Synthesis, characterization and properties of copper(II) complexes containing N,N-di-(2-pyridylmethyl)-glycine and alanine

The multidentate ligands N,N-di-(2-pyridylmethyl)-glycine (bpg) and N,N-di-(2-pyridylmethyl)-alanine (bpa) were synthesized as their lithium salts and X-ray structures of these solved. Copper(II) complexes of these ligands have been prepared and structurally characterized. X-ray structures of compounds [Li(bpg)(H2O)].H2O (1) and [Li(bpa)(H2O)].H2O (2) shown the Li(I) ions adopt a distorted trigonal bipyrimidal geometry whereas in the Cu(II) compounds [Cu(bpg)](NO3).H2O (3) and [Cu(bpa)](SO3CF3).H2O (6) the Cu(II) ions are in an approximate square pyramidal geometry. The ligand chelates the copper ion in a tetradentate fashion with two pyridine N atoms, one tertiary imine N atom occupying the equatorial positions, and one carboxylato O atom occupying an axial position. The last equatorial position is occupied by the O atom from the carboxylate group of the neighboring molecule and thus forms a covalently bonded zig-zag chain, coordination polymer. (C) 2003 Elsevier Science B.V. All rights reserved.