electron-withdrawing的例句大全

The Electron-withdrawing Effect of the Nitrogen Atom of Pyridine

吡啶环中N-原子的吸电效应

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It can be provided with some information on studying of the relationship between physical properties and chemical structure by introduction of the electron-withdrawing groups to the nitrogen of aniline.

为进一步研究在氮的位置上引入吸电子基团的聚苯胺类衍生物的物理性质与化学结构之间的关系提供了依据。

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Electron-donating groups can increase the intensity of fluorescence, but the electron-withdrawing groups have opposite functions.

供电子取代基能增加卟啉的荧光强度，而吸电子取代基作用相反；

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Conclusions: The alkanes substituted phenolshigher antioxidant activity than that of electron-withdrawing groups substituted phenols.

结论: 烷烃基类取代物易于抗氧化,卤代烃基或硝基类取代物抗氧化活性差.

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Only when the substrates with strong electron-withdrawing group were failed in this reaction.

只有当底物带有强吸电子基团，反应无法进行。

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Electron-withdrawing 2-substituents electron-donating 3-substituents of the phenyl ring are favorable for increased herbicidal activity.

苯环2位是拉 电子基,3位是给电子基有利于提高除草活性.

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Ester bond as an electron-withdrawing group could undergo as well, so the compound by ester bond connecting occurred more reduction process than ether bond connecting.

由于酯键作为一个吸电子基可以促进还原反应的发生，通过酯键连接的化合物比通过醚键连接的化合物出现更多的还原峰值。

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The [ ( 4-fluoro phenyl) methoxy] acetic acid derivatives ( 5~ 9) were prepared in order to compare electron withdrawing group F with Cl, Br and I in substituted ( phenyl methoxy) acetates the effects of tor learning and memory facilitation in mice.

为研究吸电子基-氟，对苯甲氧基乙酸酯类小鼠学习记忆促进作用的影响，合成了（4-氟苯甲氧基）乙酸衍生物（5～9）。

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The macroporous, strongly acidic, high thermally stable canon exchange resin catalysts were synthesized in the steps of polymerization of styrene and divinylbenzene, purifying copolymer, introducing electron withdrawing group, sulfonation and stabilizing active sites.

通过苯乙烯与二乙烯苯聚合、共聚物纯化、引入吸电子基团、磺化、活性基因稳定化过程，合成耐温强酸阳离子交换树脂催化剂。

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Substitution of the aromatic hydrogen atom of the Schiff base ligand with electron withdrawing group decreased the amount of the complex encapsulated in the zeolite cavities, but could improve the catalytic activity of the encapsulated complex.

席夫碱芳环上的H被吸电子基团取代后，降低了Y分子筛超笼中封装的钴配合物的量，但能改善催化活性。

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In chapter 2, we designed and synthesized two novel series of organic dyes by incorporating NC-CH2-COOH as electron withdrawing group at the carbonyl positions of QA skeleton.

在第二章中，我们通过在QA骨架的羰基位置引入吸电子基团NC-CH2-COOH设计并合成了两个系列新颖的有机染料。

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The catalytic system also showed good catalytic activity in the oxidation of other aldehydes. Benzaldehyde derivatives with electron-withdrawing group and aliphatic aldehydes were almost quantitatively converted into their corresponding acids.

应用此催化体系催化其它醛的氧化同样表现出较好的催化活性，有缺电子取代的芳香醛和脂肪醛几乎定量生成相应的羧酸。

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By contrast, the exo adduct possesses a trans relationship between the dienophile electron-withdrawing group and the trans diene substituent.

相反，不能进行成环加成反应的反应物有吸电子基团的二烯和二烯烃取代物具有反式结构。

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The results showed that dyes with strong electron-withdrawing group, asymmetrical structure and short alkyl chain substituents have better bleaching properties.

结果表明，油溶性染料分子中，取代基团的吸电性强，不对称性大，取代基含脂肪链短的，其漂白性能好。

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Poly ( 2,7-carbazole) derivatives, incorporated by electron-withdrawing group in the main chain, form a new low band gap photoactive donor materials.

聚2,7-咔唑材料的衍生物通过与吸电子基团共轭链接能够形成一类新型窄带隙光活性给体材料。

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The material with benzyl group as the linker shows higher catalytic activity and enantioselectivity than the material with propyl group as the linker, which is mainly due to the spacial rigidity and electron-withdrawing ability of the benzyl group.

研究表明以苄基作为环己二胺联结链的材料的催化活性和光学选择性高于相应的以丙基为联结链所得的材料，这主要归因于苄基的空间刚性和较强的吸电子性质。

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The photodegradation experiment showed that the introduction of electron withdrawing group on methane chain would improve the photo-stability of the dye, while electron donating group would decrease the photo-stability.

三种染料与其母核染料的光降解对比试验说明，甲川链上引入吸电子基团使得染料光稳定性提高，而供电子基团则光稳定性下降。

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We use N-ethyl carbazole as the electron donating group, and the cyanoacetate as the electron-withdrawing group, connecting the two parts together by converting different II bridge bonds.

以n-乙基咔唑作为供电子基团，氰基乙酸为拉电子基团，通过变换不同的∏桥键来合成。

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