High-resolution solid-state NMR spectroscopy of protons with homonuclear dipolar decoupling schemes under magic-angle spinning

High-resolution NMR spectroscopy of 1H spins in the solid state is normally rendered difficult due to the strong homonuclear 1H-1H dipolar couplings. Even under very high-speed magic-angle spinning (MAS) at ca. 60-70 kHz, these couplings are not completely removed. An appropriate radiofrequency pulse scheme is required to average out the homonuclear dipolar interactions in combination with MAS to get high-resolution 1H NMR spectrum in solid state. Several schemes have been introduced in the recent past with a variety of applications also envisaged. Development of some of these schemes has been made possible with a clear understanding of the underlying spin physics based on bimodal Floquet theory. The utility of these high-resolution pulse schemes in combination with MAS has been demonstrated for spinning speeds of 10-65 kHz in a range of 1H Larmor frequencies from 300 to 800 MHz.