新型稀土杂多蓝的合成及其抗艾滋病病毒(HIV-1)活性和毒性研究

合成Keggin结构钨硅、钨锗、钨磷、钨坤两电子及四电子稀土钐盐杂多蓝，铈量滴定及元素分析方法确定了化合物的还原电子数及化学组成，采用IR，UV－Vis,^183W NMR和ESR等对其结果进行了表征，在人T淋巴MT－4内，对合成的化合物进行了系统的抗艾滋病毒（HIV－1）活性及毒性测定，发现Keggin结构钨硅、钨锗四电子稀土钐盐杂多蓝具有较强的抗HIV－1活性，其中钨锗酸钐四电子杂多蓝（代号HPBR－2）具有较高的治疗指数。     

CoW11Ti/淀粉纳米复合物的合成与表征

近年来, 多酸化合物的生物活性及药物性质研究十分活跃[1], 有些多酸化合物已作为抗HIV病毒及抗肿瘤药物应用于临床或进入临床研究[2,3]. 但由于它们的毒副作用大, 在水中稳定存在的pH值范围小, 在体内易分解, 故研究尚无突破性进展[1].     

热处理过程中磷钨杂多酸修饰ZrO2气凝胶固体酸的结构及性能演变

基于N₂物理吸附、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、吸附吡啶红外(Py-FTIR)光谱、氨程序升温脱附(NH₃-TPD)等物理化学表征及催化四氢呋喃(THF)聚合反应实验结果, 探讨了120-750 °C空气气氛热处理对磷钨杂多酸(TPA)修饰ZrO₂气凝胶(ZA)(TPZA)固体酸结构、酸性质及酸催化性能的影响. 研究发现, 对于固载量(TPA质量分数)为25%的TPZA材料, 随热处理温度升高, ZrO₂表面发生了Keggin-杂多阴离子结构畸变、杂多阴离子分解、低聚合度表面多钨酸根物种形成以及多钨酸根物种沿载体表面二维方向聚合的钨物种演变过程; 材料相应地经历了其Brönsted酸性及酸催化活性失而复得的变化. 在实验考察范围内, 材料明显的Brönsted酸性及催化THF聚合反应活性发生在120-300 °C及550-750 °C两个热处理温度段. 其间, 材料的Brönsted酸性分别源于与Keggin-杂多阴离子及在载体表面二维方向上具有一定聚合度的聚钨物种相联系的酸性质子. 在350-450 °C处理温度范围内, 绝大多数Keggin-杂多阴离子的分解及钨物种沿载体表面方向聚合度的不足使得样品中难以形成明显数量的Brönsted酸中心. 此外, 在实验考察的整个温度范围内, 材料显示明显的Lewis酸性, 这应该与样品表面存在配位不饱和的Zr⁴⁺阳离子及磷的氧化物有关.     

H_3PMo_(12-n)WnO_(40)·xH_2O的电子光谱与电化学性质研究

系统地考察了H3PMo12 -nWnO4 0 ·xH2 O系列酸在不同溶剂中的电子光谱行为 ,结果表明 ,Mo Ob ,c Mo键在稀水溶液中断裂 ,而在乙醇溶液中能够稳定存在 ;W Ob ,c W键在极稀的水溶液中也能够稳定存在 ;在有机溶剂中所有酸的特征吸收峰均发生红移。电化学性质的研究表明 ,随着分子中钨原子取代数的增多 ,酸的氧化性降低 ,最高还原峰电位和分子中钨原子取代数之间存在一近似线性关系。     

多金属氧酸盐抗病毒药物研究

多金属氧酸盐在抗病毒、抗肿瘤、抗细菌方面的研究取得了重要进展,本文综述了近30年来多金属氧酸盐在抗艾滋病毒(HIV)、疱疹病毒(HSV-1、HSV-2)、流感病毒等方面的研究情况,详细总结了各种类型多金属氧酸盐的抗病毒效果。结合本课题组的研究结果比较分析了多金属氧酸盐的结构及其抗病毒效果的差异。     

