Erbium Hydroxide Ethanedisulfonate: A Cationic Layered Material with Organic Anion Exchange Capability

We
describe a cationic erbium-based material [Er12(OH)29(H2O)5]­[O3SCH2CH2SO3]3.5·5H2O.
As synthesized, the material is water stable and capable of complete
organic anion exchange for a variety of α,ω-alkanedicarboxylates.
We chose these anions as initial examples of exchange and as an analog
for pharmaceutical waste, some of which have a carboxylate functionality
at neutral pH range. Free-floating and partially anchored organosulfonate
anions reside between the cationic corrugated layers and allow for
exchange. The structure also displays a reversible hydration event
above 100 °C. Both the as-synthesized and the exchanged materials
are characterized by a variety of analytical techniques.