Abstract
A strong ¹¹B {¹H} nuclear Overhauser effect (NOE) enhancement can be observed in solid-state ¹¹B NMR spectra of borane adducts, yielding fractional enhancements, f_I{S} = (I - I⁰)/I⁰, of the magic angle spinning (MAS) NMR signal of up to 155%. This is an interesting and unusual observation as ¹¹B (spin I = 3/2) is a quadrupolar nucleus and the corresponding NOE is completely absent in solution. More generally, it shows that the NOE may have a wider role to play in solid-state NMR studies of dynamics than has been envisaged hitherto.