Spectroscopic studies of some copper(II) complexes with amino acids

Copper-amino acids complexes in aqueous solution: [Cu-(L1)2]·H2O (1), (L1 = methionine), [Cu-(L2)2]·H2O (2), (L2 = phenylalanine) and [Cu(L3)2] (3), (L3 = triptophan) were synthesized and characterized by means of elemental, thermal and IR, UV–Vis and EPR spectroscopic investigations.The IR spectra show that amino acids act as bidentate ligands with coordination involving the carboxylic oxygen and the nitrogen atom of the amino group. The ν(CO) and δ(N–H) vibrations are shifted toward higher (for 1 and 2) and lower-wave numbers for 3.Visible electronic and Powder EPR spectra at room temperature are typical for monomeric species with square-planar local symmetry around the metal ion.