catena-Poly[[bis(4-methylbenzenethiolato)cadium(II)]-μ-1,3-di-4-pyridylpropane]

In the title compound, [Cd(C7H7S)2(C13H14N2)]n, the unique CdII ion, located on a twofold rotation axis, is coordinated by two S atoms and two N atoms in a slightly distorted tetrahedral environment. Symmetry-related CdII ions are linked via bridging 1,3-di-4-pyridylpropane ligands, forming a zig-zag chain-structure parallel to [001]. In the crystal structure, there are weak intrachain π–π stacking interactions between benzene rings, with a centroid–centroid distance of 3.825 (7) Å, and pairs of chains are interdigitated with respect to the 4-methylbenzenethiolate groups.

In the title compound, [Cd(C 7 H 7 S) 2 (C 13 H 14 N 2 )] n , the unique Cd II ion, located on a twofold rotation axis, is coordinated by two S atoms and two N atoms in a slightly distorted tetrahedral environment. Symmetry-related Cd II ions are linked via bridging 1,3-di-4-pyridylpropane ligands, forming a zig-zag chain-structure parallel to [001]. In the crystal structure, there are weak intrachainstacking interactions between benzene rings, with a centroid-centroid distance of 3.825 (7) Å , and pairs of chains are interdigitated with respect to the 4-methylbenzenethiolate groups.

S1. Comment
The search for new crystalline coordination polymers is fueled by the use of such materials in catalysis, separations, magnetism, and optoelectronics (James, 2003). Recently, interest has been devoted to the entanglement of 1D coordination polymers resulting in the architectures of an overall higher dimensionality (Wang et al., 2005;Cheng et al., 2007). The organic ligand, 1,3-bis(4-pyridyl)propane (bpp), is a long and flexible multi-functional linker, which can adopt different conformations with respect to the relative orientations of the CH 2 groups (Han et al., 2007;Carlucci et al., 2002). We have reported a 2-D interwoven network entangled from zigzag chains using the bpp ligand as building unit (Han & Zhou, 2008). In an attempt to synthesize further interwoven networks we have synthesized the one-dimensional polymer formed from Cd(SC 6 H 4 Me-4) 2 and bpp and its crystal structure is reported herein.
The title compound, [Cd(SC 6 H 4 Me-4) 2 (bpp)] n , is a one-dimensional chain structure and the asymmetric unit is shown in Fig. 1. The unique Cd II ion is coordinated by two S atoms and two N atoms adopting a slightly distorted tetrahedral coordination geometry. In the chain structure, there are weak π···π stacking interactions between two symmetry related benzene rings of the 4-methylbenzenethiolate groups, within the same chain. The centroid-to-centroid distance (Cg···Cg i ) is 3.825 (7) Å (symmetry code: (i) -x, y, -z+1/2). The dihedral angle between two benzene rings is 3.2 (7)° (Fig. 2). Figure 3 shows part of the crystal structure of the title compound illustrating two interdigitated 1-D chains.

S2. Experimental
Cd(SC 6 H 4 Me-4) 2 was synthesized according to the literature (Dance et al., 1987). A mixture of Cd(SC 6 H 4 Me-4) 2 (99.5 mg) and 1,3-bis(4-pyridyl)propane (50.1 mg) in DMF (6.0 g) solution was stirred for 30 min. The solution was allowed to stand at room temperature for 5 days. Colorless block crystals of the title complex were obtained and collected by filtration with a 30% yield.

S3. Refinement
The unique H atom on C1 was located in a difference map and refined freely. Other H atoms were positioned geometrically and allowed to ride on their respective parent atoms, with C-H = 0.93 Å and U iso (H) = 1.2U eq (C) for phenyl and pyridyl H atoms, C-H = 0.96 Å and U iso (H) =1.5U eq (C) for methyl, C-H = 0.97 Å and U iso (H) = 1.2U eq (C) for methylene.  The asymmetric unit of the title compound showing 30% probability ellipsoids.

Figure 2
Part of the 1-D chain structure of title complex with 30% probability ellipsoids.  Part of the crsytal structutre showing two interdigitated 1-D chains.

catena-Poly[[bis(4-methylbenzenethiolato)cadium(II)]-µ-1,3-di-4-pyridylpropane]
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.