Fast MAS Total Through-Bond Correlation Spectroscopy

Mixing sequences for total through-bond correlation spectroscopy in solids (TOBSY) were developed. The motivation is the design of broadband, effective, and robust sequences adapted for “fast” MAS. Possible sequences with the desired Hamiltonian (the homonuclear isotropic J interaction) were identified using lowest order average Hamiltonian theory. Numerical simulations as a function of the MAS frequency were then employed to further characterize the performance. An experimental TOBSY spectrum of a uniformly 13C-labeled decapeptide at 20 kHz MAS was obtained using one of the new sequences. The spectrum allows us to assign the 13C resonances to the respective spin systems.