Bis(hexamethylenetetramine)bis(trichloroacetato)copper(II)

In the title compound, [Cu(C2Cl3O2)2(C6H12N4)2], the CuII ion (site symmetry 2) is coordinated by two trichloroacetate anions and two hexamethylenetetramine molecules, resulting in a distorted CuN2O2 geometry that is intermediate between tetrahedral and square planar. The Cl atoms are disordered over two sets of sites, with relative occupancies of 0.749 (7) and 0.251 (7). In the crystal, the packing is consolidated by intermolecular C—H⋯O interactions.

In the title compound, [Cu(C 2 Cl 3 O 2 ) 2 (C 6 H 12 N 4 ) 2 ], the Cu II ion (site symmetry 2) is coordinated by two trichloroacetate anions and two hexamethylenetetramine molecules, resulting in a distorted CuN 2 O 2 geometry that is intermediate between tetrahedral and square planar. The Cl atoms are disordered over two sets of sites, with relative occupancies of 0.749 (7) and 0.251 (7). In the crystal, the packing is consolidated by intermolecular C-HÁ Á ÁO interactions.

Related literature
For background to coordination networks, see: Chen et al. (2001). For a related structure, see: Moncol et al. (2007).

S1. Comment
Metal-organic framework coordination polymers have attracted tremendous attention because of their molecular topologies and their potentially useful ionexchange,adsorption,catalytic and magnetic properties. Much of this work has been concerned (e.g. Chen et al., 2001). In order to search for new complexes of this type, we synthesized the title compound, (I), and report its crystal structure here.
The title structure contains one copper(II), two N atoms of the hexamethylenetetramine ligands and two O atoms of trichloroacetate anions. The coordination sphere of the copper(II) ion is best described as a seriously distorted tetrahedral.
The Cu-O and Cu-N bond lengths are in agreement with those reported recently (Moncol et al., 2007). The Cl atoms are disordered over two sites, with relatives occupancies 0.749 (7) and 0.251 (7).The crystal packing is stabilized by intra-and intermolecular C-H···O hydrogen interaction (Table 1).

S2. Experimental
The title compound was obtained by adding hexamethylenetetramine (2 mmol) dropwise to a solution of trichloroacetatocopper(II) (1 mmol) in ethanol (30 ml) under stirred for 1 h at room temperature. A green solution was formed and after a few days block crystals precipitated.

S3. Refinement
H atoms were fixed geometrically and allowed to ride on their attached atoms, with C-H and N-H distances of 0.93-0.96 and 0.86 Å, and with U iso = 1.2U eq . supporting information

Figure 1
The structure of (I) showing 30% probability displacement ellipsoids. Atoms with suffix A are generated by the symmetry operation (-x, y, 1/2-z).

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 Occ. (