2-Methylimidazole Copper Iminodiacetates for the Adsorption of Oxygen and Catalytic Oxidation of Cyclohexane

The mixed-ligand copper(II) iminodiacetates [Cu(ida)(2-mim)(H(2)O)(2)]·H(2)O (1), [Cu(ida)(2-mim)(2)]·2H(2)O (2), [Cu(ida)(2-mim)(H(2)O)](n)·4.5nH(2)O (3), and [Cu(2)(ida)(2)(2-mim)(2)](n)·nH(2)O (4) (H(2)ida = iminodiacetic acid, 2-mim = 2-methylimidazole) were obtained from neutral or alkaline solutions at different temperatures. The novel complex 4 contains very small holes with diameters of 2.9 Å, which can adsorb O(2) selectively and reversibly between 1.89 to 29.90 bars, compared with the different gases of N(2), H(2), CO(2), and CH(4). This complex is stable up to 150 °C based on thermal analyses and XRD patterns. The four complexes show catalytic activities that facilitate the conversion of cyclohexane to cyclohexanol and cyclohexanone with hydrogen peroxide in a solution. The total conversion is 31% for 4.