Studies on the Chemistry of Tetraamminezinc(II) Dipermanganate ([Zn(NH3)4](MnO4)2): Low‐Temperature Synthesis of the Manganese Zinc Oxide (ZnMn2O4) Catalyst Precursor |
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| Authors: | István E Sajó László Kótai Gábor Keresztury István Gács György Pokol János Kristóf Bojan Soptrayanov Vladimir M Petrusevski Daniel Timpu Pradeep K Sharma |
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| Institution: | 1. Chemical Research Center, Hungarian Academy of Sciences, P.?O. Box 17, HU‐1525 Budapest;2. Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Pf. 91, HU‐1521 Budapest;3. University of Pannonia, Department of Analytical Chemistry, Egyetem u. 10, HU‐8200 Veszprém;4. University Sv Kiril Metodij, PMF, Institute Hemija, POB 162, Skopje 1001, Macedonia;5. Petru Poni Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda, 41A, Iasi 700487, Romania;6. Department of Chemistry, J.?N.?V. University, Jodhpur, 342005, Jodhpur, India |
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| Abstract: | Tetraamminezinc(II) dipermanganate (Zn(NH3)4](MnO4)2; 1 ) was prepared, and its structure was elucidated with XRD‐Rietveld‐refinement and vibrational‐spectroscopy methods. Compound 1 has a cubic lattice consisting of a 3D H‐bound network built from blocks formed by four MnO anions and four Zn(NH3)4]2+ cations. The other four MnO anions are located in a crystallographically different environment, namely in the cavities formed by the attachment of the building blocks. A low‐temperature quasi‐intramolecular redox reaction producing NH4NO3 and amorphous ZnMn2O4 could be established occurring even at 100°. Due to H‐bonds between the Zn(NH3)4]2+ cation and the MnO anion, a redox reaction took place between the NH3 and the anion; thus, thermal deammoniation of compound 1 cannot be used to prepare Zn(NH3)2](MnO4)2 (contrary to the behavior of the analogous perrhenate (ReO ) complex). In solution‐phase deammoniation, a temperature‐dependent hydrolysis process leading to the formation of Zn(OH)2 and NH4MnO4 was observed. Refluxing 1 in toluene offering the heat convecting medium, followed by the removal of NH4NO3 by washing with H2O, proved to be an easy and convenient technique for the synthesis of the amorphous ZnMn2O4. |
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| Keywords: | Permanganate Tetraamminezinc(II) cation H‐Bond network Spinel compounds Zinc complexes |
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