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Photochemically Activated Thiol-Michael Reactions via a Photolatent N-Heterocyclic Carbene

preprint
submitted on 02.10.2019 and posted on 04.10.2019 by Abraham Chemtob, Bao Tram Vu Ngoc, Julien Pinaud, Patrick Lacroix-Desmazes, Valérie Héroguez

While N-heterocyclic carbenes (NHCs) have proven highly effective in various polymerization reactions, the drawback is their high sensitivity towards air and water, which necessitates handling under rigorously anhydrous conditions. In this report, an air-stable two-component NHC photogenerator ─ 2-isopropylthioxanthone (ITX) as photosensitive species and 1,3-bis(mesityl)imidazolium tetraphenylborate (IMesH+ BPh4-) acting as NHC protected precursor ─ has been utilized to organocatalyze thiol-Michael reaction for small molecule and polymer synthesis. The feasibility of photoNHC catalysis in addition reactions involving thiol and ene molecules was investigated using 1H NMR spectroscopy. The synthesis of cross-linked polythioether polymer via a step-growth polymerization was then studied using FTIR spectroscopy, optical pyrometry and gel content measurements.

Funding

French National Research Agency (ANR program: DS0304 2016, contract number: ANR-16-CE07-0016)

History

Email Address of Submitting Author

abraham.chemtob@uha.fr

Institution

Institut de Science des Matériaux de Mulhouse (IS2M) UMR 7361 - CNRS/UHA

Country

France

ORCID For Submitting Author

0000-0003-4434-1870

Declaration of Conflict of Interest

No conflict of interest to declare

Version Notes

Version n°1

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