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1.
门勇  刘钰  李静  杨向光  吴越 《化学学报》2003,61(4):547-550
采用柠檬酸络合法合成了一系列含铜复合氧化物(超导体).用化学滴定方法和 O2-TPD等技术对所合成的复合氧化物的组成和表面性质进行了测定.通过探讨催化 剂结构与活性的关系,发现含铜复合氧化物中的非化学计量氧和铜离子的平均价态 与苯酚经化活性和过氧化氢分解活性密切相关.在实验中观察到酪类化合物在苯酚 经化反应循环中具有增强电子传递功能,在此基础上提出了酮类化合物参与催化循 环的机理.  相似文献   

2.
本文报道了一个新的有机膦酸铜化合物:Cu(O3PC6H4COOH)(1).该化合物具有新型层状结构,由扭曲平面结构的{CuO4}共边形成的二核单元通过{CPO3}四面体连接起来,形成一个含有4-,8-,和14-元环的无机层.苯甲酸基团通过中等强度的氢键连接起来.并填充在层与层之间.磁性表征显示铜离子之间存在反铁磁性相互作用.化合物1的晶体属单斜晶系,C2/c空间群.  相似文献   

3.
吉文斌  王勇为 《结构化学》1996,15(2):154-158
用延伸X射线吸收精细结构(EXAFS),测定了标题化合物中两个铜原子的配位结构。两个铜原子有相同的配位,确认每个铜原子均与一个氮原子,三个氧原子形成四配位结构。一氧一氮源于HSB,而另两个氧由乙酸提供。  相似文献   

4.
层状LiMnO2正极材料的研究进展   总被引:4,自引:0,他引:4  
钟辉  周燕芳  许惠 《化学通报》2003,66(7):449-453
层状LiMnO2化合物的研究是目前锂离子电池正极材料锂锰氧化物研究工作的新热点,本文综述了近年来国内外LiMnO2化合物的研究进展,主要阐述了具有层状和扭曲层状结构的m-LiMnO2和o-LiMnO2的结构、电性能、合成和改性方法等方面的研究状况,重点介绍了离子交换法合成层状LiMnO2的原因和机理。探索新的合成方法和掺杂其它金属离子改性以提高循环性能是今后LiMnO2的研究趋势。  相似文献   

5.
通过水热合成方法得到了一个基于双核铜簇[Cu2(1,4-bth)3]4+和[β-Mo8O26]4-阴离子的有机-无机杂化化合物,[Cu2(1,4-bth)3(H2O)(β-Mo8O26)](1)(1,4-bth=4-(6-(1H-1,2,4-三氮唑-1-基)正己烷)-4H-1,2,4-三氮唑),并通过元素分析、红外光谱、X-射线单晶衍射、热分析等测试对其进行了表征。晶体数据表明该化合物属于三斜晶系,P1空间群。在化合物1中,1,4-bth配体都以三齿配体的形式与3个铜离子相连,形成双核铜簇[Cu2(1,4-bth)3]4+,每个簇单元进一步和其相邻的4个同类型单元相连形成了相互平行的层状结构[Cu2(1,4-bth)3]n4n+,层与层之间又通过[β-Mo8O26]4-阴离子相连构筑成1个三维框架结构,其拓扑类型为pcu alpha-Po简单立方格子;热分析表明该化合物具有相对较高的热稳定性。  相似文献   

6.
一、引言自1986年以来所发现的氧化物超导体除Ba_(1-x)K_xBiO_3外都属于铜酸盐化合物,见表1。这些铜酸盐超导体可以分为六类:①具有  相似文献   

7.
用对硝基氯苯为原料,经七步反应合成具有季铵盐类结构的8种新标题化合物。经元素分析、核磁共振氢谱、红外吸收光谱和质谱证实。这种类型的2-氧吖丁啶化合物尚未见诸文献。对腊样芽胞杆菌产生的β-内酰胺酶均有不同程度的抑制作用。  相似文献   

8.
用4,5—二氮芴-9-酮(dafo)、邻苯二甲酸、高氯酸铜和4,5—二氯芴—9— 酮(dafo)、苯甲酸、高氯酸铜进行混和反应时分别得到亮蓝色和蓝绿色晶体,它们 的结构通过单晶X射线衍射法测定。其单晶结构表明,这两种化合物是同分异构体 ,组成都是C22H16Cl2CuN4O12。这两种化合物是通过氢键形成的具有二维网状结构 的超分子化合物,并通过元素分析、红外光谱、热分析对两种化合物进行了表征。  相似文献   

