·0.25H₂O (1), [Fe(2,2′-bipy)₃]_1.5[BW₁₂O₄₀Fe(2,2′-bipy)₂(H₂O)]·0.5H₂O (2) and [Cu₂(phen)₂(OH)₂]₂H[Cu(H₂O)₂{BW₁₂O₄₀Cu_0.75(phen)(H₂O)}₂]·1.5H₂O (3), have been hydrothermally synthesized and characterized by elemental analyses, IR, TGA and single-crystal X-ray diffraction. Compounds 1 and 2 are isostructural and both exhibit monosupporting polyoxometalate cluster structure, each of which contains a [BW₁₂O₄₀]⁵⁻ cluster decorated by one transition metal complex. Compound 3 contains a bisupporting polyoxometalate cluster anion where two {Cu_0.75(phen)(H₂O)}^0.75+ fragments are supported on the polyoxometalate dimer {Cu(H₂O)₂(BW₁₂O₄₀)₂}⁸⁻, this represents the first bisupporting polyoxometalate cluster based on a Keggin-type polyoxometalate dimer, which are further packed together via π–π stacking contacts into an extended 1-D chain.     

Synthesis,structural characterization,and thermal properties of alkaline (earth) compounds derived from 2,4-dinitroimidazole

Eight alkaline and alkaline-earth compounds derived from 2,4-dinitroimidazole (2,4-HDNI) were synthesized and characterized by elemental analysis, FT-IR, and TG–DSC, of which K(2,4-DNI) (1), Rb(2,4-DNI)(2,4-HDNI)(H₂O)₂ (2), and Ba(2,4-DNI)₂(H₂O)₄ (3) were characterized by single-crystal X-ray diffraction analysis. All the three compounds were crystallized from water, but 1 was an anhydrate. The coordination number in 1 and 3 is 10, but in 2 is 9. The 2,4-DNI adopts either η³, η², or η¹ coordination modes depending on the metal cation. In 3, there is an inversion center located on the metal. Only in 2 does water play an important role for the construction of the structure; in 3 it is a hydrogen bonding participant. TG–DSC analyses of 1 were also performed, and non-isothermal decomposition reaction kinetics were obtained.     

Hydrothermal Synthesis and Structures of Two One-Dimensional Heteropolytungstates Chains Formed by Keggin Cluster Units

Single crystals of [W₁₁Ni₁P₁O₃₉(Hbpy)](H₂bpy)₂ · 4.25H₂O (1) and (W₁₁Zn₁P₁O₃₉)(H₂bpy)₂(Hbpy) · 1.5H₂O (2) have been hydrothermally synthesized at 160 °C and both characterized by IR, elemental and single-crystal structural analyses. Compound 1 has a ladder-like chain structure by hydrogen bonding interactions, whereas 2 contains an unprecedented chain of Keggin polyoxotungstates by oxo-bridges and form a 2-D layer via hydrogen bonds. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.