Chemical Physics Letters, Vol.324, No.1-3, 20-24, 2000
One-dimensional dipolar-shift spectroscopy under magic angle spinning to determine the chemical-shift anisotropy tensors
An efficient one-dimensional dipolar-shift solid-state NMR method is reported that allows the characterization of chemical-shift anisotropy (CSA) and heteronuclear dipolar coupling tensors from powder samples. A combination of a multiple pulse sequence and magic angle spinning (MAS) is used to completely suppress the homonuclear H-1-H-1 dipolar couplings and to recover most of the H-1-X dipolar coupling along with the CSA interaction of the X nuclei (where X is N-15 or C-13 or any other less-sensitive nucleus directly bonded to H-1). This method is quick, simple to implement, and the results are accurate and easy to interpret. The efficacy of this method is demonstrated on a powder sample of a model peptide, n-acetyl-N-15-D,L-valine, under various spinning speeds.