Mufti-scale NMR characterisation of mesostructured materials using 1H→13C through-bond polarisation transfer, fast MAS, and 1H spin diffusion

A NMR method for the characterisation of materials at different length scales, robust and simple to implement, is presented. It combines selection of H-1-C-13 pairs by a through-bond polarisation transfer (INEPT here) and exploration of larger distances by the introduction of H-1 spin diffusion. This characterisation method is well adapted to the highest MAS rates and takes benefits of it. The effect of H-1 dephasing on the efficiency of the H-1 --> C-13 through-bond polarisation transfer is determined. This allows consecutively the quantification of signals. Mesostructured spherical silica-based particles containing CTA(+) cations were studied by this multi-scale characterisation method. Contrasted spin diffusion curves were found and qualitatively explained by differences in terms of mobility and spatial distributions. (C) 2003 Elsevier Science (USA). All rights reserved.