HIGH-RESOLUTION NMR AND STRUCTURAL INVESTIGATIONS OF THE 2-AMMONIUM 2-METHYL PROPANOL DIHYDROGENODIPHOSPHATE [(CH3)(2)C(NH3)CH2OH](2)H2P2O7

We report on high resolution C-13 and P-31 NMR and X-ray diffraction m easurements of the organic dihydrogenodiphosphate (C4H12NO)(2)H2P2O7. The obtained C-13 magic angle spinning (MAS) NMR spectrum at room temp erature shows four resonances at 22, 23, 57 and 66 ppm which we attrib ute to the four magnetically inequivalent carbons of the organic catio n, the two CH3, the CH2 and the quaternary carbon, respectively. The c orresponding P-31 MAS NMR spectrum presents two isotropic resonances a t -9.2 and -6.9 ppm assigned to the two crystallographically inequival ent sites of the phosphorus atoms in the structure. The obtained NMR r esults are in quite good agreement with our X-ray data on the same sam ple. These results confirm the non-centrosymmetric structure of this m aterial and its ability to exhibit non-linear optical properties. (C) 1997 Elsevier Science S.A.