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

The title complex, [Ni(C18H18N2O4)(H2O)], lies on a mirror plane with the NiII ion coordinated by two N and two O atoms of a tetradentate Schiff base ligand and one water O atom in a distorted square-pyramidal enviroment. The –CH2–CH2– group of the ligand is disordered equally over two sites about the mirror plane. The dihedral angle between the mean planes of the two symmetry-related chelate rings is 37.16 (6)°. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link complex molecules into one-dimensional chains along [100] and these chains are linked, in turn, by very weak intermolecular C—H⋯O hydrogen bonds into a two-dimensional network.

The title complex, [Ni(C 18 H 18 N 2 O 4 )(H 2 O)], lies on a mirror plane with the Ni II ion coordinated by two N and two O atoms of a tetradentate Schiff base ligand and one water O atom in a distorted square-pyramidal enviroment. The -CH 2 -CH 2group of the ligand is disordered equally over two sites about the mirror plane. The dihedral angle between the mean planes of the two symmetry-related chelate rings is 37.16 (6) . In the crystal structure, intermolecular O-HÁ Á ÁO hydrogen bonds link complex molecules into one-dimensional chains along [100] and these chains are linked, in turn, by very weak intermolecular C-HÁ Á ÁO hydrogen bonds into a two-dimensional network.

Comment
Schiff base complexes play an important role in the stereochemical models of transition metal coordination chemistry with their easy preparation, diversition and structural variation (Gamovski et al.,1993). They also have been intensively investigated owing to their strong coordination capability and diverse biological activities, such as antibacterial and antitumor activities (Yang et al., 2000;Tarafder et al., 2002). Therefore, synthesis of new shiff base Nickel(II) complexes is still the aim of many recent investigations (Garg & Kumar, 2003;Akine et al., 2005). As part of a series of crystal structure studies (Wang et al., 2007), we report here the synthesis and crystal structure of the title compound.
In the molecular structure ( Fig. 1), The Ni II ion is five coordinated by two N and two O atoms of a new tetradentate Schiff base ligand and one O atom of water molecule in a distorted square-pyramidal configuration. Two nitrogen atoms and two oxygen atoms of Schiff base occupy the basal plane, and the O atom of the coordinated water molecule is in the apical position. The dihedral angle between the planes of the two symmetry realted Ni/N/C/C/C/O chelate rings is 37.16 (6)°.
The molecule lies on a mirror plane and the -CH 2 -CH 2 -group of the ligand is disordered equally over two sites about the mirror plane.
In the crystal structure, intermolecular O-H···O hydrogen bonds link complex molecules into one-dimensional chains along [100] and these chains are linked, in turn, by very weak intermolecular C-H···O hydrogen bonds into a two-dimensional network (Fig. 2).
Experimental 1,2-ethylenediamine (1 mmol, 60.10 mg) was dissolved in hot methanol (10 ml) and added dropwise to a methanol solution (3 ml) of 3-methoxysalicylaldehyde (1 mmol, 152.14 mg). The mixture was then stirred at 323 K for 2 h. Subsequently, an aqueous solution (2 ml) of nickel chloride (1 mmol, 237.69 mg) was added dropwise and stirred for another 5 h. The solution was left at room temperature for 15 days, whereupon green block crystals suitable for X-ray diffraction were obtained.