{4,4′-Dibromo-6,6′-dimethoxy-2,2′-[1,2-phenylenebis(nitrilomethanylylidene)]-κ4 O 1,N,N′,O 1′}nickel(II)

In the title complex, [Ni(C22H16Br2N2O4)], the NiII ion is coordinated by two N atoms and two O atoms of a tetradentate Schiff base ligand, forming a slightly distorted square-planar coordination environment. The dihedral angle between the two bromo-substituted benzene rings is 10.1 (3)°.

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5411).
The molecular structure of the title complex is shown in Figure 1. The coordination of the Ni II ion is slightly distorted square-planar, formed by two N atoms and two O atoms of the Schiff-base ligand. The mean deviation from the plane formed by the two N atoms, two O atoms and the Ni II ion is 0.0426 Å. The Ni-N and Ni-O bond lengths are consistent with the corresponding distances in other nickel(II) complexes containing similar chelating tetradentate schiff-base ligands (Wang et al., 1994;Bhattacharya et al., 2011;Yu et al., 2009;Kargar et al., 2009;Felices et al., 2009).

Experimental
The Schiff-base ligand can be readily synthesized by condensation 1,2-diaminobenzene and 5-bromo-2-hydroxy-3-methoxybenzaldehyde with the ratio 1:2 in ethanol. The preparation of the title complex was carried out by the reaction of Ni(ClO 4 ) 2 .6H 2 O and the schiff-base ligand (1:1, molar ratio) in methanol. After the stirring process was continued for about half an hour at room temperature, the mixture was filtered and the filtrate was allowed to slowly evaporate in air for several days to produce crystals suitable for X-ray diffraction with a yield about 56%.

Refinement
H atoms were placed in calculated positions with C-H distances of 0.93 and 0.96 Å, and were allowed for as riding atoms with U iso (H) = 1.2U eq (C) or 1.5U eq (C methyl ).

{4,4′-Dibromo-6,6′-dimethoxy-2,2′-[1,2-phenylenebis(nitrilomethanylylidene)]-κ 4 O 1 ,N,N′,O 1′ }nickel(II)
Crystal data [Ni(C 22 H 16 where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.001 Δρ max = 1.61 e Å −3 Δρ min = −1.16 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.