桦木酸及其衍生物的制备与抗肿瘤作用的研究进展

桦木酸是一种羽扇豆烷型的五环三萜类化合物,因具有显著的抗肿瘤和抗HIV病毒特性而受到人们关注。桦木酸存在于多种植物中,可以用提取法得到,但由于桦木酸在植物中含量低,其主要来源是由合成法得到。许多桦木酸衍生物也具有抗肿瘤活性。本文介绍了桦木酸的提取与合成等制备方法,以及几种桦木酸衍生物的合成路线,并对桦木酸及其衍生物的抗肿瘤途径和机理进行了概述。     

碱熔-电感耦合等离子体发射光谱(ICP-OES)法测定钨锡矿石中钨锡钼铜铅锌硫砷

钨锡矿石共生与伴生元素多,为克服常用的钨锡矿石中锡、钨、钼、铜、铅、锌、硫、砷等8种元素检测过程程序繁琐,效率低下问题,通过在刚玉坩埚中直接加入氢氟酸挥发掉样品中的二氧化硅,用过氧化钠熔融已除硅的样品,再以酒石酸+磷酸+盐酸提取,解决了碱熔酸化的样品溶液中硅胶的影响和钨、锡等元素的不稳定性问题,建立了电感耦合等离子体发射光谱(ICP-OES)法直接测定样品中的锡、钨、钼、铜、铅、锌、硫、砷的方法。系统研究了过氧化钠熔剂的用量对各元素的影响,考察了引入单一酒石酸的络合作用和酒石酸+磷酸的混酸对各元素的影响,结果表明,过氧化钠用量为1.0 g时样品可以完全分解;单一酒石酸的络合作用有限,钨含量高的样品容易发生沉淀,而酒石酸+磷酸的混酸可以使钨在溶液中长期稳定,而对其他元素没有影响。选用5个钨、锡矿石国家一级标准物质按照本方法进行处理,测定结果均在认定值的误差范围内;采用4个实际样品与标准方法进行比对实验,各元素检测结果无显著差异。各元素的光谱强度在0～200 μg/mL浓度范围内呈良好的线性关系,相关系数（r）均在0.999 9以上,方法检出限值为3.0μg/g～25.0 μg/g,相对标准偏差RSD（n=12）为0.33%～7.0%。方法测试过程操作简便,检测结果准确、可靠,在多元素大批量的样品检测中具有明显优势。     

Dawson结构多金属氧酸电荷转移化合物[CH3NH2CH3]2[CH3NHCH3]4H4[P2W18O62]·H2O的合成、表征及晶体结构

钨磷酸;二甲胺;Dawson结构多金属氧酸电荷转移化合物[CH3NH2CH3]2[CH3NHCH3]4H4[P2W18O62]·H2O的合成、表征及晶体结构     

解聚法制备有机胂、(月弟)合钨聚多酸盐及聚合法制备相应钼聚多酸盐的研究

关于有机膦、胂合钨、钼聚多酸盐的制备,文献已有若干记载。这类化合物具有“柄状”的结构。所用钨、钼的反应物是Na₂WO₄、Na₂MoO₄(有时用MoO₃或Na₆Mo₇O₂₄),与有机膦酸或胂酸在增加或减低酸度时反应而得到这些柄状化合物。实验表明,从聚多酸盐逐步提高pH值的途径对有机胂柄状物产量有利。     

钨磷酸(钨硅酸)/聚乙烯醇复合物的制备和光、电性质研究

Kessin型的杂多酸及其盐是多酸化学中研究得最多的物种[1],近年来,以Keggin型的钨磷酸、钨硅酸为代表的多种杂多酸在固体和材料化学领域受到人们的关注[2],并在固体修饰电极、光（电）致变色材料、离子选择性电极和传感器等方面得到了广泛应用[3-5]．本文报道了Keggin型的钨磷酸、钨硅酸／聚乙烯醇复合物的合成、表征、光致变色性质及导电性．1实验方法技文献[6]方法制备H4[SiW12O40]·mH2O和H2［PW12O40］·nH对晶体,含水量用热重分析测得．将聚合度为1800士100的聚乙烯酸（PVA）0．5g溶于200mL沸水中,在65C,搅拌条件下分批…     

