Aqua(dicyanamido){μ-6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato}copper(II)sodium(I)

The molecule of the title compound, [CuNa(C18H18N2O4)(C2N3)(H2O)], is almost planar, the maximum deviation from the molecular plane being 0.48 (4) Å. The coordination environment of the Cu2+ ion is distorted square-planar and it is N 2 O 2-chelated by the Schiff base ligand. The Na+ cation has a distorted octahedral environment defined by the four O atoms of the 6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolate ligand, a water ligand and a dicyanamide anion.

The molecule of the title compound, [CuNa(C 18 H 18 N 2 O 4 )-(C 2 N 3 )(H 2 O)], is almost planar, the maximum deviation from the molecular plane being 0.48 (4) Å . The coordination environment of the Cu 2+ ion is distorted square-planar and it is N 2 O 2 -chelated by the Schiff base ligand. The Na + cation has a distorted octahedral environment defined by the four O atoms of the 6,6 0 -dimethoxy-2,2 0 -[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolate ligand, a water ligand and a dicyanamide anion.

S1. Comment
The dicyanamide ligand N(CN) 2 , has attracted attention in the past four years for the buildup of interesting extended architectures. Its versatile coordination behavior and its ability to organize solids into polymeric structures with a rich diversity of magnetic properties have attracted interest toward this research area (Ohba et al., 2000). N,N-disalicylideneethylenediamine type Schiff bases ligands present versatile steric, electronic and lipophilic properties (Correia et al. 2005). We report here the synthesis and crystal structure of the title compound.
The molecular structure is shown in Fig.1. The values of the geometric parameters in (I) are normal (Costes et al. 2004) ( Table 1). The copper and sodium cations are connected via two bridging oxygen atoms of the ligand. The Na atom is coordinated by the four O atoms of the 6,6′-Dimethoxy-2,2′-(ethane-1,2-diyldiiminodimethylene)diphenol ligand, a water ligand and a dicyanamide anion while the four-coordinate Cu gives a planar coordination.

S2. Experimental
A mixture of 6,6′-Dimethoxy-2,2′-(ethane-1,2-diyldiiminodimethylene)diphenol (1 mmol) and copper chloride (1 mmol) in methanol (15 ml) was stirred for 30 min and sodium dicyanamide (1 mmol) was added, stirred for another 15 min and then filtered. The resulting clear blue solution was vapor at room temperature for 7 days, after which large blue blockshaped crystals of the title complex suitable for X-ray diffraction analysis were obtained.

S3. Refinement
The H atoms were fixed geometrically and were treated as riding on their parent C atoms, with C-H distances in the range of 0.93-0.97Å and with U iso (H) = 1.2U eq (parent atom), or U iso (H) = 1.5U eq (C methyl ).

Figure 1
The independent molecules of the title compound, showing 30% probability displacement ellipsoids and the atomnumbering scheme.

Crystal data
[CuNa (C 18   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.