Ion-Exchange Properties of Alkali-Metal Redox-Intercalated Vanadyl Phosphate

Ion exchange of alkali metals in M_xVOPO₄·yH₂O (M=H, Na, K, Rb, Cs) is reported. The role of valence, size, and affinity of the cations in the exchange process is discussed. The interlayer distance in the H_1-xK_xVOPO₄·yH₂O system is discussed in terms of finite layer rigidity theory. Different behavior is observed for K_xNa_1-xVOPO₄·yH₂O dependening on the starting compound used. When potassium in KVOPO₄·H₂O is exchanged for Na⁺, one phase compound is formed. In contrast, K_xNa_1-xVOPO₄·yH₂O formed from NaVOPO₄·H₂O and K⁺ is a multiphase system. Ion exchange does not proceed when exchanging ions differ distinctly from each other in size, e.g., sodium and cesium.     

新型正充电单层结构有机光受体的研制

将纳米级酞菁氧钒分散于聚碳酸酯成膜剂中，成功研制了一类性能优良的单层 结构有机光受体．实验结果表明此类光受体随着酞菁氧钒在聚碳酸酯中含量的变化 ，其灵敏度、暗衰、饱和电位及残余电位出现规律性变化．控制酞菁氧钒在聚碳酸 酯中的含量可使此类光受体表现出优良的电荷保持能力，并在可见至近红外光谱范 围内具有高灵敏度、低暗衰和低残留电位，当酞菁氧钒含量为32时，光受体的光衰 灵敏度（曝光波长780nm,光强1、17uW),E1/2=1.13uL/cm^3,E1/5=1.21uJ/cm^2,充 电电位V0=623V，暗衰DD=24.5V/s，残余电位VR=12V。     

Effects of Vanadyl Complexes with Acetylacetonate Derivatives on Non-Tumor and Tumor Cell Lines

Vanadium has a good therapeutic potential, as several biological effects, but few side effects, have been demonstrated. Evidence suggests that vanadium compounds could represent a new class of non-platinum, metal antitumor agents. In the present study, we aimed to characterize the antiproliferative activities of fluorescent vanadyl complexes with acetylacetonate derivates bearing asymmetric substitutions on the β-dicarbonyl moiety on different cell lines. The effects of fluorescent vanadyl complexes on proliferation and cell cycle modulation in different cell lines were detected by ATP content using the CellTiter-Glo Luminescent Assay and flow cytometry, respectively. Western blotting was performed to assess the modulation of mitogen-activated protein kinases (MAPKs) and relevant proteins. Confocal microscopy revealed that complexes were mainly localized in the cytoplasm, with a diffuse distribution, as in podocyte or a more aggregate conformation, as in the other cell lines. The effects of complexes on cell cycle were studied by cytofluorimetry and Western blot analysis, suggesting that the inhibition of proliferation could be correlated with a block in the G2/M phase of cell cycle and an increase in cdc2 phosphorylation. Complexes modulated mitogen-activated protein kinases (MAPKs) activation in a cell-dependent manner, but MAPK modulation can only partly explain the antiproliferative activity of these complexes. All together our results demonstrate that antiproliferative effects mediated by these compounds are cell type-dependent and involve the cdc2 and MAPKs pathway.     

掺Ni钒磷氧化物催化剂的合成和表征

以VOPO4.2H2O为原料制备了钒磷氧化物催化剂,考察了镍掺杂(1%,2%和5%)对该催化剂的影响.低掺杂量的Ni明显提高了活性晶格氧物种O-的数量,降低了V5 和V4 相的还原峰温.粉末X射线衍射、程序升温还原和化学分析结果表明,高掺杂量的Ni促使V5 物相生成并抑制V4 物相出现.高含量与V5 相关的氧物种会降低正丁烷的转化率,但会提高马来酸酐的选择性.     

