An Unprecedented Tridentate-Bridging Coordination Mode of Permanganate Ions: The Synthesis of an Anionic Coordination Polymer—[CoIII(NH3)6]n[(K(κ1-Cl)2(μ2,2′,2″-(κ3-O,O′,O″-MnO4)2)n∞]—Containing Potassium Central Ion and Chlorido and Permanganato Lig

A unique compound (compound <b>1</b>) with structural features including an unprecedented tridentate-bridging coordination mode of permanganate ions and an eight-coordinated (rhombohedral) κ¹-chlorido and tridentate permanganato ligand in a potassium complex containing coordination polymer (Co^III(NH₃)₆]_n[(K(κ¹-Cl)₂(μ^2,2',2″-(κ³-O,O',O″-MnO₄)₂)_n^∞) with isolated regular octahedral hexamminecobalt(III) cation was synthesized with a yield of >90%. The structure was found to be stabilized by mono and bifurcated N-H∙∙∙Cl and N-H∙∙∙O (bridging and non-bridging) hydrogen bonds. Detailed spectroscopic (IR, far-IR, and Raman) studies and correlation analysis were performed to assign all vibrational modes. The existence of a resonance Raman effect of compound <b>1</b> was also observed. The thermal decomposition products at 500 °C were found to be tetragonal nano-CoMn₂O₄ spinel with 19-25 nm crystallite size and KCl. The decomposition intermediates formed in toluene at 110 °C showed the presence of a potassium- and chloride-containing intermediates combined into KCl during aqueous leaching, together with the formation of cobalt(II) nitrate hexahydrate. This means that the Co^III-Co^II redox reaction and the complete decomposition of the permanganate ions occurred in the first decomposition step, with a partial oxidation of ammonia into nitrate ions.