Two Unusual Chiral Lanthanide–Sulfate Frameworks with Helical Tubes and Channels Constructed from Interweaving Two Double-Helical Chains

Two novel chiral lanthanide–sulfate frameworks, Ln4(OH)4(SO4)4(H2O)3 [Ln = Y (1) and Er (2)], have been synthesized under hydrothermal reactions. X-ray crystal structure analyses reveal that 1 and 2 are isomorphous and crystallize in the orthorhombic space group P2­(1)­2­(1)­2­(1). Both compounds are isostructural and contain helical tubes and channels constructed from double left- and right-handed helical chains. Further structural analysis reveals that compound 1 is a high connected binodal net by assigning the SO42– anion as a three-connected node and the {Y4} cluster as a 12-connected node. Furthermore, the infrared, thermogravimetric analysis, and powder X-ray diffraction properties were also studied.