Synthesis, XRD structures and properties of diaqua(iminodiacetato)copper(II), [Cu(IDA)(H2O)2], and aqua(benzimidazole)(iminodiacetato)copper(II), [Cu(IDA)(HBzIm)(H2O)]

The stoichiometric reaction of copper(II) hydroxycarbonate with iminodiacetic acid (H(2)IDA) in water under reduced pressure yields good crystalline samples of [Cu(IDA)(H2O)(2)] (compound I). Using equimolar amounts of benzimidazole (HBzIm) the above reaction produces crystals of [Cu(IDA)(HBzIm)(H2O)] (compound II). Both compounds were characterised by TG analysis (with IR study of the evolved gasses in the pyrolysis), spectral and/or magnetic properties (IR, electronic, ESR spectrum, magnetic susceptibility in the 1.8-300 K range) and single crystal X-ray diffraction. The structure of I was re-determined (final R1 = 0.022) and it confirms the earlier reported distorted octahedral Cu(II) coordination (type 4 + 1 + 1), the fac-terdentate chelating and bridging roles for IDA ligand, as well as the 'polymeric' chain structure, but with a rather different hydrogen bonding network. In compound II (final R1 = 0.035) the Cu(II) exhibits a square base pyramidal coordination (type 4 + 1) and the IDA exhibits the mer-terdentate chelating configuration observed earlier for complexes having equimolar Cu(II)/IDA/HIm or Him-like ratio, but now with a large dihedral angle (31.3 degrees) between basal Cu(II) coordination and HBzIm mean planes. (C) 1999 Elsevier Science Ltd. All rights reserved.