9.
朱丽萍  叶志镇 《化学学报》2003,61(11):1844-1848
通过控制叠氮化物RN_3(R=Li, Na, K, Rb)与层状晶体β-MNCl (M = Zr, Hf) 反应的摩尔比,成功地对层状晶体β-MNCl(M=Zr, Hf)进行了电子掺杂,得到了转 变温度分别是13.5K和23.5K的超导体。实验结果还进一步表明,当摩尔比x=n (NaN_3)/n(β-ZrNCl)=0.3时,反应所得反插层化合物ZrNCl_(1-x)经450 ℃退火处 理后,其超导性质最好。作者同时利用XRD,TEM和SQUID测试结果,分析了化学反 应机理和电子掺杂原理,并研究了所得超导体在空气中的稳定性。  相似文献   

10.
芳氧乙酸-3-(α-吡啶基)丙酯的合成及生物活性研究   总被引:4,自引:0,他引:4  
以苯氧乙酸类化合物为母体分子,设计并合成了16种芳氧乙酸-3-(α-吡啶基)丙酯新化合物,探讨了反应条件对产物收率的影响.通过元素分析、IR及′HNMR,确证了化合物的结构.其中2种化合物经生物活性测定表明具有较高的除草活性。  相似文献   

11.
Recent advances in layered (Fe‐based and Bi‐based) chalcogenides as superconductors or functional materials are reviewed. The Fe–chalcogenide (FeCh) family are the simplest Fe‐based high‐Tc superconductors. The superconductivity in the FeCh family is sensitive to external or chemical pressure, and high Tc is attained when the local structure (anion height) is optimized. The Bi–chalcogenide (BiCh2) family are a new group of layered superconductors with a wide variety of stacking structures. Their physical properties are also sensitive to external or chemical pressure. Recently, we revealed that the emergence of superconductivity and the Tc in this family correlate with the in‐plane chemical pressure. Since the flexibility of crystal structure and electronic states are an advantage of the BiCh2 family for designing functionalities, I briefly review recent developments in this family as not only superconductors but also other functional materials.

  相似文献   


12.
In this communication we report the synthesis, structural and preliminary physical characterisation of a new layered oxyselenide Ce(2)O(2)FeSe(2). This material, containing a 1D portion of the structure of the layered FeSe-related superconductors, is a semiconductor with a band gap of around 0.64 eV and orders antiferromagnetically at low temperatures.  相似文献   

13.
A new layered silicate has been synthesized in the quaternary system Na2O–SiO2–H2O-polymeric organic cation. The polymeric organic cation was intercalated into the silicate during crystallization. Composition, structure, and x-ray diffraction pattern of the new silicate do not fit with any known layered silicate [1–5]. Many similarities were found to hydrous alkali silicates (metal silicate hydrates, M-SH-type).The new silicate differs from M-SH by a high structural stability, against a wide range of different energetic influences. Due to the relatively high stability, high-resolution electron microscopy (HREM) can be applied to study the layer structure of this silicate as a representative of the M-SH silicates. All known M-SH, for example, magadiite and kenyaite are decomposed by the electronic beam.  相似文献   

14.
Non-covalent interactions play an essential role in directing the self-assembly of hybrid organic–inorganic crystals. In hybrid halide perovskites, hydrogen bonding has been the paramount non-covalent interaction. Here, we show another non-covalent interaction, namely, the halogen bond interaction, that directs a symmetry-breaking assembly in a new series of two-dimensional (2D) perovskites (ICH2CH2NH3)2(CH3NH3)n−1PbnI3n+1 (n is the layer thickness, n=1–4). Structural analysis shows that the halogen bond strength varies with the layer thickness. For the odd number (n=1, 3) layered perovskites, stronger halogen interaction leads to centrosymmetric structures, whereas for the n=2 layered perovskites, weaker halogen bonds result in non-centrosymmetric structures. Transient reflection spectroscopy shows a suppressed radiative recombination rate (k2≈0) and prolonged spin lifetime for n=2 structure, suggesting an enhanced Rashba band splitting effect. The structural asymmetry is further confirmed with a reversible bulk photovoltaic effect. Our work provides a new design strategy to enable hybrid perovskites with emerging properties and functionalities associated with structural asymmetry.  相似文献   

