Bis(2-iminomethyl-5-methoxyphenolato)nickel(II)

The title compound, [Ni(C8H8NO2)2], is a centrosymmetric mononuclear nickel(II) complex. The NiII ion, lying on an inversion centre, is four-coordinated in a square-planar geometry by two phenolate O and two imine N atoms from two symmetry-related 2-iminomethyl-5-methoxyphenolate ligands. In the crystal, molecules are linked into corrugated layers parallel to (100) by N—H⋯O hydrogen bonds.

The title compound, [Ni(C 8 H 8 NO 2 ) 2 ], is a centrosymmetric mononuclear nickel(II) complex. The Ni II ion, lying on an inversion centre, is four-coordinated in a square-planar geometry by two phenolate O and two imine N atoms from two symmetry-related 2-iminomethyl-5-methoxyphenolate ligands. In the crystal, molecules are linked into corrugated layers parallel to (100) by N-HÁ Á ÁO hydrogen bonds.
Financial support from the Jiaying University research fund is gratefully acknowledged.

C. Tang
Comment Nickel(II) complexes play an important role in both bioinorganic chemistry and coordination chemistry (Suh et al., 1996;Dey et al., 2004;Angulo et al., 2001;Ramadevi et al., 2005;Edison et al., 2004). Recently, the author has reported a nickel(II) complex (Tang, 2009). As a continuation of this work, the title mononuclear nickel(II) complex ( Fig. 1), is reported in this paper.
The title complex is a centrosymmetric mononuclear nickel(II) complex. The Ni II ion, lying on the inversion centre, is four-coordinated in a square-planar geometry, with two phenolate O and two imine N atoms from two 2-(iminomethyl)-5methoxyphenolate ligands. The coordination bond lengths (Table 1) are comparable to those observed in related complexes (Kamenar et al., 1990;Costes et al., 1994).
In the crytal structure, molecules are linked through intermolecular N-H···O hydrogen bonds (Table 2)

Refinement
Atom H1 was located in a difference Fourier map and refined isotropically, with N-H distance restrained to 0.90 (1) Å and U iso set at 0.08 Å 2 . Other H atoms were constrained to ideal geometries, with C-H = 0.93-0.96 Å and U iso (H) = 1.2U eq (C) and 1.5U eq (C8).

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.