TY - JOUR
T1 - Complexation of polyoxometalates with cyclodextrins
AU - Wu, Yilei
AU - Shi, Rufei
AU - Wu, Yi Lin
AU - Holcroft, James M.
AU - Liu, Zhichang
AU - Frasconi, Marco
AU - Wasielewski, Michael R.
AU - Li, Hui
AU - Stoddart, J. Fraser
N1 - Publisher Copyright:
© 2015 American Chemical Society.
Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 2015/4/1
Y1 - 2015/4/1
N2 - 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.
AB - 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.
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U2 - 10.1021/ja511713c
DO - 10.1021/ja511713c
M3 - Article
C2 - 25757159
AN - SCOPUS:84926364713
VL - 137
SP - 4111
EP - 4118
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 12
ER -