Changwen Hu

A novel organic-inorganic hybrid material with fluorescent emission: [Cd(PT)(H2O)]n(PT = phthalate)

The novel organic-inorganic hybrid material [Cd(PT)(H2O)]n (1; PT = phthalate) has been hydrothermally synthesized. The X-ray diffraction study reveals that 1 exhibits an interesting two-dimensional (2D) honeycomb framework constructed from [CdO7] single helical chains linked via oxygen atoms of the PT ligands, which adopt the μ6-bridging coordination mode. A study of the physical properties of 1 demonstrates that it exhibits a strong fluorescent emission in the solid state at room temperature.

Convenient synthesis of single crystalline magnetic Fe3O4 nanorods

The synthesis of the uniform single crystalline magnetic Fe3O4 nanorods in a solution-phase approach in the presence of polyethylene glycol-1000(PEG-1000) is described. This is a convenient solution-phase route to large-scale synthesis of Fe3O4 nanorods with average diameters of ca. 80 nm and lengths of up to 2 μm. The composition of the nanorods is appraised by X-ray photoelectron spectroscopy (XPS). Transmission electron microscopy images show that the magnetite particles are homogenous and have the shape of rods. The mechanism of forming Fe3O4 nanorods is also discussed.

Photocatalytic degradation of aqueous organocholorine pesticide on the layered double hydroxide pillared by Paratungstate A ion, Mg12Al6(OH)36(W7O24)·4H2O

Abstract Layered double hydroxide pillared by Paratungstate A ion, Mg12Al6(OH)36(W7O24)·4H2O, was prepared via anion exchange reaction of the synthetic precursor, Mg4Al2(OH)12TA·xH2O (TA2−=terephthalate), and [W7O24]6− ion. Some physico-chemical properties were measured and the preparation conditions were studied. Trace aqueous organocholorine pesticide, hexachlorocyclohexane (HCH), was totally degraded and mineralized into CO2 and HCl by irradiating a Mg12Al6(OH)36(W7O24)·4H2O suspension in the near UV area. Disappearance of trace HCH follows Langmuir–Hinshelwood first-order kinetics. The model and mechanism for the photocatalytic degradation of HCH on the Mg12Al6(OH)36(W7O24)·4H2O were proposed, indicating that the interlayer space is the reaction field, and that photogeneration of OH radicals are responsible for the degradation pathway.

A manganese molybdenum phosphate with a tunnel: hydrothermal synthesis, structure and catalytic properties of (NH3CH2CH2NH3)10H3O)3(H5O2)Na2[MnMo12O24(OH)6(PO4)4(PO3OH)4][MnMo12O24(OH)6(PO4)6(PO3OH)2] · 9H2O

A manganese molybdenum phosphate, (NH3CH2CH2NH3)10(H3O)3(H5O2)Na2[MnMo12O24(OH)6 (PO4)4(PO3OH)4][MnMo12O24 (OH)6(PO4)6(PO3OH)2]·9H2O, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The structure of this compound may be considered to be two [Mo6O12(OH)3(PO4)2(HPO4)2]7- units bonded together by a manganese atom, although several P–O groups are not protonated on account of coordination to a Na+ cation. One-dimensional tunnels were formed in the solid. A probe reaction of the oxidation of acetaldehyde with H2O2 using this compound as catalyst was carried out in a liquid–solid system, showing that the manganese molybdenum phosphate has high catalytic activity in the reaction.

A novel chiral coordination polymer with a two-dimensional undulated (6,4)-network: [Co4(2,2′-bipy)4(H2O)2(btec)2]n(btec = 1,2,4,5-benzenetetracarboxylate)

The novel coordination polymer [Co4(2,2′-bipy)4(H2O)2(btec)2]n (btec = 1,2,4,5-benzenetetracarboxylate), 1, has been hydrothermally synthesized. X-Ray diffraction experiments reveal that 1 exhibits an interesting two-dimensional (2D) chiral undulated (6,4)-network, which represents the first example of a 2D chiral coordination polymer containing two kinds of organic ligands. The value of the Flack parameter, x = 0.52(2), shows that the crystal of 1 is an inversion twin containing approximately 50% of the right-handed and 50% of the left-handed crystal structure and the whole compound is a racemate. Variable temperature magnetic susceptibility indicates that antiferromagnetic interactions exist between metallic Co(II) centers in 1.

Preparation, characterization and photochemical properties of ordered macroporous hybrid silica materials based on monovacant Keggin-type polyoxometalates

High loading, three-dimensionally ordered macroporous (3DOM) hybrid silica materials based on monovacant Keggin-type polyoxometalates (POMs) [Xn+W11O39](12 − n)− (XW11; Xn+ = P5+, Si4+, Ge4+, B3+) were prepared via sol–gel as well as templating techniques. XW11 clusters were incorporated into the wall structures of macroporous silica, resulting in hybrid XW11–SiO2 composites. Formation of the hybrid materials was due to the chemical grafting of organosilanol groups from the silica network onto the surface oxygen atoms at vacant sites on the XW11 clusters. The products were characterized by UV diffuse reflectance spectra (UV/DRS), infrared (IR) spectra, 29Si and 31P MAS NMR, inductively coupled plasma atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption isotherms. The study indicates that the primary Keggin structures remain intact in the hybrid materials, and that the products demonstrate three-dimensionally ordered macropores with pore diameters in the range of 285 to 385 nm. The composites exhibited photocatalytic activity to degrade aqueous malic acid (MA) under irradiation in the near-UV region; leakage of XW11 from the hybrid materials was hardly observed during catalytic tests.

