检索结果-南通市图书馆

Studies on New Additions to 5-Methoxy-2 (5H)-Furanone: 1, 4-Addition of Grignard Reagents, and 1,3-Dipolar Cycloaddition of Silyl Nitronates

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第4期12卷 293-296页

作者： Zhao Yang WANG Jia Ling CUI Bao Shan DU Qing Hua CHEN Department of Chemistry Beijing Normal UniversityBeijing 100875 Dept.of Chem. South China Nor.UnivGuangzhou 510631 Present address:School of Pharm. Beijing UnivBeijing 100033

1,4-Addition reaction of Grignard's reagent to 5-methoxy-2(5H)-furanone 1 was accomplished. which provided a new possible route for synthesizing beta -alkyl-Y-alkyloxy-Y-butyrolactone. A novel concise method of prepar... 详细信息

关键词： Michael addition Grignard reagent 1 3-dipolar cycloaddition silyl nitronates.

QSAR Studies on 7-Substituted Fluoroquinolones

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2007年第1期26卷 91-97页

作者：许菊丽高树林张向飞谢异萍黄晓因谢小光 Department of Chemistry Yunnan University Computer Science Department Yunnan Agricultural University

The PM3 and B3LYP methods were employed to calculate the properties of 18 7-substituted fluoroquinolones. The correlation between biological activity （against gram-positive organisms or gram-negative organisms） and structural properties was obtained by using multiple linear regression （MLR） methods： The best model generated correlates the antibacterial activity with EHOMO and QF8 for gram-positive organisms, and EHOMO and dipole moment for gram-negative organisms, respectively. It suggests that the interaction mechanisms ,of fluoroquinolons with gram-positive and gram-negative organisms are different.

关键词： qsar fluoroquinolones gram-positive organisms gram-negative organisms

Photocatalytic Dye Methyl Orange Decomposition on Ternary Sulfide (CdIn2S4) under Visible-light

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2005年第9期16卷 1259-1262页

作者： Xiao Dan YU Xue Song QU Yi Hang GUO Chang Wen HU Faculty of Chemistry Northeast Normal University Changchun 130024 Department of Chemistry Beijing Institute of Technology Beijing 100081

A novel and efficient photocatalyst, CdIn2S4, was simply prepared by a programmed temperature hydrothermal method. The product had a nanometer size （10-15 nm） and strong absorption in the range of 200 to 580 nm, and... 详细信息

关键词： Ternary sulfides hydrothermal treatment visible-light photocatalysis methyl orange

A GEOMETRIC THEORY IN INVESTIGATION ON MODE LOCALIZATION AND FREQUENCY LOCI VEERING PHENOMENA

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1995年第4期8卷 349-355页

作者： Liu, JK Zhao, LC Fang, T NORTHWESTERN POLYTECH UNIV XIAN 710072PEOPLES R CHINA

According to the mapping theory in complex plane, the geometric features of eigen frequency loci of systems undergoing free vibrations are investigated. It is concluded that the phenomena of curve coalescence and veering can be described in a unified manner from the singularities of mapping from the complex parameter plane onto the complex frequency plane. The formation of a branch point in the parameter Space is the foundation of explaining localization and veering phenomena. By the use of condensation to reduce the dimension of a system, the scope of application of the geometric theory is widely expanded. The theory is applied to examples to verify the validity of the proposed approach. The present work is an improvement and extension of recent work by M. S. Traintafyllou et al..

关键词： complex plane mapping mode localization frequency loci veering condensation

Structure and Aromaticity of AlCO-substituted Semibullvalene

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2007年第8期26卷 897-901页

作者： YAO Wen-Zhi WU Hai-Shun Chemistry and Material Science Institute Shanxi Normal University Linfen 041004 China

The structures, energies and aromaticity （the nuclear-independent chemical shifts,NICS） of AlCO-substituted semibullvalenes were investigated at the B3LYP/6-311＋G＊＊ *** to BCO-substituted analogues, [2,6]-AlCO-semibullvalene is neutral *** NICS values reveal that the aromaticity of AlCO-substituted structures is smaller than that of BCO analogues.

