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 a cquisition. Reduction of the effects of heteronuclear dipolar coupling duri ng the multiple quantum evolution period is shown to lead to improved resol ution of Al-27 sites in crystalline chiolite (Na5Al3F14) and B-11 sites in a polyborazilene sample. (C) John Wiley & Sons, Ltd.