Synthesis, crystal structures, and magnetic properties of new tetranuclear Cu(II) complexes of bis-bidentate Schiff-base ligands

Two tetranuclear copper(II) complexes with long rigid Schiff-base ligands [Cu4(bmsbd)2]·2DMF [H2bmsbd = N,N′-bis-(3-methoxy-salicylidene)benzene-1,4-diamine] (1) and [Cu4(besbd)2]·DMF·5H2O [H2besbd = N,N′-bis-(3-methoxy-salicylidene)benzene-1,4-diamine] (2) have been synthesised and characterized. Single X-ray diffraction analysis reveals that both complexes exhibit interesting [2 × 2] molecular grid-like configuration assembled by four organic ligands in a head-to-tail mode to bind four copper(II) ions. Magnetic property investigations reveal weak antiferromagnetic interaction viaσ-bond pathway of long rigid Schiff-base ligand between the neighboring copper(II) ions in both complexes.