文档介绍：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 anic 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. Experimental 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 measured with a calibrated Eurotherm 840/T digital thermometer, connected to a thermocouple which was introduced into