Multiple-quantum 13C solid-state NMR spectroscopy under moderate magic-angle spinning

A new method for the excitation and detection of high-order 13C multiple-quantum (MQ) nuclear magnetic resonance (NMR) signals in solids under magic-angle spinning (MAS) condition is presented. In this experimental scheme, high-order 13C MQ coherences are generated by relaying several sequentially generated 13C double-quantum (DQ) coherences in dipolar coupled networks. Numerical simulations and experimental implementations are presented to demonstrate the efficiency of this method under a moderate MAS frequency regime. 13C MQ signals up to 10-quantum coherences are observed experimentally on the model compound 1-13C-labeled glycine, at an MAS frequency of 12 kHz.