{6,6′-Diethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenolato}(2-ethoxy-6-formylphenolato)cobalt(III)–ethanol–water (1/1/1)

The asymmetric unit of the title compound, [Co(C23H28N2O4)(C9H9O3)]·C2H5OH·H2O, comprises one complex molecule, a water molecule of crystallization and an ethanol molecule of crystallization, which is disordered over two positions with a ratio of refined site occupancies of 0.567 (10):0.433 (10). The CoIII ion is in a slightly distorted octahedral geometry involving an N2O2 atom set of the tetradenate Schiff base ligand and two O atoms of 2-ethoxy-6-formylphenolate. The H atoms of the water molecule act as donors in the formation of bifurcated intermolecular O—H⋯(O,O) hydrogen bonds with the O atoms of the hydroxy and ethoxy groups with R 1 2(5) ring motifs, which may influence the molecular conformation. The crystal structure is further stabilized by intermolecular O—H⋯O and C—H⋯O interactions.

The asymmetric unit of the title compound, [Co(C 23 H 28 N 2 O 4 )-(C 9 H 9 O 3 )]ÁC 2 H 5 OHÁH 2 O, comprises one complex molecule, a water molecule of crystallization and an ethanol molecule of crystallization, which is disordered over two positions with a ratio of refined site occupancies of 0.567 (10):0.433 (10). The Co III ion is in a slightly distorted octahedral geometry involving an N 2 O 2 atom set of the tetradenate Schiff base ligand and two O atoms of 2-ethoxy-6-formylphenolate. The H atoms of the water molecule act as donors in the formation of bifurcated intermolecular O-HÁ Á Á(O,O) hydrogen bonds with the O atoms of the hydroxy and ethoxy groups with R 1 2 (5) ring motifs, which may influence the molecular conformation. The crystal structure is further stabilized by intermolecular O-HÁ Á ÁO and C-HÁ Á ÁO interactions.

Comment
Schiff base complexes are one of the most important stereochemical models in transition metal coordination chemistry, with the ease of preparation and structural variations (Granovski et al., 1993). Metal derivatives of the Schiff bases have been studied extensively, and they play a major role in both synthetic and structurel research (Elmali et al., 2000;Blower et al., 1998). The structure of the title compound was determined to clarify the identity of the synthesis product.
The asymmetric unit of the title compound, Fig. 1 et al., 1995) which may influence the molecular conformation. The crystal structure is further stabilized by the intermolecular C-H···O and O-H···O interactions (Table 1).

Experimental
The title compound was synthesized by adding 6,6'-Diethoxy-2,2'-[2,3-dimethyl-propylenebis(nitrilomethylidyne)]-diphenol (2 mmol) to a solution of CoCl 2 . 6 H 2 O (2 mmol) in ethanol (30 ml). The mixture was refluxed with stirring for half an hour. The resultant red solution was filtered. Brown single crystals of the title compound suitable for X-ray structure determination were recrystallized from ethanol by slow evaporation of the solvents at room temperature over several days.

Refinement
The H atoms of the water molecule were located in a difference Fourier map and constrained to refine with the parent atom with U iso (H) = 1.5 U eq (O). The H atoms of the ethanol molecules were positioned geometrically and constrained to refine with the parent atoms with U iso (H) = 1.5 U eq (O). The rest of the H atoms were positioned geometrically and refined using a riding model with U iso (H) = 1.2 or 1.5 U eq (C). Distant restraints were applied to the ethanol molecules. Fig. 1. The asymmetric unit of the title compound, showing 30% probability displacement ellipsoids and the atomic numbering. All H atoms except those of water and ethanol molecules were omitted for clarity. Intramolecular hydrogen bonds are drawn as dashed lines.

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 supplementary materials sup-3 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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )