Selective isolation of gold facilitated by second-sphere coordination with α-cyclodextrin

Zhichang Liu, Marco Frasconi, Juying Lei, Zachary J. Brown, Zhixue Zhu, Dennis Cao, Julien Iehl, Guoliang Liu, Albert C. Fahrenbach, Youssry Y. Botros, Omar K. Farha, Joseph T. Hupp, Chad A. Mirkin, J. Fraser Stoddart*

*Corresponding author for this work

Research output: Contribution to journalArticle

93 Scopus citations

Abstract

Gold recovery using environmentally benign chemistry is imperative from an environmental perspective. Here we report the spontaneous assembly of a one-dimensional supramolecular complex with an extended {[K(OH 2) 6 ][AuBr 4 ](α-cyclodextrin) 2 } n chain superstructure formed during the rapid co-precipitation of α-cyclodextrin and KAuBr 4 in water. This phase change is selective for this gold salt, even in the presence of other square-planar palladium and platinum complexes. From single-crystal X-ray analyses of six inclusion complexes between α-, β- and γ-cyclodextrins with KAuBr 4 and KAuCl 4, we hypothesize that a perfect match in molecular recognition between α-cyclodextrin and [AuBr 4 ] - leads to a near-axial orientation of the ion with respect to the α-cyclodextrin channel, which facilitates a highly specific second-sphere coordination involving [AuBr 4 ] - and [K(OH 2) 6 ] + and drives the co-precipitation of the 1:2 adduct. This discovery heralds a green host-guest procedure for gold recovery from gold-bearing raw materials making use of α-cyclodextrin - an inexpensive and environmentally benign carbohydrate.

Original languageEnglish (US)
Article number1855
JournalNature communications
Volume4
DOIs
StatePublished - Jun 12 2013

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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    Liu, Z., Frasconi, M., Lei, J., Brown, Z. J., Zhu, Z., Cao, D., Iehl, J., Liu, G., Fahrenbach, A. C., Botros, Y. Y., Farha, O. K., Hupp, J. T., Mirkin, C. A., & Stoddart, J. F. (2013). Selective isolation of gold facilitated by second-sphere coordination with α-cyclodextrin. Nature communications, 4, [1855]. https://doi.org/10.1038/ncomms2891