Dichloridobis{1-[(2-methylbenzimidazol-1-yl-κN 3)methyl]benzotriazole}zinc

The title mononuclear ZnII complex, [ZnCl2(C15H13N5)2], is isotypic with the previously reported HgII complex. The ZnII atom is located on a twofold rotation axis and has a distorted tetrahedral environment of two Cl atoms and two N atoms from two heterocyclic ligands. In the crystal, complex molecules are extended by intermolecular π–π interactions [centroid–centroid distance = 3.792 (2) Å] into a three-dimensional supramolecular network.

The title mononuclear Zn II complex, [ZnCl 2 (C 15 H 13 N 5 ) 2 ], is isotypic with the previously reported Hg II complex. The Zn II atom is located on a twofold rotation axis and has a distorted tetrahedral environment of two Cl atoms and two N atoms from two heterocyclic ligands. In the crystal, complex molecules are extended by intermolecularinteractions [centroid-centroid distance = 3.792 (2) Å ] into a threedimensional supramolecular network.

Experimental
Crystal data [ZnCl 2 (C 15 (Liu et al., 2012;Bondar et al., 2012). Among them, the ligands bearing benzotriazole or benzimidazole groups are good candidates because of their various coordiantion modes and biological activities (Shao et al., 2008;Su et al., 2003). The 1-(2-methylbenzoimidazol-3-yl-methyl)-benzotriazole, simultaneously has the benzotriazole group and the benzoimidazole group, which can be an excellent ligand to form new structures. In this work, we selected this ligand as linker to self-assemble with ZnCl 2 and obtained the title mononuclear complex, ZnCl 2 (C 15 H 13 N 5 ) 2 , which is isostructural with the previously reported Hg II complex (Wu et al., 2009). The Zn atom placed on twofold axis. As shown in Fig. 1, the Zn II is in a distorted tetrahedral geometry and coordinated by two Cl atoms and two N atoms from two 1-(2-methylbenzimidazol-1-yl-methyl)benzotriazole ligands. Because the 2-position substituent methyl of benzimidazole ring is an electrondonating group, the N atom of benzimidazole ring has higher electron density than others. Therefore, the N atom of benzimidazole ring is prior to coordinate with metal ions, which leads to the ligand adopting a monodentate fashion. In addition, intramolecular π-π interactions between the imidazole rings and phenyl rings of benzimidazole rings (centroid-to-centroid separation: 3.631 (19)Å), intermolecular π-π interactions between phenyl rings of benzotriazole rings (centroid-to-centroid separation: 3.792 (2)Å) consolidate the crystal packing, as depicted in Fig. 2.

Refinement
The H atoms were generated geometrically and refined as riding atoms, with C-H = 0.93Å for aromatic H, C-H = 0.97Å for methylene H and C-H = 0.96Å for methyl H. The U iso (H) = xU eq (C), where x = 1.5 for methyl H and x = 1.2 for all other H atoms.

Computing details
Data collection: CrystalClear (Rigaku/MSC, 2006); cell refinement: CrystalClear (Rigaku/MSC, 2006); data reduction: CrystalClear (Rigaku/MSC, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXS97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).   View of the crystal packing of the title complex, showing the three-dimensional supramolecular structure. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.25 e Å −3 Δρ min = −0.30 e Å −3 Special details Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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