1. Studies on the Chemistry of TetraamminezincII Dipermanganate ZnNH34MnO42: LowTemperature Synthesis of the Manganese Zinc Oxide ZnMn2O4 Catalyst Precursor.
- Author
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IstvánE. Sajó, László Kótai, Gábor Keresztury, István Gács, György Pokol, János Kristóf, Bojan Soptrayanov, VladimirM. Petrusevski, Daniel Timpu, and PradeepK. Sharma
- Abstract
TetraamminezincII dipermanganate ZnNH34MnO42; 1 was prepared, and its structure was elucidated with XRDRietveldrefinement and vibrationalspectroscopy methods. Compound 1has a cubic lattice consisting of a 3D Hbound network built from blocks formed by four MnO$\rm{ {_{4}^{-}}}$anions and four ZnNH342+cations. The other four MnO$\rm{ {_{4}^{-}}}$anions are located in a crystallographically different environment, namely in the cavities formed by the attachment of the building blocks. A lowtemperature quasiintramolecular redox reaction producing NH4NO3and amorphous ZnMn2O4could be established occurring even at 100°. Due to Hbonds between the ZnNH342+cation and the MnO$\rm{ {_{4}^{-}}}$anion, a redox reaction took place between the NH3and the anion; thus, thermal deammoniation of compound 1cannot be used to prepare ZnNH32MnO42contrary to the behavior of the analogous perrhenate ReO$\rm{ {_{4}^{-}}}$ complex. In solutionphase deammoniation, a temperaturedependent hydrolysis process leading to the formation of ZnOH2and NH4MnO4was observed. Refluxing 1in toluene offering the heat convecting medium, followed by the removal of NH4NO3by washing with H2O, proved to be an easy and convenient technique for the synthesis of the amorphous ZnMn2O4. [ABSTRACT FROM AUTHOR]
- Published
- 2008