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1.
4,6—二硝基苯并氧化呋咱的合成   总被引:1,自引:0,他引:1  
王乃兴  李纪生 《合成化学》1995,3(3):260-262
采用新的合成方法,以苦基氯为原料,经过叠氮化和脱氮环化反应,合成了苯并氧化呋咱化合物。对其结构作了理论分析和实验鉴定,认为该化合物具有杂芳结构。  相似文献   

2.
基于所获的受体光合作用D1蛋白结构模型,运用生物合理设计方法,设计并合成了保留氰基丙烯酸酯类化合物基本结构框架的标题化合物,对所合成的化合物进行了光合作用希尔反应抑制活性的初步测试,结果表明,部分化合物显示出一定的活性。  相似文献   

3.
二茂铁甲氨基烷氧基硅烷的合成与水敏感性研究   总被引:7,自引:0,他引:7  
以二茂铁甲氨基醇与氯硅烷反应,合成了12种二茂铁甲氨基烷氧基硅烷,研究了该化合物的合成方法,水敏感性与结构的关系,并由元素分析,红外光谱和核磁共振氢谱鉴定了化合物的结构。  相似文献   

4.
基于包获的受体光合作用D1蛋白结构模型,运用生物合理设计方法,设计并合成了保留氰基丙烯酸酯类化合物基本结构框架的标题化合物,对所合成的化合物进行了光合作用希尔反应抑制活性的初步测试,结果表明,部分化合物显示出一定的活性。  相似文献   

5.
杂氮硅三环是一类分子内具有N→Si配位键的化合物,作者曾报道了一系列该类化合物的合成方法和化学结构。对于一个分子内带两个对称的硅三环结构的双一杂氮硅三环化合物的合成,文献报道还很少啪。我们用下  相似文献   

6.
15种1,3-氧硫杂环戊烷类香料化合物的合成   总被引:10,自引:0,他引:10  
以对甲苯磺酸为催化剂,巯基乙醇分别与羰基化合物在苯中共沸脱水,合成了15种1,3-氧硫杂环戊烷类香料化合物,经IR、GC-MS和^1H NMR分析,确证了产物结构。此合成方法简便易行。  相似文献   

7.
对α-唑基-α-芳氧烷基频哪酮及其醇式衍生物的合成和生物生进行了研究,合成了33个新型化合物,所有化合物的结构均经核磁共振和元素分析证实;初步的生物活性测试结果表明,该类化合物具有一定的杀菌活性和植物生长调节活性。  相似文献   

8.
对α-唑基-α-芳氧烷基频哪酮(芳乙酮)及其醇式衍生物的合成和生物活性进行了研究,合成了33个新型化合物,所有化合物的结构均经核磁共振和元素分析证实;初步的生物活性测试结果表明,该类化合物具有一定的杀菌活性和植物生长调节活性.  相似文献   

9.
合成了17个在结构上具有一定递变规律的新磺酰脲类化合物,经元素分析、 ̄1HNMR和IR确定了其结构。讨论了该类化合物的分子及晶体结构特征。测定了所合成化合物的除草活性,并讨论了活性规律。  相似文献   

10.
本文通过两种路线合成了十个新的五员和六员环烯烃并吡咯类化合物,讨论了化合物8的合成途径和分子结构。  相似文献   

11.
The adsorption and dissociation of hydrogen on stepped surface (511) of nickel are studied with the embedded-atom model (EAM) method. The adsorption energy, the length of the adsorption bond and the adsorption height for a single hydrogen atom are calculated. Three kinds of stable sites are found for hydrogen adsorption. There are the double-fold bridge site B on the step edge, the three-fold hollow site H3′ on the step surface and the four-fold hollow sites H1 and H2 on the terrace surface. Compared with a hydrogen atom adsorbed on low-index (001) surface, there are two other adsorption sites near the step: the two-fold bridge site B on the step edge and the three-fold hollow site H3′ on the step surface. At the same time, the absorbability of the hydrogen atom at the site H1 is intensified. The results show that hydrogen adsorption on Ni (511) is affected by the existence of the step. The active barriers, adsorption energy and corresponding bond length for dissociation of a hydrogen molecule on the stepped surface are presented. The results show that the dissociation is easier at the bottom of the step. It is shown that the steps are the active sites for hydrogen adsorption and dissociation.  相似文献   

