{4,4′,6,6′-Tetraiodo-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethanylylidene)]diphenolato}copper(II)

In the title compound, [Cu(C19H16I4N2O2)], the CuII atom and the substituted C atom of the diamine segment lie on a crystallographic twofold rotation axis. The geometry around the CuII atom is distorted square-planar, which is supported by the N2O2 donor atoms of the coordinated Schiff base. The dihedral angle between the symmetry-related substituted benzene rings is 29.40 (19)°. In the crystal, a short I⋯I [3.8766 (6) Å] contact is present and links neighbouring molecules into chains propagating along the a axis.

In the title compound, [Cu(C 19 H 16 I 4 N 2 O 2 )], the Cu II atom and the substituted C atom of the diamine segment lie on a crystallographic twofold rotation axis. The geometry around the Cu II atom is distorted square-planar, which is supported by the N 2 O 2 donor atoms of the coordinated Schiff base. The dihedral angle between the symmetry-related substituted benzene rings is 29.40 (19) . In the crystal, a short IÁ Á ÁI [3.8766 (6) Å ] contact is present and links neighbouring molecules into chains propagating along the a axis.
The asymmetric unit of the title compound, Fig. 1, comprises half of a tetradentate Schiff base ligand. Atoms Cu1 and C9 lie on a crystallographic two-fold rotation axis. The geometry around the Cu II atom is distorted square-planar which is supported by the N 2 O 2 donor atoms of the coordinated Schiff base. The dihedral angle between the symmetry-related substituted benzene rings is 29.40 (19)°. The bond lengths (Allen et al., 1987) and angles are within the normal ranges and are comparable to those reported for a related structure (Kargar et al., 2012).
In the crystal, a short I···I [3.8766 (6) Å] contact is present, which is shorter than the sum of the van der Waals radii of I atoms [3.96 Å;Bondi, 1964]. It links neighbouring molecules along the a axis forming chains.

Experimental
The title compound was synthesized by adding 3,5-diiodo-salicylaldehyde-2,2-dimethyl-1,3-propanediamine (2 mmol) to a solution of CuCl 2 . 4H 2 O (2.1 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for 30 min. The resultant solution was filtered. Red single crystals of the title compound, suitable for X-ray structure analysis, were obtained from ethanol by slow evaporation of the solvent at room temperature over several days.

Refinement
The H-atoms were included in calculated positions and treated as riding atoms: C-H = 0.93, 0.96 and 0.97 Å for CH, CH 3 and CH 2 H-atoms, respectively, with U iso (H) = k x U eq (C), where k = 1.5 for CH 3 H-atoms, and = 1.2 for other Hatoms.   Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.