31 January 2002

Chemistry: Route and branch

Dendrimers are synthetic macromolecules built up from branched subunits that form a structure with tree-like topology. In a spherical polyphenylazomethine dendrimer, binding of tin ions to the imine groups in each subunit is shown to occur in a stepwise fashion: the ions bind first at the core, then at each successive dendritic shell, or generation, until the periphery is reached. By attaching an electron-withdrawing group to the core subunit, the electron density of the core imines is reduced so they are complexed last. Refinements of this strategy could allow controlled incorporation of metal ions into dendrimer structures, yielding new metal-hybrid nanomaterials.

Stepwise radial complexation of imine groups in phenylazomethine dendrimers
KIMIHISA YAMAMOTO, MASAYOSHI HIGUCHI, SATOSHI SHIKI, MASANORI TSURUTA & HIROSHI CHIBA
Nature 415, 509–511 (31 January 2002)
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Chemistry: One generation at a time
CHRISTOPHER GORMAN
Controlled binding of atoms or molecules within a larger structure could offer new routes to drug delivery or nanoscale materials. Synthetic dendrimers can be tailored to bind ions in just such a regulated manner.
Nature 415, 487–488 (31 January 2002)
| Full Text | PDF (124 K) |