Aqua{μ-N-[3-(dimethylamino)propyl]-N′-(2-oxidophenyl)oxamidato(3−)}(1,10-phenanthroline)dicopper(II) nitrate

The title complex, [Cu2(C13H16N3O3)(C12H8N2)(H2O)]NO3, consists of a nitrate ion and a binuclear CuII unit in which the oxamide ligand has a cis geometry, is fully deprotonated and acts in a bidentate fashion to one CuII atom and in a tetradentate fashion to the other CuII atom. The CuII atom coordination geometries are distorted square-planar and distorted square-pyramidal. In the crystal structure, binuclear complexes and nitrate ions are connected by classical O—H⋯O and non-classical C—H⋯O hydrogen bonds into a three-dimensional framework. The alkyl chains of the anion are equally disorded over two positions.

The title compound, C 25 H 25 N 6 O 4 Cu 2 + , NO 3 is a binuclear copper(II) complex and the structure is similar to that seen previously in a resemble compound (Wang et al., 2003) (Fig. 1). In the dinuclear cation, the oxalate groups bridge the two copper(II) ions. The separation of copper atoms is 5.192 (2) Å. The Cu-atom coordination geometries are regarded as distorted square and square pyramid, respectively. The oxamide ligand has a cis geometry, is fully deprotonated and acts in a hexadentate fashion. Cu-O and Cu-N bond lengths are shown in Table 1. For Cu1, the four atoms (O1, N1, N2, N3) from the oxalate groups build the square plane. The average value of the copper to N1, N2 and N3 bond distance is 1.969 Å. For Cu2, the donors on the oxamide (O2, O3) and the phen (N4, N5) offer the basal plane and the oxygen of a water molecule occupies an apical position with a bond length of 2.275 (2) Å. The maximum displacement from the least-square plane is 0.0055 (2) Å for O2 and the Cu2 atom lies 0.1282 (8) Å out of this plane.
In the crystal, the neutral binuclear complexes and nitrate ions are connected by classcial O-H···O and non-classical C-H···O hydrogen bonds into a three-dimensional framework (Fig. 2, Table 2).

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 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 )