steric hindrance

By introducing the steric hindrance effects of peripheral and axial substitutions , the red-shift and broadening of the bands are weakened as the structure of the thin films become amorphous .

通过加入分子周边取代和中心取代，从而引入空间位阻效应使薄膜的结构变为非定形，表现在其吸收带的线宽变窄，红移变小。

Finally , we studied the influence of steric hindrance to the reaction .

最后，研究探讨了空间位阻对该反应的影响。

In the end , the steric hindrance of the substitute was discussed .

最后，讨论了清除过程中取代基的空间位阻效应。

The effect of steric hindrance and electron on aromatic aldehydes reduced by BER

BER还原芳醛的位阻效应和电子效应

Steric Hindrance Effect on Hydrogenation of Styrene Catalyzed by Ruthenium Hydride Complex

单氢钌配合物催化氢化苯乙烯的位阻效应

The stereoselectivity was improved by increasing steric hindrance of the reactions .

通过增加反应的空间位阻改进了反应的立体选择性。

The hydrolysis stability would increase when groups around silicon atom or nitrogen atom were of high steric hindrance .

硅原子或氮原子上带有较大空间位阻的基团后，其水解稳定性提高。

Steric Hindrance Amine & a New Selective Desulfuration Solvent

空间位阻胺&新型选择性脱硫溶剂

Their extraction ability markedly decreases with the increase of the steric hindrance from ester alkyl group .

萃取能力随着酯烷基空间位阻的增大而显著降低。

Also we used oxygen to replace the acetyl acetone base to minimize space steric hindrance to improve activity .

另外，还采用氧替换乙酰丙酮基的方法以减小有机钛化合物空间位阻来提高催化活性。

In the synthesis , Span-80 was used as surfactant , due to its steric hindrance effect .

此处使用Span-80为分散剂，是利用其空间位阻作用。

Based on this , the selectivity and steric hindrance for the adsorption of bile acids are discussed .

对树脂吸附胆酸过程中的选择性和位阻作了讨论。

Synthesis of tertiary amines ligands with highly steric hindrance

高位阻叔胺配位体的合成

Synthesis and application of lauric acid ester quaternary ammonium salt cationic surfactant in condition of steric hindrance

位阻月桂酸阳离子酯表面活性剂的合成及应用

The steric hindrance model was verified to be applicable for the evaluation of the structure of nanofiltration membranes .

结果讨论表明细孔模型适用于纳滤膜的结构评价。

Thus , we concluded that the steric hindrance of C-terminus might play an important role in opioid receptor affinity .

因此我们推测C-末端空间位阻的大小对于阿片受体的活性可能起着很重要的作用。

The selectivity of this reactions depended on the steric hindrance of the electrophilic groups .

并且通过进一步的研究发现，该反应的顺反选择性，取决于亲电基团的位阻大小。

The Effect of Steric Hindrance on the Photophysical Behavior of Substituted Styryl Pyrazine Derivatives

结构受阻对取代苯乙烯基吡嗪光物理行为的影响

We presumed the possible reason is that high steric hindrance and adopted conformation of molecule are unfavorable to coordinate .

推测是由于分子较大的空间位阻及采取的构象不利于配位所致。

Excellent dispersing performance of ASP is the result of co-action of electrostatic repulsion and steric hindrance .

ASP良好的分散能力是静电斥力和空间位阻共同作用的结果。

This approach covers the substrate range of aliphatic , aromatic , heterocyclic and steric hindrance ketones .

该催化剂适用于各种脂肪酮、芳香酮、杂环酮和位阻酮。

The effect of steric hindrance in the Stephen reaction and the syntheses of some substituted benzaldehydes

关于空间阻碍在Stephen反应中所起的作用及一些芳香醛的合成

The steric hindrance of the solvent molecules and intermolecular interactions result in longer relaxation time in THF solution than in gas phase .

溶剂分子的空间位阻以及溶质-溶剂分子间相互作用导致溶液中构型转化过程的弛豫时间比气相中增长。

The large steric hindrance group avails to the enantioselectivity , but too much steric hindrance reduces the activity .

大位阻取代基有利于提高对映选择性，但位阻过大降低催化活性。

The electronic effects of the substituents on the benzene ring and the steric hindrance do not significantly alter the reaction time and yield .

反应时间和反应收率不明显受苯环取代基团电子效应及空间位阻的影响。

Space steric hindrance resulted by length lateral chain and electrostatic repulsion of charged ion made the main contribution to water-reducing effect of PAA .

自制PAA系列的减水机理主要为其长侧链引起的空间位阻作用及其带电离子的静电斥力作用。

The two phen ligands chelating to each Cu (ⅱ) center arrange in almost perpendicular orientation to avoid the severe steric hindrance .

为了减小空间位阻效应，与中心Cu（Ⅱ）离子螯合配位的两个邻菲咯啉配体之间近似呈垂直排列。

The size and steric hindrance of substituent of porphyrin is one of the crucial factors to affect the interaction between porphyrins and DNA .

吡啶取代基的大小和空间位阻是影响相互作用方式的关键因素之一。

Meanwhile , research revealed that this synthetic route could , in a degree , increase the reactivity of hydrosilylation between reactants with high steric hindrance .

同时，探索研究出了一条在一定程度上能够提高某些高位阻反应物之间硅氢加成反应活性的方法。

But N , methyl chitosan is an exception , its Tg is slightly higher than chitosan because of the steric hindrance of side group .

但N-甲基壳聚糖例外，其Tg略高于壳聚糖，空间阻碍在这里起决定的作用。