Resolution enhancement by homonuclear J decoupling in solid-state MAS NMR

It is shown that in 13C MAS NMR experiments on fully labelled compounds a significant line narrowing can be achieved by homonuclear 13C-13C J decoupling. The linewidth for proteins can be reduced by up to 100 Hz, making assignments for larger molecules possible. The practical usefulness of decoupling in indirectly observed frequency dimensions of multidimensional spectra is demonstrated by spin-diffusion experiments on fully labelled l-threonine and l-arginine hydrochloride. A 3D spin-diffusion experiment is demonstrated for obtaining a 2D spin-diffusion spectrum which correlates well resolved chemical shifts.