Water helicate (H2O)5 hosted by a novel 2D CoII-coordination framework with left- and right-handed helical units

A novel 2D cobalt(II) coordination polymer comprising left- and right-handed helical chains, {[H2bpp][Co2(bpp)2(Hbtec)2(H2O)4]·(H2O)5}n (1) (bpp = 1,3-bis(4-pyridyl)-propane and H4btec = 1,2,4,5-benzenetetracarboxylate), was prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction method. Complex 1 provides suitable hydrophilic channel in which lattice water molecules accumulate, forming a (H2O)5 helicate, stabilized by anchoring to the host structure through hydrogen-bonding interactions involving alternating water molecules and the carboxylate oxygen atoms of Hbtec3− ligands.

Graphical abstractA novel form of water aggregate, viz., (H2O)5 helicate, has been trapped in the hydrophilic channel of a novel 2D cobalt(II) coordination polymer comprising left- and right-handed helical chains {[H2bpp][Co2(bpp)2(Hbtec)2(H2O)4]·(H2O)5}n (1) (bpp = 1,3-bis(4-pyridyl)-propane and H4btec = 1,2,4,5-benzenetetracarboxylate).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► One novel 2D cobalt(II) coordination polymer was synthesized and characterized. ► The coordination polymer comprises left- and right-handed helical chains. ► A novel water helicate (H2O)5 has been trapped in the hydrophilic channel of the coordination polymer.