新型层柱化合物合成、表征及催化活性

将含过氧铌一、三取代钨硅、钨磷过氧杂多阴离子利用离子交换法嵌入Zn2Al类水滑石中制得层柱化合物,利用XRD,IR,UV等方法对产物的结构进行了表征。结果表明在层柱化合物中过氧杂多阴离子仍然保持Keggin结构,并且过氧键没被破坏。层柱化合物在酯化反应中显示优良的催化性能。     

过氧杂多阴离子柱撑水滑石的合成、表征及催化性能的研究

通过离子交换法, 将含钛过渡金属离子一、三取代钨硅、钨磷过氧杂多配合物嵌入Zn2Al类水滑石中, 获得了柱撑化合物, 并用XRD, IR, XPS, 元素分析等手段对产物的结构和组成进行了表征。结果表明, 过氧杂多阴离子进入水滑石层间后, 水滑石的层间距从0.92nm增大到1.47nm, 且O2^2^-链没有被破坏。柱撑产物在环己烯氧化反应中显示优良的催化性能。     

过氧杂多阴离子柱撑水滑石类层状化合物的合成与表征

以硝酸根型水滑石作交换前驱体，通过离子交换法合成了过渡金属离子一、三钛取代的Ｋｅｇｇｉｎ结构过氧钨硅杂多阴离子柱撑水滑石Ｚｎ２Ａｌ（ＯＨ）６－［ＳｉＷ１１（ＴｉＯ２）Ｏ３９］及Ｚｎ２Ａｌ（ＯＨ）６－［ＳｉＷ９（ＴｉＯ２）３Ｏ３７］，用元素分析、ＸＲＤ、ＩＲ、ＸＰＳ、化学分析等手段对产物的组成和结构进行了表征。结果表明，过氧杂多阴离子进入水滑石层间，使水滑石的层间距从０．９２ｎｍ增加到１．４７ｎｍ。     

P-Cu-Mo杂多阴离子柱撑水滑石的制备

杂多阴离子柱撑水滑石作为一类新型的催化材料,近年来日益受到人们的关注。但由于杂多化合物对碱不稳定及水滑石在酸性条件下层结构易被破环,故文献中仅有制得钨硅系杂多阴离子柱水滑石的报道。作者将过渡金属引入钼磷酸的Keggin结构骨架中,提高了其溶液稳定性,并在微波场中快速地制得了P-Cu-Mo杂多阴离子柱撑水滑石。     

杂多阴离子柱撑水滑石类层柱材料中层柱相互作用研究

合成了具有不同组成的类水滑石层状化合物和杂多酸，据此制备了一系列杂多阴离子柱撑水滑石，用ＩＲ光谱、ＤＴＡ等方法研究了此类层柱材料中层与柱的相互作用，发现类水滑石层状化合物中的Ｍ＾３＋离子的种类和具有Ｋｅｇｇｉｎ结构的杂多阴离子的组成元素，无论处于四面体中、还是位于八面体中，对层柱的相互作用皆有明显影响，此外，这种相互作用还导致杂多阴离子中四面体和八面体对称性及相关性质的改变。     

P—W系杂多阴离子柱水滑石的制备及表征

本文采用微波法，首次制了第四周期系过滤金属取代三元杂多阴离子（ＰＺＷ１１）柱水滑石。经ＸＲＤ、ＤＴＡ、ＩＲ、ＵＶ－ＤＲＳ和ＥＳＲ表征。结果表明插入层间的柱高约为１．０ｎｍ，进入水滑石层间的杂多阴离子与其盐的ＩＲ振动类型和振动频率很相近，并且在水滑石层间ＰＷ１２基团不能稳定存在，可能已部分发生降解，而ＰＺＷ１１则能稳定的存在于水滑石层间。ＵＶ结果表明，进入水滑石层间的杂多阴离子的桥氧与钨（Ｏｂ／Ｏｃ     

钨磷杂多化合物嵌入ZnAl类水滑石层间及其酸碱催化活性的研究

将含过渡金属Ni、Co的钨磷杂多化合物引入ZnA1类水滑石中,获得了柱撑化合物,并用XRD、IR等手段对其晶相和内部结构进行了表征。元素分析结果表明,杂多化合物基本符合ZPW₁₁结构。用DTA研究了其热稳定性。这类化合物在异丙醇反应中显示出较强的酸催化性能,完全改变了ZnA1硝酸根型化合物的碱催化活性。     