Pd/WO3-ZrO2催化剂的结构对乙烯直接氧化制乙酸的影响

利用浸渍法制备了一系列具有不同W/Zr比和不同WO3-ZrO2焙烧温度的1%pd/WO3-ZrO2催化剂.通过X射线衍射、N2吸附、氨程序升温吸附、吡啶吸附红外光谱和程序升温还原方法表征了催化剂的晶体结构、表面状态以及酸性.结果表明,制备条件对W和Pd的表面状态具有很人的影响.随着W/Zr比的增加和焙烧温度的提高,催化剂表而的WOx经历了从聚钨酸物种到聚钨酸/WO3晶体共存再到WO3品体颗粒的转化.W/Zr比为0.2且焙烧湍度为1073K的催化剂具有最多的聚钨酸物种,而该催化剂具有最好的活性.因此,聚钨酸物种的最决定了催化剂的活性.Pd的分散状态只依赖于WO3-ZrO2的焙烧温度.Pd物种分散性好,则乙酸选择性高,而分散性差的人颗粒Pd会导致乙烯的燃烧反应.     

Arsenic(III) as a non-metallic atom in heteropolytungstates: Toward very large polyanions

A review of the synthesis and structures of polytungstate ions containing arsenic(III) is presented. The lone pair of electrons on the As(III) inhibits formation of the classic Keggin structure of these ions. However, this site of unsaturation may be used to construct novel high nuclearity species. Application of this concept has led to the formation of a phospho(V)polytungstate ion containing 48 tungsten atoms.     

Spectrophotometric and Paper Electrophoretic Studies of Uranium(IV) Polyoxotungstogermanate Complexes

The starting point of this study is the monolacunar structure of the Keggin polytungstate anion [GeW₁₁O₃₉]^8–having the capacity of functioning as the coordinating ligand for the uranium U⁴⁺ cation, and the formation of the complex polytungstate anions of the [U(GeW₁₁O₃₉)₂]^12– type. The pH range of the complex formation was established and the stability constants were calculated by the electrophoresis method. By applying the molar ratio method to spectrophotometry, the molar ratio of polyoxometalate ligands and U⁴⁺ cations have been found to have the values of 1:1 and 2:1, respectively.     

Synthesis and study of cerium(IV) polytungstate nanolayers

For the first time the conditions for the synthesis of cerium(IV) polytungstate nanolayers on the silicon surface by the method of ion layering were defined. The layers were studied by scanning electron microscopy, X-ray microanalysis and transmission FT-IR spectroscopy. The synthetized layer is shown to have a globular structure with the size of the globules in the range of 30–50 nm, with the ratio of cerium/tungsten atomic concentrations equal to 0.8.     

Effect of Structure of Pd/WO3-ZrO2 Catalyst on Its Activity for Direct Oxidation of Ethylene to Acetic Acid

A series of 1%Pd/WO₃-ZrO₂ catalysts with different W/Zr ratios and calcination temperatures of WO₃-ZrO₂ were prepared by an impregnation method. Their crystal structure, surface state, and acidity were determined using X-ray diffraction, N₂ adsorption, NH₃ temperature-programmed desorption, pyridine infrared spectroscopy, and temperature-programmed reduction. Special attention was paid to the surface states of tungsten and palladium under different preparation conditions. The results revealed that WO_x surface species underwent a transformation from polytungstate species to coexistent polytungstate/crystalline WO₃ and further to crystalline WO₃ particles with increase of W/Zr ratio and calcination temperature. The W/Zr = 0.2 sample calcined at 1 073 K showed the maximum amount of polytungstates, which were responsible for the excellent activity. Moreover, the state of palladium was only dependent on the calcination temperature. Well-dispersed Pd species were responsible for high selectivity to acetic acid, and large metallic Pd particles were favorable for ethylene combustion.     

