catena-Poly[[dichloridozinc(II)]-μ-1,4-bis(1H-imidazol-1-yl)benzene]

In the title one-dimensional coordination polymer, [ZnCl2(C12H10N4)]n, the ZnII atom (site symmetry 2) is coordinated by two chloride ions and two 1,4-bis(imidazol-1-yl)benzene ligands, generating a distorted tetrahedral ZnCl2N2 geometry for the metal ion. The bridging ligand, which is completed by crystallographic inversion symmetry, links the ZnII atoms into zigzag chains propagating in [101]. Within the ligand, the dihedral angle between the central benzene ring and terminal imidazole ring is 27.82 (13)°.

In the title one-dimensional coordination polymer, [ZnCl 2 -(C 12 H 10 N 4 )] n , the Zn II atom (site symmetry 2) is coordinated by two chloride ions and two 1,4-bis(imidazol-1-yl)benzene ligands, generating a distorted tetrahedral ZnCl 2 N 2 geometry for the metal ion. The bridging ligand, which is completed by crystallographic inversion symmetry, links the Zn II atoms into zigzag chains propagating in [101]. Within the ligand, the dihedral angle between the central benzene ring and terminal imidazole ring is 27.82 (13) .

Structure Reports Online
Single-crystal X-ray diffraction analysis reveals that the title compound (I) crystallizes in the monoclinic space group C2/c. The geometry of the Zn(II) ion is surrounded by two imidazole rings of distinct L ligands and two chlorine anions, which illustrates a slightly distorted tetrahedral coordination environment (Fig 1). Notably, as shown in Fig 2, the four-coordinated Zn(II) center is connected by the linear ligand L into an infinite one-dimensional zigzag chain.

Experimental
A mixture of C 2 H 5 OH and H 2 O (1:1, 8 ml), as a buffer layer, was carefully layered over a solution of ZnCl 2 (0.02 mmol) in H 2 O (6 ml). Then a solution of 1,4-Bis(imidazol-1-yl)phenyl (L, 0.06 mmol) in C 2 H 5 OH (6 ml) was layered over the buffer layer, and the resultant reaction was left to stand at room temperature. After ca three weeks, colorless blocks of (I) appeared at the boundary. Yield: ~30% (based on L).

Refinement
C-bound H atoms were positioned geometrically and refined in the riding-model approximation, with C-H = 0.93 Å and U iso (H) = 1.2 U eq . Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radius.  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 Rfactors(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.

Figures
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )