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Trapping a diradical transition state by mechanochemical polymer extension.

Publication ,  Journal Article
Lenhardt, JM; Ong, MT; Choe, R; Evenhuis, CR; Martinez, TJ; Craig, SL
Published in: Science (New York, N.Y.)
August 2010

Transition state structures are central to the rates and outcomes of chemical reactions, but their fleeting existence often leaves their properties to be inferred rather than observed. By treating polybutadiene with a difluorocarbene source, we embedded gem-difluorocyclopropanes (gDFCs) along the polymer backbone. We report that mechanochemical activation of the polymer under tension opens the gDFCs and traps a 1,3-diradical that is formally a transition state in their stress-free electrocyclic isomerization. The trapped diradical lives long enough that we can observe its noncanonical participation in bimolecular addition reactions. Furthermore, the application of a transient tensile force induces a net isomerization of the trans-gDFC into its less-stable cis isomer, leading to the counterintuitive result that the gDFC contracts in response to a transient force of extension.

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Published In

Science (New York, N.Y.)

DOI

EISSN

1095-9203

ISSN

0036-8075

Publication Date

August 2010

Volume

329

Issue

5995

Start / End Page

1057 / 1060

Related Subject Headings

  • General Science & Technology
 

Citation

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Lenhardt, J. M., Ong, M. T., Choe, R., Evenhuis, C. R., Martinez, T. J., & Craig, S. L. (2010). Trapping a diradical transition state by mechanochemical polymer extension. Science (New York, N.Y.), 329(5995), 1057–1060. https://doi.org/10.1126/science.1193412
Lenhardt, Jeremy M., Mitchell T. Ong, Robert Choe, Christian R. Evenhuis, Todd J. Martinez, and Stephen L. Craig. “Trapping a diradical transition state by mechanochemical polymer extension.Science (New York, N.Y.) 329, no. 5995 (August 2010): 1057–60. https://doi.org/10.1126/science.1193412.
Lenhardt JM, Ong MT, Choe R, Evenhuis CR, Martinez TJ, Craig SL. Trapping a diradical transition state by mechanochemical polymer extension. Science (New York, NY). 2010 Aug;329(5995):1057–60.
Lenhardt, Jeremy M., et al. “Trapping a diradical transition state by mechanochemical polymer extension.Science (New York, N.Y.), vol. 329, no. 5995, Aug. 2010, pp. 1057–60. Epmc, doi:10.1126/science.1193412.
Lenhardt JM, Ong MT, Choe R, Evenhuis CR, Martinez TJ, Craig SL. Trapping a diradical transition state by mechanochemical polymer extension. Science (New York, NY). 2010 Aug;329(5995):1057–1060.
Journal cover image

Published In

Science (New York, N.Y.)

DOI

EISSN

1095-9203

ISSN

0036-8075

Publication Date

August 2010

Volume

329

Issue

5995

Start / End Page

1057 / 1060

Related Subject Headings

  • General Science & Technology