Resolution enhancement in solid-state MQ-MAS experiments achieved by composite decoupling

It is shown that, in the presence of strong heteronuclear dipolar couplings, resolution can be significantly improved in solid-state multiple quantum magic angle spinning NMR experiments on half integer quadrupolar nuclei by applying composite decoupling schemes during triple quantum evolution and acquisition. Reduction of the effects of heteronuclear dipolar coupling during the multiple quantum evolution period is shown to lead to improved resolution of 27Al sites in crystalline chiolite (Na5Al3F14) and 11B sites in a polyborazilene sample.