15.
A novel isopropanol-pyrogallol[4]arene forms a layered structure via hydrogen bonding and C–H…π interactions. The layered structure results in encapsulation of one isopropanol molecule. The application of NMR methods to determine solution structures and crystal structures provides insight into host–guest properties and the molecular interactions between them.  相似文献   

16.
赵侦超  张维萍 《物理化学学报》2016,32(10):2475-2487
二维层状分子筛前驱体具有三维分子筛的层结构单元,具备母体分子筛的特性,其开放二维片层骨架结构给合成新分子筛以及基于其改性得到新衍生结构分子筛提供新机遇,是近年来分子筛研究领域一个新热点。大量二维片层前驱体可直接合成或通过三维分子筛后处理获得,基于二维片层前驱体人们发展了溶胀、剥层、柱撑、原子扩孔、层重组等层操纵的策略,通过这些策略一些常规方法难以合成或不符合理论规则的分子筛被合成出来,这极大地丰富了二维层状分子筛前驱体的研究领域,扩展了其应用范围。本文概述了二维层状分子筛前驱体的结构特点,系统总结了近年来二维层状分子筛前驱体的合成方法,在此基础上着重阐述了其改性获得新结构分子筛的新策略,并介绍了在多相催化反应中的应用。  相似文献   

17.
Two types of layered hydroxide zinc m‐aminobenzoate compounds with structures of layered basic metal salt (LBMS) were prepared by the reaction of zinc hydroxide with m‐aminobenzoic acid solution in the temperature range of 40–120°C. The formation reactions, structures, chemical compositions, and exfoliation reactions of the layered compounds in alcohol solvents were investigated by XRD, TG‐DTA, SEM, and TEM. One layered phase with a basal spacing of 1.08 nm has a α‐Ni(OH)2‐like structure, and its chemical formula can be written as Zn(OH)0.67(m‐NH2C6H4COO)1.33. This phase has strip‐like particle morphology and cannot be exfoliated into its nanosheets in alcohol solvents. The other layered phase with a basal spacing of 2.66 nm has a zinc hydroxide‐nitrate‐like structure, and can be exfoliated in alcohol solvents.  相似文献   

18.
Micellar structures of amphiphilic poly(1,2‐butadiene)‐block‐poly(ethylene oxide) diblock copolymers have been crosslinked in aqueous solution by γ‐irradiation. By transmission electron microscopy (TEM) of negatively stained specimens it is shown that the predominant structures present are copolymer vesicles (which appear to be double‐layered). These fixed vesicles are stable with respect to their shape and can be transferred from water into a good solvent for both blocks, such as tetrahydrofuran, thus demonstrating the effectiveness of the crosslinking. In addition to the vesicles, a small number of flexible cylindrical/filamentous structures, sequentially fused vesicles/strings of vesicles and giant sheet‐like vesicles are also visible after cross‐linking. The vesicle chains seem to be formed by fusion of the double‐layered vesicles; the outer layer of the vesicles apparently fuses sequentially, whereas the inner shell remains intact, creating periodic linear thickenings.  相似文献   

19.
Layer network formation of poly(styrene‐altn‐octadecylmaleimide) in dodecane is investigated. It is shown that the polymer in the bulk exhibits lamellar structures of alternated alkane side‐chain and main‐chain layers. Adding dodecane into the polymer separates the polymer layers, increases the mean distance between the layers, and results in a less orderly layered structure. Crystallization of the alkane side chains introduces linkages to staple the layers together and builds up a layer network. Dimensional analysis predicts that the modulus (G) of the layer network is simply related to the long period (L) of the layer network through a cubic power law, i.e., GL−3. This prediction is indeed observed experimentally. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 667–677, 1999  相似文献   

20.
Based on FLAPW-GGA calculations, a comparative study of the features of interatomic interactions in LaFeAsO, SrFe2As2, and LiFeAs layered crystals (basic phases of new 18–56 K superconductors) is carried out. Original Russian Text Copyright ? 2009 by I. R. Shein and A. L. Ivanovskii __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 573–576, May–June, 2009.  相似文献   

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