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121.
Takeshi Kaneda 《Journal of fluorine chemistry》2005,126(1):17-26
Synthesis and synthetic utilities of stereocontrolled α,α-difluoro-β-hydroxy-γ,δ-unsaturated carbonyl compounds via enzymatic resolution with lipase PS (Pseudomonas cepacia, Amano Pharmaceutical Co. Ltd.) or lipase MY (Candida rugosa, Meito Sangyo Co. Ltd.) were described, and then the absolute configuration of obtained chiral materials was determined by the modified Mosher's method. 相似文献
122.
The heats of dilution of nine ternary solutions of urea and polyols have been determined at 25°C. Excess enthalpies and their virial coefficients h
xy
have been evaluated and compared with the data reported in the literature for mono- and polyfunctional alcohols and other oxygenated nonelectrolytes. The group additivity approach of Savage and Wood was applied and the contributions to the enthalpy coefficients, due to the water mediated interactions between urea and the functional groups –CH2–, –OH, and –O– were determined. On the other hand, by using empirical combination rules among the cross- and self-enthalpic interaction coefficients it is possible to emphasize the large differences in the behavior (even in the presence of urea) of the polyols (and in particular of cyclitols) and of saccharides. 相似文献
123.
Horn M Ihringer J Glink PT Stoddart JF 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(17):4046-4054
A template-directed dynamic clipping procedure has generated a library of nine [2]rotaxanes that have been formed from three dialkylammonium salts-acting as the dumbbell-shaped components-and three dynamic, imino bond-containing, [24]crown-8-like macrocycles-acting as the ring-shaped components-which are themselves assembled from three dialdehydes and one diamine. The rates of formation of these [2]rotaxanes differ dramatically, from minutes to days depending on the choice of dialkylammonium ion and dialdehyde, as do their thermodynamic stabilities. Generally, [2]rotaxanes formed by using 2,6-diformylpyridine as the dialdehyde component, or bis(3,5-bis(trifluoromethyl)benzyl)ammonium hexafluorophosphate as the dumbbell-shaped component, assembled the most rapidly. Those rotaxanes containing this particular electron-deficient dumbbell-shaped unit, or 2,5-diformylfuran units in the macroring, were the most stable thermodynamically. The relative thermodynamic stabilities of all nine of the [2]rotaxanes were determined by competition experiments that were monitored by (1)H NMR spectroscopy. 相似文献
124.
Dzhemilev U. M. Ibragimov A. G. Khafizova L. O. Khalilov L. M. Vasil"ev Yu. V. Tomilov Yu. V. 《Russian Chemical Bulletin》2001,50(2):297-299
1-Ethyl-2,3-fullerenoaluminacyclopropanes (EtAl)n(2-C60) were synthesized by the reaction of fullerene C60 with an excess of EtAlCl2 in the presence of Mg and using Cp2TiCl2 as the catalyst in a THF--toluene solution at 20 °C. Deuterolysis of fullerenoaluminacyclopropanes afforded a mixture of deuteriofullerenes C60Dm, where m = 6--12. 相似文献
125.
126.
S. A. Gromilov T. V. Basova D. Yu. Emel’yanov A. V. Kuzmin S. A. Prokhorova 《Journal of Structural Chemistry》2004,45(3):471-475
Layers of [(CH3)3SiO]8(SiO1.5)8 and [(CH3)3SiO]12(SiO)6 organosilicon compounds obtained by chemical vapor deposition were investigated by X-ray diffraction (DRON-RM4, R = 192 mm, CuK
radiation) and Raman spectroscopy (Triplemate, SPEX). The layers were found to be ideally oriented polycrystalline films. The octakis-(trimethylsiloxy)octasilsesquioxane polycrystals are oriented in one crystallographic direction — [001], while the dodecakis-(trimethylsiloxy)cyclohexa-siloxane polycrystals are oriented in the
and
directions. Crystal structure analysis in these directions yielded the type of the planar lattice followed by the molecules and their orientation relative to the support.Original Russian Text Copyright © 2004 by S. A. Gromilov, T. V. Basova, D. Yu. Emelyanov, A. V. Kuzmin, and S. A. ProkhorovaTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 497–501, May–June 2004. 相似文献
127.
六次甲基四胺与酚类化合物包结现象的研究 总被引:1,自引:0,他引:1
Bishop开发的主体化合物1,6-二甲基-1,6-二羟基二环[3,3,1]壬烷可与乙酸乙酯等形成包结物~[1,2],柏木醇通过氢键作用可与酚类化合物形成包结物~[3].比较上述两个主体分子的结构可知,其相似之处在于它们都是桥环化合物,且具有近似球状的分子结构.考虑到六次甲基四胺也是一个球状桥环化合物,且具有与客体分子形成氢键的条件,故它与酚类化合物的包结现象也有助于氢键共晶现象的研究~[4]. 相似文献
128.
129.
Maria Nowakowska Mirosława Smoluch Dorota Sendor 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(3):213-219
The effect of -, - and -cyclodextrin onthe photochemical stability of 7-amino-4-methylcoumarin (C120)was studied. Using spectroscopic techniques (UV/Vis absorption spectroscopy, fluorescence, fluorescence anisotropy and circular dichroism) combined with HPLC/MS and MS analysis it was demonstrated that addition of -cyclodextrin to the aqueoussolution of C120 markedly inhibits the photodegradation of that dye. This results from theformation of an inclusion complex between C120 and -cyclodextrin. 相似文献
130.
用比较力场分析研究了N-亚硝基化合物的结构与致癌活性的关系,考察了网络结构和探针原子对结果的影响.结果表明,立体效应和静电作用场是描述其致癌活性和进行结构性能关系研究的最重要的结构参数。 相似文献