Re: ORGLIST: Diastereotopic shifts

Date view Thread view Subject view Author view Attachment view

From: Rzepa, Henry (h.rzepa$##$ic.ac.uk)
Date: Fri May 03 2002 - 09:23:27 EDT

>Dear all,
>It is well known that diastereotopic protons give differently shifted
>signals in the 1H-NMR spectrum, but what about difference as great as 1 -
>1.5 ppm? Do you think it is possible and has anyone ever observed such a
>fenomenon?
>

I have certainly seen 2ppm in my time. The anisochronicity
is determined by a 1/r6 dependence, and since it can persist out
across quite a few bonds, I suppose it must be very strong at
shorter distances. 

--

Henry Rzepa.
+44 (0870) 132 3747 (eFax) +44 0778 6268 220 (Mobile)
 http://www.ch.ic.ac.uk/rzepa/ Dept. Chemistry, Imperial College, London, SW7  2AY, UK.

__________________

ORGLIST - Organic Chemistry Mailing List
Website / Archive / FAQ: http://www.orglist.net/
List coordinator: Joao Aires de Sousa (jas$##$mail.fct.unl.pt)
Date view Thread view Subject view Author view Attachment view

This archive was generated by hypermail 2.1.4 : Fri Sep 19 2003 - 12:16:54 EDT