12.
A class of excitable media described by the Fitzhugh-Nagumo equation is investigated. Based on the stable and self adaptive theory, the error between the systems grid variables and the standard sampling of the periodical signal or constant signal was feed back into the system both globally and locally. When the controller was then shut off, automatically, the whole system became homogeneous. Additionally, the scheme was tested under noisy conditions. The numerical simulations results demonstrate its effectiveness. The system reached a homogeneous state and a spiral wave was converted into a target wave, resulting in a wonderful pattern emerging using a different controller. The scheme proved robust in resisting the effects of noise.  相似文献   

13.
为从分子水平认识多糖分子与小分子之间相互作用的机理,应用光谱法研究了壳聚糖(CTS)与锌试剂(ZCN)的相互作用机理;测得ZCN-CTS复合物吸收光谱出现新的吸收峰所需的临界ZCN/CTS摩尔比为2.67×103, CTS对ZCN的最大结合数为6.93×103,实验值与理论值相吻合,证明了多糖与生物探针相互作用理论模型的可靠性;探讨了ZCN与CTS相互作用产生变色反应的机理,认为其是在ZCN与CTS大分子间发生静电相互作用的基础上,主要由ZCN与CTS大分子间的疏水相互作用所引起.  相似文献   

14.
TiO2膜光催化剂的改进及表征   总被引:4,自引:0,他引:4  
提出用粉末-溶胶法制备TiO2薄膜型光催化剂,介绍了粉溶法的制备工艺及改变pH值对催化活性的影响.研究结果表明, 利用粉溶法或添加浓HNO3后制备的TiO2薄膜光催化剂表现出了较高的光催化活性.结合结构表征详细分析了其中的原因.认为粉溶法制备的催化剂表面更粗糙,比表面积增大,膜厚度减小,这些都可能是其催化活性提高的原因.而加酸后膜催化活性提高主要是因为酸性条件下表面几乎没有Ti3+表面态,利于光生电子与光生空穴的分离.  相似文献   

15.
The static polarizabilities and polarizability anisotropies of Cun,Agn and Aun (n≤9)clusters have been calculated by the B3LYP density functional method,which is a three parameter mixture of density functional and"exact" Hartree Fock exchange. The calculated results are compared with experimental polarizabilities of sodium clusters. It is shown that the size dependency of the static polarizabilities per atom of Cun,and Agn clusters possesses the same trend as that observed in sodium clusters exception of the Aunclusters while the polarizability of Au atom is much smaller than these of Cu and Ag.The(α-)of Au atom is the smallest and the(α-)per atom of Au approach to the values of Cu from the dimmer to the hexamer. It indicates that in Au clusters the electrons are more strongly attracted by the nuclei because of the more electrons. However,the absolute polarizabilities of the noble mental clusters are considerably smaller than those of the sodium clusters and the electronic structures of the noblemental are much more compact.  相似文献   

16.
Experimental data are presented for the solubility in water of benzoic and toluic acids from 5° to 65°C. From the solubility the molality of the monomeric form of the acid is calculated using literature data for both ionization and dimerization of the acid. These data for the monomer combined with data from the literature for vaporization of the solid and ionization in both the gas phase and the aqueous phase yield entropy and enthalpy changes for the solvation of molecular and anionic forms of the acid. A similar procedure is also applied to literature data for the solubility of benzene in water. It is shown that the hydration entropies of the monomeric forms are a linear function of their partial molar volumes. It is concluded that hydration of the undissociated o-toluic acid may be crucial to the increased acidity of that acid compared to benzoic acid.  相似文献   

