Dinuclear Cobalt(II) Complexes of an Acyclic Phenol-Based Dinucleating Ligand with Four Methoxyethyl Chelating Arms − First Magnetic Analyses in an Axially Distorted Octahedral Field

Abstract

An end-off type acyclic ligand with four methoxyethyl chelating arms, 2,6-bis[bis(2-methoxyethyl)aminomethyl]-4-methylphenol [H(bomp)], formed dinuclear cobalt(II) complexes [Co2(bomp)(MeCO2)2]BPh4 (1) and [Co2(bomp)(PhCO2)2]BPh4 (2). X-ray analysis revealed that complex 1·CHCl3 contains two cobalt ions bridged by a phenolic oxygen and two acetate groups, forming a μ-phenoxo-bis(μ-acetato)dicobalt(II) core. Magnetic susceptibility was measured for 1 and 2 over the temperature range 1.8−300 K. The data were successfully analyzed using a new theoretical method assuming an axially distorted octahedral field (Δ = 753 and 775 cm−1, respectively) for each cobalt(II) ion to reveal weak antiferromagnetic interactions (J = −0.96 and −1.74 cm−1, respectively).