The chiral structure induced by lone-pair electrons: syntheses and characterization of two novel chiral rare-earth selenites containing homochiral helical chains

Two novel layered chiral rare-earth selenites [Ln(H2O)(HSeO3)(SeO3)] H2O (Ln=Dy, 1, and Gd, 2) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, XPS spectra, TG analyses and the single crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic system, space group P212121, with a=6.5767(13) Å, b=6.9320(14) Å, c=16.333(3) Å, and Z=4. Compound 2 crystallizes in the orthorhombic system, space group P212121, with a=6.6216(13) Å, b=7.0086(14) Å, c=16.424(3) Å, and Z=4. Compounds 1 and 2 are isostructural, and both exhibit interesting chiral layer constructed from {Ln(H2O)(HSeO3)}n left-handed helical chains linked by [SeO3]2− anions. Furthermore, the chiral layers are connected by strong hydrogen bonding interactions to form the three-dimensional structure with chiral channels along the [100] directions.