查询词典 sulfonium

Two kinds of sulfonium salt s as photo-acid generator possess high thermo-decomposition temperature and good solubility in some organic solvents.

对合成的两种新型锍鎓盐光生酸剂进行了基本物性考察，表明它们有较高的热分解温度和在常用有机溶剂中有较好的溶解性，并考察了其在405、365nm 下乙腈中的分解及产酸性能。

Based on the crystal structure of sulfonium salt and the reaction results, it was proposed that the β-hydroxy of the sulfonium salt play a key role in the highly stereoselective cyclopropantion reation.

根据硫盐晶体结构和硫盐在反应中所表现的性质，认为硫叶立德 b -位的羟基可能是反应取得高对映选择性的关键。

The ee value of the majorproduct is up to 94.9%. In addition, further investigation of aziridination via sulfonium ylides as thecontinuation of my M.S.

此外，作为硕士工作的延续，我们对经由硫叶立德途径的氮杂环丙烷化做了进一步的研究。

It was found that the allylide of sulfonium salt could react with aryl aldehydes to afford corresponding trans-epoxides in good yield with good trans/cis selectivity and excellent enantioselectivity.

根据反应条件对反应的影响并结合通过单晶测定的反式环氧化产物的绝对构型，我们提出了氢键起主导作用的手性诱导机制。

The bulk and solution photopolymerization of vinyl butyl ether were studied using diph-enyl-4-thiophenoxyphenyl sulfonium salt as photoinitiator.

以二苯基-4-苯硫基代苯基硫鎓盐为光引发剂，研究了乙烯基正丁醚的本体和溶液光聚合。

Thus, the corresponding chiral sulfonium ylide was designed and its precursor was found to be readily available from the coresponing sulfide that was easily prepared from D-camphor in two steps.

从价廉易得的手性源 D-樟脑出发，合成了硫原子 b -位含有羟基的手性硅基烯丙基硫盐。

It was found that the endo-type sulfonium salts were also worked but afforded the corresponding cyclopropanes with opposite absolute configuration compared with that from the exo-type salt.

考察了硫盐结构对反应的影响，当硫盐中碳-硫键位于樟脑骨架 endo 位置和碳-硫键位于 exo 位置时所得环丙烷化反应主产物的绝对构型相反。

Work was also carried out. From numerous facts of ourprevious work, it might be seen that the stereoselectivity of aziridination viasulfonium ylides depends upon the sulfonium salts and C=X compounds. The moreactive the sulfonium ylide and C=X compound are, the more cis product is generated.Whereas, trans product will be major if the activity of the sulfonium ylide and C=Xcompound is low.

通过对以往工作的总结，我们发现，在经由硫叶立德途径的小环化反应中有一个经验规律：产物的立体选择性与所用的锍盐和C=X化合物有关，即锍盐和C=X化合物的活性增强，有利于形成顺式产物，反之，锍盐和C=X化合物的活性降低，有利于反式产物的形成。

Two special structural features of the sulfonium salt were proved to stabilize its corresponding ylide and depress the 2,3-sigma rearrangement. One is that there is a trimethylsilyl in the end of the allylic double band. This silicon atom can stabilize a α-carbon anion and the corresponding ylide. Another is that there is hydroxy group in the beta-position of sulfonium atom. The oxygen of this hydroxy group may stabilize the sulfonium cation.

为了稳定生成的烯丙基硫叶立德，并抑制它的2， 3-sigma 重排反应，在硫叶立德结构上做了两方面的考虑：一是在烯丙基双键的未端引入硅基，利用硅原子对 a -碳负离子的稳定作用来稳定烯丙基硫叶立德；二是在硫原子的 b -位引入羟基，利用羟基氧对硫正离子的作用来稳定硫叶立德。

Two cationic photoinitiators are successfully synthesized,which are S,S-dialkyl-S-(3,5-dimethyl-4-hydroxyphenyl)sulfonium(4HPS) and S,S-dialkyl-S-(3,5-dimethyl-2-hydroxyphenyl)sulfonium(2HPS).

合成两种紫外光阳离子引发剂，S，S-二甲基(3，5-二甲基-4-羟苯基)硫鎓六氟磷酸盐(4HPS)和S，S-二甲基(3，5-二甲基-2-羟苯基)硫鎓六氟磷酸盐(2HPS)，并用红外光谱、1H-NMR、元素分析确证合成产物即为目标产物。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。