Assembly of the transition metal substituted polyoxometalates ZnW11M(H2O)O-39(n-) (M = Mn, Cu, Fe, Co, Cr, Ni, Zn) on 4-aminobenzoic acid modified glassy carbon electrode and their electrochemical study

Through layer-by-layer assembly, a series of undecatungstozincates monosubstituted by first-row transition metals, ZnW11M(H2O)O-39(n-) (M=Cr, Mn, Fe, Co, Ni, Cu. or Zn) were first successfully immobilized on a 4-aminobenzoic acid modified glassy carbon electrode surface. The electrochemical behaviors of these polyoxometalates were investigated. They exhibit some special properties in the films different from those in homogeneous aqueous solution. The Cu-centered reaction mechanism in the ZnW11Cu multilayer film was described. The electrocatalytic behaviors of these multilayer film electrodes to the reduction of H2O2 and BrO3- were comparatively studied.

Self-immobilized catalysts for ethylene polymerization: neutral, single-component salicylaldiminato phenyl nickel(II) complexes bearing allyl substituents

A new family of self-immobilized ethylene polymerization catalysts, derived from neutral, single-component salicylaldiminato phenyl nickel complexes, is described.

水杨醛亚胺镍/MMAO催化降冰片烯加成聚合

用水杨醛亚胺镍 / MMAO催化降冰片烯聚合获得了热稳定、高分子量、可溶性的加成聚合产物 . Al、Ni摩尔比、单体浓度、反应温度与时间对催化剂的活性和聚合物分子量均有较大影响 .在优化条件下 ,催化剂的活性达 1 3 t/ (mol· h) ,聚降冰片烯的粘均分子量达 1× 1 0 6.

Syntheses and properties of thermotropic copolyesters of p-hydroxybenzoic acid

Two series of thermotropic copolyesters of p-hydroxybenzoic acid (HBA) were synthesized by direct thermal polycondensation. One comprised aromatic copolyesters from HBA, terephthalic acid, bis(4-hydroxyphenyl) ketone (BHP) and resorcinol. The other comprised semi-aromatic copolyesters from HBA, terephthalic acid, BHP and alpha,-diols with carbon atom number of 4, 6, 8, 10. The properties of the two series were characterized by polarized light microscopy, differential scanning calorimetry and wide angle X-ray diffraction. Most of the resulting copolyesters could form a nematic phase over a wide temperature range above their melting points. The effects of Variation in composition and monomer structure on the properties of copolyesters were discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.

Investigation on moleculare and crystal structures of metal complexes with aminopolycarboxylic acids (VII) - Syntheses and structure determination of Na-3[Hg (I) (edta) C1] center dot 6H(2)O

In this paper we describe the moleculare and crystal structures of the Na-3[Hg( II )(edta)Cl] . 6H(2)O (edta=ethylenediamine-N,N,N',N'-tetraacetate). The crystal data are as follows: orthorhombic, a=8. 083 (2) Angstrom , b=13. 870(3) Angstrom , c=38. 617(5) Angstrom , v=4329. 4 (13) Angstrom(3) , Z=8, Dc= 1. 798 g . cm(-3), mu=5. 564 mm(-1), P(000)=2280, R=0. 0317 and R-w=0. 0731 for 3883 unique reflections. In complex, the complex anion [Hg ( II ) (edta)Cl](3-) has a seven-coordination structure like a mono-capped trigonal-prism (C-2v-MTP) in which the edta(4-) acts as a hexadentate ligand with four O atoms and two N atoms and a Cl- caps a quadrilateral face as a seventh ligand. It can be known that the Hg2+ which has a d(10) electronic structure can form a high-coordinate compound with a hexadentate ligand (edta) because it has a big ionic radius.

Synthesis of novel cyclic aryl ether thioether ketone (Sulfone) oligomers

Two kinds of macrocyclic oligomers containing aromatic sulfide linkages have been synthesized by the solution polycondensation in high yield. The cyclic compounds were characterized by H-1 and C-13 NMR, by and MALDI - TOF MS.

(NH4)(3)[PMo12O40]center dot 21H(2)O

The determination of the crystal structure of the title compound, triammonium hexatriacontaoxo(tetraoxophosphato)dodecamolybdate(3-) henicosahydrate, shows that the polyanion has a pseudo-Keggin structure with m (3) over bar m symmetry. The central PO4 group is disordered with P-O distances of 1.55 (3) Angstrom. The Mo-O distances range from 1.617 (14) to 2.414 (14) Angstrom.

