Draw the expected 11B NMR signal pattern for BF3

Draw the expected ¹¹B NMR signal pattern for BF₃

Expert Solution

Boron has two naturally occurring NMR active nuclei. Both nuclei have spins of greater than ½ and are quadrupolar. 11B has a spin of 3/2 and 10B is spin 3. 11B is the better nucleus in all respects, having the lower quadrupole moment and being more sensitive. Regular NMR tubes are made of borosilicate glass and therefore contain boron. As a result there is a broad signal in the spectrum arising from the tube. It is therefore preferable to use quartz tubes that do not contain boron although these are much more expensive and fragile than regular tubes. Both nuclei have the same wide chemical shift range. Each type of signal has a characteristic chemical shift range which is the same for both nuclei.

10B-NMR has a lower sensitivity and yields broader signals than 11B. It is therefore preferable to use 11B unless the sample is enriched in 10B as may be the case for samples intended for neutron capture applications.

queen_honey_blossom answered 2 years ago

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