作者volley (你媽的鐵支)
看板Chemistry
標題Re: aniline在ortho位接上EDG時.....
時間Fri Nov 4 22:24:44 2005
※ 引述《peapea37 (.....)》之銘言：
一般來說....
在aniline的ortho para上接有EWG會使aniline的鹼性降低
但為何接上EDG也會使其鹼性降低呢?? Orz....
麻煩強者替我解答一下吧....
electron withdrawing groups bearing on ortho- or para- positions of
anilines decrease the basicity due to the inductive effect and
resonance, respectively.
To image a methoxy group on the ortho- position of anilines,
you will observe a hydrogen bond between aniline hydrogen and methoxy
oxygen, this binding is the major effect that affects the basicity.
To check the ortho-alkyl anilines or dialkyl anilines, the basicity
would not be affected with a considerable deviation from their un-
alkylated analogs.
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1F：推 luoyang:ortho會有鄰位效應，算是立體效應 11/04 20:17
this description may not be correct.
basicity is the ability that a base traps a proton.
is proton sterically bulky? Of course not.
actually, to explain basicity by steric effect is "ridiculous"
--
在茫茫人海中
我將尋找唯一的靈魂伴侶
得之我幸,不得我命
如此而已
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◆ From: 140.112.54.28
2F：推 peapea37:也就是說並非全部的EDG都會使aniline的鹼性降低囉?! 11/04 22:38
3F：推 luoyang:鄰位效應:Morrison&Boyd 6/e 19.14&23.4 11/04 22:43
4F：→ peapea37:只有會與aniline形成H-bond的EDG才會使其鹼性下降,right? 11/04 22:42