NMR in Isotropic Liquids

Relaxation times of deuterium are not particularly short and fall typically in the range 5.04 s in toluene-i/a to 0.05 s in larger molecules such as 2-benzamido-4,5-d2-norborneol. There is nevertheless a maximum molecular size, above which high-resolution deuterium NMR will not be possible owing to the increasing effectiveness of the quadrupole relaxation mechanism. The relaxation behavior is considered in detail in Ref. 1. 

In other studies, the correlation time of Co(en)j+ is measured as 30-35 ps but increases to about 160 ps in the presence of due to the formation of ion pairs. 

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