Progress in the synthesis and reactivity studies of metallabenzenes

Metallabenzenes are metallacyclohexatriene complexes that are derived by replacement of one of the CH groups in benzene with a transition-metal fragment. Their synthesis and aromatic properties have recently attracted considerable attention. This paper summarizes the progress in the synthesis, aromatic property, and reactivity studies of metallabenzenes. We will describe the synthesis and reactivity of typical metallabenzenes with various metals (e.g. osmium, iridium, and ruthenium, etc.), the synthesis and structure of a recent reported example of metallanaphthalene and several rare examples of novel and stable metallabenzynes. Finally, the possible future developments in this field have also been suggested.     

配位聚合物[Co2(C3H4N2)4(C10H2O8)]n的晶体结构、磁性及光-电性能

采用溶液热合成方法, 得到了新颖的Co(Ⅱ)配位聚合物单晶体. 它是以[Co₂(C₃H₄N₂)₄(C₁₀H₂O₈)]为重复单元、用均苯四甲酸根为桥而联成的一维无限链状聚合物. 该配合物单晶属三斜晶系, 空间群P 1, ( — ) a = 0.9610(1) nm, b = 0.9684(1) nm, c = 0.7924(1) nm, α = 96.695(9)°, β = 102.741(6)°, γ = 116.551(5)°, V = 0.6236(2) nm³, Z = 2, R₁ = 0.0342, wR² = 0.0990. 表面光电压光谱测试结果表明, 它在300~800 nm范围内, 表现出了较明显的光伏响应带. 另外从该化合物的变温磁化率研究结果可以看出, 该聚合物具有弱的反铁磁物质行为.     

Synthesis and crystal structure of tetranuclear zinc benzoate

A tetranuclear zinc benzoate Zr4O(C6H5CO2)6 was synthesized and characterized by X-ray single crystal determination. It crystallizes in cubic, space group Ia-3d. Its crystal cell is very large, α=4.10063(18)nm, V=68.953(5)nm^3 and Z=48. The structure is composed of discrete Zr4O(C6H5CO2)6 molecules. In each molecule, four zinc atoms are held together by a central oxygen atom, which results in the formation of a regular tetrahedron. All benzoate ligands coordinate to zinc atoms in a bidentate bridging mode. Each zinc atom is in a slightly distorted tetrahedral geometry, coordinated by three benzoate oxygen atoms and the central oxygen atom. The intermolecular interactions result in the formation of a three-dimensional supramolecular framework, with non-intersecting parallel channels.     

Rapid synthesis of ZSM-5 zeolite catalyst for amination of ethanolamine

ZSM-5 zeolite was rapidly synthesized in system containing ethylenediamine from the initial gel: (5-8) Na2O:44 EDA:A12O3:100 SiO2:4000 H2O. The crystals were lath-shaped. The effect of pretreatment and alkalinity on crystallinity was investigated. The pretreatment of silicate source can cut down the crystallization time. Tuning the system alkalinity and controlling crystallization time can ensure forming of pure crystal.     

不同质量恒星的核合成产率

恒星核合成产率是星系化学演化模型中一个非常重要的参量,采用不同的产率会得到元素的不同演化行为,从而给出不同的星系化学演化信息.而由于采用不同的核合成计算参数,不同研究者计算出的产率有所区别.评述了最近发表的中、小质量恒星及大质量恒星的演化与核合成计算结果,并对他们所采用的参数进行了比较,为恒星核合成计算及星系化学演化研究提供有益的参考与指导.     

新型聚碳酸酯研究进展

介绍了几种新型聚碳酸酯(简称PC),并讨论了其合成方法及应用。其中包括脂肪族PC、支化型PC、高分子量PC、超高分子量PC、液晶PC、阻燃PC、耐热耐溶剂PC及其它一些具有特殊功能的PC。这些新型聚碳酸酯弥补了普通双酚A型PC的一些缺点,扩大了PC的应用领域,具有一定的实际意义。     

一种新的肼基硫代酸苄酯的合成及荧光性质

合成了一个新的化合物,4-(N,N-二乙酰氧乙基氨基)苯甲醛缩肼基硫代酸苄酯,运用FT-IR,1H-NMR,UV-Vis,元素分析等进行了表征分析,测定了该化合物的荧光性质,从理论上分析了该化合物"反常"的双重荧光现象。     

TVOD系统设计

VOD即"按需服务电视".介绍了国外的相关研究工作,指出电视系统不应停留在数字化技术上,而应以此为基础向智能化与Web集成的方向发展.从电视业务级别的划分入手,定义了TVOD的概念,并区别了TVOD与VOD的技术思路和应用范畴.详细讨论了TVOD概念系统的结构和关键技术.     

羟甲基-双(二茂铁基)丙烷的合成方法研究

双二茂铁丙烷通过Vilsmeier反应得到了一元和二元的甲酰基-双(二茂铁)丙烷.并通过正交实验法获得了较好的产率(一元醛产率约70%～75%)和转化率(80%～86%).一元和二元的甲酰基-双(二茂铁)丙烷经KBH4/CH3CH2OH还原得到了两个新的化合物,即一元和二元的羟甲基-双(二茂铁)丙烷.     

两种新的DS合成法则仿真近似算法

DS合成法则计算时间复杂度是影响DS理论广泛应用的主要原因之一,介绍了几种著名的近似算法,并分析了它们的优劣性,指出了这些方法的存在的问题。给出了两种新的仿真近似算法,这两种新方法不需要预先限定焦元的个数,计算过程直观、方便,结果合理。仿真试验结果表明,这两种方法的计算结果和Bayesian方法非常接近,但不存在Bayesian方法的不合理之处。对几种算法作了进一步分析研究,给出了三种算法间的关系。