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

Two novel chiral lanthanide–sulfate frameworks, Ln 4 (OH) 4 (SO 4 ) 4 (H 2 O) 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 P 2(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 SO 4 2– anion as a three-connected node and the {Y 4 } cluster as a 12-connected node. Furthermore, the infrared, thermogravimetric analysis, and powder X-ray diffraction properties were also studied.