Qiuxia Han

A Novel Keggin Units-Supported Complex: Synthesis, Characterization and Crystal Structure of [(CH3)2NH2]6[Cu(DMF)4(GeW12O40)2] · 2DMF

A novel hybrid compound, [(CH3)2NH2]6[Cu(DMF)4(GeW12O40 4-)2] ⋅ 2DMF, has been synthesized from H4GeW12O40 ⋅ n H2O, CuCl2 and N, N -dimethylformamide (DMF) in aqueous solution and characterized by elemental analysis, UV and IR spectra. Single crystal X-ray structure analysis shows that the crystal consists of a α-Keggin heteropolyanion-supported anion [Cu(DMF)4(GeW12O40 4-)2], two free N, N-dimethylformamide molecules, six protonated dimethylamine (DMA) molecules, and that the coordinating atoms of DMF are the oxygen atoms of C=O group. Thermal analysis indicates that the thermal stability of the GeW12O40 4- anion in the title compound is stronger than that in acid.

Beat over the Old Ground with New Strategy: Engineering As···As Interaction in Arsenite-Based Dawson Cluster β-[W18O54(AsO3)2]6–

By reaction of [As2W19O67(H2O)](14-), NiCl2·6H2O, and phen under hydrothermal conditions, a new organic-inorganic tungstoarsenate hybrid [Ni(phen)3]4[As2W18O60]{[Ni(phen)2][H2As2W18O60]}·12H2O (where phen = 1,10-phenanthroline) (1) was obtained via self-assembly and characterized by elemental analysis, infrared (IR) spectroscopy, solid UV-vis absorption spectrum, and single-crystal X-ray diffraction (XRD). An unprecedented 18-tungstoarsenate Dawson cluster, β-[W18O54(AsO3)2](6-), encapsulating two pyramidal arsenite AsO3(3-) anions as templates and exhibiting interesting intramolecular As···As interaction is first achieved. 1 displays a one-dimensional (1D) chain architecture constructed by alternating β-[W18O54(AsO3)2](6-) and nickel(II) complexes [Ni(phen)2)](2+). The resulting hybrid can act as a photocatalyst to prompt the degradation of Rhodamine B (RhB) with excellent efficiency.

Synthesis, Crystal Structure and Electrochemistry of Two Complexes （YLn）3＋[PW12O40]3-（L=Me2SO, Me2NCHO）

The reaction of α-H3[PW12O40] with Y(NO3)3 in the presence of DMF or DMSO leads to two complexes with the formulae {Y(DMSO)7}·PW12O40(1) and {[Y(DMF)7]2PW12O40}·PW12O 40(2). The crystal structures indicate that complex 1 consists of discrete [YLn]3+ cations and α-Keggin heteropolyanions [PW12O40]3−, whereas, in complex 2, donor-acceptor interaction results in a cation-anion-cation triplet. In addition, the electrochemical behavior of the two complexes indicates the usual successive reduction processes of the W atoms in the anions.

Synthesis, Crystal Structure and Properties of Novel Composite Complex: [La(Nmp)4(H2o)4][HsiMo12O40]·2nmp·H2o

A new composite complex of [La(NMP)4(H2O)4][HSiMo12O40]·2NMP·H2O (NMP = N-methyl-2- pyrrolidone) was synthesized and characterized by IR, UV, ESR, TG-DTA and single crystal structural analysis. The water and organic ligands (NMP) coordinate directly with La(III) to form a dodecahedral complex and the SiMo12O4− 40 anion is the counter ion. IR and X-ray analysis show that there is strong interaction between the polyoxometalate and organic donors. The complex is strongly photosensitive under irradiation with sunlight, resulting in a charge-transfer complex by oxidation of the N-methyl-2-pyrrolidone and reduction of the polyoxometalate. Low temperature ESR spectra indicate thermal electron delocalization among the Mo atoms in the title compound.

Hydrolytic cleavage of a DNA-model phosphodiester: a new inorganic–organic hybrid constructed from a Zn-cluster with a polyoxometalate

An inorganic–organic hybrid constructed from a Zn-cluster with a polyoxometalate {[Zn3Na2(μ-OH)2(bpdo)6(H2O)16][PW12O40]2}·(bpdo)3·C2H5OH·2H2O (bpdo = 4,4′-bis(pyridine-N-oxide)) (1) has been synthesized by hydrothermal reaction and characterized by elemental analyses, IR spectra, and single crystal X-ray diffraction. The structural analysis indicates that 1 is an S-like complex constructed by [Zn3Na2(μ-OH)2(bpdo)6(H2O)16]6− with two PW12O40 3− with water occupying several coordination sites and have the potential to act as labile ligands, allowing for substrate and nucleophile binding. Kinetic experiments for hydrolytic cleavage of the DNA-model phosphodiester bis(p-nitropheny1)phosphate (BNPP) were followed spectrophotometrically for absorbance increase at 400 nm in 4-(2-hydroxyethyl)piperazine-1–propane sulfonic acid (EPPS) buffer solution due to the formation of p-nitrophenoxide with 1 at pH 4.0 and 50 °C. UV spectroscopy indicates cleavage of the phosphodiester bond proceeds with pseudo-first-order rate constant 6.7(±0.2) × 10−7 s−1, giving an inorganic phosphate and p-nitrophenol as the final products of hydrolysis. The results demonstrate that 1 exhibits good catalytic activity and reusability for hydrolytic cleavage of BNPP.

