rotamers in n.m.r. experiment

From: Kay Kreidler <kreidler #*at*# hp817s.rz.uni-duesseldorf.de>
Subject: rotamers in n.m.r. experiment
Date: Fri, 17 Mar 95 10:14:59 MEZ

 Dear netters!
 I am investigating conformational equilibria of chemical compounds
 containing Ethane rotors, for example derivatives of succinic acid. I try
 to calculate the amount of each canonical rotamer due to the time axis
 of an n.m.r. experiment in aqueous solution. The programs I use are
 force field programs like MM+ (Hyperchem) and Quanta/CHARMm, semiempirical
 programs like MOPAC93, VAMP 4.4 and the ab-initio program Gaussian92.
 Aside of the question of the reliability of the results of anionic
 structures I am searching for a model substance, in which the rotation is
 slowly enough to show the individual rotamers as *seperate* signals in the
 n.m.r. experiment. Does any one of you remember such a case?
 I will summarize to the mailing list.
 Thanks a lot
 Kay Kreidler