Toward Fractioning of Isomers through Binding-Induced Acceleration of Azobenzene Switching

Rosaria Vulcano, Paolo Pengo, Simone Velari, Johan Wouters, Alessandro De Vita, Paolo Tecilla, Davide Bonifazi

Research output: Contribution to journalArticlepeer-review


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 4-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 NN double bond, caused by an increase of its g∗ antibonding character. This results in a reduction of the NN 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.

Original languageEnglish
Pages (from-to)18271-18280
Number of pages10
JournalJournal of the American Chemical Society
Issue number50
Publication statusPublished - 20 Dec 2017


Dive into the research topics of 'Toward Fractioning of Isomers through Binding-Induced Acceleration of Azobenzene Switching'. Together they form a unique fingerprint.

Cite this