Synthesis and crystal structure of a manganese(II) complex, Mn(phen)2(phcoo)2 • 2H2O

The title complex has been prepared by the reaction of Mn(phcoo)(2) with phen in EtOH/H2O solution (where phcoo = the anion of benzoic acid, phen = 1,10-phenanthroline). The crystal structure has been determined by X-ray diffraction. The complex molecule has distorted octahedron geometry. Carboxyl O atoms coordinate to Mn(II) from unidentate ligands with a cis-configuration. Two uncoordinated O atoms of benzoate anions locate on the one side of the coordination plane so that there is free space on the other side of the plane; such a spatial arrangement may promote the attack of a water molecule at the manganese atom in the oxygen evolution process in photosystem II.