Communication
Structural Characterization of Novel Olefinic Cation Radicals: X-ray Crystallographic Evidence of σ–π Hyperconjugation
Jay K. Kochi,
Rajendra Rathore,
Chengjian Zhu, and,
Sergey V. Lindeman,
Jay K. Kochi
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorRajendra Rathore
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorChengjian Zhu, and
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorSergey V. Lindeman
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorJay K. Kochi,
Rajendra Rathore,
Chengjian Zhu, and,
Sergey V. Lindeman,
Jay K. Kochi
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorRajendra Rathore
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorChengjian Zhu, and
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorSergey V. Lindeman
Department of Chemistry University of Houston Houston, TX 77204-5641 (USA) Fax: (+1) 713-743-2709
Search for more papers by this authorFirst published: 13 October 2000
Citations: 20
We thank the National Science Foundation and the Robert A. Welch Foundation for financial support.
Abstract
A 29° twist of the central olefinic bond is observed in the sesquihomoadamantene cation radical (SH+.). A careful comparison of the X-ray structures of neutral SH (right) and its cation radical (left) reveal the twist is not a result of relieving steric strain. Moreover, the changes in the bond lengths in SH+.—the central C−C bond lengthens by 5 pm and the four single C−C bonds directly attached to the olefinic carbonatoms shorten by 3 pm—provide the first experimental evidence for the (classical) hyperconjugative stabilization of cationic charges.
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The one-electron oxidation of SH to its purple cation radical can also be carried out electrochemically at E
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