17.
Using CD-measurements the influence of nonionic surfactants (dodecyl polyoxyethylene, ethoxylated para tert. octyl phenol, commercial nonionic WON 100 and octyl diethyl phosphinoxid) on the secondary structure of gelatin in aqueous solutions was investigated. At surfactant concentrations smaller than the c.m.c. the triple helical content of the gelatin is increased. At concentrations exceeding the c.m.c. the triple helical content decreases. Chain reversals of the peptide chains after the destruction of the triple helical structure were shown to appear in acidic environment at 298 K. This destruction is reversible by rechilling the solution.  相似文献   

18.
Theoretical studies on the α- and β-forms nitroguanidine were carried out using ab initio theoretical methods, at the MP2/6-31G(d,p) level. The predicted geometrical parameters were in good agreement with the available theoretical values, which calculated by other author. The three C-N bond lengths in α-form nitroguanidine were different, the longest bond length was 1.430 A, the shortest was 1.283 A. But they were almost similar in β-form, the longest was 1.375 A, the shortest was 1.322 A. Therefore there were conjugative effects in β-form but not in α-form. The calculated results also show that the β-form is stable with respect to the α-form from energetically, lower 28.16 kJ/mol corrected with zero point vibrational energy. The transition-state for the unimolecular isomerization was conformed by the IRC calculation. The calculated energy barrier for the direct intramolecular hydrogen atom transfer isomerization process was 132.95 kJ/mol. The isomerization reaction, exothermal reaction, is a typical intramolecular hydrogen atom synfacial transfer reaction. Rate constants of the isomerization reaction were evaluated within the temperature range of 200-1773 K by the classical transition state theory. The rate constant was 1.99×10-11 s-1 and the equilibrium constant was 1.00×105 at 298 K. With the temperature increasing, the equilibrium value decayed and the reaction process was more difficult.  相似文献   

19.
Gas-phase metal ion affinities and optimized structures of RNA nucleic acid bases for the Ca+ were determined at a density functional level employing the hybrid B3LYP exchange correlation potential in connection with the 6-311+G(2df,2p) basis set. All the molecular complexes, obtained by the interaction between several low-lying tautomers of RNA nucleic acid and Ca+ on the different binding sites, were considered. For Cytosine, the most stable complex was obtained starting from the most stable tautomer of the free nucleic acid base tautomers. As to thymine, the bond energy of the ion with the most stable tautomer of the free nucleic acid base is the weakest among the three tautomer’s complexes, and that of the ion with least stable tautomer of the free nucleic acid base is the strongest . Uracil is similar to thymine. The two kinds of relation, bond energy and total energy for the complex, are in disagreement, as the metal affinities of RNA bases for the Ca+ depend on binding sites, and total energy of complex (Ca+-RNA base) relies on all atoms and their relative positions in the complex.  相似文献   

20.
Polymer degradation is readily observed in flows where the extensional component surpasses the rotational component of the velocity gradient. This type of flow is conveniently obtained by pushing a liquid into a convergent channel across an orifice. Kinetics of chain scission is sensitive to subtle modification of the coil conformation, which in turn depends on the details of the pervading flow field. By changing the orifice diameter and the conical angle of the inlet, it is possible to modify the spatial distribution of the velocity gradient, and hence, the residence time of a fluid element in the high strain-rate region. Degradation yields, measured under -conditions in decalin by Gel Permeation Chromatography, showed a strong dependence on the fluid velocity at the orifice, but not on the magnitude of the strain-rate. This result is contrary to the common belief that assumes viscous friction, proportional to the strain-rate, is the determining factor for the scission rate of a bond under stress. Rather, experimental findings tend to indicate that the driving force for chain scission was provided by the energy accumulated in the coil during the flow-induced deformation process. The sharp propensity for mid-chain scission was maintained regardless of the nozzle geometry.Dedicated to Prof. W. R. Pechhold on the occasion of his 60th birthday  相似文献   

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