Two one-dimensional coordination polymers generated from a new benzimidazole bridging ligand and CdX2 (X = Br and I).

The novel asymmetric bridging ligand 1-[(pyridin-3-yl)methyl]-2-[4-(pyridin-3-yl)phenyl]-1H-benzimidazole (L) has been used to construct the coordination polymers catena-poly[[[dibromidocadmium(II)]-μ3-1-[(pyridin-3-yl)methyl]-2-[4-(pyridin-3-yl)phenyl]-1H-benzimidazole] monohydrate], {[CdBr2(C24H18N4)]·H2O}n, (I), and catena-poly[[diiodidocadmium(II)]-μ3-1-[(pyridin-3-yl)methyl]-2-[4-(pyridin-3-yl)phenyl]-1H-benzimidazole], [CdI2(C24H18N4)]n, (II). Compounds (I) and (II) are closely related one-dimensional polymers based on 16- and 20-membered macrocycles along the chains, but they are not isomorphous. The chains are crosslinked into a two-dimensional network via hydrogen bonds and π-π interactions in (I), and into a three-dimensional framework through π-π interactions in (II). One well-ordered solvent water molecule per asymmetric unit is included in (I) and forms O···Br hydrogen bonds.