Aqua{4,4′-dibromo-6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}copper(II)

The title complex, [Cu(C18H16Br2N2O4)(H2O)], lies on a crystallographic mirror plane with the CuII ion coordinated by two N atoms and two O atoms of a tetradentate Schiff base ligand and one O atom from a water ligand in a slightly distorted square-pyramidal environment. The mirror plane, which coincides with the Cu—Owater bond, imposes disorder of the atoms of the ethylene group. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link complex molecules into extended chains along [100].

The title complex, [Cu(C 18 H 16 Br 2 N 2 O 4 )(H 2 O)], lies on a crystallographic mirror plane with the Cu II ion coordinated by two N atoms and two O atoms of a tetradentate Schiff base ligand and one O atom from a water ligand in a slightly distorted square-pyramidal environment. The mirror plane, which coincides with the Cu-O water bond, imposes disorder of the atoms of the ethylene group. In the crystal structure, intermolecular O-HÁ Á ÁO hydrogen bonds link complex molecules into extended chains along [100].

H. Xie
Comment Schiff-bases can readily form stable complexes with most transition metals, in which some may exhibit interesting properties (Yu et al., 2007;Ghosh et al., 2006;Singh et al., 2007;Nayka et al., 2006). Here, we report a Cu(II) complex based on the tetradentate Schiff-base ligand N,N'-ethylenebis(5-bromo-3-methoxysalicylaldimine. The molecular structure of the title compound is shown in Fig. 1. The complex lies on a crystallographic mirror plane with the Cu II ion coordinated in a slightly distorted square-pyramidal environment. The basal plane is occupied by two N atoms and two O atoms of the Schiff-base ligand, and the apical site is occupied by the O atom of the coordinated water molecule. The Cu II ion is displaced towards the Cu-O water bond from the plane formed by the two N atoms and two O atoms by 0.224 (4) Å. The Cu-N and Cu-O bond lengths are consistent with the corresponding distances found in other Cu Schiff base complexes (Nathan, et al., 2003;Saha, et al., 2007;Xing, 2009).

Experimental
Condensation of ethyl diamine and 5-bromo-3-methoxyl-2-hydroxy-benzaldehyde with the ratio 1:2 in ethanol gave the Schiff base ligand. The title compound was synthesized by treatment Cu(ClO 4 ) 2 .6H 2 O and the schiff-base ligand (1:1, molar ratio) in methanol. After the mixture was stirred for for about 30 min at room temperature, it was filtered and the filtrate was allowed to partial evaporate in air for one week to produce crystals suitable for X-ray diffraction with a yield about 52%.

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 calculat-supplementary materials sup-3 ing 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (