catena-Poly[[[(acetato-κ2 O,O′)cadmium]-μ-acetato-κ3 O,O′:O′-μ-{1,2-bis[4-(pyridin-3-yl)pyrimidin-2-ylsulfanyl]ethane}-κ2 N 4,N 4′] trihydrate]

The title compound, {[Cd(CH3COO)2(C20H16N6S2)]·3H2O}n, exists as a one-dimensional zigzag polymer in which the CdII ion shows a seven-coordinate [CdO5N2] distorted pentagonal–bipyramidal geometry with the N atoms in axial positions and an N—Cd—N angle of 176.94 (13)°. The metal atoms are bridged by 1,2-bis[4-(pyridin-3-yl)pyrimidin-2-ylsulfanyl]ethane ligands, giving a polymeric chain extending along the b axis. Adjacent chains related by an inversion center are further bridged by Cd—O bonds formed between the O atom of one of the acetate ligands and the metal atom. The five Cd—O bond lengths are in the range 2.329 (3)–2.485 (3) Å. There are π–π stacking interactions between the aromatic rings of adjacent polymeric chains, the centroid–centroid distances being 3.556 (3) and 3.698 (3) Å, organizing the chains into a three-dimensional framework. This framework is additionally stabilized by extensive O—H⋯O and O—H⋯N hydrogen bonding between water molecules and the ligands.

The title compound, {[Cd(CH 3 COO) 2 (C 20 H 16 N 6 S 2 )]Á3H 2 O} n , exists as a one-dimensional zigzag polymer in which the Cd II ion shows a seven-coordinate [CdO 5 N 2 ] distorted pentagonalbipyramidal geometry with the N atoms in axial positions and an N-Cd-N angle of 176.94 (13) . The metal atoms are bridged by 1,2-bis[4-(pyridin-3-yl)pyrimidin-2-ylsulfanyl]ethane ligands, giving a polymeric chain extending along the b axis. Adjacent chains related by an inversion center are further bridged by Cd-O bonds formed between the O atom of one of the acetate ligands and the metal atom. The five Cd-O bond lengths are in the range 2.329 (3)-2.485 (3) Å . There arestacking interactions between the aromatic rings of adjacent polymeric chains, the centroid-centroid distances being 3.556 (3) and 3.698 (3) Å , organizing the chains into a three-dimensional framework. This framework is additionally stabilized by extensive O-HÁ Á ÁO and O-HÁ Á ÁN hydrogen bonding between water molecules and the ligands.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.   et al., 2009;Dong,Yang et al., 2008;Dong, Zhu et al., 2008). Here we report the structure of the title one-dimensional cadmium(II) complex, The title compound exists as a one-dimensional zigzag polymer, with seven-coordinate CdO 5 N 2 core, in which Cd II centers are bridged by the organic ligand to give polymeric chain, and two oxygen atoms from two anions bridge two adjacent polymeric chains as shown in Figure 1. The axial N3-Cd-N6 bond angle is 176.91 (14)°. There are π-π stacking interactions between the aromatic rings from adjacent polymeric chains with the centroid-centroid distances of 3.556 and 3.698 Å, organizing the chains into a three-dimensional framework. This framework is additionally stabilized by numerous hydrogen bonds between water molecules and the ligands (Fig. 2) .

Experimental
All solvents and chemicals were of analytical grade and were used without further purification. The title compound was

Refinement
Hydrogen atoms from the L ligand were geomemetrically positioned (C-H 0.93-0.97 Å) and refined as riding, with U iso (H)=1.2-1.5 U eq of the parent atom. Positions of the water molecules H atoms were calculated geometrically assuming their involvement in hydrogen bonding and refined as riding with U iso (H)=1.5 U eq (O) .

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.