Multiple hindered rotators in a gyroscope-inspired tribenzylamine hemicryptophane

Najat S. Khan, Jose Manuel Perez-Aguilar, Tara Kaufmann, P. Aru Hill, Olena Taratula, One Sun Lee, Patrick J. Carroll, Jeffery G. Saven, Ivan J. Dmochowski

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Abstract

A gyroscope-inspired tribenzylamine hemicryptophane provides a vehicle for exploring the structure and properties of multiple p-phenylene rotators within one molecule. The hemicryptophane was synthesized in three steps in good overall yield using mild conditions. Three rotator-forming linkers were cyclized to form a rigid cyclotriveratrylene (CTV) stator framework, which was then closed with an amine. The gyroscope-like molecule was characterized by 1H NMR and 13C NMR spectroscopy, and the structure was solved by X-ray crystallography. The rigidity of the two-component CTV-trismethylamine stator was investigated by 1H variable-temperature (VT) NMR experiments and molecular dynamics simulations. These techniques identified gyration of the three p-phenylene rotators on the millisecond time scale at -93 °C, with more dynamic but still hindered motion at room temperature (27 °C). The activation energy for the p-phenylene rotation was determined to be ?10 kcal mol-1. Due to the propeller arrangement of the p-phenylenes, their rotation is hindered but not strongly correlated. The compact size, simple synthetic route, and molecular motions of this gyroscope-inspired tribenzylamine hemicryptophane make it an attractive starting point for controlling the direction and coupling of rotators within molecular systems.(Figure Presented)

Original languageEnglish
Pages (from-to)1418-1424
Number of pages7
JournalJournal of Organic Chemistry
Volume76
Issue number5
DOIs
Publication statusPublished - 4 Mar 2011

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ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Khan, N. S., Perez-Aguilar, J. M., Kaufmann, T., Hill, P. A., Taratula, O., Lee, O. S., Carroll, P. J., Saven, J. G., & Dmochowski, I. J. (2011). Multiple hindered rotators in a gyroscope-inspired tribenzylamine hemicryptophane. Journal of Organic Chemistry, 76(5), 1418-1424. https://doi.org/10.1021/jo102480s