Synthesis and crystal structures of two new zigzag versus helical coordination polymers based on diphenic acid

Abstract

Two new coordination polymers, [Mn(dpa)(2,2′-bipy)] n (1) and [Ni(dpa)(2,2′-bipy)] n (2) (H2dpa = 3,4′-biphenyl-dicarboxylic acid, 2,2′-bipy = bipyridine), have been synthesized and structurally characterized by elemental analysis, IR, and X-ray diffraction. Single-crystal X-ray analyses revealed that 3,4′-diphenic acid acts as a bridging ligand, exhibiting rich coordination modes to link metal ions: μ 2–η 1: η 1, μ 1–η 1: η 1, and μ 1 –η 1: η 0. Compound 1 demonstrates a 1-D zigzag chain. Compound 2 is a 1-D helical chain. In 1 and 2, there exist intermolecular π–π stacking interactions and non-covalent interactions responsible for the stabilization of the supramolecular structure. In 1, the Mn(II) chains exhibit a weak antiferromagnetic interaction.