Synthesis and Characterization of an Asymmetric, Linear, Trinuclear Manganese(II) Complex

After prolonged heating in acetonitrile, a highly asymmetric, trinuclear manganous complex self-assembles from MnCl2 and bis(2-pyridylmethyl)-1,2-ethanediamine (bispicen). The central Mn(II) ion is bridged to the terminal metal ions in the molecule by single chloride anions. The organic ligands each bind to a single Mn(II) ion. The central Mn(II) and only one of the terminal Mn(II) ions are six-coordinate and bound to bispicen ligands. The remaining terminal Mn(II) ion is coordinated by a tetrahedral array of chloride anions, endowing the trinuclear cluster with a high degree of asymmetry. Variable temperature magnetic measurements are consistent with an S = 5/2 system, indicating net antiferromagnetic coupling.