Magnetism of novel Schiff-base copper(II) complexes derived from aminoacids

Magnetic properties of five copper(II) complexes of the formula [CuL3(H2O)(2)] or [CuL4(H2O)] were investigated. These contain a Schiff-base L derived from salicylaldehyde and aminoacids. The ligand L is represented by four bonding isomers (1 through 4) and it is either tridentate (L-3) or tetradentate (L-4). The fifth ligand contains sulfonato group instead of the carboxyl one. Structurally, two complexes are monomers (I and 4), one is a dimer (5), and two are polymers (2 and 3). Their magnetic behaviour is more complex: 1 behaves as an antiferromagnetic Heisenberg diad, 2 and 4 are ferromagnetic chains, 3 is a combined ferromagnetic/antiferromagnetic ladder (ribbon), and 5 exhibits a complex 3D-ordering with unusual temperature evolution of the effective magnetic moment. (C) 2013 Elsevier Ltd. All rights reserved.