Structural effects of lone-pair electrons: a novel three-dimensional,open-framework metal selenite constructed from {CoSeO3}n double helical chains linked via ethylenediamine pillars

A novel three-dimensional, open-framework selenite H₂N(CH₂)₂NH₂]_0.5·CoSeO₃ (1) has been hydrothermally synthesized and characterized by elemental analyses, IR spectrum, XPS spectrum, TG analysis and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P2₁/n, with a?=?6.6018(14)?Å, b?=?9.2559(19)?Å, c?=?7.9097(16)?Å, β?=?113.56(3)°, V?=?443.02(16)?ų, and Z?=?4. Compound 1 exhibits an interesting three-dimensional open-framework structure constructed from unique {CoSeO₃}_n layers aggregated from double helical chains pillared by en ligands. Furthermore, the open framework of 1 possesses three types of one-dimensional channels, in which the triangular channel is particularly rare in covalently bonded microporous materials.