In situ synthesis of manganese(III) complexes under control: Crystal structure and magnetic properties

Three new manganese(III) compounds have been synthesized via in situ ligand transformation and oxidation of Mn(II) ions. In the presence/absence of N3− anion in the reaction solutions, the dinuclear/mononuclear Mn(III) coordination compounds were formed, respectively. A structural analysis of the dinuclear compounds (1, 2) shows that the six coordination Mn(III) atoms are linked by two methanolato oxygen atoms from two ligands to form a rectangular arrangement of the metal ions and oxygen atoms. In complex 3, two facially coordinating tridentate ligands are bound to the Mn(III) ion, resulting in a MnN4O2 chromophore with an axially-compressed octahedral geometry. In addition, variable-temperature magnetic analysis of 1 shows that a weak antiferromagnetic coupling interaction was mediated through the methanolato oxygen bridge between two Mn(III) ions and the exchange parameter is given as J = − 3.6 cm− 1.