MOLECULAR-STRUCTURE AND SPECTROSCOPY OF AQUA-(1,10-PHENANTHROLINE) (L-METHIONINATO-N,O) COPPER(II) NITRATE MONOHYDRATE

The crystal and molecular structure of aqua(1,10-phenanthloline)(methioninato-N, O)-copper(II) nitrate monohydrate, [Cu(phen)(met)(H2O)]NO3 . H2O, has been determined by single crystal X-ray diffraction. In the mixed complex, the methionine act as bidentate ligand with the amino and carboxylate groups as donors. The geometry around the copper ion is square pyramidal, the axial position being occupied by a water molecule. The asymmetric units are hydrogen bonded to their neighbors, forming a polymeric hydrogen-bonded lattice. Stacking interactions between the phenanthroline rings from the different asymmetric units is observed. The strength of the stacking interaction is dependent on the amino acid coordinated. Visible absorption spectra and epr of frozen solution suggest that the structure is similar to that of analogous complexes in aqueous solution, with a CuN3O3 chromophore, where two of the coordinated oxygens are from two waters axially coordinated. Main crystal data: C17H22CuN4O7S, monoclinic, P2(1), a = 12.026(2),b = 6.8680(10), c = 13.355(3), beta = 113.58(3), Vol. = 1010.9 Angstrom(-3), Z = 2, formula weight = 490.0.