Manganese(III) Formate: A Three-dimensional Framework that Traps Carbon Dioxide Molecules

The reaction of KMnO4 with 95% formic acid led to the formation of "manganese(III) formate" of compn. Mn(HCOO)3·1/2CO2·1/4HCOOH·2/3H2O, which was characterized spectroscopically, by TGA, and by x-ray crystallog. (cubic, space group Im-3, R1 = 0.0520). The structure of "manganese(III) formate" is a three-dimensional framework of manganese ions bridged by six nearest formate ligands, and the resulting open cages trap carbon dioxide and formic acid mols. Jahn-Teller distortion of the MnIII ions was shown by the magnetic properties, which also indicated ferromagnetic intralayer and weaker antiferromagnetic interlayer interactions.