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Updated: Oct 15, 2025

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand
Published on: September 8, 2016
Acid-Tolerant Sulfate Tetrahedral Cages from Anion-Coordination-Driven Assembly
Wenyao Zhang1, Yang Feng1, Boyang Li1
1Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an, 710069, P. R. China.
Abstract:
Supramolecular cages have been constructed by anion-coordination-driven assembly (ACDA) in recent years and have shown unique host-guest interactions. However, most of the reported cages are made of the phosphate ion (PO4 3- ); other anions have rarely been explored. Here we show for the first time that the sulfate ion (SO4 2- ) is also able to form the A4 L4 tetrahedral motif with tris-bis(urea) ligands, but this is dependent on the stoichiometry of the sulfate ion (in solution). Notably, the sulfate cages display enhanced resistance for both Brønsted (pH as low as 4.3 in acetone containing 15 % water) and Lewis acids (metal complexes) compared to the corresponding phosphate cages, and thus could find applications where an acidic (proton or metals) environment is required.
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