Dipolar switched angle spinning, an NMR technique due to Terao et al.
[Terao, T.; Miura H.; Saika, A, J. Chem. Phys. 1986, 85, 3816], has be
en used to measure C-13-C-13 distances in the solid state. The experim
ent involves rotation of the sample at two different angles during dif
ferent periods of a two-dimensional experiment. An evolution period wi
th off-magic-angle spinning and chemical shift refocusing, followed by
detection of the signal under magic angle spinning, yields scaled Pak
e patterns in omega(1), correlated with their isotropic shifts in omeg
a(2) allowing the high-resolution measurement of dipolar couplings. We
demonstrate this experiment on samples of doubly C-13 labeled zinc ac
etate and a 14 amino acid peptide, in which we show that under optimal
conditions distances of up to 5 Angstrom may be measured.