Optimization of a molecular mechanics force field for polyoxometalates based on a genetic algorithm

A stochastic technique based on genetic algorithms was implemented to develop new force fields by optimizing molecular mechanics (MM) parameters. These force fields have been optimized for inorganic compounds such as polyoxometalates (POMs) and especially for type‐I polymolybdate and polytungstate clusters. Focussing on the methodology of the development of the force fields, they were tested for the prediction of structural parameters, comparing the MM optimized structures with the geometry obtained after an optimization based on density functional theory. Results show that the genetic algorithm converges toward an optimum combination of parameters which successfully reproduces POMs structures with a high degree of accuracy. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011     

Effect of Electrode Material on Electrodeposition of Tungsten Oxide

Influence exerted by the nature of an electrode-substrate on the electrochemical deposition of tungsten oxides from a metastable acid solution of isopolytungstate was studied. As substrates for obtaining tungsten oxide deposits served metallic electrodes made of gold and platinum, films of mixed indium-tin oxide on glass (ITO-electrodes) and also glassy carbon electrodes and glassy carbon electrodes coated with films of conducting polymers: polyaniline, polypyrrole, and poly-3,4-ethylenedioxythiophene. It was shown that the nature of a substrate noticeably affects the electrochemical properties of tungsten oxide deposits. These differences are attributed to the adsorption of hydrogen on platinum in the range of the deposition potentials of tungsten oxide and to the chemical interaction of polytungstate ions with the thiophene sulfur of the polymer.

     

Synthesis and characterization of [PW11O39Ir(H2O)]4-: successful incorporation of Ir into polyoxometalate framework and study of the substitutional lability at the Ir(III) site

The first Keggin-type heteropolyanion, [PW(11)O(39)Ir(H(2)O)](4-) (1), was synthesized by hydrothermal reaction from two different polytungstate precursors and [IrF(6)](2-). It was isolated as (Bu(4)N)(4)[PW(11)O(39)Ir(H(2)O)] (1a), which was completely characterized by multinuclear (31)P and (183)W NMR, ESI-mass spectrometry and cyclic voltammetry. A rapid screening methodology to ascertain the intrinsic substitutional lability at the Ir site is also presented, based on ESI-MS.     

Divacant polyoxotungstates: reactivity of the gamma-decatungstates [γ-XW10O36]8-(X = Si, Ge)

The dilacunary, Keggin-based gamma-decatungstate ions [γ-XW(10)O(36)](8-) (X = Si, Ge) {XW(10)} exhibit an exciting and versatile solution chemistry, which is probably unmatched by any other lacunary polytungstate. The reactivity of {XW(10)} in the presence, and even absence, of electrophiles, includes loss/gain of tungsten, isomerization, and dimerization. Ever since the syntheses and structures of {XW(10)} were reported, many research groups around the world have investigated the reactivity of these polyanions towards nucleophiles (mostly d-block metal ions) and different products with various shape, size and composition were obtained. Here we provide an overview of the state-of-the-art in this subarea of polyoxometalate chemistry, with a focus on synthetic and structural aspects.     

Effect of tungsten oxide loading on metathesis activity of ethene and 2-butene over WO<Subscript>3</Subscript>/SiO<Subscript>2</Subscript> catalysts

The metathesis of ethene and 2-butene to propene was studied over WO₃/SiO₂ catalysts with various WO₃ loadings (2, 4, 8, 12, 16, and 24 wt%). The 2-butene conversion and propene selectivity increased greatly with WO₃ loading increasing from 2 to 8 wt%, reached maximum at 8–12 wt% WO₃ loading, and then decreased when the WO₃ loading was higher than 12 wt%. From the above results and taking the economics into account, the optimal amount of WO₃ loading was ~8 wt%. The catalysts were characterized by physico-chemical and spectroscopic techniques to elucidate the effect of different tungsten oxide loadings on the metathesis reactivity of ethene and 2-butene. The characterization data indicated that three types of tungsten species (i.e., surface tetrahedral tungsten species, surface octahedral polytungstate species, and WO₃ crystallites) were present in the catalysts. It was found that WO₃ was not the active centers, and surface tetrahedral tungsten species might be more active than octahedral polytungstate species in metathesis reaction. The reduced form of tungsten species [W⁺⁴, W⁺⁵, and W^+(6−y) (0 < y < 1)] may be the suitable state of W species acting as metathesis active centers.