Mobility and exchange of protons and methanol molecules in H3PW12O40 pseudoliquid phase detected by solid state NMR

The dynamic behavior of CH3OH molecules absorbed in the ''pseudoliquid phase'' of a heteropolyacid, H3PW12O40, was analyzed by high resolution solid-state C-13, H-1 and P-31 NMR. When CH3OH absorbed was less than 3 molecules/heteropolyanion, CH3OH molecules were all protonated and the rest of the protons remained presumably directly bonded to the bridging oxygen atoms of heteropolyanion. The hydroxyl protons of CH3OH and the protons of heteropolyacid exchanged rapidly in a wide range of absorption level, and CH3OH molecules became very mobile when the absorption amount exceeded 6 molecules/anion.