Synthesis and Characterization of Dinuclear Rare Earth Complexes Bearing N-heterocyclic Olefin Moieties

The oxygen-bridged dinuclear rare earth complexes(Ln=Nd(1),Y(2))bearing N-heterocyclic olefin moieties were synthesized by treating the imidazolidinium salt[SIMes-H]Br with potassium amide and rare earth bis(trimethylsilyl)amides.Complex 1 was characterized by X-ray diffraction analysis and complex 2 was characterized by 1H NMR spectroscopy.Both complexes were characterized by elemental analysis.Crystal data of complex 1:C74H138O2N8Si8Nd2,Mr=1685.12,orthorhombic,space group Pbca,a=25.1105(7),b=11.9188(2),c=29.6151(7)?,V=8863.4(4)?^3,Z=4,Dc=1.263 g·cm^-3,μ=1.311 mm^-1,F(000)=3544,the final R=0.0418 and wR=0.0770 for all data.The ring-opening of tetrahydrofuran molecule was proven,the possible mechanism for the formation of N-heterocyclic olefin(NHO)-rare earth complexes was speculated and the electronic and steric properties of SIMes and rare earth amides were discussed.This work provides a better understanding of N-heterocyclic carbene rare earth chemistry.     

New class of organic-inorganic hybrid aggregates based on polyoxometalates and metal-Schiff-base

By combination of heteropolymolybdates and metal-Schiff-base complexes, two new organic-inorganic hybrid compounds {Mn(salen)(2)(H(2)O)(2)[AlMo(6)(OH)(6)O(18)]}[arg]·16H(2)O (1) and {Mn(salen)(2)(H(2)O)(2)[CrMo(6)(OH)(6)O(18)]}[arg]·11H(2)O (2) (salen = N,N'-ethylene-bis(salicylideneiminate) have been successfully isolated. Compounds 1 and 2 were structurally characterized by elemental analyses, IR spectra, thermogravimetric analysis, and single-crystal X-ray diffraction. To the best of our knowledge, compounds 1 and 2 represent the first single-crystal structures of metal-Schiff-base decorated polyoxometalates (POMs) compounds. Photocatalytic experiments indicated that both 1 and 2 exhibit high catalytic activity for photodegradation of RhB with UV irradiation. In addition, the magnetic properties of 1 were also investigated.     

高效WO3掺杂MCF催化剂的合成及其在环戊烯选择氧化制戊二醛反应中的应用

以钨酸钠和正硅酸乙酯为前驱体直接合成高含量WO₃掺杂介孔氧化硅泡沫(MCF)催化剂. 在773 K焙烧后显示出更高的热稳定性. 小角X射线散射, N₂-物理吸附和透射电子显微镜结果表明钨物种嵌入后, 材料仍保持MCF特征的三维织构介孔特征. 紫外拉曼和紫外可见漫反射光谱结果表明钨物种主要以孤立的或者低聚态的氧化钨形式存在, 所以在氧化钨质量分数(w)低于20%时氧化钨物种能够高度分散在载体上. 在环戊烯选择氧化制戊二醛反应中, 反应16 h 后环戊烯的转化率达到100%, 戊二醛的产率达到83.5%. 催化剂重复利用实验表明催化剂的稳定性较好, 没有钨物种的脱落. 这种优异的催化性能归结于合适的氧化钨含量和高分散的钨物种.     

