Chloride capture using a C-H hydrogen-bonding cage

Yun Liu; Wei Zhao; Chun-Hsing Chen; Amar H Flood

doi:10.1126/science.aaw5145

Chloride capture using a C-H hydrogen-bonding cage

Science. 2019 Jul 12;365(6449):159-161. doi: 10.1126/science.aaw5145. Epub 2019 May 23.

Authors

Yun Liu¹, Wei Zhao¹, Chun-Hsing Chen¹, Amar H Flood²

Affiliations

¹ Department of Chemistry, Indiana University, Bloomington, IN 47405, USA.
² Department of Chemistry, Indiana University, Bloomington, IN 47405, USA. aflood@indiana.edu.

PMID: 31123106
DOI: 10.1126/science.aaw5145

Abstract

Tight binding and high selectivity are hallmarks of biomolecular recognition. Achieving these behaviors with synthetic receptors has usually been associated with OH and NH hydrogen bonding. Contrary to this conventional wisdom, we designed a chloride-selective receptor in the form of a cryptand-like cage using only CH hydrogen bonding. Crystallography showed chloride stabilized by six short 2.7-angstrom hydrogen bonds originating from the cage's six 1,2,3-triazoles. Attomolar affinity (10¹⁷ M^-1) was determined using liquid-liquid extractions of chloride from water into nonpolar dichloromethane solvents. Controls verified the additional role of triazoles in rigidifying the three-dimensional structure to effect recognition affinity and selectivity: Cl^- > Br^- > NO₃ ^- > I^- This cage shows anti-Hofmeister salt extraction and corrosion inhibition.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.