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Preparation and Characterization of Preyssler‐type Phosphotungstic Acid, H 15– n [P 5 W 30 O 110 M n + ], with Different Encapsulated Cations ( M = Na, Ca, Bi, Eu, Y, or Ce), and their Thermal Stability and Acid Catalyst Properties
Author(s) -
Takahashi Keita,
Sano Tsuneji,
Sadakane Masahiro
Publication year - 2014
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201400038
Subject(s) - phosphotungstic acid , titration , thermal stability , nuclear chemistry , proton , inorganic chemistry , molecule , polyoxometalate , infrared spectroscopy , materials science , analytical chemistry (journal) , catalysis , chemistry , crystallography , organic chemistry , physics , quantum mechanics
Preyssler‐type phosphotungstic acid, H 15– n [P 5 W 30 O 110 M n + ], with different encapsulated cations ( M = Ca 2+ , Bi 3+ , Eu 3+ , Y 3+ , Ce 3+ ) were prepared and characterized using 31 P NMR and IR spectroscopy, acid‐base titration, and elemental analyses. The p K a value of an internal proton of Ca‐encapsulated derivative, [P 5 W 30 O 110 CaH in ] 12– , was estimated to be 5.9. Their thermal stabilities and acid catalyst properties were compared with a parent Na‐encapsulated Preyssler‐type phoshotungstic acid, H 14 [P 5 W 30 O 110 Na]. Thermal stability of the Preyssler‐type molecule was increased by exchanging the encapsulated Na + with Bi 3+ , Eu 3+ , or Ce 3+ , with keeping their high acidic properties.