检索结果-南通市图书馆

Molecular modeling and spectroscopic studies on the binding of guaiacol to human immunoglobulin

Science china chemistry 2006年第6期49卷 550-559页

作者： HE Wenying1,2. YAO Xiaojun1, LIU Pengjun2. GAO Zhenxia2.& HU Zhide1 1. department of chemistry, Lanzhou {2., Lanzhou 730000, china 2. department of chemistry, hainan normal university, hainan 571158, china 1. department of chemistry Lanzhou University Lanzhou 730000 China 2. department of chemistry Hainan Normal University Hainan 571158 China

The fluorogenic property of guaiacol was exploited for the first time to analyze the interaction with target protein as a probe by molecular modeling, fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy. Molecular docking was performed to reveal the possible binding mode or mechanism and suggested that guaiacol can strongly bind to human immu- noglobulin (HIgG). It is considered that guaiacol binds to HIgG mainly by a hydrophobic interaction and there are two hydrogen bond interactions between the drug and the residues LEU 80 and ASP 65, which is in good agreement with the results from the experimental thermodynamic parameters (the enthalpy change △H0 and the entropy change △S0 were calculated to be 65.55 kJ·mol-1 and 132.95 J·mol-1·K-1 according to the Vant’ Hoff equation). Data obtained by the fluorescence spectroscopy indicated that binding of guaiacol with HIgG leads to dramatic enhancement in the fluorescence emission intensity along with significant occurrence of efficient Frster resonance energy transfer (FRET) from the residue of HIgG to the protein bound guaiacol. From the low value of fluorescence anisotropy (r = 0.06), it is argued that the probe molecule is located in the motionally unrestricted environment of the protein. The alterations of protein’s secondary structure in the presence of guaiacol in aqueous solution were quantitatively calculated by the evidences from FT-IR and CD spectroscopes.

关键词： guaiacol, human immunoglobulin, molecular modeling, fluorescence enhancement, Fourier transform infrared (FT-IR) spectroscopy, circular dichroism (CD).

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Preparation of CaS:Eu^(2.) Phosphor by Microwave Heating Method and its Luminescence

引用

Chinese Chemical Letters 2000年第9期11卷 843-846页

作者： Peng Jun LIU Ying Liang LIU department of chemistry, Jinan {2., Guangzhou 510632.department of chemistry, hainan normal College, Haikou 571158 Jinan Univ Dept Chem Guangzhou 510632 Peoples R China hainan normal Coll Dept Chem Haikou 571158 Peoples R China

This is the first report of using the microwave heating technique to synthesize calcium sulphide activated by europium whose structure is determined as the face-centered cubic by conventional X-ray powder diffraction method. The phosphor has maximum excitation peaks located at 2.0 urn and 560 urn and the maximum emission of the phosphor is 630 nm. When the concentration of Eu^(2.) in CaS increases from I .0 × 10^(-5) to l.0 × 10^(-2. mole per mole host, the body colour of the calcium sulphide activated with europium changes from white, through light-red to pink to deep-red. The phosphor obtains the longest afterglow at the concentration of 0.1% Eu^(2.)doped and is a kind of good material excited by sunlight.

关键词： Microwave radiation heating calcium sulphide europium luminescence.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A local spin evaluation into the active site models of [2.e2.] ferrodoxin [Fe_2._2.SR)_4]^(2.) (R=-H, -CH_3)

引用

Science china chemistry 2007年第3期50卷 327-334页

作者： WEI JiChong1,2. WANG Yan3 & JU GuanZhi2.3 1 department of chemistry,{2., Haikou 571158, china 2.State Key Laboratory of Theoretical and Computational chemistry, Jilin university, Changchun 13002., china 3 department of chemistry, Nanjing university, Nanjing 2.0093, china 1. department of chemistry Hainan Normal University Haikou 571158 China 2. State Key Laboratory of Theoretical and Computational chemistry Jilin University Changchun 130023 China 3. department of chemistry Nanjing University Nanjing 210093 China

