Guest–host chemistry with dendrimers: Stable polymer assemblies by rational design

Authors

  • Michael Pittelkow,

    1. Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
    Current affiliation:
    1. H. C. Ørsted Institute, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Denmark
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  • Jørn B. Christensen,

    Corresponding author
    1. Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
    Current affiliation:
    1. H. C. Ørsted Institute, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Denmark
    • Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
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  • E. W. Meijer

    Corresponding author
    1. Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
    • Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
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Abstract

A new type of guest has been designed and synthesized for the exo-type supramolecular functionalization of adamantyl-urea-terminated poly(propylene imine) dendrimers. This new type of guest motif features a uriedo methane sulfonic acid moiety that binds very selectively to the surfaces of dendrimers via a combination of noncovalent interactions forming well-defined complexes. The guest–host properties have been examined for a fifth-generation adamantyl-urea-functionalized poly(propylene imine) dendrimer capable of binding 32 guest molecules and for a model host molecule that can bind only one guest molecule. The guest–host chemistry has been studied with 1H NMR spectroscopy, nuclear Overhauser enhancement spectroscopy NMR spectroscopy, T1-relaxation NMR experiments, and IR spectroscopy. The 1:32 ratio with the dendrimer has been confirmed unambiguously from 1H NMR spectra of the complex after size exclusion chromatography. Competition experiments with guests bearing a carboxylic acid instead of a sulfonic acid in the binding motif have demonstrated that the sulfonic acid has superior binding strength. Also, the importance of a combination of noncovalent interactions has been shown via competition experiments with a guest lacking the uriedo moiety. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3792–3799, 2004

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