Display options
Cite
Nikitin K, Muldoon J, Müller-Bunz H, et al. A ferrocenyl kaleidoscope: slow interconversion of six diastereo-atropisomers of 2,6-di-tert-butyl-9,10-diferrocenyltriptycene. Chemistry. 2015;21(12):4664-70doi: 10.1002/chem.201405968.
Nikitin, K., Muldoon, J., Müller-Bunz, H., & McGlinchey, M. J. (2015). A ferrocenyl kaleidoscope: slow interconversion of six diastereo-atropisomers of 2,6-di-tert-butyl-9,10-diferrocenyltriptycene. Chemistry (Weinheim an der Bergstrasse, Germany), 21(12), 4664-70. https://doi.org/10.1002/chem.201405968
Nikitin, Kirill, et al. "A ferrocenyl kaleidoscope: slow interconversion of six diastereo-atropisomers of 2,6-di-tert-butyl-9,10-diferrocenyltriptycene." Chemistry (Weinheim an der Bergstrasse, Germany) vol. 21,12 (2015): 4664-70. doi: https://doi.org/10.1002/chem.201405968
Nikitin K, Muldoon J, Müller-Bunz H, McGlinchey MJ. A ferrocenyl kaleidoscope: slow interconversion of six diastereo-atropisomers of 2,6-di-tert-butyl-9,10-diferrocenyltriptycene. Chemistry. 2015 Mar 16;21(12):4664-70. doi: 10.1002/chem.201405968. Epub 2015 Feb 12. PMID: 25678469.
Copy Download .nbib Format: NLM
Share it on

Chemistry. 2015 Mar 16;21(12):4664-70. doi: 10.1002/chem.201405968. Epub 2015 Feb 12.

A ferrocenyl kaleidoscope: slow interconversion of six diastereo-atropisomers of 2,6-di-tert-butyl-9,10-diferrocenyltriptycene.

Chemistry (Weinheim an der Bergstrasse, Germany)

Kirill Nikitin, Jimmy Muldoon, Helge Müller-Bunz, Michael J McGlinchey

Affiliations

  1. School of Chemistry & Chemical Biology, University College Dublin, Belfield, Dublin 4 (Ireland). [email protected].

PMID: 25678469 DOI: 10.1002/chem.201405968

Abstract

The title triptycene, 6, has been isolated as the product of 9,10-cycloaddition of benzyne to 9,10-diferrocenyl-2,6-di-tert-butylanthracene, 5, whose X-ray crystal structure is reported. Each ferrocenyl unit in 6 has access to the same three non-equivalent molecular environments, and their rotations relative to the molecular paddlewheel give rise to six slowly interconverting atropisomers. Their dynamic behaviour in solution is a challenging NMR puzzle that can be successfully solved by taking advantage of the recently described very large diamagnetic anisotropy of the ferrocenyl moiety, together with the C2 symmetry of particular atropisomers. Application of one- and two-dimensional NMR techniques over a range of temperatures together, with a detailed analysis of the homo- and heteronuclear correlations in 6, resulted in unequivocal mapping of the 99 (1)H and 162 (13)C positions in the six interconverting systems. Variable-temperature 2D-EXSY measurements revealed that, while the stability of the atropisomers is almost identical, they are separated by energy barriers which the ferrocenyls must overcome in the course of their interconversions. The heights of two different rotational barriers have been identified and these experimental findings are in good agreement with DFT calculations.

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords: EXSY NMR spectroscopy; diamagnetic anisotropy; ferrocene; specific rotamer interchanges; triptycene

Publication Types