A new tetranuclear copper(II) Schiff base complex containing Cu ₄O₄ cubane core: Structural and spectral characterizations

A new tetra-nuclear coordination complex [Cu₄(HL)₄] (1) containing Cu₄O₄ cubane core has been synthesized by using Schiff base ligand [(OH)C₆H₄CHNC(CH ₃)(CH₂OH)₂] (H₃L), obtained by the 1:1 condensation of 2-amino-2-methyl-1,3-propanediol with salicylaldehyde and thoroughly characterized by micro-analytical, FT-IR, UV-Vis, thermal and room temperature magnetic susceptibility measurements. Structural characterization of the complex has been done by single crystal X-ray diffraction analysis. Structural elucidation reveals versatile coordination modes for two identical alkoxo oxygen atoms of the Schiff base ligand; one in its deprotonated form exhibits µ₃-bridging to bind three similar copper(II) centers whilst the protonated one remains as monodentate or non-coordinating. Structural analysis also shows that the Cu₄O₄ cubane core in 1 consists of four µ₃-alkoxo oxygen bridged copper(II) atoms giving an approximately cubic array of alternating oxygen atoms and copper(II) atoms where the metal centers display both distorted square pyramidal and distorted octahedral geometries. © 2011 Elsevier B.V. All rights reserved.