类水滑石及其杂多阴离子柱撑物的合成与表面酸性研究

合成了一些类水滑石和过渡金属取代型杂多酸盐，并由此制备了相应杂多阴离子柱撑水滑石层柱材料。用ＸＲＤ，ＩＲ和元素分析等手段对合成产物进行组成和结构表征，用ＮＨ３－ＴＰＤ，Ｐｙ－ＩＲ研究了合成产物的表面酸性和酸类型，并在异丙醇反应中考察了合成物的酸碱催化行为，结果表明，水滑石和柱撑水滑石均同时存在酸碱中心，且酸碱相对强度与柱阴离子类型密切相关。杂多阴离子进入水滑石层，同时改变了水滑石和杂多酸盐的酸强度     

过氧锆杂多化合物的合成、表征及催化活性

过氧锆钨硅杂多化合物;异构体;环氧化反应;催化活性;过氧锆杂多化合物的合成、表征及催化活性     

钨磷杂多化合物嵌入ZnAl类水滑石层间及其酸碱催化活性的…

将含过渡金属Ｎｉ、Ｃｏ的钨磷杂多化合物引入ＺｎＡｌ类水滑石中，获得了柱撑化合物，并用ＸＲＤ、ＩＲ等手段对其晶相和内部结构进行了表征。元素分析结果表明，杂多化合物基本符合ＺＰＷ１１结合。用ＤＴＡ研究了其热稳定性。这类化合物在异丙醇反应中显示出较强的酸催化性能，完全改变了ＺｎＡｌ硝酸根型化合物的碱催化活性。     

Hybrid inorganic-metalorganic compounds containing copper(II)-monosubstituted Keggin polyanions and polymeric copper(I) complexes

Four hybrid inorganic-metalorganic compounds containing copper(II)-monosubstituted Keggin polyoxotungstates, K3[Cu(I)(4,4'-bpy)]3[SiW11Cu(II)O39].11H2O (1), (paraquat)3[SiW11Cu(II)O39].6H2O (2; paraquat = N,N'-dimethyl-4,4'-bipyridinium), K3[Cu(I)(4,4'-bpy)]3[GeW11Cu(II)O39].11H2O (3), and Na2[Cu(I)(4,4'-bpy)]3[PW11Cu(II)O39(H2O)].4H2O (4), have been synthesized under autogenous pressure hydrothermal conditions and characterized by elemental analysis and infrared spectroscopy (FT-IR). The crystal structures of 1, 2, and 4 have been established by single-crystal X-ray diffraction. The crystal packings are characterized by the presence of monodimensional extended entities: either the polymeric polyanion [SiW11CuO39]n(6n-) (2), the cationic [Cu(4,4'-bpy)]n(n+) chain (4), or both simultaneously as in compound 1, where the inorganic and metalorganic sublattices are mutually perpendicular. To asses the influence of packing in the copper(I) complex structural diversity found in compounds 1 and 4, a search in the CSD database has been performed and the resulting geometrical features have been analyzed and compared with experimental crystallographic data and DFT calculations.     

Cation-directed synthesis of tungstosilicates. 1. Syntheses and structures of K10A-alpha-[SiW9O34].24H2O,of the sandwich-type complex K10.75[Co(H2O)6]0.5[Co(H2O)4Cl]0.25A-alpha-[K2(Co(H2O)2)3(SiW9O34)2].32H2O and of Cs15[K(SiW11O39)2].39H2O

The influence of the nature of alkali metal cations on the structure of the species obtained from the trivacant precursor A-alpha-[SiW(9)O(34)](10-) has been studied. Starting from the potassium salt 1, K(10)A-alpha-[SiW(9)O(34)].24H(2)O, the sandwich-type complex 2, K(10.75)[Co(H(2)O)(6)](0.5)[Co(H(2)O)(4)Cl](0.25)A-alpha-[K(2)(Co(H(2)O)(2))(3)(SiW(9)O(34) )(2)].32H(2)O, has been obtained. The crystal structures of these two compounds consist of two A-alpha-[SiW(9)O(34)](10-) anions linked by a set of potassium (1) or cobalt plus potassium cations (2), and the relative orientation of the two half-anions is the same. Attempts to link two A-alpha-[SiW(9)O(34)](10-) anions by tungsten atoms instead of cobalt failed whatever the alkali metal cation. Moreover, the nondisordered structure of Cs(15)[K(SiW(11)O(39))(2)].39H(2)O is described. Two [SiW(11)O(39)](8-) anions are linked through a potassium cation with a "trans-oid" conformation, and the potassium occupies a cubic coordination site.     

Orientations of Rare—earth—containing Heteropolyoxometalates with Different Sizes in the Interlayer of Synthetic Multibilayer Films

Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5O18)2],K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibilayer films of dimethyldioctadecylammonium chloride and exhibited different orientations.     

