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Synthesis of Helical Analogue of Kekulene: a Flexible π-Expanded Helicene with Large Helical Diameter Acting as a Soft Molecular Spring.

08:00 EDT 19th October 2018 | BioPortfolio

Summary of "Synthesis of Helical Analogue of Kekulene: a Flexible π-Expanded Helicene with Large Helical Diameter Acting as a Soft Molecular Spring."

A π-expanded helicene, that is the helically twisted analogue of kekulene, was synthesized using a 6-fold ring-closing olefin metathesis (RCM) reaction as a key step. The π-expanded geometry with large helical diameter ( d = 10.2 Å), consisting only of carbon and hydrogen atoms (CH), was unambiguously determined by single-crystal X-ray analysis. We found that the π-expanded helicene with large helical diameter will act as a soft molecular spring with a small spring constant. Interestingly, the mechanical properties of molecular springs roughly satisfied a physical formula for macroscopic spring materials, i.e., the force constant of the elongation of molecular spring ( k) is inversely proportional to the third power of the helical diameter.

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Name: Journal of the American Chemical Society
ISSN: 1520-5126
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