薄层分离-导数光谱法测定大豆中异黄酮

以大豆异黄酮成分之一染料木素为标准品 ,一阶导数光谱法在 2 71nm测定了总黄酮的含量。染料木素标准品的线性范围为 2— 30 μg/ m L,r=0 .9999,平均回收率为 99.80 % ,相对标准偏差为 1.93%。本法简单、准确 ,可以有效地消除提取液中非异黄酮类成分的干扰 ,可作为检测大豆提取物中异黄酮含量的方法之一。     

多酸基光敏剂在染料敏化太阳能电池中的应用

染料敏化太阳能电池(dye-sensitized solar cells,简写为DSSCs)是由Michael Gr覿tzel等开发的第三代光伏电池,它具有低成本、制作简单、光学性能可调、光电转换效率高等优势。其中光敏剂是DSSCs的重要组成部分,通过吸收可见光将电子传递到半导体导带,对整个电池的电子循环至关重要。广泛采用的光敏剂为N719等贵金属配合物,但其价格非常昂贵,很难实现大规模产业化。因此寻找低成本的非贵金属光敏剂是该领域的一项挑战。多金属氧酸盐(简称多酸,Polyoxometalates,简写为POMs)是一类具有纳米尺寸的分子基纳米材料,是分子型无机类半导体材料。多酸的富氧表面可以被活化和修饰,吸收光谱可以覆盖可见区甚至近红外区,具有合适的氧化还原电势,良好的热稳定性和溶解性。近年来,一系列研究表明多酸可以作为光敏剂应用在DSSCs中。本文中,我们以课题组多年来在POMs和太阳能电池领域的研究工作积累以及国内外同行专家的研究工作为基础,对多酸基光敏剂在DSSCs中的应用进行了详细综述。首先我们阐述了DSSCs的研究意义、多酸的简介、多酸的能级测量及调控。之后我们重点综述了多酸作为DSSCs中的光敏剂和共敏剂的研究。最后,我们对多酸基光敏剂在DSSCs领域的发展前景进行了总结和展望。本文有望引起多酸化学、材料化学及新兴交叉学科领域研究者的广泛研究兴趣,并为太阳能电池光敏剂的研究提供新的思路。     

Highly efficient VOx/SBA-15 mesoporous catalysts for oxidative dehydrogenation of propane

Highly dispersed vanadia species on SBA-15 mesoporous silica have been found to exhibit a highly efficient catalytic performance for the oxidative dehydrogenation (ODH) of propane to light olefins (propene + ethylene).     

A new arbutin derivative from the leaves of Vaccinium dunalianum wight

A new arbutin derivative, namely dunalianosides J (1), along with six known compounds, arbutin (2), robustaside A (3), 6′-O-caffeoylarbutin (4), dunalianoside D (5), kaempferol 3-O-β-D-glucopyranoside (6) and kaempferol 3-O-β-D-sambubioside (7) were isolated from the leaves of Vaccinium dunalianum Wight (Ericaceae). The structure of 1 was elucidated by extensive 1D and 2D NMR, HR-MS and CD spectroscopic analyses. In which, kaempferol 3-O-β-D-sambubioside (7) was isolated from the genus Vaccinium for the first time.     

Novel economic and green approach to the synthesis of highly active W-MCM41 catalyst in oxidative cleavage of cyclopentene

A highly active and perfectly structured W-MCM41 catalyst for the oxidative cleavage of cyclopentene to glutaraldehyde was synthesized through a novel economic and green synthetic method by using Na2SiO3 as the Si source and CH3COOC2H5 as the hydrolyzer.     

甲醇水蒸气重整制氢的高效碳纳米管改性Cu/ZnO/Al2O3催化剂

以碳纳米管为助剂,制备用于甲醇水蒸气重整制氢的新型高效Cu/ZnO/Al₂O₃催化剂,并与传统Cu/ZnO/Al₂O₃催化剂在相同条件下的催化性能进行了比较.结果表明,添加适量碳纳米管可显著提高催化剂的低温催化活性和选择性,在大幅度提高产氢速率的同时有效降低了重整产气中CO的含量.SEM和XRD分析证实适量碳纳米管的添加有效促进了Cu/ZnO/Al₂O₃催化剂结构特性的改善,有利于活性铜物种的分散,从而显著提高了催化剂的低温催化性能.     

一种改进的烯丙基缩水甘油醚的合成方法

烯丙基缩水甘油醚;环氧氯丙烷;烯丙醇钠;烯丙醇;合成