Synthesis, characterization and magnetic properties of six new copper(II) complexes with aminoacids as bridging ligand, exhibiting ferromagnetic coupling

The synthesis, crystallographic analysis and magnetic studies of six new copper(II) complexes of formulae [Cu(μ-ala)(im)(H2O)]n(ClO4)n (1), [Cu(μ-ala)(pz)(μ-ClO4)] (2), [Cu(μ-phe)(im)(H2O)]n(ClO4)n (3), [Cu(μ-gly)(H2O)(ClO4)]n (4), [Cu(μ-gly)(pz)(ClO4)]n(5) and [Cu(μ-pro)(pz)(ClO4)]n (6) have been carried out (ala = alanine; phe = phenylalanine; gly = glycine; pro = proline; im = imidazole; pz = pyrazole). In all cases, the deprotonated aminoacid ligand acts as chelate through the N(amine) and one O(carboxylato), whereas the second O atom of the same carboxylato acts as a bridge to the neighbouring copper(II) ion. The coordination of copper(II) ions is square-pyramidal in all complexes but 2 (elongated Oh). All complexes (1–6) are uniform chains with syn–anti (equatorial–equatorial) coordination mode of the carboxylato bridging ligand, exhibiting intrachain ferromagnetic interactions.