Anion binding of a bis(pyridylcarbamate) receptor bearing a diethylene glycol spacer

A flexible bis(pyridylcarbamate) receptor, 3-pyridyl-carbamic-acid-oxydi-1,2-ethanediylester (L2) and the anion complexes (1–3) of the doubly protonated ligand ([L2H2]2+) with Cl , S and Cl− are reported. The binding modes of [L2H2]2+ with the anions in 1–3 in the solid state are established by X-ray single crystal diffraction. Compounds 1 and 3 feature intriguing anionic polymer fashions. In compound 1, two zigzag perchlorate–water chains are encapsulated in the 1D channel constructed by 2+2 (2[L2H2]2++2Cl ) hydrogen-bonded macrocycles, while in 3 the chloride ions are trapped on the wall of the hydrogen-bonded 1D channel formed by two U-shaped ligands. For compound 2, the packing diagram displays a corrugated layer structure, with the sulphate ions and the water molecules located between the layers. Receptor L2 crystallises with perchlorate from the acid mixture HClO4, H2SO4 and HCl.