Synthesis and crystal structure of copper and zinc chloride complexes with bidentate imidazole-benzimidazole ligands

In order to elucidate substituent effects in the 2-(1-vinyl- and 2-(1-ethyl)imidazol-2-yl)benzimidazole molecules (L and L') and the effect of complexing metals on the conformation, the degree of bond conjugation, and molecular interactions in the crystals, two complexes, [Cu(L)Cl-2] (I) and [Zn(L')Cl-2] (II), were studied by X-ray diffraction. The crystals are monoclinic, I: a = 6.270(1) , b = 13.316(1) , c = 16.069(1) , beta = 102.36(1)A degrees, space group P2(1)/c, R = 0.042; II: a = 10.216(1) , b = 10.297(1) , c = 13.844(1) , beta = 107.19(1)A degrees, space group P2(1)/n, R = 0.029. The structural function of both L in I and L' in II is N,N-bidentate chelating. At the same CN = 4, the coordination polyhedra of the complexing metals are different, a distorted square of copper in I and a distorted tetrahedron of zinc in II.