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81.
掺杂阴离子对电化学合成的聚邻甲苯胺性质的影响 总被引:3,自引:0,他引:3
邻甲苯胺在酸性介质中的聚合速率与酸的种类有关,聚合速率影响了各种掺杂阴离子聚合物膜的形态,聚合物的电导率、循环伏安曲线形状受掺杂阴离子的影响,其电容量与掺杂阴离子的种类及形态有关,阴离子的种类对电极电位和紫外-可见光谱无影响。 相似文献
82.
Mounir Maafi Belkacem Laassis Jean-Jacques Aaron M. Carmen Mahedero Arsenio Muñoz De La Peña Francisco Salinas 《Journal of inclusion phenomena and macrocyclic chemistry》1995,22(3):235-247
The photooxidation of Azure A and fluorescence properties of Azure A and its photoproduct have been investigated in aqueous media and in the presence of-cyclodextrin (-CD). The fluorescence intensity of the complex formed between the photoproduct and -CD was found to be three times higher than that of the uncomplexed Azure A photoproduct. A complex formation constant of 110±40 M–1 was calculated using the Benesi-Hildebrand treatment of the fluorescence emission data. Although the stoichiometry of the Azure A photoproduct: -CD complex was found to be 1: 1, it seems that the Azure A structure is only partially included. Calibration graphs were plotted for the free Azure A photoproduct and the photogenerated product included in -CD. The analytical parameters and quantification limits were determined. 相似文献
83.
84.
STM study on quinacridone derivative assemblies: modulation of the two-dimensional structure by coadsorption with dicarboxylic acids 总被引:4,自引:0,他引:4
Yang X Mu Z Wang Z Zhang X Wang J Wang Y 《Langmuir : the ACS journal of surfaces and colloids》2005,21(16):7225-7229
We describe the two-dimensional (2D) assemblies of N,N'-dialkyl-substituted quinacridone derivatives on highly orientated pyrolytic graphite observed by scanning tunneling microscopy, and focus our discussion on whether the supramolecular organization can be modulated by the coadsorption of dicarboxylic acids. Our experiments have demonstrated that the quinacridone derivatives can form different 2D nanostructures when coadsorbed with dicarboxylic acids of different length at the liquid/graphite interface. Interestingly, N,N'-dihexadecyl-substituted quinacridone derivative alternately takes two different conformations in two columns for its coadsorption with pentadecanedioic acid and form a gridlike structure. It is shown that a cooperative effect of different interactions can be modulated by introducing guest molecule, leading to formation of different self-assembled nanostructures. 相似文献
85.
Martin JN Muñoz EM Schwergold C Souard F Asensio JL Jiménez-Barbero J Cañada J Vicent C 《Journal of the American Chemical Society》2005,127(26):9518-9533
Sugar-oligoamides have been designed and synthesized as structurally simple carbohydrate-based ligands to study carbohydrate-DNA interactions. The general design of the ligands 1-3 has been done as to favor the bound conformation of Distamycin-type gamma-linked covalent dimers which is a hairpin conformation. Indeed, NMR analysis of the sugar-oligoamides in the free state has indicated the presence of a percentage of a hairpin conformation in aqueous solution. The DNA binding activity of compounds 1-3 was confirmed by calf thymus DNA (ct-DNA) NMR titration. Interestingly, the binding of the different sugar-oligoamides seems to be modulated by the sugar configuration. Semiquantitative structural information about the DNA ligand complexes has been derived from NMR data. A competition experiment with Netropsin suggested that the sugar-oligoamide 3 bind to DNA in the minor groove. The NMR titrations of 1-3 with poly(dA-dT) and poly(dG-dC) suggested preferential binding to the ATAT sequence. TR-NOE NMR experiments for the sugar-oligoamide 3-ct-DNA complex both in D(2)O and H(2)O have confirmed the complex formation and given information on the conformation of the ligand in the bound state. The data confirmed that the sugar-oligoamide ligand is a hairpin in the bound state. Even more relevant to our goal, structural information on the conformation around the N-glycosidic linkage has been accessed. Thus, the sugar asymmetric centers pointing to the NH-amide and N-methyl rims of the molecule have been characterized. 相似文献
86.
盐酸溶液中阴离子表面活性剂在铝表面上的吸附 总被引:2,自引:0,他引:2
用失重法研究了盐酸溶液中阴离子表面活性剂十二烷基磺酸钠(DSASS),十二烷基苯磺酸钠(DBSAS)以及十二烷基硫酸钠(SDS)在铝表面上的吸附作用,提出这种吸附作用与铝的失重量有关,且符合Lang-muir方程,计算出吸附热,吸附熵和吸附自由能等热力学参数。认为这种吸附主要靠静电作用,根据接触角的变化讨论了阴离子表面活性剂分子在铝表面上的吸附取向。 相似文献
87.
88.
del Mar Graciani M Rodríguez A Muñoz M Moyá ML 《Journal of colloid and interface science》2001,235(2):260-264
The reaction of dehydrobromination of 2-(p-nitrophenyl)ethyl bromide with hydroxide ions has been studied in aqueous micellar solutions of N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, SB3-14. The kinetic effects of added salts (NaF, NaCl, NaBr, and NaNO(3)) on the reaction rate in SB3-14 aqueous micellar solutions have also been studied. They were rationalized by considering the binding of the anions, which come from the salt, to the sulfobetaine micelles and their competition with the reactive hydroxide ions for the micellar surface. The equilibrium binding constant of the 2-(p-nitrophenyl)ethyl bromide to the sulfobetaine micelles was estimated by recording the changes in the spectra of the organic substrate when the SB3-14 concentration in the micellar medium changed. This value was in agreement with that obtained from fitting of kinetic data. The second-order rate constant in the micellar pseudophase revealed that the reaction is faster in SB3-14 micelles than in water. This acceleration seems independent of the presence of added salts and can be explained by considering that SB3-14 micelles favor reactions in which charge is delocalized in the transition state. Copyright 2001 Academic Press. 相似文献
89.
Muñiz K 《Chemical Society reviews》2004,33(3):166-174
Imido complexes of osmium tetroxide are versatile compounds for olefin functionalisation. This tutorial review offers a brief historical overview on these compounds and discusses the electronic properties and reactivities of isolated imido osmium compounds in what had been the original stoichiometric aminohydroxylation reaction. The recently emerging catalytic Sharpless aminohydroxylation is discussed with special emphasis on mechanistic details. The final section deals with diamination of olefins, which relies on the chemistry of bisimido and trisimido osmium complexes. 相似文献
90.
Maria Luisa Moyá Antonio Barrios Maria del Mar Graciani Rafael Jiménez Ernestina Muñoz Francisco Sánchez John Burgess 《Transition Metal Chemistry》1991,16(2):165-168
Summary The kinetics of replacement of 4,4-bipyridine, (4,4-bipy), and 4-cyanopyridine, (4-CNpy), by cyanide in [Fe(CN)5-(4,4-bipy)]3-. at 298 K have been studied in binary aqueous mixtures containing different amounts of t-butanol, methanol, glycerol, ethyleneglycol and sucrose. The plots of logarithms of the limiting rate constantsversus the mole fraction of water are linear over the entire composition range studied, showing the importance of solvation phenomena. A different straight line of log (kL/s–1)versus XH2O is obtained for each mixture, indicating the influence of other solvent parameters on the reaction rate. A multiparameter regression of G
exp
with A (acidity vector), B (basicity vector) and GE is used for both reactions; plots of G
calc
versus G
exp
are linear with slopes of near unity. 相似文献