帮忙解释一下

he003

忘了上传图片

he003

这两张图是同一个化合物中的不同基团（PhCH2-O-和Ph-CH2-N-）出的峰，我的意思是：如果将裂分理解为同碳耦合的ABq，那么Ph-CH2-N-中CH2裂分的各个峰之间的距离明显不同，即耦合常数有两个，所以图2不符合同碳耦合规律。

北冥有鱼

(1) 5.267-5.236=0.031
      5.193-5.162=0.031    same         J=0.031*400=12.4 Hz
delta mu/J=0.074/0.031=2.4 second order, but the J value is 12.4.

(2) 3.671-3.636=0.035
     3.869-3.384=0.035     same         J=0.035*400=14.0 Hz
delt mu/J=0.178/0.035=5 first order

the impurity 3.887-3.853=0.034
                  3.691-3.636=0.034        J=0.034*400=13.6 Hz
There is a small amount of isomer present in the sample.


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[此贴子已经被作者于2009-5-30 5:51:11编辑过]

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北冥有鱼

HSQC or HMQC will resolve the dispute if you still have some doubt.  It also can confirm the impurity.

2J value can be changed in a range of 1Hz-16Hz, not fixed with one value. But there is no big difference between the two -CH2- groups in your sample. The bond angle is similar.
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[此贴子已经被作者于2009-5-27 23:28:04编辑过]

zlfbaggio

the impurity 3.887-3.853=0.034
3.691-3.636=0.034 J=0.034*400=13.6 Hz

3.691-3.636=0.034 ？

北冥有鱼

 You are right. I was wrong for typing the wrong number. It is not 3.636, but 3.657.

3.691-3.657=0.034 ppm.

he003

谢谢北冥有鱼耐心的分析！