Solid-state NMR study of ordered mesoporous aluminosilicate MCM-41 synthesized on a liquid-crystal template.

A novel mesoporous aluminosilicate MCM-41, synthesized in a liquid-crystal system, was characterized by magic angle spinning NMR. Conventional Bloch decay and cross-polarization spectra were compared. The 27Al spectra showed that the calcined material was highly siliceous, while 29Si NMR proved that it was rich in single and geminal silanol groups. Two kinds of the silanol groups were detected: exchanging and non-exchanging protons with water on the timescale of the 1H experiment. The 13C spectra of the uncalcined material were consistent with the concept of the micellar arrangement of the cetyltrimethylammonium template inside MCM-41.