Selective Separation of Hexachloroplatinate(IV) Dianions Based on Exo-Binding with Cucurbit[6]uril

Huang Wu, Yu Wang, Leighton O. Jones, Wenqi Liu, Long Zhang, Bo Song, Xiao Yang Chen, Charlotte L. Stern, George C. Schatz, J. Fraser Stoddart*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The recognition and separation of anions attracts attention from chemists, materials scientists, and engineers. Employing exo-binding of artificial macrocycles to selectively recognize anions remains a challenge in supramolecular chemistry. We report the instantaneous co-crystallization and concomitant co-precipitation between [PtCl6]2− dianions and cucurbit[6]uril, which relies on the selective recognition of these dianions through noncovalent bonding interactions on the outer surface of cucurbit[6]uril. The selective [PtCl6]2− dianion recognition is driven by weak [Pt−Cl⋅⋅⋅H−C] hydrogen bonding and [Pt−Cl⋅⋅⋅C=O] ion–dipole interactions. The synthetic protocol is highly selective. Recognition is not observed in combinations between cucurbit[6]uril and six other Pt- and Pd- or Rh-based chloride anions. We also demonstrated that cucurbit[6]uril is able to separate selectively [PtCl6]2− dianions from a mixture of [PtCl6]2−, [PdCl4]2−, and [RhCl6]3− anions. This protocol could be exploited to recover platinum from spent vehicular three-way catalytic converters and other platinum-bearing metal waste.

Original languageEnglish (US)
Pages (from-to)17587-17594
Number of pages8
JournalAngewandte Chemie - International Edition
Volume60
Issue number32
DOIs
StatePublished - Aug 2 2021

Keywords

  • anion separation
  • co-crystallization
  • outer-surface interactions
  • precious metals
  • resource recovery
  • supramolecular chemistry

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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