High resolution NMR and structural investigations of the 2-ammonium 2-methyl propanol dihydrogenodiphosphate [(CH3)2C(NH3)CH2OH]2H2P2O7

We report on high resolution 13C and 31P NMR and X-ray diffraction measurements of the organic dihydrogenodiphosphate (C4H12NO)2H2P2O7. The obtained 13C magic angle spinning (MAS) NMR spectrum at room temperature shows four resonances at 22, 23, 57 and 66 ppm which we attribute to the four magnetically inequivalent carbons of the organic cation, the two CH3, the CH2 and the quaternary carbon, respectively. The corresponding 31P MAS NMR spectrum presents two isotropic resonances at − 9.2 and − 6.9 ppm assigned to the two crystallographically inequivalent sites of the phosphorus atoms in the structure. The obtained NMR results are in quite good agreement with our X-ray data on the same sample. These results confirm the non-centrosymmetric structure of this material and its ability to exhibit non-linear optical properties.