Hydrothermal Synthesis,Crystal Structure,and Catalytic Performance of Four Organic–Inorganic Hybrids Based on Polyoxometalates and O/N-Containing Groups

Four new network organic–inorganic hybrid supramolecular compounds [PW₁₂O₄₀](C₂H₄N₃)₃·6H₂O (1), [PMo₁₂O₄₀](C₂H₄N₃)₃·6H₂O (2), [H₄SiW₁₂O₄₀]₈[C₆NO₂H₄]₄[C₆NO₂H₅]₁₆[C₅NH₆]₄·39H₂O (3) and [H₃VW₁₂O₄₀] (C₆H₆NO₂)₂(CHO₂)₂·4H₂O (4) composed by keggin type heteropolyanion and O/N-containing organic groups of 1H-1,2,4-Triazole or 2,3-Pyridinedicarboxylic acid have been successfully synthesized by hydrothermally method, and characterized by infrared spectrum (IR), thermogravimetric–differentialthermal analysis (TG–DTA), cyclic voltammetry (CV) and single crystal X-ray diffraction (XRD). Compounds 1–4 exhibit three dimensional supramolecular network via hydrogen bonds and/or π–π stacking interactions. These compounds exhibit good thermal stability and catalytic ability. They are active for catalytic oxidation of methanol in a continuous-flow fixed-bed micro-reactor, when the initial concentration of methanol is 2.5 g m^?3 in air and flow rate is 10 mL min^?1, the corresponding elimination rates of methanol are 65% (125 °C), 85% (125 °C), 94% (150 °C), and 80% (125 °C), respectively.     

Rare-Earth–Transition-Metal Organic–Inorganic Hybrids Based on Keggin-type Polyoxometalates and Pyrazine-2,3-dicarboxylate

Five rare-earth–transition-metal (RE–TM) heterometal organic–inorganic hybrids based on Keggin-type silicotungstates and mixed ligands H2pzda (pzda=pyrazine-2,3-dicarboxylate) and en (en=ethylenediamine) (enH2)[Cu(en)2(H2O)]2{[Cu(en)2][Cu(en)2(H2O)][(α-SiW11 O39)RE(H2O)(pzda)]}2⋅n H2O (n≈4; RE=YIII ( 1 ), DyIII ( 2 ), YbIII ( 3 ), and LuIII ( 4 )) and [Cu(en)2(H2O)]2{[Cu(en)2]2[Cu(pzda)2][(α-H2SiW11O39)Ce(H2O)]2}⋅n H2O ( 5 ; n≈8) have been hydrothermally synthesized and structurally characterized. Compounds 1–5 all contain the dimeric mono-RE substituted Keggin [RE(α-SiW11O39)]210− subunits linked by H2pzda ligands. Interestingly, 1–4 exhibit discrete structures, in which the H2pzda ligand acts as a tetradentate ligand to bind the RE and Cu cations, whereas 5 displays a 1D double-chain architecture, in which the H2pzda ligand adopts a new pentadentate mode to connect the Ce and Cu cations. To our knowledge, 1–5 represent the first monovacant Keggin-type silicotungstates containing both RE–TM heterometals and mixed ligands. The luminescence of 2 is derived from the combination of the DyIII cations and H2pzda ligands, whereas the luminescence properties of 1 and 3–5 are attributable to the H2pzda ligands.     

Crystal Structures and Photoluminescence of Two Inorganic–Organic Hybrids of Anderson Anions

Two supramolecular compounds (Hbipy)₂[Cr(OH)₆Mo₆O₁₈H](bipy) (1) and (Hbipy)₃[Al(OH)₆Mo₆O₁₈]·3H₂O (2) were synthesized and their crystal structures were analyzed with x-ray diffraction technique. In 1 the Anderson anion with six hydroxyl groups forms six hydrogen bonds with bipy molecules, forming a supramolecular layer, the layers are linked by hydrogen bonds between anions. In 2 the Anderson anion with three hydroxyl groups and terminal/bridging oxygen atoms forms six hydrogen bonds with bipy molecules, and lattice water molecules and the anions form also hydrogen bonds, constructing a supramolecular architecture. The intensive emission in 650–740 nm of 1 is attributed to R-lines of Cr³⁺ and the high intensity may be caused by energy transfer of bipy molecules through hydrogen bonds. In contrast, 2 gives only the π* → π emission of bipy molecules at 460 nm.     

pH-Dependent Assembly of Two Novel Organic–inorganic Hybrids Based on Vanadoantimonate Clusters

Two novel organic–inorganic hybrid vanadoantimonate compounds, [Zn₂(dien)₃][{Zn(dien)}₂V₁₆Sb₄O₄₂(H₂O)]·4H₂O (1) and [Zn(dien)₂]₂ [{Zn(dien)}₂(V₁₄Sb₈O₄₂)₂(H₂O)]·4H₂O (2) (dien = Diethylenetriamine), have been synthesized hydrothermally at different pH value, and structurally characterized by elemental analyses, FT-IR, XPS, TGA and single crystal X-ray diffraction analysis. Compound 1 is composed of the rare [V₁₆Sb₄O₄₂]⁸⁻ cluster covalently linked by two [Zn(dien)]²⁺ coordination cations to yield a novel one-dimensional linear chain. Compound 2 exhibits a one-dimensional zigzag chain constructed from the [V₁₄Sb₈O₄₂]⁴⁻ cluster and [Zn(dien)]²⁺ coordination polymer. The two examples represent the first one-dimensional assemblies based on vanadoantimonate cluster and the metal–organic complex moieties.     

