Water structure and dynamics in H3PW12O40.nH2O and H3PMo12O40.nH2O: a deuterium magnetic resonance study

Probing surface acidity, basicity, and dipolarity/polarizability of 12-tungstophosphoric acid by means of solvatochromic dyes

“…Heteropolyacids have been widely used in homogeneous and heterogeneous catalytic systems as well as photocatalysts. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] They and related compounds have attracted increasing interest in catalysis owing to their ability to catalyze both acidic and redox processes. [18][19][20][21][22] The acidic strength of heteropolyacids in solution has been studied by conductivity, 23 UV/vis spectroscopy of Hammett (H 0 ) indicators, 24 NMR spectroscopy, 25 and 13 C NMR chemical shift of mesityl oxide as a probe.…”

Dynamic studies of Ormosil membranes

“…They should correspond to the presence of two kinds of water molecules with different motions, or also some charged deuterons clusters (D 3 O + , D 2 O þ 5 ) as it was also observed by deuterium NMR of pure POM [28][29][30]. At 245 K, half of the remaining signal disappears, and a much broader signal appears.…”

“…Similar behavior was also already reported in pure hydrated and deuterated POM [28], and associated to the presence of mobile deuterons (mobile water), mobile [D 3 O] + and immobile deuterons (water molecules without mobility). The ratio of these different species is related to the hydration ratio of the POM [29,30].…”

Water Dynamics in Na3PW12O40·nH2O: A 2H-NMR and 31P-NMR Investigation

“…4.83 3.9 0.50 1.9 8.0 × 10 -9 5.5 × 10 -4 5.25 3.9 0.53 2. 7 8.0 × 10 -9 5.5 × 10 -4 5.77 3.9 0.55 3.3 8.0 × 10 -9 5.5 × 10 -4 6.40 3.9 0.70 5. 4 8.0 × 10 -9 2.8 × 10 -4 6.50 3.9 0.89 7.2…”

“…On the other hand, we have shown , that 2 H-NMR and 31 P-NMR spectroscopies give valuable informations on the structure and dynamics of water molecules chemisorbed in the acid H 3 PW 12 O 40 · n H 2 O. In fact, 2 H-NMR spectral profiles recorded from deuterated crystallization water can be used to establish the type of motion and the related characteristic times, while the line width and relaxation time of the single spectral line generated by the 31 P nucleus are both sensitive to water dynamics and structure …”