Exchange Reactions by NMR without Variable Temperature
Trevor G. Appleton and John D. Cotton University of Oueensland Brisbane, Australia 4067
I
An experiment using ally-palladium complexes
Most undergraduate lecture courses now include some discussion on the application of nmr spectroscopy to thestudy of rapid exchange reactions in solution. In such experiments, variation in temoerature is usuallv used t o varv t h e reaction rate, so t h a t thespectra in both "&ow exchange" and "rapid exchange" limits may he observed. Although a n undergraduate experiment using variable-temperature n m r has been recentlv described ( I ) . ~ r o h l e m scould arise if more than a very few students a r e i&olved. Variahle-temperature n m r is much more time-consumina and requires closer supervision than routine operation. ~u&hermo;e, instrument tuning is usuallv unstable for some time after t h e probe has returned t o room temperature, which does n o t endear t h e operators to subsequent users. In the experiment described here, reaction rates are varied, at room r~rnparoture,b\. adlurtma reawnt c
