Dichloridobis{2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole-κN 3}zinc(II)

In the title complex, [ZnCl2(C10H9N5)2], the ZnII ion is coordinated by two N atoms from two 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole (tmb) ligands and by two chloride ligands in a slightly distorted tetrahedral geometry. In the tmb ligands, the benzimidazole rings systems are essentially planar, with maximum deviations from the mean plane of 0.021 (3) and 0.030 (3) Å, and form dihedral angles of 73.2 (2) and 83.5 (2)° with the triazole rings. In the crystal, N—H⋯N hydrogen bonds link complex molecules into chains along [010]. In addition, weak C—H⋯Cl and C—H⋯N hydrogen bonds complete a three-dimensional network. Two weak intramolecular C—H⋯Cl hydrogen bonds are also observed.


Comment
In recent years we have focused our attention on the design and synthesis of complexes based on the 2-[(1H-1,2,4triazol-1-yl)methyl]-1H-benzimidazole (tmb) ligand since it possesses various coordination modes and can act as both a hydrogen bond acceptor and donor due to the amino group of benzimidazole ring and N atoms of benzimidazole and imidazole rings (Jin et al., 2012;Wang et al., 2012). In order to enrich the categories and numbers of complexes with this ligand, we have selected tmb as the ligand to self-assemble with ZnCl 2 . The crystal structure of the title complex is reported herein.
Colourless crystals were obtained from the filtrate and dried in air.

Refinement
H atoms were positioned geometrically and refined as riding atoms, with C-H = 0.93 (aromatic) Å and 0.97 (CH 2 ) Å, N-H = 0.86 Å. All H atoms were refined with U iso (H) = 1.2 U eq (C,N).  View of the title complex showing 30% probability displacement ellipsolids.

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.

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