Synthesis, crystal structure and properties of a new complex constructed from coordinated Dy(III) unit and the polyanion [SiMo12O40]4−: [Dy(NMP)4(H2O)3]H[SiMo12O40]·2NMP

The synthesis, X-ray crystal structure, IR, UV and ESR spectra, and thermal properties of the new complex formulated [Dy(NMP)4(H2O)3]H[SiMo12O40]·2NMP (NMP = N-methyl-2-pyrrolidone), are reported. The crystal structure indicates that the coordinated ion combines with [SiMo12O40]4− by an electrostatic force. There are several kinds of hydrogen bonding in the complex and the crystal structure shows that the water molecules in the coordination sphere play a dual role: they coordinate to the rare earth ions on one hand and form strong hydrogen bonds on the other. The complex is strongly photosensitive under irradiation with sunlight, resulting in charge transfer by oxidation of the N-methyl-2-pyrrolidone and reduction of the polyoxometalate. The low-temperature ESR spectra indicate that thermal electron delocalization occurs among the Mo atoms in the complex.

Synthesis and Structural Characterization of a New Two-dimensional Organic-Inorganic Hybrid Molybdoarsenate: [Cu(en)2]2[(CuO6)Mo6O18(As3O3)2]

A new organic-inorganic hybrid molybdoarsenate constructed from a unit with two (As3O3) rings capping Anderson-type moieties, [Cu(en)2]2[(CuO6)Mo6O18(As3O3)2] (1) (en = ethylenediamine), has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction and thermogravimetric analysis. The compound crystallizes monoclinically, space group P21/c, with unit cell dimensions a = 9.1541(7), b = 19.6348(14), c = 14.5205(8) Å ,β = 129.082(3)◦,V = 364.20(4) Å3, Z = 2, T = 296(2) K. Complex 1 represents the first example of a 2D network of a POM polymer where [(CuO6)Mo6O18(As3O3)2]4− building blocks are connected by complex fragments {Cu(en)2}2+. Graphical Abstract Synthesis and Structural Characterization of a New Two-dimensional Organic-Inorganic Hybrid Molybdoarsenate: [Cu(en)2]2[(CuO6)Mo6O18(As3O3)2]

Synthesis, crystal structure and characterization of a series of complexes constructed from coordinated Lanthanides(III) and the heteropolyanion [SiMo12O40]4−

The reaction of α-[SiMo12O40]4− with trivalent cations Ln3+ and N-methyl-2-pyrrolidone leads to a series of complexes of formula [Ln(NMP)4(H2O) n ]H[SiMo12O40] · 2NMP · mH2O [where Ln = La (1), Pr (2), Nd (3), Sm (4), Gd (5), n = 4, Ln = Dy (6), Er (7), n = 3. NMP = N-methyl-2-pyrrolidone]. The syntheses, X-ray crystal structures, IR, and ESR spectra and thermal properties of the complexes 1, 2, 4, 6, 7 have been reported previously. Here, we report X-ray crystal structures, IR, UV, ESR spectra and thermal properties of the complexes [Nd(NMP)4(H2O)4]H[SiMo12O40] · 2NMP · 1.5H2O (3), and [Gd(NMP)4(H2O)4]H[SiMo12O40] · 2NMP · H2O (5). In addition, the electrochemical behaviour of this series of complexes in aqueous solution and aqueous-organic solution has been investigated and systematic comparisons have been made. All these complexes exhibit successive reduction process of the Mo atoms.

Two inorganic–organic hybrids based on a polyoxometalate: Structures, characterizations, and epoxidation of olefins

Abstract Two new inorganic–organic hybrids, [Co3(bpdo)6(H2O)4Cl2][SiW12O40]·H2O (Co-SiW) and [Ni3(bpdo)6(H2O)4Cl2][SiW12O40]·H2O (Ni-SiW) (bpdo = 4,4′-bis(pyridine-N-oxide)), were synthesized from the Keggin-type [SiW12O40] anion and Co(II) and Ni(II) under hydrothermal conditions, respectively, and characterized by elemental analyses, powder XRD, IR spectra, and single-crystal X-ray diffraction. The structural analysis indicates that the 1D chain is constructed from a POM-based half-cage as a secondary building block linked by bridging bpdo ligands. The zigzag chains further stack into a three-dimensional body with channels. The 3D network structure with amphiphilic cavities is shaped by electrostatic interactions through the planes, which has potential to allow molecules such as styrene and H2O2 ingress and egress. Both of the hybrids demonstrated catalytic activity for epoxidation of olefins, which was examined using styrene and aqueous hydrogen peroxide (30%) as oxidant in acetonitrile, along with Co-SiW and Ni-SiW in a heterogeneous manner at 60 °C. Moreover, the conversion of epoxidation reaction in a heterogeneous manner is close to that of homogeneous catalysis, while being conveniently recovered and steadily reused without change of catalyst structure after epoxidation reactions.

A new Keggin-type heteropolyanion decorated with dinuclear copper-organic coordination ions: {[Cu(Phen)(μ-Cl)Cu(Phen)2]2[SiW12O40]} · H2O

A new Keggin-type heteropolyanion decorated with dinuclear copper-organic coordination ions, {[Cu(Phen)(μ-Cl)Cu(Phen)2]2[SiW12O40]}· H2O (I), has been hydrothermally synthesized and structurally characterized by IR spectroscopy and single-crystal X-ray diffraction. X-ray crystallography analysis showed that two dinuclear copper-organic [Cu(Phen)(μ-Cl)Cu(Phen)2]3+ units are supported on the reduced α-Keggin polyoxoanion [SiW12O40]6− via two terminal oxygen atoms from opposite sides of the Keggin polyoxoanion, and I further acts as a neutral molecular unit for the construction of a one-dimensional chain-like framework by