To test the feasibility of local spin theory of Davidson and Clark for ferrodoxin clusters, the models [Fe2.2.SR)4]2. (R=-H, -CH3) are chosen for evaluation. This purpose is realized by calculating the local spin expectation values , 2.>, and mA and discussing the connection between these expected values and the Heisenberg spin model (HSM) and the Noodleman broken-symmetry approach. In practical calculation, the spin-unrestricted Hartree-Fock (UHF) and spin-polarized density functional theory (DFT) are used and the calculational qualities of these two methods are also discussed. In addition, the theoretical magnetic coupling constants JAB of these models are calculated by various computational schemes for comparison with both theoretical and experimental results previously reported.

关键词： local spin iron-sulfur protein model density function theory magnetic coupling constant

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

引用

Science china chemistry 2006年第4期49卷 296-307页

作者： LI Ming1, ZHENG Wenxu2.& TIAN Anmin2.1. department of chemistry, Southwest-{2. normal university, Chongqing 400715, china 2. department of chemistry, Sichuan university, Chengdu 610064, china 1. department of chemistry Southwest-China Normal University Chongqing 400715 China 2. department of chemistry Sichuan University Chengdu 610064 China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Nitrogen Ion Implantation on the Structure and Corrosion Resistance of Equiatomic NiTi Shape Memory Alloy

引用

Journal of Wuhan university of Technology(Materials Science) 2006年第4期21卷 36-39页

作者：华英杰 department of chemistry Hainan Normal University Haikou 571158China

To protect the surface of NiTi from corrosion, an ion implantation method was proposed. In the present work, a surface oxidized sample was implanted with nitrogen at energy of 100 keV. The corrosion resistarwe property was examined by the anodic polarization method in a simulated body fluid （SBF） at a temperature of 37 ℃ and contrasted to non-implanted NiTi samples. The composition and structure of the implanted layers were investigated by XPS. The experimental results from the electrochemical measurements provide an evidence that the nitrogen ion-implantation increases the corrosion resistance of NiTi shape memory alloy.

关键词： biocompatibility NiTi shape memory alloy ion implantation corrosion resistance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

引用

Science china chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1,2. ZHAO Hongmei1 & LI Zonghe1 1. department of chemistry, Beijing {2. university, Beijing 100875, china 2. department of chemistry, Qujing {2. College, Qujing 655000, china 1. department of chemistry Beijing Normal University 100875 Beijing China 2. department of chemistry Qujing Normal College 655000 Qujing China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1 method with partial optimization, the density function theory B3LYP/6-311G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2.CN)C─ N=N─ C(CN)Me2. 2.e2.CN)C?+N2.is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2.CN)CN=N─C(CN)Me2.? Me2.CN)CN=N?+ Me2.CN)C?? Me2.CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2.CN)C?radical as well as N2.molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Approach to synthesis of novel chiral 3-chloro-2.5H)- furanone and its application in asymmetric reactions

引用

Chinese Science Bulletin 2000年第8期45卷 711-716页

作者： HUANG Hui & CHEN Qinghua1. department of chemistry, Tonghua Teacher’s College, Tonghua 134002.{2. 2. department of chemistry, Beijing normal university, Beijing 100875,{2. department of chemistry Tonghua Teacher’s College Tonghua China department of chemistry Beijing Normal University Beijing China

The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3-chloro-2.(5H)-furanone 5a and its application in asymmetric reactions were investigated. 5a is easily obtained in highly optical purity, and acts as a stable acceptor of Michael addition with oxygen nucleophiles in tandem double Michael addition / internal nucieophilic substitution to offer the spiro-cyclopropane derivative containing four stereogenic centers 8, which it is difficult to obtain by routine methods. The synthetic methods for 5a and 8 are reported in detail and the new compounds are identified on the basis of their analytical data and spectroscopic data, such as UV, IR, H NMR,13 C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes, spiro [1-chloro-4-(/-menthyloxy)-5-oxo-6-oxa-biscyclo[3.1.0]hexane-2.3i(4’-/-menthyloxy-5’-/-menthyloxy- butyrolactone)] 8 was established by X-ray crystallography. This result can provide important synthetic strategy in synthesis of some complex

