Three isomorphous two-dimensional coordination polymers generated from a benzimidazole bridging ligand and ZnX2 (X = Cl, Br and I).

A novel bridging asymmetric benzimidazole ligand, 4-{2-[3-(pyridin-4-yl)phenyl]-1H-benzimidazol-1-ylmethyl}benzoic acid, was used to construct three isomorphous two-dimensional coordination polymers, namely catena-poly[chlorido(μ3-4-{2-[3-(pyridin-4-yl)phenyl]-1H-benzimidazol-1-ylmethyl}benzoato)zinc(II)], [Zn(C26H18N3O2)Cl]n, (I), and the bromide, (II), and iodide, (III), analogues. Neighbouring two-dimensional networks are stacked into three-dimensional frameworks via interlayer π-π interactions. The luminescent properties of (I)-(III) were investigated and they display an obvious red-shift in the solid state at room temperature.