纳米尖晶石LixMn2O4的制备与电化学性能表征

Nano-spinel Li_xMn₂O₄(0.6 ≤x≤ 1.0) was synthesized by two steps of coprecipitation and calcination. The influences of calcination temperature, time and Li/Mn ratio on the crystal structure and the particle size of Li_xMn₂O₄ were investigated. It was shown that the higher the calcination temperature, the more complete the crystal structure, and the larger the particle size. Moreover, the influence of calcination time on the crystal structure was insignificant when it was more than 3h at 700℃. With the increase of x in Li_xMn₂O₄ in the range of 0.6～1.0, the d111 and lattice parameter a increased first and then decreased. The electrochemical properties of nano-spinel LiMn₂O₄ using as cathode material of lithium-ion battery were studied. The low discharge capacity might be due to the irreversible capacity loss brought by the large surface area and lattice vacancies of the nano-spinel.     

The synthesis and crystal structure of metal complexes S-alkyl-N-(ferrocenyl-1-methyl-methylidene)-dithiocarbazate and the study on their quenching the luminescence ofruthenium(bipyridine)_~3(2+)

The cobalt, nickel, copper, zinc and cadmium complexes of S-methyl-N-(ferrocenyl-l-methyl-methylidene)-dithiocarbazate (H-LSM) and S-benzyl-N-(ferrocenyl-l-methyl-methylidene)-dithiocarbazate (H-LSB) were synthesized and the crystal structure of Cd[Fe-C(CH3) = NNCSS. (CH3)]2 was solved by X-ray diffraction. The crystal is in the orthorhombic system with space group Pbca, cell parameters a=19.741(3), b=19.924(5), c=15.452(4) A, and the final factors of R=0.032. The study on quenching the luminescence of Ru(bpy)3 by those complexes showed that bimolecular quenching constants obtained from the Stern-Vohner constant and the excited-state lifetime were related to the redox potential of the quencher. Linear relationship is shown in the plot of logkq vs. E1/2(Q+/Q). The main factor which influences the quenching rate constant and the redox potential is the coordinating ability of the metal in the complex.     

影响α-磷酸锆结晶度和生长形态的因素

采用HF络合法, 通过改进实验条件制得了α-磷酸锆(α-ZrP)微晶。讨论了HF/Zr比, P/Zr比, Zr浓度, 玻璃瓶质和反应温度等因素对α-ZrP结晶度和生长形态的影响。发现α-ZrP趋向于生成片状, 其片状最大外表面是α-ZrP的层板平面(001), 析晶速度的快慢影响该面的面积和厚度。d002, d110, d112衍射峰的相对衍射强度(XRD结果)与析晶速度有关并与晶体形状(SEM结果)存在着对应关系。     

Crystal Structure,Electrochemical Properties and Third-order Nonlinear Optical Response of 4-Methyloxy benzaldehyde Thiosemicarbazone and Its Copper(Ⅱ)Complex

Thecurrentsurgeofinterestinthefield0fnon-linearoptics(NL0)isderivedbothfromaquestforafundamentalunderstanding0fthenon-linearprocess,anditSimPortanceinthetechn0logyofphotonics.Amongnon-linearphen0mena,thethird-ordernon-linearophcsoccuPyanimPortantp0sihonbecauseitprovidesthemechanicsforophcalswitching,ophcallogic,andreal-hmeholograPhy"'.0rganicmaterialwithextendednconjugahonsandlargeRdelocalizahonsarewellknownastheimPortantmaterialsofachievinglargethird-ordernonlinearihes3.ForexamPle,thiosen…     

双核镍(Ⅱ)配合物的合成、晶体结构和磁性质

合成了通过N-N键桥联的不对称的N₂O₃席夫碱配体(H₃L)的镍(Ⅱ)配合物[Ni₂(HL)₂]₂(DMF)₈(H₂O)₂ (1)。配合物晶体属于三斜晶系，空间群为P1，a=1.273 5(2) nm，b=1.360 4(3) nm，c=1.427 6(3) nm，α=85.358(4)°，β=63.513(3)°，γ=79.545(4)°，V=2.176 8(7) nm³，Z=1，F(000)=980，R₁=0.073 6。配合物1的不对称单元中含有两个双核结构Ni₂(HL)₂(DMF)₂(H₂O)₂ (Ⅰ)和Ni₂(HL)₂(DMF)₄ (Ⅱ)以及两个DMF溶剂分子。通过酚基氧原子桥联的镍-镍距离分别为：Ni(1)-Ni(1A)，0.308 4 nm；Ni(2)-Ni(2B)，0.310 3 nm(对称操作：A：1-x，2-y，-z；B：1-x，1-y，1-z)。金属镍(Ⅱ)离子采取扭曲的八面体配位构型，一个配体的NO₂三齿配位单元和另一个配体的酚基氧原子位于赤道面位置，两个溶剂分子占据轴向位置。晶体中存在着分子内以及分子与溶剂分子间的两种氢键作用。配合物1的变温磁化率测定表明，Ni(Ⅱ)离子之间的反铁磁耦合作用在它的磁性质中起主导作用。     

MATLAB在化学计量学中的应用

化学计量学是数学和统计学，化学及计算机科学相互交叉形成的一门新的化学分支学科，是解决化学问题的强有力工具，目前运用于化学计量学的商品软件有MATLAB、Maple,MathCAD,EXCEL,SPSS等。MATLAB是一种高性能的数值计算的科学计算语言，具有程序开发环境简洁直观，数值稳定性好，函数资源丰富的特点，本文以几种常用的化学计量学方法为例，讨论了MATLAB在化学中的应用。     

聚己内酯－聚乙二醇嵌段共聚物Ⅱ．组成、结晶性同降解性间关系

采用ＤＣＳ法测定了新嵌段共聚物聚己内酯－聚乙二醇嵌段共聚物的结晶性，研究了共聚物的结晶性同组成及降解性的关系。结果表明随着共聚物中ＰＥＧ组分的含量和分子量增加，共聚物的结晶性下降，亲水性提高，降解速度加快。     

Two New Sesquiterpenes from Eupatorium lindleyanum

Various germacrane sesquiterpenes have been isolated from many species of the Eupatorium.In recent years these compounds have been increasing interest due to their insecticidal,cytotoxic,antitumor-promoting and insect-antifeedant activities1.In our present study,we have investigated the chemical constituents of Eupatorium lindleyanum DC.,which is a geo-authentic medicine of Jiangsu province.It is used as a antipyretic drug.Two novel germacrane sesquiterpenes(Figure1)were found by us from th…     

合成天然产物曲古抑菌素A的新方法

报道了一条组蛋白去乙酰化酶抑制剂曲古抑菌素A的有效合成路线. 通过L-脯氨酸催化对硝基苯甲醛与丙醛的羟醛缩合反应, 高立体选择性地构建了目标分子的手性中心, 羟醛缩合产物的ee值大于99%, anti∶syn＝16∶1. 随后的合成过程中无消旋化现象, 合成的曲古抑菌素A是单一R型异构体, ee值大于99%.     

双核三螺旋铁配合物的合成和结构

本文选择了2-羟基-1-萘醛与水合肼形成的席夫碱,[(HO)(C₁₀H₆)CH=N-N=CH(C₁₀H₆)(OH)],作为配体,设计组装了双核三螺旋的三价铁配合物。配合物中每一个铁离子以准八面体的配位方式分别与三个NO双齿单元配位, 三个配体分别桥联两个金属形成特定的三螺旋构型。分子内和分子间的π-π堆积作用对螺旋体的形成和堆积方式起着十分重要的作用。作为对照,本文还报道了配体的晶体结构。