Photo-and Electro-luminescence of the New Ternary Europium(III) Complex

In recent years, the interest in developing luminescent lanthanide complexes has been greatly stimulated by their potential use in electroluminescent displays1. Europium complexes appear most attractive in view of the high photoluminescent efficiency and the high monochromatic red light that are widely exploited in full-color displays2. It has been approved that the second ligand plays an important role in europium complexes, the synergistic complexation of the second ligand can not only lead …     

An electrochemical investigation on (MoO<Subscript>3</Subscript>+PVP+PVA) nanobelts for lithium batteries

Molybdenum trioxide (MoO₃) xerogel films modified with poly(vinyl alcohol)+poly(vinyl pyrrolidone) (PVP+PVA) polyblends were obtained by ion-exchange method with sol-gel technique. Investigations were conducted using X-ray “diffractometry”, Fourier transform infrared spectroscopy, and cyclic voltammetry. The results show that the H atoms in polyblend are H-bonded with the O atoms in the Mo=O bonds of MoO₃ xerogel, which effectively shield the electrostatic interaction between MoO₃ interlayer and Li⁺ ions when MoO₃ xerogel is modified by the intercalation of (PVP+PVA). The reversibility of the insertion/extraction of Li⁺ ions is greatly improved by the modification with polyblend of MoO₃ nanocomposite films. MoO₃ and (PVP+PVA) _x MoO₃ (x = 0, 0.5) nanobelts were obtained by a simple hydrothermal process from MoO₃ sol. The electrochemical cells with configuration Li/(LiPF₆+EC+DMC)/MoO₃ modified by (PVP+PVA) were fabricated and their discharge profiles studied.     

Electrochemical study on the keto-enol tautomerization of p-hydroxyphenylpyruvic acid in aqueous solution

The keto-enol tautomerization of p-hydroxyphenylpyruvic acid (pHPP) in aqueous solutions and the complexation reaction between enolic pHPP and boric acid have been studied by electrochemical techniques including linear sweep voltammetry (LSV), pulse voltammetry, and cyclic voltammetry (CV), combining with UV spectrometry. Electrochemical techniques reveal that in aqueous solution, there are two tautomers of pHPP: enolic form and ketonic form; the former exists mainly in freshly prepared pHPP solution, and the latter exists mainly in equilibrium solution. Both enolic and ketonic pHPP are electroactive. The electrochemical oxidation of enolic pHPP gives rise to two anodic waves, I(a) and II(a), while the electrochemical oxidation of ketonic pHPP only results in the observation of the second wave II(a). The oxidation process I(a) is revealed to be associated with the quasi-reversible, two-electron two-proton oxidation of "C=C"group at the side chain of enolic pHPP, and the oxidation process II(a) is proposed to result from the irreversible oxidation of phenolic hydroxyl group. It is observed that in aqueous solution, enolic pHPP can quickly complex with boric acid to yield enol-borate complex that can also oxidize at a glassy carbon electrode to yield an anodic wave.     

PU大分子单体水溶液性质

双亲聚合物一般由亲水和亲油 2种链段构成 ,有嵌段型[1,2 ] 和接枝型[3 ] 2种 ,其中通过大分子单体法合成双亲接枝聚合物备受关注[4] 。如以亲水性大分子单体和亲油性小分子单体共聚 ,大分子单体构成共聚物主链上支链 ,具有较大活动性 ,亲水效能高。采用对氯甲基苯乙烯[5] 或甲基丙烯酰氯[6] 与聚氧化乙烯大分子的一端相反应 ,可得到亲水性大分子单体 ,但其分子量及结构变化有限。本文采用常规条件 ,合成了嵌段式水溶性聚氨酯大分子单体 ,其分子量较大 ,共聚接枝的支链较长。利用该大分子单体具有非离子高分子表面活性剂的性质 ,采用无皂乳…     

Two—dimensional Network Crown Ether Complex.Synthesis and Crystal Structure of 18—Crown—6 Complex：[K（18—C—6）]2[Cd—（nmt）2]

The novel complex [K(18-C-6)]2[Cd(mnt)2][18-C-6-18-crown-6,nmt=1,2-dicyanoethene-1,2-dithiolate,C2S2-(CN)2^2-] was synthesized and characterized by elemental analysis,IR spectrum and X-ray diffraction analysis.The complex displays two-dimensional network structure of [K(18-C-6)] complex segments and [Cd(nmt)2] complex segment bridged by S-K-S,S-K-N and N-K-N interactions between adjacent[K(18-C-6)] and [Cd(mnt)2]units.     

高活性的茂基钛配合物／正丁基锂加氢催化体系的研究

考察了茂环上不同取代基及钛上阴离子配体对茂基钛配合物／正丁基锂催化体系加氢活性和稳定性的影响。在充分发挥该体系催化活性的条件下，由配合物Ｃｐ２ＴｉＣｌ２、Ｃｐ２ＴｉＦ２和Ｃｐ２Ｔｉ［ＯＣ６Ｈ３（ＣＨ３－２）Ｃｌ－４］２组成的催化体系对辛烯－１加氢的最高活性（或初活性）达到４６￣５８ｓ＾－１。     

1,2,2,6,6-五甲基哌啶醇对聚丙烯光稳定作用的研究

<正> 关于受阻胺类光稳定剂的稳定作用机理,是近年来光稳定研究领域中广泛探讨的课题,我们用异辛烷溶液研究了1,2,2,6,6-五甲基哌啶醇的光稳定作用,结果已在前文报道,本工作是上述研究的继续,主要研究五甲基哌啶醇对聚丙烯膜的光稳定作用。     

Further explorations on bridged 1,2,4-trioxanes

Three new bicyclo[3.2.1]-type 1,2,4-trioxanes have been designed and synthesized. One of them demonstrates better tolerance of the intramolecular hemiketals to steric crowding in hydroperoxidation. The other represents a prototype for possible manipulation of the transient radicals generated in cleavage reactions. A new substitution pattern in the bridged system is explored through synthesis of the third molecule. The configurations of all stereogenic centers in the bridged system can be effectively controlled by the chirality of the allyl alcohol as illustrated by the enantioselective synthesis of the fourth molecule. Finally, similar bicyclo[3.3.1]-type 1,2,4-trioxanes are shown very difficult to be synthesized because of the involvement of a conformer with two substituents at axial positions at the same time.     

NaCl-CsCl熔盐中Ce(Ⅲ)离子的阴极过程研究

以钨微盘为研究电极采用循环伏安法和方波伏安法研究了温度为873K的NaCl-CsCl熔盐中Ce3 离子的阴极行为.结果表明,摩尔比为1:2的NaCl-CsCl熔盐体系中Ce3 离子分两步还原,其电化学反应历程为:Ce3 e=Ce2 ,Ce2 2e-=Ce.进一步计算得到熔盐体系中Ce3 离子的扩散系数(D).     

Selective Oxidation of Methane to Methanol Using Molecular Oxygen on MoOx／（LaCoO3＋Co3O4） Catalysts

Comparatively high CH3OH selectivity (60.0%) and yield (6.7%) were obtained on MoOx/(LaCoO3 Co3O4) catalysts in selective oxidation of methane to methanol using molecular oxygen as oxidant. The interaction between MoOx and La-Co-oxide modified the molecular structure of molybdenum oxide and the ratio of O^-/O^2- on the catalyst surface, which controlled the catalytic performance of MoOx/(LaCoO3 Co3O4) catalysts.