catena-Poly[[bis(dicyanamido-κN 1)cobalt(II)]bis{μ-1,2-bis[(1,2,4-triazol-1-yl)methyl]benzene-κ2 N 4:N 4′}]

In the title complex, [Co(C2N3)2(C12H12N6)2]n the CoII atom lies on a centre of symmetry and displays a slightly distorted octahedral coordination geometry. The 1,2-bis[(1,2,4-triazol-1-yl)methyl]benzene ligands link adjacent metal atoms into polymeric chains parallel to the c axis, forming centrosymmetric 26-membered metallamacrocycles. The conformation of the metallamacrocycles is stabilized by pairs of C—H⋯N hydrogen bonds. The dihedral angles formed by the planes of the triazole rings with those of the benzene ring are 79.4 (2) and 79.1 (2)°. In the crystal, the chains interact through C—H⋯N hydrogen bonds, forming a three-dimensional network.

In the title complex, [Co(C 2 N 3 ) 2 (C 12 H 12 N 6 ) 2 ] n the Co II atom lies on a centre of symmetry and displays a slightly distorted octahedral coordination geometry. The 1,2-bis[(1,2,4-triazol-1yl)methyl]benzene ligands link adjacent metal atoms into polymeric chains parallel to the c axis, forming centrosymmetric 26-membered metallamacrocycles. The conformation of the metallamacrocycles is stabilized by pairs of C-HÁ Á ÁN hydrogen bonds. The dihedral angles formed by the planes of the triazole rings with those of the benzene ring are 79.4 (2) and 79.1 (2) . In the crystal, the chains interact through C-HÁ Á ÁN hydrogen bonds, forming a three-dimensional network.

Comment
A large number of mononuclear, oligonuclear and polynuclear transition metal complexes of 1,2,4-triazole derivatives have been synthesized and characterized due to their magnetic properties and novel topologies (Haasnoot, 2000;Cui et al., Han et al., and Wang et al., 2012). As a contribution to this field, we report herein the crystal structure of the title compound.
The asymmetric unit of the title compound is shown in Fig. 1. Each cobalt(II) atom lies on a centre of symmetry and displays a slightly distorted octahedral coordination geometry, provided by four nitrogen atoms from four symmetryrelated obtz ligands forming the equatorial plane and by two nitrogen atoms from two dca anions at the apices (obtz = 1,2-bis(1,2,4-triazol-1-ylmethyl)benzene, dca = dicyanamide). Two centrosymmetrically-related obtz ligands link adjacent cobalt(II) atoms to form 22-membered metallamacrocycles, which are connected into one-dimensional chains running parallel to the c axis (Fig. 2). The Co···Co separations within the chain are equal to the c-axis translation  (Table 1). In the crystal, chains interact through C-H···N hydrogen bonds (Table 1) to form a three-dimensional network. for C 28 H 24 CoN 18 (I): C, 50.08; H, 3.60; N, 37.55%.

Figure 2
The polymeric one-dimensional chain in the title compound. Hydrogen atoms are omitted for clarity.

Crystal data
[Co(C 2 N 3 ) 2 (C 12 H 12 N 6 ) 2 ] M r = 671.58 Triclinic, P1 Hall symbol: -P 1 a = 8.517 (2) Å b = 9.092 (2) Å c = 9.622 (3) Å α = 93.984 (7) where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.22 e Å −3 Δρ min = −0.29 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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.