文档介绍：7512 J . Org. Chem. 1997, 62, 7512-7515
NMR Ch em ica l Sh ifts m on
La bor a tor y Solven ts a s Tr a ce Im p u r ities
Hugo E. Gottlieb,* Vadim Kotlyar, and
Abraham Nudelman*
Department of Chemistry, Bar-Ilan University,
Ramat-Gan 52900, Israel
Received J une 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
more concentrated samples, and run at lower ic
fields, than today’s practice.
We therefore decided to collect 1H and 13C chemical
shifts of what are, in our experience, the most popular
“extra peaks” in a variety monly used NMR
solvents, in the hope that this will be of assistance to
the practicing chemist.
Exp er im en ta l Section
NMR spectra were taken in a Bruker DPX-300 instrument
( and MHz for 1H and 13C, respectively). Unless
otherwise indicated, all were run at room temperature (24 ( 1
°C). For the experiments in the last section of this paper, probe
temperatures were measur