Cavitand

A cavitand cucurbituril bound with a guest p-xylylenediammonium[1]

In chemistry, a cavitand is a container-shaped molecule.[2] The cavity of the cavitand allows it to engage in host–guest chemistry with guest molecules of a complementary shape and size. The original definition proposed by Cram includes many classes of molecules: cyclodextrins, calixarenes, pillararenes and cucurbiturils.[3] However, modern usage in the field of supramolecular chemistry specifically refers to cavitands formed on a resorcinarene scaffold by bridging adjacent phenolic units.[4] The simplest bridging unit is methylene (−CH2), although dimethylene (−(CH2)2), trimethylene (−(CH2)3), benzal, xylyl, pyridyl, 2,3-disubstituted-quinoxaline, o-dinitrobenzyl, dialkylsilylene, and phosphonates are known. Cavitands that have an extended aromatic bridging unit, or an extended cavity containing 3 rows of aromatic rings are referred to as deep-cavity cavitands and have broad applications in host-guest chemistry.[5][6] These types of cavitands were extensively investigated by Rebek, and Gibb, among others.

Applications of Cavitands

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Specific cavitands form the basis of rigid templates onto which de novo proteins can be chemically linked. This template assembled synthetic protein (TASP) structure provides a platform for the study of protein structure.[7]

Silicon surfaces functionalized with tetraphosphonate cavitands have been used to singularly detect sarcosine in water and urine solutions.[8]

See also

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References

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  1. ^ Freeman, Wade A. (1984). "Structures of the p-xylylenediammonium chloride and calcium hydrogensulfate adducts of the cavitand 'cucurbituril', C36H36N24O12" (PDF). Acta Crystallographica Section B. 40 (4): 382–387. doi:10.1107/S0108768184002354.
  2. ^ D. J. Cram (1983). "Cavitands: organic hosts with enforced cavities". Science. 219 (4589): 1177–1183. Bibcode:1983Sci...219.1177C. doi:10.1126/science.219.4589.1177. PMID 17771285. S2CID 35255322.
  3. ^ Moran, John R.; Karbach, Stefan; Cram, Donald J. (October 1982). "Cavitands: synthetic molecular vessels". Journal of the American Chemical Society. 104 (21): 5826–5828. doi:10.1021/ja00385a064.
  4. ^ Jordan, J. H.; Gibb, B. C. (2017). "1.16 - Water-Soluble Cavitands☆". In Atwood, Jerry (ed.). Comprehensive Supramolecular Chemistry II. Elsevier. pp. 387–404. ISBN 9780128031995.
  5. ^ Wishard, A.; Gibb, B.C. (2016). "A chronology of cavitands". Calixarenes and beyond. Springer. pp. 195–234. doi:10.1007/978-3-319-31867-7_9. ISBN 978-3-319-31867-7.
  6. ^ Cai, X.; Gibb, B. C. (2017). "6.04 - Deep-Cavity Cavitands in Self-Assembly". In Atwood, Jerry (ed.). Comprehensive Supramolecular Chemistry II. Elsevier. pp. 75–82. ISBN 9780128031995.
  7. ^ Tuchscherer, Gabriele (April 20, 1999). "Extending the concept of template-assembled synthetic proteins". Journal of Peptide Research. 54 (3): 185–194. doi:10.1034/j.1399-3011.1999.00120.x. PMID 10517155.
  8. ^ Biavardi, Elisa (February 14, 2011). "Exclusive recognition of sarcosine in water and urine by a cavitand-functionalized silicon surface". Proceedings of the National Academy of Sciences of the United States of America. 109 (7): 2263–2268. Bibcode:2012PNAS..109.2263B. doi:10.1073/pnas.1112264109. PMC 3289311. PMID 22308349.