Probing the local environments of phosphorus in aluminophosphate-based mesostructured lamellar materials by solid-state NMR spectroscopy

We have characterized a series of mesostructured aluminophosphate (AlPO)-based lamellar materials by several solid-state NMR techniques. In particular, we were able to estimate the average number of Al atoms and identify the nature of other ancillary groups in the second coordination sphere for each P site. Our work has shown that a combination of several dipolar coupling-based P-31/Al-27 double-resonance techniques such as transfer of population in double-resonance (TRAPDOR), rotational echo double-resonance (REDOR), and heteronuclear correlation spectroscopy (HETCOR) as well as H-1 --> P-31 cross polarization (CP) can provide more detailed structural information regarding the local environments of P and Al atoms in AlPO-based mesostructured materials, which is not readily available from straightforward P-31 and Al-27 magic-angle spinning (MAS) experiments.