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 MnO4- anions and four [Zn(NH 3)4]2+ cations. The other four MnO 41 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 NH 4NO3 and amorphous ZnMn2O4 could be established occurring even at 100°. Due to H-bonds between the [Zn(NH 3)4]2+ cation and the MnO4 - 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 (ReO4-) 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.
ASJC Scopus subject areas
- Drug Discovery
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry