Resorcinarenes are hexameric capsules in solution
- Tamar Evan-Salem*,
- Inbal Baruch*,
- Liat Avram*,
- Yoram Cohen*,
- Liam C. Palmer†, and
- Julius Rebek, Jr.†,‡
- †The Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037; and
- *School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Tel Aviv, Israel
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Contributed by Julius Rebek, Jr., June 8, 2006
Abstract
The host–guest complexes of resorcin[4]arenes with small molecules in organic solutions are examined using modern NMR spectroscopic methods. The complexation of glutaric acid and β-methyl d-glucopyranoside in chloroform were investigated through 2D COSY, 2D NOESY, 1D NOE, and diffusion-ordered NMR spectroscopy (DOSY) techniques. These methods indicate that the complex is a self-assembled capsule composed of six resorcinarenes that surround six guest molecules of glutaric acid or three molecules of β-methyl d-glucopyranoside inside. The multiplicity of guest proton signals shows that the capsule provides an asymmetric magnetic environment that persists on the 1H NMR time scale. The encapsulation of these guests and common solvents suggests that the phenomenon of reversible encapsulation in chemistry may be a century old.
Footnotes
- ‡To whom correspondence should be addressed. E-mail: jrebek{at}scripps.edu
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Author contributions: J.R. designed research; T.E.-S., I.B., L.A., Y.C., and L.C.P. performed research; T.E.-S., I.B., L.A., Y.C., and L.C.P. contributed new reagents/analytic tools; T.E.-S., I.B., L.A., Y.C., L.C.P., and J.R. analyzed data; and J.R. wrote the paper.
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Conflict of interest statement: No conflicts declared.
- © 2006 by The National Academy of Sciences of the USA
