Tetramanganese(II) cluster with centered trigonal topology: Structure and magnetic properties

A new tetranuclear manganese(II) compound, [Mn₄L ₆](ClO₄)₂ (L is the Schiff base derived from 2-pyridylaldehyde and 2-aminophenolate), has been synthesized and characterized structurally and magnetically. The compound is the first example of tetramanganese clusters with centered planar trigonal topology in which a central Mn(II) ion is connected with three peripheral Mn(II) ions by double phenoxo bridges, generating a trigonal Mn[(μ-phenoxo)₂Mn] ₃ core. Magnetic studies have demonstrated a very weak ferromagnetic interaction between the central and peripheral Mn(II) ions, which leads to a high-spin ground state (S = 10). The ferromagnetic interaction has been tentatively related to distortion of the metal coordination environments after comparing the magnetic and structural data of the known Mn(II) complexes with similar bridging moieties.