Triple-quantum correlation NMR experiments in solids using J-couplings
Résumé
We show that triple-quantum–single-quantum (TQ–SQ) correlation spectra of crystalline and disordered solids can be obtained under MAS using pulse sequences based on through-bond J-couplings. The feasibility of the experiments in coupled spin-1/2 systems is demonstrated for fully 13C-labelled L-alanine and Pb3P4O13 crystalline compounds, considered as model three-spin and four-spin systems, respectively. In the case of phosphate glasses, we show that the obtained TQ–SQ correlation spectra provide an improved description of the glass forming network connectivities and of the chain length distribution in the disordered network.