异丙基膦酸单(1-已基-4-乙基)辛酯的某些基本常数的测定

用两相滴定法测定异丙基膦酸单(1-己基-4-乙基)辛酯(PT-2,HL)在水中的溶解度S，在水中的解离常数K在水-正庚烷中的分配常数Kd及二聚常数K2，利用SOLWR计算程序，简单快速地处理两相滴定数据，得到结果为：S=3.68×10-5mol/L，pKa=5.49，logK2=4.67，logKd=2.67(25±0.5℃)

Synthesis, characterization and catalytic activity for H2O2 decomposition of tetrabasic tungstovanadophosphate heteropoly rare earth element complexes with Dawson structure

Nine tetrabasic tungstovanadophosphate heteropoly rare earth element complexes with Dawson structure were synthesized. Their general molecular formulas are K15H4[Ln . (P2W16VO61)(2)] . xH(2)O(Ln = La3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Dy3+, Yb3+). Their structures and properties were investigated by IR, UV, NMR, ESR, XRD, TG-DTA. The results showed that the series of complexes have the same structure as K-16[Ce(P2W17O61)(2)] . 50H(2)O. At the same time, the catalytic activity of the complexes for H2O2-decomposition was also investigated.

镧系元素Dawson结构钨钒磷四元杂多配合物的合成、表征以及对H_2O_2分解的催化活性

合成了通式为Ｋ_（１５）Ｈ_３［Ｃｅ（Ｐ_２Ｗ_（１６）ＶＯ_（６１））_２］·６１Ｈ_２Ｏ、Ｋ_（１５）Ｈ_４［Ｌｎ（Ｐ_２Ｗ_（１６）ＶＯ_（６１））_２］·ｘＨ_２Ｏ（Ｌｎ＝Ｌａ￣（３＋），Ｐｒ￣（３＋），Ｎｄ￣（３＋），Ｓｍ￣（３＋），Ｅｕ￣３＋，Ｇｄ￣（３＋），Ｄｙ￣（３＋），Ｙｂ￣（３＋））的９种镧系元素Ｄａｗｓｏｎ结构的钨钒磷四元杂多配合物，并用ＩＲ、ＵＶ、ＮＭＲ、ＥＳＲ、ＸＲＤ、ＴＧ－ＤＴＡ等对其结构和性质进行了研究。该类配合物具有与Ｋ_（１６）［Ｃｅ（Ｐ２Ｗ（１７）ＶＯ（６１））２］·５０Ｈ２Ｏ类似的结构，对Ｈ２Ｏ２分解有较高的催化活性。

BIS(ETA-HEPTYLAMMONIUM) TETRACHLOROZINCATE

The crystal structure of (C7H18N)(2)[ZnCl4] is composed of alternating layers of inorganic ions and paraffinic chains. It differs from the structures of analogous compounds that have a hydrocarbon chain containing an even number of C atoms. This may explain the odd-even effects observed in differential scanning calorimetry (DSC) measurements on these compounds.

STUDY ON THE ELECTROOXIDATION OF BILIVERDIN BY IN-SITU THIN-LAYER SPECTROELECTROCHEMISTRY

The electrooxidation reaction of biliverdin (BY) is studied by in situ spectroelectrochemistry with rapid spectra scanning in an optically transparent thin-layer cell. The study reveals that the oxidation process of BY is very complicated and involves many stages. The average formal potential of BY is obtained for the first time as E-degrees' = 0.634 V (vs- Ag/AgCl), and the electrooxidation mechanism of BY is proposed.

激光热透镜光度法测定痕量锑

利用He-Ne激光,观测了锑-孔雀绿络合物的激光热透镜效应。其在苯中最低检测浓度为10ng/ml Sb,测定线性浓度范围为1～120ng/ml,测定的相对标准偏差为6.5％。本方法比常规光度法的测定灵敏度高12倍,相当于吸光度3.3×10~(-4)。

EPITAXIAL CRYSTALLIZATION OF TRANS-1,4-POLYBUTADIENE ON HIGHLY ORIENTED ISOTACTIC POLY(PROPYLENE) FILMS

Epitaxial crystallization of trans-1,4-polybutadiene (PBD) on highly oriented isotactic poly(propylene) (iPP) has been investigated at different crystallization temperatures and rates. From electron microscopy and electron diffraction, it is confirmed that epitactic growth of the low-temperature modification (monoclinic) with microcrystals of PBD on the iPP films takes place with their chain directions about +/- 50-degrees apart. No epitaxial relationship occurs between the high-temperature modification (hexagonal) of PBD and the iPP substrate. Thermal analyses of PBD-PP layered films indicate that the epitaxy has an important effect on the formation of the high-temperature modification of PBD.

时间分辨激光荧光光谱分析方法研究——Ⅱ混合稀土中铽的测定

本文介绍了利用自装的时间分辨激光荧光光谱装置对混合稀土中铽的测定方法。装置采用氮分子激光器为激发光源,Boxcar积分器为信号处理系统,选择了Tb-Sal-乙醇溶液为荧光体系,用标准加入法对样品进样行了测定。并将已知样品的测定结果与其它方法测定结果进行了比较。本法测定铽的相对标准偏差为7.4％,检出限为1.3×10~(-4)μg/ml。