关键词： DFT semibullvalene AlCO aromaticity

Synthesis and Crystal Structure of Bis(barbiturato)triwater Complex of Copper(Ⅱ)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2003年第3期22卷 270-274页

作者：杨文斌卢灿忠吴传德吴鼎铭卢绍芳庄鸿辉 State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter The Chinese Academy of Sciences Fuzhou Fujian 350002 China

The crystal structure of the bis(barbiturato)triwater copper(Ⅱ) complex formulated as Cu(barb)2(HO2)3 (barb = barbiturato) has been determined by single-crystal X-ray diffraction. The analysis was carried out by direct and Fourier methods and the structure was refined by full-matrix least-square computations. The title compound crystallizes in orthorhombic, space group Fdd2 with a = 11.691(1), b = 30.200(4), c = 7.1901(9) , V = 2538.7(5) 3, Z = 8, C8H12CuN4O9, Mr = 371.76, Dc = 1.945 g/cm3, m(MoKa) = 1.781 mm-1, F(000) = 1512, the final R = 0.0347 and wR = 0.0766 for 827 observed reflections (I > 2s(I)). The copper atom is square- pyramidally bonded to the exocyclic oxygen atoms of the barbital anions (CuO, 1.976(3)) and the water molecules (CuO, 1.926(4) and 2.164(7) ?. The molecules are held together to form an extensive three-dimensional network via OH贩稯 and NH贩稯 hydrogen-bonded contacts.

关键词： barbital complexes copper (Ⅱ) complex crystal structure

Entry into Major Groups Retaining Taxol via Sinenxan A

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2002年第2期13卷 135-138页

作者： Meng ZHANG Da Li YIN Ji Yu GUO Xiao Tian LIANG Institute of Materia Medica Chinese Academy of Medical Science&Peking Union Medical CollegeBeijing 100050

Compound 1 as a key intermediate of 1, 7, 9-trideoxytaxol was synthesized in ten steps from a biosynthetically available taxane, Sinenxan A. The key steps in the synthesis were deoxygenation at C-14, allylic oxidatio... 详细信息

关键词： Taxol Sinenxan A deoxygenation.

THIRD ORDER NONLINEAR OPTICAL PROPERTIES OF PERNIGRANILINE SOLUTION IN CONCENTRATED SULFURIC ACID

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 1996年第1期14卷 80-85页

作者：万梅香李明米辛姜谦叶佩弦 Institute of Chemistry Academia Sinica Beijing 100080 Institute of Physics Academia Sinica Beijing 100080

The fully oxidized state of polyaniline (PANI), pernigraniline (PN), was synthesized by oxidation of the emeraldine base form of PAM dissolved in NMP solvent with m-chloroperoxybenzoic acid. The resulted PN was characterized by FTIR and UV-Visible spectra. The third-order nonlinear optical properties of PN in concentrated sulfuric acid (PN/H2SO4) were measured by a degenerated four wave mixing (DFWM) method. The results obtained suggest that the soliton-pair intermediate state associated with the degenerated state does not play a major role in the third order nonlinear optical properties of PANI.

关键词： polyaniline pernigraniline degenerated four waves mixing (DFWM) third-order nonlinear optical properties

Theoretical Study on the Di-, Tri- and Tetra-cage Coplanar Cubane

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2004年第7期23卷 768-772页

作者：刘奉岭王海燕于淑媛李怀祥 Department of Chemistry Shandong Normal UniversityJinan 250014China

The di-, tri- and tetra-cage coplanar cubanes have been studied at B3LYP/D95** and MP2/D95** levels, and their vibrational frequencies have been calculated at B3LYP/D95** level. All of these species have no imaginary vibrational frequency, so that each of the molecules is a mini- mum at the potential energy hypersurface. Many properties of the molecules, such as geometries, heats of formation and the first ionization potentials, have been studied in this paper.

关键词：二笼立方烷三笼立方烷四笼立方烷量子化学振动频率几何构型