NMR Characterization of Mesostructured Aluminophosphates

The atomic structure of ordered mesostructured aluminophosphates with dodecyl phosphate as the structure-directing template was investigated by multinuclear solid-state NMR. Two different types of materials were studied: one with the template headgroup as the only phosphate source and one where additionally phosphoric acid was used in the synthesis. All 31 P and 27 Al NMR resonances can be subdivided into three groups depending on the sample composition. Furthermore, 2D heteronuclear correlation NMR measurements allow a conclusive and unambiguous identification of the phosphate headgroup resonances of the template molecules and the determination of water and/or hydroxyl units. Most notably, there is an obvious correlation between the d 001 values of the samples as measured by powder X-ray diffraction and the appearance of the various groups of 27 Al and 31 P resonances.