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111.
吡喃并[4,3-b]吡喃衍生物与牛血清白蛋白作用的荧光光谱 总被引:1,自引:0,他引:1
用荧光光谱法分析了在生理条件下一种吡喃并[4,3-b]吡喃衍生物—2-氨基-7-甲基-4-(4-硝基苯)-5-氧代-4H,5H-吡喃并[4,3-b]吡喃-3-腈与牛血清白蛋白的作用机制。求得不同温度下二者的结合常数和结合位点数,探讨了微量金属离子对实验体系结合常数的影响,并根据热力学参数确定了这种吡喃并[4,3-b]吡喃衍生物与牛血清白蛋白之间的作用力类型。根据Frster非辐射能量转移机理,测定了这种吡喃并[4,3-b]吡喃衍生物与牛血清白蛋白相互结合时,能量给体-受体间的作用距离和能量转移效率,并用同步和三维荧光技术讨论了其衍生物对牛血清白蛋白构象的影响。结果表明,吡喃并[4,3-b]吡喃衍生物主要以静态猝灭方式使牛血清白蛋白荧光强度显著降低,二者主要凭借氢键和范德华力结合。 相似文献
112.
113.
A series of KF/Al2O3 catalyzed Michael-addition reactions between malononitrile and α,β-unsaturated cycloketones in DMF solution were studied. At room temperature, 2-cyano-3-aryl-3-(1,2,3,4-tetrahydronaphthalen-1-one-2-yl) propionitrile derivatives were synthesized by the reaction between 2-arylmethylidene-1,2,3,4-tetra-hydronaphthalen-1-one and malononitrile. However, if the temperature was increased to 80℃, 2-amino-3-cyano-4-aryl-4H-benzo[h]chromene derivatives were obtained in high yields. When the α,β-unsaturated ketones were replaced by 2,6-biarylmethylidenecyclohexanone or 2,5-biarylmethylidenecyclopentanone, another series of 2-amino-3-cyano-4H-pyran derivatives was isolated successfully. The structures of the products were confirmed by X-ray diffraction analysis. 相似文献
114.
《Electroanalysis》2004,16(11):938-948
The theory for an EC mechanism in chronopotentiometric techniques – reversal chronopotentiometry, cyclic chronopotentiometry and reciprocal derivative chronopotentiometry – is developed. The equations of this article are valid for spherical electrodes of any size and present a compact and easy‐to‐manage form. Methods for determining kinetic parameters of the chemical reaction are proposed and the influence of the electrode radius is discussed. We conclude that large errors in the determination of these parameters are committed if electrode sphericity is neglected. Reciprocal derivative chronopotentiometry has been applied in its traditional form (dt/dE vs. E), and in a more recently proposed modality consisting of plotting dt1/2/dE vs. E. These techniques are very convenient for studying an EC mechanism since the response is obtained in the form of peaks which are quantitatively related to the kinetic parameters of the chemical reaction. A comparison of the chronopotentiometric methods analyzed leads us to conclude that working curves based on the dt1/2/dE vs. E curves are more suitable to obtain accurate values of the rate constants of the chemical reaction. 相似文献
115.
Summary: Polypyrrole (PPy) microtubes with an actinomorphic morphology are synthesized by a chemical method in the presence of an inclusion complex (IC) of mono [6‐deoxy‐6‐(2‐butenedinitrile‐2,3‐dimercapto sodium salt)]‐β‐cyclodextrin (6‐mnt‐β‐CD) with methyl orange (MO) as a dopant in aqueous solution. The morphologies of the obtained PPy were studied using transmission electron microscopy (TEM). It was found that the IC of 6‐mnt‐β‐CD with MO significantly affects the morphology of the resulting PPy.
116.
A simple, sensitive and rapid derivative spectrophotometric method using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) has been developed for simultaneous determination of Co(II), Ni(II) and Fe(II) which have very similar chemical behavior and appear together in many real samples. The complexes of all these metal ions with 5-Br-PADAP were formed immediately at pH 7.0 ammonium acetate buffered solution and were stable for at least 24 h. Second derivative spectra were selected for evaluation, because working wavelength determination was more precise and spectral overlap was less than in the ordinary and first derivative spectra. Three wavelengths at which the complexes exhibit extremum 2D values for Co(II), Ni(II) and Fe(II) were selected as analytical wavelengths, i.e., 640, 600 and 740 nm, respectively. Calibration curves drawn with zero-to-peak values at mentioned wavelengths were linear between 80 and 2000 ng ml−1 for each metal ion. Concentrations of Co(II) and Ni(II) were calculated from the total 2D values and the sum of the linear equations for these three cations at 640 and 600 nm, after Fe(II) assay by making use of the 2D value at 740 nm. Limits of detection (LOD) for Co(II), Ni(II) and Fe(II) were 2.7, 13.9 and 3.0 ng ml−1, respectively. The method has been applied to tool steel and heater resistance wire samples successfully. 相似文献
117.
合成了一个供体-受体(D-A)型含芘萘啶衍生物2-(芘-1-基)-1,8-萘啶(PN)。 通过核磁共振波谱(NMR)、傅里叶变换红外光谱(FTIR)、液-质联用仪(LC-MS)表征了其结构。 通过电子光谱和Z-扫描技术方法分别研究了化合物PN的线性光学性质和三阶非线性光学吸收,采用综合热分析方法测定了它的热稳定性。 结果表明,在532 nm、180 fs条件下,PN的三阶非线性吸收行为为反饱和吸收,其吸收系数为β=9.0×10-14 m/W,显示出超快三阶非线性光学响应。 运用密度泛函理论方法计算了分子轨道能量、极化率和超极化率,结果表明电子转移能够在分子内部进行。 2-(芘-1-基)-1,8-萘啶的紫外光谱在450 nm以上无吸收,在非线性光学吸收、激光防护、吸收型光开关或双稳器件等方面可作备选材料。 相似文献
118.
通过水热方法合成了一个新的化合物[Co2(L)2(1,5-PDC)2].0.5H2O(L为邻菲啰啉衍生物2-(2-fluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline,1,5-PDC为庚二羧酸阴离子),并对该化合物进行了元素分析、红外和X射线单晶衍射表征。该化合物属于三斜晶系,空间群P1,晶胞参数C104H86Co4F4N16O17,a=1.108 2(5)nm,b=1.390 2(4)nm,c=1.601 7(6)nm,α=90.806(5)°,β=93.429(3)°,γ=111.312(5)°,V=2.293 0(15)nm3,Z=1,R=0.059 7,wR=0.160 8。在该化合物中,1,5-PDC阴离子桥联着相邻的钴离子从而形成了一维链状结构。存在于相邻链之间的π-π相互作用使一维链形成了二维超分子结构。此外,N-H…O和O-H…N氢键进一步地稳定了此二维超分子结构。 相似文献
119.
壳聚糖衍生物的制备及其吸附性能 总被引:18,自引:2,他引:18
壳聚糖衍生物的制备及其吸附性能曲荣君,马千里,郑秀丽,孙言志(烟台师范学院化学系烟台264025)关键词壳聚精衍生物,制备,吸附壳聚糖(CTS)是重金瞩离子的吸附剂 ̄[1,2],由于壳聚精分子中的-NH_2在pH较低的水溶液易形成而使CTS溶于水,造... 相似文献
120.