Gated, Selective Anion Exchange in Functionalized Self‐Assembled Cage Complexes. Issue 11 (12th January 2023)

• Record Type: Journal Article
• Authors: da Camara, Bryce; Ziv, Noa Bar; Carta, Veronica; Mota Orozco, Gabriela A.; Wu, Hoi‐Ting; Julian, Ryan R.; Hooley, Richard J.
• Is Part Of: Chemistry. Volume 29:Issue 11(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-12
• Subjects: anion binding -- coordination chemistry -- molecular recognition -- self-assembly -- supramolecular chemistry; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202203588
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Appending functional groups to the exterior of Zn4 L4 self‐assembled cages allows gated control of anion binding. While the unfunctionalized cages contain aryl groups in the ligand that can freely rotate, attaching inert functional groups creates a "doorstop", preventing rotation and slowing the guest exchange rate, even though the interiors of the host cavities are identically structured. The effects on anion exchange are subtle and depend on multiple factors, including anion size, the nature of the leaving anion, and the electron‐withdrawing ability and steric bulk of the pendant groups. Multiple exchange mechanisms occur, and the nature of the external groups controls associative and dissociative exchange processes: these bulky groups affect both anion egress and ingress, introducing an extra layer of selectivity to the exchange. Small changes can have large effects: affinities for anions as similar as PF6 − and SbF6 − can vary by as much as 400‐fold between identically sized cavities. Abstract : Appending functional groups to the exterior of Zn4 L4 self‐assembled cages allows gated control of anion binding. The external groups act as a "doorstop", preventing ligand rotation and slowing the guest exchange rate. Bulky groups affect both anion egress and ingress, introducing an extra layer of selectivity to the exchange. Small changes can have large effects: affinities for anions as similar as PF6 − and SbF6 − can vary by as much as 400‐fold between identically sized cavities.