Synthesis,Characterization and Crystal Structures of Two New Compounds of Polyoxometalates and Diaminocyclohexanetetraacetate–Copper Complexes

The two new compounds (NH₄)₂[Cu₅(H₂O)₁₀(DCTA)₂] [β-Mo₈O₂₆]·4H₂O (1) and Cu₂[Cu₃K₂(H₂O)₁₀(DCTA)₂(HBW₁₂O₄₀)]·14H₂O (2) (DCTA = 1,2-diaminocyclohexanetetraacetate anion) were synthesized in aqueous solutions and characterized by elemental analyses, TGA, IR spectroscopy and single-crystal X-ray diffraction technique. Single-crystal structure analyses indicate they are constructed by the complexes with different nuclearity and polyoxometalates. In 1 DCTA chelates Cu2 ion and bridges Cu1 and Cu3 ions, forming a tetra-nuclear-ring cation chain extending along [110] direction. In 2 DCTA chelates Cu2/Cu1 and combines Cu3 and K ions, leading to a cyclic ten-heteronuclear complex cation; the K2 ions combine the complex cations and BW₁₂O₄₀ ^5? anions, forming a complex cation-BW₁₂ layer extending on ab-plane. The variable-temperature magnetic susceptibilities of newly prepared crystalline sample of 1 were measured and 1 exhibits a weak antiferromagnetic interaction.     

Polyoxometalates–Directed Assembly of Inorganic–Organic Hybrid Compounds with Copper Multinuclear Nano-cluster Based on Flexible Double Tetrazole-based Thioether

Two new inorganic–organic hybrid compounds constructed from different polyoxometalates (POMs) and copper multinuclear clusters, [Cu(bmte)(H₂Mo₈O₂₆)_0.5]·3H₂O (1) and [Cu₃(bmte)₃(HSiMo₁₂O₄₀)]·H₂O (2) (bmte = 1,2-bis(1-methyl-5-mercapto-1,2,3,4-tetrazole)ethane), have been synthesized under hydrothermal conditions with a flexible double tetrazole-based thioether and characterized by IR, TG and single-crystal X-ray diffraction analyses. In compound 1, two bmte ligands chelate two Cu^I ions with three N atoms to form a binuclear nano-scale subunit [Cu₂(bmte)₂]²⁺, then the binuclear Cu^I subunits are connected by [Mo₈O₂₆]⁴⁻ anions to build a one dimensional (1D) chain. In compound 2, a trinuclear nano-scale subunit [Cu₃(bmte)₃]³⁺ constructed from three Cu^I ions and three bmte ligands has been obtained, and the adjacent trinuclear subunits are linked by [SiMo₁₂O₄₀]⁴⁻ anions to form a “zipper” 1D chain. The adjacent chains of the title compounds are ultimately extended into 2D layers by hydrogen bonds between bmte and POMs. The structural difference of the two compounds indicates that the POMs play an important structure-directed role on the final networks. In addition, the electrochemical behavior of 2-modified carbon paste electrode (2-CPE) and its electrocatalytic reduction of nitrite have been discussed.     

Synthesis and Structural Characterization of Three New Inorganic ＂Host-gues＂ Polyoxomolybdates

Since two interesting inorganic “host‐guest” polyoxomolybdates 1 and 2 have been reported previously, we have now succeeded in selectively isolating three new acetated “host‐guest” polyoxomolybdates 3–5, which considerably extend the range of structures in the cyclic polyoxomolybdate catalogue. 3 crystallizes in the triclinic space group P‐1 with a = 1.22235(1) nm, b = 1.52977(2) nm, c = 1.54022(1) nm, a = 113.746(1)°, β = 96.742(1)°, γ = 101.564(1)°, V = 2.51892(4) nm³, Z =1, D_c = 2.568 g. cm^?3. 4 and 5 crystallize in the monoclinic system: P2(1)/n, a = 1.08298(2) nm, b = 1.54029(1) nm, c = 2.78893(5) nm, β =94.2730(10)°, V = 4.63929(12) nm³, Z = 2 and D_c = 2.671 g. cm^?3 for 4, and C2/c, a =2.59907(8) nm, b = 1.65992(3) nm, c = 2.28473(7) nm, β‐93.4370(10)°, V = 9.8392(5) nm³, Z = 4 and D_c = 2.556 g. cm^?3 for 5. The structures of 3, 4 and 5 consist of 18‐membered “host‐guest” polyoxoanions [ Na (X)₂| ∈ |(μ_3‐OH)₄Mo^y₈Mo^VI₁₀52(μ₂‐CH₃COO)₂]^?(R+9 (X = CH₃COO^?for 3, DMF for 4 and H₂O for 5), which are connected via Na* ions or hydrogen bonds into infinite extended frameworks.     

