PLS HELP~on chemistry question about Hnmr

[匿名]

2008-04-30 10:53 am

when we doing Hnmr exercise...there some information will be provided, such as:

0.8(2H,m) , 5.82(1H,bd) , 2.1(3H,bs)

i would like to ask what are the meanings of "bd" and "bs" above???
I know "m" means multiplets...but how about "bd" and "bs"??

pls help!!!><

回答 (1)

Po Hung

2008-04-30 11:42 pm

✔ 最佳答案

I thought "bd" and "bs" means broad doublet and broad singlet respectively. Due to the fast H-exhange rate, the peak of the H singal may be broadened. Sometimes, the peak is even disappeared. Also, if the hydrogen is bonded to nitrogen, the nitrogen can provide a faster relaxation of the excited hydrogen, it can increase the certainty of the signal and thus the peak is broadened. To solve the problm, you can try with the low temperature H-NMR and see if the peak is sharpened again.

參考: My old NMR knowledge over 10 years ago

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