Tetra­kis(μ₃-2-{[1,1-bis­(hy­droxy­meth­yl)-2-oxidoeth­yl]imino­meth­yl}-6-nitro­pheno­lato)tetra­copper(II)

The title cluster, [Cu₄(C₁₁H₁₂N₂O₆)₄], was obtained from the Cu⁰–FeCl₂·4H₂O–H₄L–Et₃N–DMF reaction system (in air), where H₄L is 2-hy­droxy­methyl-2{[(2-hy­droxy-3-nitro­phen­yl)methyl­idene]amino}­propane-1,3-diol and DMF is di­methyl­formamide. The asymmetric unit consists of one Cu²⁺ ion and one dianionic ligand; a -4 symmetry element generates the cluster, which contains a {Cu₄O₄} cubane-like core. The metal ion has an elongated square-based pyramidal CuNO₄ coordination geometry with the N atom in a basal site. An intra­molecular O—H...O hydrogen bond is observed. The solvent mol­ecules were found to be highly disordered and their contribution to the scattering was removed with the SQUEEZE procedure in PLATON [Spek (2009). Acta Cryst. D65, 148–155], which indicated a solvent cavity of volume 3131 ų containing approximately 749 electrons. These solvent molecules are not considered in the given chemical formula.

Crystal structure of {2-[({2-[(2-amino­eth­yl)amino]­eth­yl}imino)­meth­yl]pheno­lato}aqua­copper(II) bromide

In the mononuclear copper(II) title complex, [Cu(C₁₁H₁₆N₃O)(H₂O)]Br, the Cu^II atom is coordinated by one O and three N atoms of the Schiff base ligand that forms together with one water mol­ecule a slightly distorted [CuN₃O₂] square-pyramidal polyhedron. The deviation of the Cu^II atom from the mean equatorial plane is 0.182 (2) Å. The equatorial plane is nearly coplanar to the aromatic ring of the ligand [angle between planes = 10.4 (1)°], and the water molecule is situated in the apical site. All coordinating atoms (except the imine nitro­gen) and the bromide ion contribute to the formation of the N—H...Br, O—H...Br and O—H...O hydrogen bonds, which link mol­ecules into chains along [01-1].