Synthesis and Structural Characterization of Three New Inorganic “Host-guest”Polyoxomolybdates

Introduction　　Stimulatedbyvariousandalluringtopologiesanddrivenbypotentialapplicationsincatalysis ,biology ,medicineandmaterialsscience ,inorganic“polyoxometa latechemistryhasrecentlywitnessedsomeremarkableachievements .1Nowadays ,awidevarietyofsuchcomplex escontaining“guest”anionslikeCl- ,N- 3andNO- 3,cationslikeNa+ andK+ ,moleculeslikeCH3CN ,orcation/anionaggregateslikeNH+ 4/Cl- ,havebeensynthe sizedandstructurallycharacterized .2 Generally ,theseguestsareattachedtotheendooxygenato…     

Hydrothermal Synthesis and Crystal Structure of a New 2-D Organic–Inorganic Hybrid Wells–Dawson-Type Polyoxometalate

Abstract  

A new 2-D organic–inorganic hybrid Wells–Dawson-Type polyoxotungstate K[Cu(Im)₂]₆P₂W₁₈O₆₂·2H₂O·(OH) (Im = Imidazole) (1) has been synthesized under hydrothermal conditions and characterized by IR spectroscopy, TG, and single crystal X-ray structural analysis. Crystal data for 1: triclinic, P-1, a = 15.3676(12) ?, b = 15.5059(14) ?, c = 24.6437(19) ?, α = 98.088(2)°, β = 96.930(2)°, γ = 119.312(2)°, Z = 2. Single crystal X-ray structural analysis reveals that the [P₂W₁₈O₆₂]⁶⁻ polyoxoanion is linked by [Cu(Im)₂]⁺ cation to form a 1-D chain along the a axis which is connected by K⁺ cation down the c axis to form a 2-D layer.     

Synthesis and Characterization of Novel Organic／Inorganic Hybrid Polymers Containing Polyhedral Oligosilsesquioxanes

Hybrid polymers, poly(vinyl pyrrolidone-co-isobutyl styryl polyhedral oligomeric silsesquioxanes)s (PVP-POSS) were synthesized by one step polymerization and characterized using GPC and DSC. Addition of POSS significantly increases the Tg of polyvinylpyrrolidone at a fair high POSS content and obtained high molecular weight polymers with very narrow molecular distribution. The POSS content in the resulted hybrids can be controlled by varying the POSS feed ratio.     

Synthesis and Characterization of a Novel 3D Organic–Inorganic Hybrid Framwork Templated by Keggin Anions

A novel 3D compound, {K₃H₂[Cu(Gly)₂]₃BW₁₂O₄₀}·10H₂O 1 (Gly = glycine), has been synthesized and characterized by elemental analyses, IR, TG analyses, cyclic voltammetry, and single-crystal X-ray diffraction. Compound 1 contains square-grid layers constructed by potassium cations and copper-glycine coordination complexes, the [BW₁₂O₄₀]^4? anions as templates are accommodated in the square grids by connecting with the K atoms. The K atoms link [BW₁₂O₄₀]^4? anions from different layers together to yield a 3D novel structure. The crystal data for compounds 1: monoclinic, space group p2(1)/n, a = 18.832(4) Å, b = 16.488(3) Å, c = 20.570(4) Å, β = 106.21(3)°, V = 6133(2) Å³, Z = 4.     

Synthesis,Characterization, DFT Calculations and Non-linear Optical Properties of a New Organic–Inorganic Arsenate

This paper undertakes the synthesis by slow evaporation method at room temperature of a new organic–inorganic hybrid material with the general formula [C₁₂H₁₃N₂O]H₂AsO₄. The newly developed hybrid is characterized by X-ray single crystal diffraction, Infrared, Raman spectroscopy and density functional theory (DFT) calculations. At ambient temperature, this compound crystallizes in the non-centrosymmetric space group P2₁2₁2₁ of the orthorhombic system. The structural arrangement is formed by infinite anionic chains extending parallel to the direction [100]. The organic entities are linked to these chains by N–H···O type hydrogen bonds which play an important role in the cohesion of the one-dimensional network. The optimized molecular structure, vibrational spectra and the optical properties were calculated by the DFT method using the B3LYP function with the LanL2DZ basis set. The vibrational wavenumbers were evaluated for this compound by using transferable scale factor. The first hyperpolarizability value β_tot of the title compound is equal to 15.94?×?10^?31 esu. Hence, the large β value calculated by the B3LYP method shows that the studied compound is a good NLO material and is suitable for future non-linear optical studies. The HOMO–LUMO energy gap and other related molecular properties are going to be discussed and reported later.     

Synthesis and Characterization of Novel Polyimides Based on Pyridine-containing Diamine

A new aromatic diamine monomer containing pyridine unit, 2,6-bis （4-aminophenoxy- 4＇-benzoyl）pyridine（BABP）, was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly（amic acid） precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight.