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Full size image available through contact |
Yamaguchi and Gibson were the first to demonstrate the linear array. The work was first published in Angewandte Chemie just this year. (Angew. Chem. Int. Ed. 1999, 38, No. 1/2: "Formation of Supramolecular Polymers from Homoditopic Molecules Containing Secondary Ammonium Ions and Crown Ether Moieties," by Yamaguchi and Gibson.)
The second arrangement of the same components resulted in dendritic pseudorotaxanes. Benzyl ether dendrons (wedge shaped molecules) with crown ether hosts at the "focal point" assemble in layers on a three-armed ammonium salt to form a macromolecular aggregate.
The huge supramolecule takes three days to form. Again the process was first described in Angewandte Chemie. (Angew. Chem. Int. Ed. 1998, 37, No. 23: "Dendritic Pseudorotaxanes," by Yamaguchi, Lesley M. Hamilton, and Gibson.) The result is "kind of a glob," says Gibson. Within the glob are pockets of a specific size that can be used to trap target molecules, which can then be transported and released by reversing the construction of the dendrimer. Gibson explains that the structures are sensitive to pH and synthesis can be reversed by exposure to base.
Yamaguchi will present the work on "Non-covalent synthesis of dendrimers," (Orgn #119) co-authored by Hamilton and Gibson, on Monday, March 22 at 11:30 a.m. in the Hilton Pacific ballroom B. A poster, "Non-Covalent Polymers" (PMSE #241), of Yamaguchi's and Gibson's work will be on display on Tuesday, March 23, beginning at 6 p.m. in the Convention Center Hall 3.
Contact for more information: Dr. Harry Gibson, hwgibson@vt.edu or 540-231-5902,
or Nori Yamaguchi at nyamaguc@vt.edu
Dr. Gibson will be available at the above number during and after the meeting.
Yamaguchi will be at the meeting.
Journal
Angewandte Chemie