钒氧酞菁(VOPc)与钒酞菁(VPc)分子的扫描隧道显微镜图像模拟

利用第一性原理方法模拟了自由钒氧酞菁(VOPc)和钒酞菁(VPc)分子的扫描隧道显微镜(STM)图像,与实验观察结果相当符合.理论STM图像都显示出亚分子内结构,外围呈四叶状.其主要差异表现在VOPc分子中心处的钒氧离子在STM图像中为一空洞,而在VPc分子的STM图像中钒离子为突起的亮斑.通过分析VOPc和VPc分子的电子结构,对模拟结果给出自洽的理论解释.造成两者图像显著不同的物理原因是VPc分子在费米能级附近有明显含dz2成分的分子轨道,导致钒离子在STM图像中央为突起的亮斑.而在VOPc分子中dz2分态密度峰位由于氧原子的加入使之远离费米能级,使STM不能“看到”VOPc分子中钒氧离子. 关键词： 钒氧酞菁 钒酞菁 STM图像模拟 电子结构     

Multi-electron transfer processes for molecular conversions

Multi-electron transfer plays an important role in many chemical reactions. A collection of examples, both of metal complexes that exhibit one-step, multi-electron transfer process, and of chemical reactions based on a multi-electron transfer system, is presented. Emphasis is placed on the role of multi-electron transfer process in a sense that some molecular conversion systems such as reduction of O₂ and oxidation of H₂O become feasible through multi-electron transfer. As an important example of molecular conversion, oxidative polymerization of sulfur-containing compounds through two-electron transfer, is also reviewed.     

2-Alkanol Intercalated VOPO4 and NbOPO4: Structure Modeling of Intercalate Layers

Intercalates of VOPO₄2H₂O and NbOPO₄3H₂O with a homologous series of 2-alkanols (from 2-propanol to 2-undecanol) were prepared and characterized by X-ray powder diffraction, thermogravimetric analysis, and IR spectroscopy. A method for structure modeling of the intercalate layers is described and possible arrangements of alkanol carbon chains in the intercalates are discussed. A bimolecular packing of the guest molecules in the interlayer space was proposed as the most plausible with regard to the determined interlayer distance and stoichiometry.     

Characterization of tetravalent vanadium functional centres in metal oxides derived from a spin-Hamiltonian analysis

The electronic and structural characterization of vanadium functional centres in metal oxides by means of electron paramagnetic resonance (EPR) defines an important topic in solid-state research. In that respect, transfer of determined spin-Hamiltonian parameters into electronic and structural information often imposes a ‘bottleneck’ to interpret the obtained EPR spectra. Using two semi-empirical models, EPR spin-Hamiltonian parameters for tetravalent vanadium can be analysed first to distinguish between either V⁴⁺ and vanadyl VO²⁺-centres and second to determine the location of the corresponding centre either in the ‘bulk’ or at the surface region of metal oxide particles.     

Glyoxal-promoted homogeneous catalytic oxygenation of cyclohexane with hydrogen peroxide in the presence of V and Co compounds

The efficiency of cyclohexane oxidation with hydrogen peroxide catalyzed by vanadyl acetylacetonate at 40 °C and atmospheric pressure is enhanced by glyoxal additive. The process selectively produces a mixture of cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone with a high rate (up to 4400 catalyst turnover number). Cobalt(II) acetylacetonate is much less active but more selective with respect to cyclohexyl hydroperoxide.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 307–310, February, 2005.     

Liquid-phase oxidation of anthracene by hydrogen peroxide in the presence of heterogenized vanadyl acetylacetonate

The synthesis of heterogenized vanadyl acetylacetonate was accomplished by alkylation of a chloromethylated styrene—divinylbenzene copolymer via activation by Co(II) complexes. The effect of heterogenization on the structure of the complexes and their catalytic properties in the peroxide oxidation of anthracene was investigated by kinetic studies and EPR spectroscopy. Increased stability during oxidation of the catalytic centers of the polymer sample as compared with homogeneous vanadyl acetylacetonate was demonstrated.Department of Fine Organic Synthesis, Institute of Chemistry, Bashkir Science Center, Ural Branch, Russian Academy of Sciences, Ekaterinburg 620219. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 4, pp. 800–804, April, 1992.