(2,2′-Bipyridine-κ2 N,N′)bis(4-chlorobenzoato-κO)zinc

In the title compound, [Zn(C7H4ClO2)2(C10H8N2)], the ZnII atom is coordinated by two O atoms from two 4-chlorobenzoate ligands and two N atoms from a chelating 2,2′-bipyridine (bpy) molecule in a distorted N2O2 tetrahedral geometry. The ZnII atom is located on a twofold rotation axis, which also passes through the mid-point of the central C—C bond of the bpy ligand. In the crystal, weak C—H⋯O hydrogen bonds and π–π stacking interactions between the pyridine rings of the bpy ligands [centroid–centroid distance = 3.642 (3) Å] link the complex molecules into a two-dimensional supramolecular structure parallel to (100). An intramolecular C—H⋯O hydrogen bond is also observed.

In the title compound, [Zn(C 7 H 4 ClO 2 ) 2 (C 10 H 8 N 2 )], the Zn II atom is coordinated by two O atoms from two 4-chlorobenzoate ligands and two N atoms from a chelating 2,2 0bipyridine (bpy) molecule in a distorted N 2 O 2 tetrahedral geometry. The Zn II atom is located on a twofold rotation axis, which also passes through the mid-point of the central C-C bond of the bpy ligand. In the crystal, weak C-HÁ Á ÁO hydrogen bonds andstacking interactions between the pyridine rings of the bpy ligands [centroid-centroid distance = 3.642 (3) Å ] link the complex molecules into a two-dimensional supramolecular structure parallel to (100). An intramolecular C-HÁ Á ÁO hydrogen bond is also observed.

Experimental
ZnCl 2 (0.0687 g, 0.504 mmol) was dissolved in appropriate amount of water and then 1M Na 2 CO 3 solution was added.
ZnCO 3 was obtained by filtration, which was then washed with distilled water for 5 times. The freshly prepared ZnCO 3 , 2,2′-bipyridine (0.0388 g, 0.273 mmol) and 4-chlorobenzoic acid (0.0396 g, 0.255 mmol), CH 3 OH/H 2 O (v/v = 1:2, 15 ml) were mixed and stirred for 2 h. The resulting cream suspension was heated in a 23 ml Teflon-lined stainless steel autoclave at 433 K for 97 h. After the autoclave was cooled to room temperature within 43 h, the solid was filtered off.
The resulting filtrate was allowed to stand at room temperature and slow evaporation for 6 weeks afforded colorless block single crystals.

Refinement
H atoms were placed in calculated positions and refined as riding atoms, with C-H = 0.93 Å and U iso (H) = 1.2U eq (C).

(2,2′-Bipyridine-κ 2 N,N′)bis(4-chlorobenzoato-κO)zinc(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.