Bis{2-methoxy-6-[(3-methoxypropyl)iminomethyl]phenolato-κ2 N,O 1}copper(II)

The title complex, [Cu(C12H16NO3)2], adopts a distorted square-planar coordination geometry with the CuII ion situated on a crystallographic inversion center. The two Schiff base ligands are coordinated in a trans fashion. In the crystal structure, non-classical intermolecular C—H⋯O hydrogen bonds involving the ether O atoms link the Schiff base molecules into a two-dimensional network parallel to (101).

The title complex, [Cu(C 12 H 16 NO 3 ) 2 ], adopts a distorted square-planar coordination geometry with the Cu II ion situated on a crystallographic inversion center. The two Schiff base ligands are coordinated in a trans fashion. In the crystal structure, non-classical intermolecular C-HÁ Á ÁO hydrogen bonds involving the ether O atoms link the Schiff base molecules into a two-dimensional network parallel to (101).
We are grateful to the National Science Council of Taiwan for financial support.
Both intramolecular and intermolecular non-classical H-bonds of the type C-H···O exist ( Table 1). The intermolecular H-bonds link the complex into a two-dimensional network.

S2. Experimental
Synthesis of (E)-2-methoxy-6-((3-methoxypropylimino)methyl)phenol: The compound was synthesized by the condensation reaction between O-vaniline and NH 2 (CH 2 ) 3 OMe in methanol. After complete removal of the solvent, the resulting yellow liquid was used without purification.

S3. Refinement
All the H atoms were positioned geometrically and refined as riding atoms, with C aryl -H = 0.95, C methyl -H = 0.98, C methylene -H = 0.99, C methine -H = 0.95 Å while U iso (H) = 1.5U eq (C) for the methyl H atoms and U iso (H) = 1.2U eq (C) for all the other H atoms.

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.

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