Li Shuben

Synthesis, characterization and antitumour properties of metal(II) solid complexes with Morin

SummarySix metal(II) complexes with Morin ML2·nH2O [L = Morin(2′-OH group deprotonated); M = Mn, Co, Ni, Cu, Zn, or Cd; n = 2 or 3] have been synthesized and characterized by elemental analysis, molar conductance, i.r., 1H-n.m.r., t.g.-d.t.a and u.v.-vis. spectroscopic techniques and by fluorescence analysis. Comparative antitumour activities of Morin·2H2O and two complexes [ZnL2·3H2O and CuL2·2H2O] were tested by in vitro screening. The results show that the inhibitory ratio of complexes against the tested tumour cells was higher than that of Morin.

Adsorption of chromium(VI) ions on to TiO2 from aqueous solution

The study of the adsorption of the CrVI ion on to TiO2 not only provides information on the removal of heavy metal ions from polluted aqueous solutions; but is also useful for further investigation of the photocatalytic decontamination of the CrVI ion or of CrVI–organic species which co-exist as pollutants with TiO2 when the latter is used as a stable and highly efficient photocatalyst. It has been found that dark adsorption of the CrVI ion on to TiO2 is mainly dependent on the acidity of the system and the initial concentration of the CrVI ion. As the pH of the system increases, so the extent of adsorption of the CrVI ion decreases. The greatest adsorption was obtained with an initial CrVI ion concentration of ca. 300 μmol/l. The presence of phosphate or acetate ions in the system dramatically decreases the adsorption efficiency of the CrVI ion. In contrast, the addition of formic acid leads to a limited increase in the extent of CrVI ion adsorption. Other organic ions and organic compounds examined showed no interference in CrVI ion adsorption. FT-IR spectroscopic methods were used for the characterization of CrVI ion adsorption on to TiO2.

Alteration of the catalytic properties of anatase by shock-wave loading

Abstract The alteration of the properties of anatase by exposure to a shock wave was investigated by X-ray diffraction spectroscopy (XRD), electron spin resonance (ESR), inductively coupled plasma atomic emission spectroscopy (ICP) and transmission electron microscopy (TEM) methods. Broadening of XRD profiles was observed after shock-wave loading. The isotropic ESR signal for g = 2.000, ascribed to F-centers, increased 2.5 times after that treatment. In contrast, the signal strength for g = 1.993 decreased to half of the original. Shocked anatase TiO 2 exhibited 1.5 times higher photoactivity for hydrogen evolution than that of unshocked material. A possible mechanism of shock-wave alteration is proposed.

DFT Study on the Active Sites in Mn-Na 2 WO 4 /SiO 2 Catalyst

利用密度泛函方法(DFT)研究了Mn-Na2WO4/SiO2催化剂表面的活性中心结构.计算表明,在α-方石英的(111)面上,W能以单个或三个桥氧与载体作用形成稳定的四面体配位结构,Mn则能以单个桥氧与载体配位或形成不同结构的氧化物团簇；以单个桥氧担载的[WO4]四面体是最可能的甲烷活化中心.

Preparation of polyethers with viologen moieties and their application to the debromination of diphenyl bromomethane

Abstract Polyethers with viologen moieties were prepared by the reaction of iodinated poly(ethylene glycol) (PEG) with 4,4′-bipyridine. These polymers were used as electron-transfer catalysts (ETC) for the reduction of diphenyl bromomethane (Ph2CHBr). Results disclosed that these polymers could induce the debromination of Ph2CHBr to afford tetraphenyl ethane effectively. An EPR method proved that the reduced viologen cation radical in a PEG chain was more stable, and an active intermediate was detected by employing the spin-trapping agent (POBN). This showed that the debromination of Ph2CHBr proceeded via a radical mechanism.

Purification and biochemical characterization of soluble methane monooxygenase hydroxylase from Methylosinus trichosporium IMV 3011

Methane monooxygenase hydroxylase was purified by chromatography and characterized by electrophoresis and spectroscopy. The molecular mass of hydroxylase was 201.3 KDa as determined by gel filtration, whereas the total molecular mass was 234 KDa as judged by SDS–PAGE. Structure study indicated that the enzyme is a homodimer structure, consisting of three subunits, designated α, β, and γ, with molecular masses of 58 KDa, 36 KDa, and 23 KDa respectively. IEF analysis indicated that the enzyme has a pI of 5.2. The UV–Vis spectrum of hydroxylase revealed an absorption peak near 281 nm and a weak shoulder peak around 395 nm–420 nm, and a fluorescence spectrum revealed an emission peak at 341.3 nm. Circular dichroism measurement indicated that hydroxylase mainly consists of α-helical regions. Finally, phylogenetic analysis indicated that this strain is very close to Methylosinus trichosporium OB3b.

Microwave Synthesis of Zr (Ti)-Si-Al HDN Catalytic Material

Abstract The Zr (Ti)-Si-Al HDN Catalytic Materials have been synthesized rapidly with a new route heated by microwave. The synthesis conditions such as synthesis temperature, microwave oven pressure, pH value of synthesis solution and raw material were examined by experimentation. The thermostability, pore volume, surface area, surface Si/Al and hydrodenitrogen activity of the synthesis samples were also characteristiced.

INVESTIGATION OF PHOTOCATALYTIC DEHYDROGENATION OF METHANOL-WATER SYSTEM UNDER THE ILLUMINATION OF VISIBLE LIGHT

Investigation of photocatalytic dehydrogenation of methanol-water system over the visible light illuminated Rh2O3/CdS was reported in this paper. The experiments indicated that this reaction not only results in high hydrogen production rate (0.72 mmol/hr. for 80 mg cat. 80 ml solution) and high energy conversion efficiency (calculated value is ca. 3%) but also suppresses the photocorrosion of CdS effectively due to the transfer of photogenerated holes toward the Rh2O3 sites and exhaustion of primary oxygen through the oxidation of methanol. As a result, the catalyst stability was improved remarkably. In the period of 54 hrs continuous reaction, no obvious lowering of activity was observed. A schematic mechanism has been suggested and discussed.

VISIBLE LIGHT INDUCED FORMATION OF HYDROGEN FROM HYDROGEN SULFIDE

A photocatalytic system consisting of Rh2 O3 deposited on CdS particles can generate hydrogen under illumination by visible light. CdS loaded with Rh2O3 inhibited photocorrosion.