Steric and electronic control of 1,3-dipolar cycloaddition reactions in carbon nanotube nanoreactors

Miners, Scott A.; Fay, Michael W.; Baldoni, Matteo; Besley, Elena; Khlobystov, Andrei N.; Rance, Graham A.

Abstract

The use of single-walled carbon nanotubes as effective nanoreactors for preparative bimolecular reactions has been demonstrated for the first time. We show that the extreme spatial confinement of guest reactant molecules inside host carbon nanotubes increases the regioselectivity for 1,4-triazole in thermally initiated azide–alkyne cycloaddition reactions. Through comparison of the internal dimensions of the nanotube and the steric bulk of the reactants, we demonstrate that the formation of the more linear 1,4-regioisomer can be enhanced by up to 55% depending on the extent of spatial restrictions imposed within the nanoreactors. Furthermore, through systematic variation of the substituents in the para-position of the alkyne reactants, we reveal the unexpected influence of the reactants’ electronic properties on the regioselectivity of reactions within nanoreactors, which act to either oppose or promote the preferential formation of the 1,4-regioisomer induced by steric effects, reflecting the unique ability of carbon nanotubes to stabilize the dipole moment of confined reactants. Thus, we show that the observed regioselectivity of azide–alkyne cycloaddition reactions confined within carbon nanotube nanoreactors reflects a subtle interplay between both steric and electronic factors.

Citation

Miners, S. A., Fay, M. W., Baldoni, M., Besley, E., Khlobystov, A. N., & Rance, G. A. (2019). Steric and electronic control of 1,3-dipolar cycloaddition reactions in carbon nanotube nanoreactors. Journal of Physical Chemistry C, 123(10), 6294-6302. https://doi.org/10.1021/acs.jpcc.9b01190

• Journal Article Type: Article
• Acceptance Date: Feb 20, 2019
• Online Publication Date: Feb 20, 2019
• Publication Date: Mar 14, 2019
• Deposit Date: Mar 19, 2019
• Publicly Available Date: Feb 21, 2020
• Journal: Journal of Physical Chemistry C
• Print ISSN: 1932-7447
• Electronic ISSN: 1932-7455
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 123
• Issue: 10
• Pages: 6294-6302
• DOI: https://doi.org/10.1021/acs.jpcc.9b01190
• Keywords: General energy; Physical and theoretical Chemistry; Electronic, optical and magnetic materials; Surfaces, coatings and films
• Public URL: https://nottingham-repository.worktribe.com/output/1666263
• Publisher URL: https://pubs.acs.org/doi/10.1021/acs.jpcc.9b01190
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpcc.9b01190
• Contract Date: Mar 20, 2019