A two-dimensional molybdenum (V) phosphate with covalently bonded transition metal coordination complexes: hydrothermal synthesis and structure characterization of Na2[{Mn(phen)2(H2O)}{Mn(phen)2}3{Mn Mo12vO24 (HPO4)6(PO4)2(OH)6}]·4H2O (phen=1, 10-phenanthroline)

An organic-inorganic hybrid molybdenum phosphate, Na-2[{Mn(phen)(2)(H2O)} {Mn(phen)(2)}(3){(MnMo12O24)-O-v (HPO4)(6)(PO4)(2) (OH)(6)}] . 4H(2)O (phen=1,10-phenanthroline), involving molybdenum present in V oxidation state and covalently bonded transition metal coordination complexes, has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a=16.581(l)Angstrom, b=18.354(1)Angstrom, c=24.485(2)Angstrom, alpha=80.589(l)degrees, beta=71.279(1)degrees, gamma=67.084(1)degrees, V=6493.8(8)Angstrom(3), Z=2, lambda(MoKalpha)=0.71073Angstrom (R(F)=0.0686 for 29,053 reflections). Data were collected on a Bruker Smart Apex CCD diffractometer at 293 K in the range of 1.76 < theta < 28.06degrees using omega-2theta scans technique. The structure of the title compound may be considered to be based on {Mo6O12(HPO4)(3)(PO4)(OH)(3)} units bonded together with {Mn(phen)(2)} subunits into a two-dimensional network. Two types of tunnels are observed in the solid of the title compound.

Synthesis, properties and structural characterization of an intermolecular photosensitive complex: (HGly-Gly)3PMo12O40·4H2O

The first heteropoly acid–dipeptide complex, (HGly-Gly)3PMo12O40·4H2O, was synthesized and characterized by elemental analysis, IR, UV, 1H NMR and single crystal X-ray diffraction. The X-ray crystallographic study showed that the crystal structure was constructed from N–H⋯O and O–H⋯O hydrogen bonds among the (HGly-Gly)+, H2O and PMo12O403− units. This structure represents a model interaction between polyoxometalates and proteins. The complex has photosensitivity under irradiation by sunlight. The fluorescent activity of this compound is also reported.

A novel application of mixed-valence Keggin-type polyoxometalates as non-aqueous electrolytes in polyacenic semiconductor secondary batteries

Abstract Mixed-valence Keggin-type lithium polyoxometalates (POMs) were used as the electrolytes of polyacenic semiconductor (PAS) secondary batteries substituting for LiClO 4 for the first time. The discharging, cycle and self-discharging properties of these PAS/Li secondary batteries and the effect of current density and temperature on the properties of the batteries have been investigated. The results indicate not only that the lithium POMs can overcome the disadvantages of LiClO 4 , which is apt to explode when heated or rammed, but also that some of the PAS/Li secondary batteries assembled with the novel electrolytes have larger capacity and smaller self-discharging than that assembled with LiClO 4 . Therefore, it is believed that Keggin-type mixed-valence lithium POMs are novel and better electrolytes of PAS secondary batteries and exhibit promising practical application.

Heteropolyoxometalates which are included in microporous silica, CsxH3−xPMo12O40/SiO2 and CsyH5−yPMo10V2O40/SiO2, as insoluble solid bifunctional catalysts: synthesis and selective oxidation of benzyl alcohol in liquid–solid systems

Abstract Heteropolyoxometalates (HPOMs) which are included in microporous silica, Cs x H 3− x PMo 12 O 40 /SiO 2 and Cs y H 5− y PMo 10 V 2 O 40 /SiO 2 , have been synthesized by a sol–gel technique and characterized by IR, UV–VIS, X-ray and N 2 adsorption isotherms. IR and UV–VIS data indicate that the identities of Cs x H 3− x PMo 12 O 40 and Cs y H 5− y PMo 10 V 2 O 40 are preserved within these synthesized compounds. TEM image and BET adsorption isotherms confirm the presence of nanometer particles and microporous structures. X-ray powder patterns prove that the cesium salts of the HPOMs are uniformly dispersed in the silica network. As insoluble solid bifunctional catalysts, they show high catalytic activity and selectivity for selective oxidation of benzyl alcohol into benzyl aldehyde by H 2 O 2 in liquid–solid systems. The highest activity is observed at x =1.5 or y =2.5 in Cs x H 3− x PMo 12 O 40 /SiO 2 or Cs y H 5− y PMo 10 V 2 O 40 /SiO 2 , respectively.