Unprecedented 4/5-methylimidazole linkage isomerism within a binuclear copper(II) complex molecule

A new dinuclear copper(II) complex namely [Cu2(μ2-1,4-CDTA)(H4Meim)(H5Meim)(H2O)2]·2H2O (1,4-CDTA = Trans-14-cyclohexanediaminotetraacetate(4-) ion, H4Meim/H5Meim = 4/5-methylimidazole) has been synthesized and characterized by elemental analysis, thermo-gravimetry (TG), FT-IR and electronic (diffuse reflectance) spectroscopy. Single-crystal X-ray diffraction analysis reveals that in the dinuclear copper(II) complex molecule each tautomer (4-methylimidazole or 5-methylimidazole) is linked to a different metallic center within the same molecule. The results are briefly discussed on the basis of the previous literature. Attention is paid to the driving forces of this unusual reported structure in order to deepen on the factors that influence the linkage isomerism.