关键词： new chiral synthon. 5-l-menthyloxy-3-chloro-2.(5H)-furanone absolute configuration spiro-cyclopropane derivative containing multiple chiral centers.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Theoretical study on the reaction mechanism of (CH3)3CO(.) radical with NO

引用

Science china chemistry 2004年第4期47卷 289-294页

作者： ZHAO Hongmei1,2. LIU Kun1, SUN Chengke1 & LI Zonghe1 1. department of chemistry, Beijing {2. university, Beijing 100875, china 2. department of chemistry, Beihua university, Jilin 132.13, china 1. department of chemistry Beijing Normal University 100875 Beijing China 2. department of chemistry Beihua University 132013 Jilin China

The reaction mechanism of (CH3)3CO? radical with NO is theoretically investigated at the B3LYP/6-31G* level. The results show that the reaction is multi-channel in the single state and triplet state. The potential energy surfaces of reaction paths in the single state are lower than that in the triple state. The balance reaction: (CH3)3CONO(CH3)3CO?+NO, whose potential energy surface is the lowest in all the reaction paths, makes the probability of measuring (CH3)3CO? radical increase. So NO may be considered as a stabilizing reagent for the (CH3)3CO? radical.

关键词： (CH3)3CO. radical DFT reaction mechanism NO

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Progress in the study of molecular organized assemblies by dielectric relaxation spectroscopy

引用

Progress in Natural Science:Materials International 2006年第3期16卷 221-230页

作者： ZHAO Kongshuang, HE Kejuan and WEI Suxiang (department of chemistry, Beijing {2. university, Beijing 100875, china department of chemistry, South china {2. university, Guangzhou 510631, china) [a]department of chemistry Beijing Normal University Beijing China [b]department of chemistry South China Normal University Guangzhou China

Because dielectric spectroscopy covers a great many problems in physical and chemical systems occurring in an extremely wide frequency range, the study of this method plays an important role in physical chemistry. As an effective tool to detect inner properties of substance systems, the dielectric spectroscopy method is widely used in chemical systems and has been dramatically developed in recent decade. This review paper describes the applications of the dielectric spectroscopy in the chemical field, and main concentrations are focused on the micelle, microemulsion and other so-called molecular organized assemblies. Some dielectric principles and models proposed for these systems are introduced. In addition, recent technical developments in dielectric spectroscopy and developing trend of this method in other chemical systems are reviewed.

关键词： dielectric relaxation micelle microemulsion vesicle relaxation time.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Synthesis and Crystal Structure of CoCl(ieaa)(C_(10)H_7-ieai)(C_(10)H_7NH_2.

引用

Chinese Journal of Structural chemistry 2002年第1期21卷 22-25页

作者： FENG Yun-Long (department of chemistry, Zhejiang {2. university Jinhua 2.1004,china) department of chemistry Zhejiang Normal University Jinhua 231004

The title complex CoCl(ieaa)(C10H7-ieai)(C10H7NH2., C32.32.lCoN4O7, Mr= 679.00; (ieaa- and C10H7-ieai- are the anions of isonitrosoethylacetoacetate and its N-a- naphthylamine derivative of Schiff base, respectively, C10H7NH2.is a-naphthylamine), crystallizes in the monoclinic system, space group P2./n with a=11.846(2., b=2..912.5), c=12.783(3)? b=116.54(3), V=32.9(1)?, Dc=1.392./cm3, F(000)=1408, Mr=679.00, m(MoKa)=0.665mm-1, Z=4, final R=0.0584 and wR=0.1388 for 4177 observed reflections (I ≥ 2.(I)). A nitrogen atom of the ieaa- ligand and two nitrogen atoms of the C10H7-ieai- ligand define one of the triangular faces in the distorted octahedral geometry about the cobalt atom. The title complex contains isonitroso-b-ketoimine.

关键词： cobalt complex isonitroso-b-ketoimine Schiff base crystal structure

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：