文档介绍：7512 J. Org. Chem. 1997, 62, 7512-7515
NMR Chemical Shifts mon
Laboratory Solvents as Trace Impurities
Hugo E. Gottlieb,* Vadim Kotlyar, and
Abraham Nudelman*
Department of Chemistry, Bar-Ilan University,
Ramat-Gan 52900, Israel
Received June 27, 1997
In the course of the routine use of NMR as an aid for
organic chemistry, a day-to-day problem is the identifica-
tion of signals deriving mon contaminants
(water, solvents, stabilizers, oils) in less-than-analyti-
cally-pure samples. This data may be available in the
literature, but the time involved in searching for it may
be considerable. Another issue is the concentration
dependence of chemical shifts (especially 1H); results
obtained two or three decades ago usually refer to much Figure 1. Chemical shift of HDO as a function of tempera-
more concentrated samples, and run at lower ic ture.
fields, than today’s practice.
1 13
We therefore decided to collect H and C chemical dependent (vide infra). Also, any potential hydrogen-
shifts of what are, in our experience, the most popular bond acceptor will tend to shift the water signal down-
“extra peaks” in a variety monly used NMR field; this is particularly true for nonpolar solvents. In
solvents, in the hope that this will be of assistance to contrast, in . DMSO the water is already strongly
the practicing chemist. hydrogen-bonded to the solve