Tetrakis[μ-4-(diethylamino)benzoato-κ2 O:O′]bis[(N,N-diethylnicotinamide-κN 1)cobalt(II)]

In the centrosymmetric binuclear title complex, [Co2(C11H14NO2)4(C10H14N2O)2], the two CoII cations [Co⋯Co = 2.6199 (5) Å] are bridged by four 4-(diethylamino)benzoate (DEAB) anions. The four nearest O atoms around each CoII ion form a distorted square-planar arrangement, the distorted square-pyramidal coordination geometry being completed by the pyridine N atom of an N,N-diethylnicotinamide (DENA) ligand. The dihedral angle between the benzene ring and the carboxylate group is 7.06 (11)° in one of the independent DEAB ligands and 4.42 (9)° in the other. The benzene rings of the two independent DEAB ligands are oriented at a dihedral angle of 86.35 (8)°. The pyridine ring is oriented at dihedral angles of 31.43 (6) and 57.92 (7)° with respect to the two benzene rings. In the crystal, weak intermolecular C—H⋯O interactions link the molecules into a three-dimensional network. Weak C—H⋯π interactions are also present in the crystal structure.

In the centrosymmetric binuclear title complex, [Co 2 (C 11 H 14 -NO 2 ) 4 (C 10 H 14 N 2 O) 2 ], the two Co II cations [CoÁ Á ÁCo = 2.6199 (5) Å ] are bridged by four 4-(diethylamino)benzoate (DEAB) anions. The four nearest O atoms around each Co II ion form a distorted square-planar arrangement, the distorted square-pyramidal coordination geometry being completed by the pyridine N atom of an N,N-diethylnicotinamide (DENA) ligand. The dihedral angle between the benzene ring and the carboxylate group is 7.06 (11) in one of the independent DEAB ligands and 4.42 (9) in the other. The benzene rings of the two independent DEAB ligands are oriented at a dihedral angle of 86.35 (8) . The pyridine ring is oriented at dihedral angles of 31.43 (6) and 57.92 (7) with respect to the two benzene rings. In the crystal, weak intermolecular C-HÁ Á ÁO interactions link the molecules into a three-dimensional network. Weak C-HÁ Á Á interactions are also present in the crystal structure.
In the crystal structure, weak intermolecular C-H···O interactions (Table 2) link the molecules into a two-dimensional network, in which they may be effective in the stabilization of the structure. Two weak C-H···π interactions (Table 2) are also found.

Experimental
The title compound was prepared by the reaction of CoSO 4 .7H 2 O (1.41 g, 5 mmol) in H 2 O (50 ml) and DENA (1.78 g, 10 mmol) in H 2 O (50 ml) with sodium p-diethylaminobenzoate (2.16 g, 10 mmol) in H 2 O (100 ml). The mixture was filtered and set aside to crystallize at ambient temperature for one week, giving blue single crystals.
supplementary materials sup-2 Refinement 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) = xU eq (C), where x = 1.5 for methyl H and x = 1.2 for aromatic H atoms. Fig. 1. The molecular structure of the title molecule with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The hydrogen atoms are omitted for clarity. Primed atoms are generated by the symmetry operator:(') -x, 1 -y, -z.

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.