Theoretical Study on the Structures and Stability of Isomers and Complex of[Si,C,O,O] Sytem

A detailed singlet potential energy surface(PES) of [Si,C,O,O] system including a van der Waals (vdW) comples SiO……CO2,eight isomers,and twelve transiton states is investigated by MP2 and QCISD(T) (single-point)methods.At the final QCISD(T)/6-311 G(2df)//MP2/6-311G(d) level with zero-point energy included,the complex SiO……CO is found to be thermodynamically and kinetically the most stable species.Although eight ismoers are located as local energy minima,they are rather unstable toward isomerization to the dissociation fragments or comples.For the reaction of silocon atoms with carbon dioxide,two competitive reaction channels are found,and the primary pathway,which leads to the products of SiO and CO fragments,is the direct oxygen-abstraction process from carbon dioxide by silicon atom with a41.16 kJ/mol reaction barrier height.Our predications are in good agreement with previous experimental and theoretical studies.     

Investigation of Isomerization of 2—Seleno—1,3,2—diazaphospholidine Derivatives

For the first time the isomerization of 1,3,2-diazaphospholidine-2-sclenide dervatives in refluxing benzene in the presence of trace water was observed. The structures of isomerized products were determined by IR, ^1H NMR,^31P NMR, elemental analysis and X-ray crystallography. The mechanism of isomerization was also proposed.     

几种卟啉在化学还原沉积银膜上的表面增强拉曼光谱特征

应用 Ｊｏｂｉｎ－Ｙｖｏｎ Ｕ—１０００型拉曼光谱仪和ＬＡＢＲＡＭＩ型拉曼光谱系统研究了 ３种卟啉ＴＯＨＰＰ、ＴａｍＰＰ和ＴＳＰＰ在化学还原沉积法制备的银膜上的ＲＳ和ＳＥＲＳ光谱特征。结果表明：化学还原法制备的银膜可以作为这几种卟啉的拉曼增强活性载体。这３种卟啉在获谱的过程中都形成二聚态化合物和发生银离子搀和作用，较长的放置和测谱时间有利于银离子的搀和。     

A NEW ONE-STEP REDUCTIVE N-ALKYLATION OF AMINO ACIDS AND THEIR ESTERS

The reductive alkylation of amine with carbonyl compounds usingsodium hydrogen telluride has been investigated in recent years.Application of this method to the synthesis of N-alkyl derivativesof biologically important amino acids and their esters is described.     

水杨酸与烟草铜锌超氧化物歧化酶的相互作用

利用邻苯三酚自氧化法监测了磷酸盐缓冲体系中水杨酸（SA）对超氧化物歧化酶（SOD）活力的影响。通过荧光光谱法研究了水杨酸与超氧化物歧化酶的相互作用机制，求得两者结合的形成常数和配位数，使用Forster非辐射能量转移技术求出了两者的结合位置距色氨酸残基间的距离为2.60nm。     

A New β-Carboline Alkaloid and a New Derivate of Isoferulic Acid from Anemone altaica

A new β-carboline alkaloid, 4-（9H-β-carbolin-1-yl）-4-oxobutyric acid and a new derivate of isoferulic acid, （E）-3-（3-hydroxy-4-methoxyphenyl）acrylic acid carboxymethyl ester, were isolated from the roots of Anemone altaica. Their structures were determined on the basis of spectral data.     

Influence of neutral cyclodextrin concentration on plate numbers in capillary electrophoresis

A quantitative theory of plate number N in capillary electrophoresis was developed for buffers containing neutral cyclodextrins (CDs) capable of forming inclusion complexes. In the theory, N was modeled by longitudinal diffusion, injection extent, width of the detection window, and the detector time constant. The apparent mobility was modeled as a weighted sum of the mobilities of the free-solution analyte and the inclusion complex. The apparent diffusion coefficient was modeled as a similarly weighted sum. Both the apparent mobility and diffusion coefficient were corrected by functions that compensated for increases of buffer temperature caused by Joule heat. The experimental N's and apparent mobilities of neutral thiourea and of the anions, dansyl D- and L-leucine, dansyl D- and L-aspartic acid, benzoate, and 4-nitrophenolate, were determined in buffers containing from 0 to 15 mM beta-CD. The binding constants, and mobilities and diffusion coefficients of the free-solution analyte and inclusion complex, were calculated as regression coefficients by fitting theory to these determinations. The regression coefficients were shown to have physicochemical meaning, as assessed by literature values, independent measurements, and theoretical predictions. The assessment showed the Nernst-Einstein equation does not relate mobilities and diffusion coefficients at the electrolyte concentration used. The interdependence of mobilities, diffusion coefficients, binding constants, and other dispersion sources was interpreted to evaluate the factors affecting the variation of N with CD concentration. From the interpretation, an approximate equation for N in low-concentration CD buffers was derived. The equation depends on free-solution and inclusion-complex mobilities and diffusion coefficients, the binding constant, the potential difference over the effective capillary length, and the number of plates in a CD-free buffer.     

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…     

酶联免疫吸附法直接测定血清雌二醇

本合成了３种不同载体蛋白的雌二醇抗原，研究了载体蛋白免疫原性对雌二醇抗体产生的影响。应用酶联免疫吸附分析法测定了血清中雌二醇，浓度范围为５－１６０ｎｇ／ｍｌ（１．８×１０＾－＾８－５．９×１０＾－＾７ｍｏｌ／Ｌ）．ＲＳＤ％小于１０．％，检测限为１．９７ｎｇ／ｍｌ，相当于９８．５ｐｇ／孔（按空白平均值的二倍标准偏差计算）。另外，本还建立了一种用考马斯亮蓝Ｇ－２５０测定半抗原与蛋白结合比的方法，提     

富勒烯四甲氧基衍生物的合成与表征

富勒烯四甲氧基衍生物的合成与表征甘良兵，周胜，姜剑峰，黄春辉（北京大学化学与分子工程学院，北京，１００８７１）武轶，吕木坚，潘景歧（北京微量化学研究所）（北京大学分析测试中心）关键词Ｃ＿６０衍生物，甲氧基，四氮杂环十二烷富勒烯化学是目前人们研究的热门...