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 31P and 27Al 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 d001 values of the samples as measured by powder X-ray diffraction and the appearance of the various groups of 27Al and 31P resonances.