Chemical Shift Correlation NMR Spectroscopy with Indirect Detection in Fast Rotating Solids:  Studies of Organically Functionalized Mesoporous Silicas

The first indirectly detected 13 C− 1 H solid-state NMR correlation spectra of species bound to a surface are reported. The experiments were performed at 14.1 T under fast (40 kHz) MAS. The sensitivity gain was demonstrated on a mesoporous silica sample containing approximately 300 μg of covalently bound allyl groups, in the absence of templating molecules and without isotope enrichment. A well-resolved two-dimensional spectrum was acquired in 15 min, which is more than 10 times faster than using direct detection of 13 C nuclei.