Manganese(II) complexes of an acyclic phenol-based dinucleating ligand with four methoxyethyl chelating arms: synthesis, structure, magnetism and electrochemistry

Dinuclear manganese(II) complexes [Mn2(bomp)(PhCO2)2]BPh4 (1), [Mn2(bomp)(MeCO2)2]BPh4 (2), and [Mn2(bomp)(PhCO2)2]PF6 (3) were synthesized with a dinucleating ligand 2,6-bis[bis(2-methoxyethyl)aminomethyl]-4-methylphenol [H(bomp)]. Dinuclear zinc complex [Zn2(bomp)(PhCO2)2]PF6 (4) was also synthesized for the purpose of comparison. X-ray analysis revealed that the complex 1·CHCl3 contains two manganese ions bridged by the phenolic oxygen and two benzoate groups, forming a μ-phenoxo-bis(μ-benzoato)dimanganese(II) core. Magnetic susceptibility measurements of 1–3 over the temperature range 1.8–300 K indicated antiferromagnetic interaction (J=−4 to −6 cm−1). Cyclic voltammograms of 3 showed a quasi-reversible oxidation process at +0.9 V versus a saturated sodium chloride calomel reference electrode, assigned to MnIIMnII/MnIIMnIII.