Toward fractioning of isomers through binding-induced acceleration of azobenzene switching

Vulcano, Rosaria, Pengo, Paolo, Velari, Simone, Wouters, Johan, De Vita, Alessandro, Tecilla, Paolo and Bonifazi, Davide ORCID: https://orcid.org/0000-0001-5717-0121 2017. Toward fractioning of isomers through binding-induced acceleration of azobenzene switching. Journal of the American Chemical Society 139 (50) , pp. 18271-18280. 10.1021/jacs.7b09568

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Abstract

The E/Z isomerization process of a uracil-azobenzene derivative in which the nucleobase is conjugated to a phenyldiazene tail is studied in view of its ability to form triply-H-bonded complexes with a suitably complementary 2,6-diacetylamino-4-pyridine ligand. UV-Vis and 1H-NMR investigations of the photochemical and thermal isomerization kinetics show that the thermal Z→E interconversion is four-fold accelerated upon formation of the H-bonded complex. DFT calculations show that the formation of triple H-bonds triggers a significant elongation of the N=N double bond, caused by an increase of its πg∗ antibonding character. This results in a reduction of the N=N torsional barrier and thus in accelerated thermal Z→E isomerization. Combined with light controlled E→Z isomerization this enables controllable fractional tuning of the two configurational isomers.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Publisher:	American Chemical Society
ISSN:	0002-7863
Date of First Compliant Deposit:	31 October 2017
Date of Acceptance:	19 October 2017
Last Modified:	06 Jan 2024 20:37
URI:	https://orca.cardiff.ac.uk/id/eprint/106107

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