Tetrakis(μ-3-chlorobenzoato-κ2 O:O′)bis[(N,N-diethylnicotinamide-κN 1)copper(II)]

In the title centrosymmetric binuclear CuII complex, [Cu2(C7H4ClO2)4(C10H14N2O)2], the two CuII cations [Cu⋯Cu = 2.6314 (4) Å] are bridged by four 3-chlorobenzoate (CB) anions. The four carboxylate O atoms around each CuII cation form a distorted square-planar arrangement, the distorted square-pyramidal coordination geometry being completed by the pyridine N atom of the N,N-diethylnicotinamide (DENA) molecule. The dihedral angle between the benzene ring and the carboxylate group is 4.49 (11)° in one of the independent CB ligands and 12.00 (10)° in the other. The benzene rings of the independent CB ligands are oriented at a dihedral angle of 84.13 (6)°. In the crystal, weak C—H⋯O hydrogen bonds link the binuclear complex molecules into supramolecular chains running along [101].

In the title centrosymmetric binuclear Cu II complex, [Cu 2 (C 7 H 4 ClO 2 ) 4 (C 10 H 14 N 2 O) 2 ], the two Cu II cations [CuÁ Á ÁCu = 2.6314 (4) Å ] are bridged by four 3-chlorobenzoate (CB) anions. The four carboxylate O atoms around each Cu II cation form a distorted square-planar arrangement, the distorted square-pyramidal coordination geometry being completed by the pyridine N atom of the N,N-diethylnicotinamide (DENA) molecule. The dihedral angle between the benzene ring and the carboxylate group is 4.49 (11) in one of the independent CB ligands and 12.00 (10) in the other. The benzene rings of the independent CB ligands are oriented at a dihedral angle of 84.13 (6) . In the crystal, weak C-HÁ Á ÁO hydrogen bonds link the binuclear complex molecules into supramolecular chains running along [101].
In the crystal structure, weak intermolecular C-H···O interactions (Table 2) link the molecules into infinite chains through the centrosymmetric dimers running along the [1 0 1] direction.

Experimental
The title compound was prepared by the reaction of CuSO 4 .5H 2 O (1.25 g, 5 mmol) in H 2 O (100 ml) and diethylnicotinamide (1.78 g, 10 mmol) in H 2 O (20 ml) with sodium 3-chlorobenzoate (1.79 g, 10 mmol) in H 2 O (100 ml). The mixture was set aside to crystallize at ambient temperature for five days, giving green single crystals.

Refinement
The C-bound H-atoms were positioned geometrically with C-H = 0.93, 0.97 and 0.96 Å, for aromatic, methylene and methyl H-atoms, respectively, and constrained to ride on their parent atoms, with U iso (H) = k × U eq (C), where k = 1.5 for methyl H-atoms and k = 1.2 for all other H-atoms.

Tetrakis(µ-3-chlorobenzoato-κ 2 O:O′)bis[(N,N-diethylnicotinamide-κN 1 )copper(II)]
Crystal data 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 )
x y z U iso */U eq