Two helical coordination polymers constructed from V-shaped and chelate ligands

Abstract

The synthesis and X-ray characterization of two supramolecular isomers, [Co(oba)(2,2′-bpy)] n (1 and 2) (oba = 4,4′-oxybis(benzoate), 2,2′-bpy = 2,2′-bipyridine) are reported. Crystal data for 1: a = 12.026(2), b = 15.120(3), c = 11.361(2) Å, β = 91.46(3)°, Z = 4, R 1 = 0.0330, wR 2 = 0.0949. Crystal data for 2: a = 16.171(3), b = 19.162(4), c = 22.914(5) Å, α = 107.66(3), β = 91.46(3), γ = 98.99(3)°, Z = 2, R 1 = 0.0388, wR 2 = 0.0456. They are conformational supramolecular isomers without solvent molecules in the structures, and exhibit different one-dimensional helical structures that are further assembled into distinct two-dimensional layers via π–π stacking interactions. The results indicate that the geometry of ligand is one of the most important factors for the construction of a helical motif.