Aqua-[4-chloro-2-(2-pyridylmethyl-imino-meth-yl)phenolato]copper(II) nitrate monohydrate

Hexanuclear copper(II) complex of 2-hy-droxy-N,N'-bis-[1-(2-hy-droxy-phen-yl)ethyl-idene]propane-1,3-di-amine incorporating an open-cubane core

The title mol-ecular structure, namely, di-aqua-tris-(μ3-1,3-bis-{[1-(2-oxidophen-yl)ethyl-idene]amino}-propan-2-olato)-μ3-hydroxido-dinitrato-hexa-copper(II) ethanol tris-olvate, [Cu6(C19H19N2O3)3(NO3)2(OH)(H2O)2]·3C2H5OH, corres-ponds to a non-symmetric hexa-nuclear copper complex. The complex exhibits one core in which three CuII metal centres are mutually inter-connected, two by two, via three phenolato oxygen anions acting in a μ2-mode. These three copper cations are inter-connected in a μ3-mode by one hydroxyl group. An open-cube structure is generated in which each of the CuII cations of the three CuO4N units is connected by two μ2-O anions from phenolate groups and one μ3-O atom from a hy-droxy anion. Each of the three penta-coordinated CuII cations situated in the open-cube unit has a distorted NO4 square-pyramidal environment. Each of these three CuII centres is inter-connected with another CuII cation via one enolate O atom in μ2-mode, yielding one CuNO4 unit and two CuNO3 units. The penta-coordinated CuII atom has a distorted square-pyramidal environment while the two tetra-coordinated copper(II) cations are situated in a square-planar environment. A series of intra-molecular O-H⋯O hydrogen bonds are observed. In the crystal, the units are connected two by two by inter-molecular C-H⋯O and O-H⋯O hydrogen bonds, thus forming sheets parallel to the ac plane.

A second polymorph of aqua-{4-chloro-2-[(pyridin-2-ylmeth-yl)imino-meth-yl]-phenolato}copper(II) nitrate mono-hydrate

The title complex, [Cu(C₁₃H₁₀ClN₂O)(H₂O)]NO₃·H₂O, was obtained by the reaction of 5-chloro­salicyl­aldehyde, 2-(amino­meth­yl)pyridine and copper nitrate in methanol. The first reported polymorph of this complex was triclinic [Liang et al. (2010 ▶). Acta Cryst. E66, m40]. The present polymorph crystallized in the monoclinic space group P2₁/c. The Cu^II ion is in a square planar environment and is coordinated by one phenolate O, one imine N and one pyridine N atom of the tridentate Schiff base ligand and by one water O atom. In the crystal, mol­ecules are linked through inter­molecular O—H⋯O hydrogen bonds to form chains along the a axis.