{6,6′-Diethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenolato}copper(II) monohydrate

In the title complex, [Cu(C23H28N2O4)]·H2O, the CuII ion has a distorted planar geometry, coordinated by the N2O2 unit of the tetradentate Schiff base ligand. The asymmetric unit comprises one complex molecule and a water molecule of crystallization. The water H atoms form bifurcated O—H⋯(O,O) intermolecular hydrogen bonds with the O atoms of the phenolate and ethoxy groups with R12(5) and R12(6) ring motifs, which may, in part, influence the molecular configuration. The dihedral angle between the two O—Cu—N coordination planes is 31.02 (6)° and the dihedral angle between the two benzene rings is 34.98 (7)°. In the crystal structure, molecules are linked together by intermolecular C—H⋯O interactions, forming extended chains along the a axis. The crystal structure is further stabilized by intermolecular C—H⋯π and π–π [centroid–centroid = 3.5068 (13) Å] interactions.

In the title complex, [Cu(C 23 H 28 N 2 O 4 )]ÁH 2 O, the Cu II ion has a distorted planar geometry, coordinated by the N 2 O 2 unit of the tetradentate Schiff base ligand. The asymmetric unit comprises one complex molecule and a water molecule of crystallization. The water H atoms form bifurcated O-HÁ Á Á(O,O) intermolecular hydrogen bonds with the O atoms of the phenolate and ethoxy groups with R 1 2 (5) and R 1 2 (6) ring motifs, which may, in part, influence the molecular configuration. The dihedral angle between the two O-Cu-N coordination planes is 31.02 (6) and the dihedral angle between the two benzene rings is 34.98 (7) . In the crystal structure, molecules are linked together by intermolecular C-HÁ Á ÁO interactions, forming extended chains along the a axis. The crystal structure is further stabilized by intermolecular C-HÁ Á Á and -[centroid-centroid = 3.5068 (13) Å ] interactions.
The Cu II ion of the title compound ( Fig. 1), shows a distorted planar geometry which is coordinated by two imine N atoms and two phenol O atoms of the tetradentate Schiff base ligand. The bond lengths (Allen et al.,, 1987) and angles are within normal ranges and are comparable with the related structures (Clark et al., 1968(Clark et al., , 1969(Clark et al., , 1970 (Bernstein et al., 1995), which may, in part, influence the molecular configuration. The dihedral angle between the two benzene rings is 34.98 (7)°. In the crystal structure, the molecules are linked together by intermolecular C-H···O interactions, forming 1-D extended chains along the a axis (Fig. 2). The crystal structure is further stabilized by intermolecular C-H···π (Table 1) and π-π interactions [Cg3···Cg3 i = 3.5068 (13) Å, Cg3 is the centroid of the Cu1/O1/C1/C6/C7/N1 ring, symmetry operation i = 1-x, 1-y, 1-z].

Refinement
The water H-atoms were located from the difference Fourier map and freely refined. The rest of the hydrogen atoms were positioned geometrically [C-H = 0.95-99 Å] and refined using a riding approximation model with U iso (H) = 1.2 or 1.5 U eq (C). A rotating-group model was used for the methyl groups of the ethoxy substituents.

Special details
Experimental. The crystal was placed in the cold stream of an Oxford Cyrosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1)K.
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq supplementary materials sup-9