Poly[(μ4-decanedioato)cobalt(II)]

In the title compound, [Co(C10H16O4)]n, the CoII atom is bonded in a slightly distorted tetrahedral environment by four O atoms from the bridging sebacate dications, comprising two separate half-ligands which lie across crystallographic inversion centres. In the three-dimensional network coordination polymer, there are two different spatial extensions of CoII atoms, one with the CoII atoms lying parallel to (100) [Co⋯Co = 4.653 (1) Å], the other lying parallel to (010) [Co⋯Co = 4.764 (1) Å].

In the title compound, [Co(C 10 H 16 O 4 )] n , the Co II atom is bonded in a slightly distorted tetrahedral environment by four O atoms from the bridging sebacate dications, comprising two separate half-ligands which lie across crystallographic inversion centres. In the three-dimensional network coordination polymer, there are two different spatial extensions of Co II atoms, one with the Co II atoms lying parallel to (100) [CoÁ Á ÁCo = 4.653 (1) Å ], the other lying parallel to (010) [CoÁ Á ÁCo = 4.764 (1) Å ].
Supporting information for this paper is available from the IUCr electronic archives (Reference: ZS2284).
designed building-blocks (Desiraju, 2003). To date it is still a big challenge the exact prediction of the structure of a molecular solid because crystal packing is driven by many weak non-covalent interactions (Gavezzotti, 1994). Suitable substrates to design specific architectures should bear functional groups apt to develop predefined interactions synthones (Sarma & Desiraju, 2002) for this purpose, often, planar aromatic or linear aliphatic molecules with carboxylic groups (Biradha et al., 1998) were exploited as building-blocks (Hosseini, 2003) to yield particular crystal lattice. Crystal structure of sebacic acid was first determined by Morrison & Robertson (1949) it has been redetermined at low temperature (180 K) (Bond et al., 2001). Sebacic acid both in its protonated or deprotonated forms has been found in several metal complexes, either coordinated to the metal center or as a counter ion, or in co-crystals in its protonated form. In all the examined compounds, the alkyl chain of either the free or coordinated sebacate or sebacic acid are usually linear with a few exceptions (Zhou et al., 2010;Thuéry, 2008). In the title zinc sebacate complex, [CoC 10 H 16 O 4 ] n the linear chain is evidenced by the C1-C10 separation of 11.452 (4) Å, equal within the e.s.d's to the corresponding value of 11.466 (5) Å found in the low-temperature X-ray structure of sebacic acid (Bond et al., 2001).The shortest separation [11.419 (4) Å] for the linear C1···C10 chain was found in a dimeric uranil sebacate complex (Borkowski & Cahill, 2006).
The asymmetric unit of the title complex comprises a cobalt cation coordinated by four carboxyl O-atom donors from two non-equivalent half-sebacate anions which lie across crystallographic inversion centres (Fig. 1). The cobalt has close to ideal tetrahedral geometry [Co-O range, 1.953 (3) -1.972 (3) Å (Table 1)]. The C-O bond lengths in the carboxylate groups range from 1.252 (5) Å to 1.262 (5) Å, this narrow range being smaller than the usual range found in monodentate carboxylates. The title complex forms a three-dimensional network polymer in which there are two different arrangenments of cobalt atoms (Fig. 2). The column of cobalt atoms with the oxygen atoms linked to it extends parallel to the crystallographic b axis and in this column the Co-Co separation is exactly the length of b axis [4.7640 (7) Å]. The second column extends almost parallel to (1 0 0) with a Co···Co separation of 4.6528 (8) Å. The overall molecular packing is illustrated in Fig. 3.

Experimental
The polymer was synthesized by reaction of cobalt chloride hexahydrate (0.05 mmol) with sebacic acid (0.05 mmol) sealed in a teflon-lined stainless steel autoclave filled with 8 ml of water, which was heated at 130 °C for 3 days under autogenous pressure. After slow cooling to room temperature over 6 h, two different types of crystal were observed, the expected pink violet product, the title complex (yield 50%) and transparent colourless crystals, which tested separately appear to be unreacted sebacic acid.

Refinement
The H atoms were included in the refinement at calculated positions [C-H = 0.97 Å] and were allowed to ride, with U eq (H) = 1.2U eq (H).

Figure 1
Molecular configuration and atom numbering for the title complex with non H-atoms represented as displacement ellipsoids plotted at the 50% probability level and H atoms shown as small spheres of arbitrary radius. The broken bonds C5-C5 iii and C6-C6 iv link the inversion-related halves of the sebacate ligands. For symmetry codes (i) and (ii), see Table 1. For other codes: (iii) -x + 3/2, -y -1/2, -z + 1/2; (iv) -x, -y, -z.  Packing diagram of the three-dimensional compound viewed along the b axis.

Poly[(µ 4 -decanedioato)cobalt(II)]
Crystal data  Special details Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles. 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 > 2σ(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. Structure has been solved and refined in the centrosymmetric monoclinic C2/c space group. Refining the structure in the non standard I2/a space group leads to identical R value results, but at a value of G.o.f. (1.014) significantly closer to the ideal value of 1, for this reason we prefer the non-standard space group.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq