13C–13C polarization transfer by resonant interference recoupling under magic-angle spinning in solid-state NMR

A novel mechanism for 13C–13C polarization transfer under magic angle spinning (MAS) is presented. By applying a recently proposed 13C–1H recoupling sequence under MAS, the spin part of the 13C–1H dipolar interaction is modulated with a particular frequency so that non-commutable time-dependent 13C–1H and 13C–13C dipolar interactions interfere with each other. This novel polarization-transfer approach is theoretically explained and experimentally demonstrated using [1,3-13C] L-alanine.