过氧钛钨硅杂多配合物的合成、表征及催化活性

合成了过氧钛钨硅杂多酸盐α-M6-mHm[SiW11(TiO2)O39].xH2O和α-M10-mHm[SiW9(TiO2)3O37].xH2O(M=K, TBA), 用IR, UV吸收光谱,极谱-循环伏安, 183W NMR, XPS和XRD等测试方法对其性质、结构进行研究。结果表明, 它们都是具有Keggin结构的过氧杂多配合物,TiO2基的引入将其极谱半波电位提高至-0.3V以上, 它们对顺丁烯二酸的H2O2环氧化反应具有显著高的催化活性。     

Selective precipitation of prions by polyoxometalate complexes

The efficacy of a variety of polyoxometalate anions in selectively precipitating the infectious isoform of the prion protein (PrPSc) over the normal, cellular protein (PrPC) was tested as a means of improving the sensitivity of a conformation-dependent immunoassay (CDI). Experiments utilizing neutralized aqueous solutions containing MgCl2.6H2O and Na2H[PW12O40] (1) indicated that use of the former is detrimental to selectivity, while use of the latter gives optimal selectivity at a concentration of 2.48% w/v, much higher than the 0.31% w/v employed in the current CDI protocol. Similar experiments using Na4[SiW12O40] (2), K5[BW12O40] (3), and Na6[H2W12O40] (4) were performed to probe the role of charge density in polyoxometalate anions possessing the Keggin structure. These, coupled with assignment of solution structures via NMR and infrared spectroscopy, revealed the following trend in optimal concentrations: [HBW11O39]8- < [SiW11O39]8- < [PW11O39]7- = [H2W12O40]6-. Interestingly, use of the salts K10[Zn4(H2O)2(PW9O34)2] (5), Na16[Zn4(H2O)2(P2W15O56)2] (6), and Na27[NaAs4W40O140] (7), containing larger polyoxometalate anions, was found to suppress PrPSc precipitation in a concentration-dependent manner. Taken together, the results suggest a precipitation mechanism wherein Keggin-type anions link multiple PrPSc moieties by binding a somewhat hindered cleft featuring one or more positively charged residues.     

Surface modification of mesoporous, macroporous, and amorphous silica with catalytically active polyoxometalate clusters

Transition-metal-substituted polyoxometalates (TMSP) of the type [MII(H2O)PW11O39]5- (M = Co, Zn) and [SiW9O37(CoII(H2O))3]10- have been chemically anchored to modified macroporous (400 nm pores), mesoporous (2.8 nm pores), and amorphous silica surfaces. The materials were characterized by solid-state 31P MAS NMR, UV-vis, FT-IR spectroscopy, and N2 adsorption experiments to verify cluster attachment and the structure of the TMSP on the support. On the basis of the spectroscopic evidence, clusters were attached datively to the surface, and the integrity of the [CoPW11] cluster was maintained for nonaqueous impregnation with TBA5[CoPW11]; partial degradation of the cluster occurred when it was impregnated from aqueous solution using the K5[CoPW11] salt. Both the amine surface groups and the cobalt centers in the clusters were found to be necessary to prevent cluster loss during washing or reaction processes. The catalytic activities of the supported TMSP clusters were tested by the epoxidation of cyclohexene to cyclohexene oxide in the presence of isobutyraldehyde. The percent conversion of the substrate and the amount of product formed per unit time were similar for [CoPW11] clusters on each of the three silica supports, but slightly lower than for purely homogeneous reactions. [SiW9Co3] clusters with three available cobalt centers exhibited higher catalytic activity with nearly identical performance on a silica support or in homogeneous solution.     

Cation-controlled assembly of Na+-linked lacunary alpha-Keggin tungstosilicates

Two novel salts of lacunary tungstosilicates with guanidinium and alkali metal cations, (CH6N3)7Na[SiW11O39].(CH3)2CO.8H2O (1) and (CH6N3)K6Na[SiW11O39].11.5H2O (2), have been synthesized and their crystal structures have been determined by synchrotron X-ray diffraction. In both crystals, the Na+ cations link the lacunary Keggin-type tungstosilicate anions into linear structures. The neighboring [SiW11O39]8- anions are related by two-fold screw and translational operations in compounds 1 and 2, respectively. Second harmonic generation was observed for compound 1.     

The proton conductivity of heteropoly compounds

Five kinds of molybdovanadophosphoric acid: H7[P2Mo17VO62], H8[P2Mo16V2O62], H9[P2Mo15V3O62], H8[P2Mo14V4O61(H2O)] and H9[P2Mo13V5O61(H2O)] have been synthesized. The salts, K13[Ln(SiW11O39)2] (Ln=La, Ce, Pr, Nd or Gd) have also been prepared. The proton conductivities (C) of all the above compounds have been measured, and are dependent not only on the nature of compound itself, but also on external factors such as temperature and frequency. The general trend of proton conductivity, changing with the hydration number, frequency and temperature is summarized and important conclusions have been drawn based on experimental measurements. The resulting data have not been reported hitherto in the literature.