Solution and solid state study of copper(II) ternary complexes with some dipeptides presence in Aβ-42 peptide and methionine

The ternary complexes of Cu(II) with some dipeptides and methionine were studied both in aqueous solution and in solid state. The values of the constants for CuL1L2 species (L1 = GlyGly, GlyVal, GlyLeu or GlyPhe; L2 = Met) were 15.66, 15.75, 15.69 and 16.31, respectively. The complexes [Cu(GlyGly)Met]K (1), [Cu(GlyVal)Met]K·2H2O (2), [Cu(GlyLeu)(Met)(H2O)2]K·H2O (3) and [Cu(GlyPhe)(Met)(H2O)]K·2H2O (4) were isolated in pH around 7 and characterized through microanalyses, thermogravimetry, UV-Vis, infrared and EPR spectroscopies. The presence of the sulfur noncoordinated to metal in these ternary complexes can exert reduction action in biological systems under stress conditions.