Complexation of polyoxometalates with cyclodextrins

Yilei Wu, Rufei Shi, Yi Lin Wu, James M. Holcroft, Zhichang Liu, Marco Frasconi, Michael R. Wasielewski, Hui Li, J. Fraser Stoddart

Research output: Contribution to journalArticle

83 Citations (Scopus)

Abstract

Although complexation of hydrophilic guests inside the cavities of hydrophobic hosts is considered to be unlikely, we demonstrate herein the complexation between γ- and β-cyclodextrins (γ- and β-CDs) with an archetypal polyoxometalate (POM) - namely, the [PMo12O40]3- trianion - which has led to the formation of two organic-inorganic hybrid 2:1 complexes, namely [La(H2O)9]{[PMo12O40]âŠ⊂[γ-CD]2} (CD-POM-1) and [La(H2O)9] {[PMo12O40]âŠ⊂[β-CD]2} (CD-POM-2), in the solid state. The extent to which these complexes assemble in solution has been investigated by (i) 1H, 13C, and 31P NMR spectroscopies and (ii) small- and wide-angle X-ray scattering, as well as (iii) mass spectrometry. Single-crystal X-ray diffraction reveals that both complexes have a sandwich-like structure, wherein one [PMo12O40]3- trianion is encapsulated by the primary faces of two CD tori through intermolecular [C-H···Oî - Mo] interactions. X-ray crystal superstructures of CD-POM-1 and CD-POM-2 show also that both of these 2:1 complexes are lined up longitudinally in a one-dimensional columnar fashion by means of [O-H···O] interactions. A beneficial nanoconfinement-induced stabilizing effect is supported by the observation of slow color changes for these supermolecules in aqueous solution phase. Electrochemical studies show that the redox properties of [PMo12O40]3- trianions encapsulated by CDs in the complexes are largely preserved in solution. The supramolecular complementarity between the CDs and the [PMo12O40]3- trianion provides yet another opportunity for the functionalization of POMs under mild conditions by using host-guest chemistry.

Original languageEnglish
Pages (from-to)4111-4118
Number of pages8
JournalJournal of the American Chemical Society
Volume137
Issue number12
DOIs
Publication statusPublished - Apr 1 2015

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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  • Cite this

    Wu, Y., Shi, R., Wu, Y. L., Holcroft, J. M., Liu, Z., Frasconi, M., Wasielewski, M. R., Li, H., & Stoddart, J. F. (2015). Complexation of polyoxometalates with cyclodextrins. Journal of the American Chemical Society, 137(12), 4111-4118. https://doi.org/10.1021/ja511713c