Synthesis, structural characterization and redox properties of copper(II) and manganese(II) complexes containing tridentate (N-(2-methylpyridine)-2-aminomethyl benzoate) ligand

Two new complexes, [Cu(mamba)2] and [Mn(mamba)2] (mamba−, N-(2-methylpyridine)-2-aminomethyl benzoate) were synthesized and characterized by X-ray crystallography. Whereas the [Cu(mamba)2] complex crystallizes in a monoclinic P21/c space group, the [Mn(mamba)2] complex crystallizes in a triclinic space group. The nature of the metal ion greatly influences the lattices and the molecular structures of the compounds. In the crystal lattice of the copper complex are four cocrystallized methanol solvent, which are all involved in building six strong H-bonds with the complex. However, the lattice for the manganese complex contain only one cocrystallized methanol, along with one NaClO4, that is also involved in making one H-bond with the [Mn(mamba)2] unit. Nevertheless, the sodium ion is coordinated to the ClO4−, the methanol and two [Mn(mamba)2] to form a stable extended chain metal complex. Electrochemical studies indicated that both complexes undergo quasi reversible one electron reduction in acetonitrile.