Heteronuclear X-Y double quantum MAS NMR inorganic solids Applications for indirect detection and spectral editing of rare-spin resonances

Heteronuclear double quantum MAS NMR experiments in the solid state, involving pairs of highly abundant P-31 spins and the rare spins Cd-113, Se-77, and Si-29, are described for the three crystalline compounds CdSiP2, CdGeP2, and Ag7PSe6. These experiments offer the opportunity of indirectly detecting the rare-spin resonance via chemical shift evolution of heteronuclear double quantum coherence. For suitable cases, this method results in significantly enhanced detection sensitivities. Criteria for favorable indirect detection experiments are established. Besides offering high sensitivity, the pulse sequence also acts as a heteronuclear double quantum filter, hence providing heteronuclear correlation and useful spectral editing for peak assignments.