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Séminaire Chimie ED459

In-situ generated ruthenium-arene catalyst for ring-opening metathesis photopolymerization through photolatent N-heterocyclic carbene (NHC) ligand

Dr. Abraham Chemtob (IS2M Institut des Sciences des Matériaux de Mulhouse, UMR 7361 CNRS, Université de Haute-Alsace, Mulhouse)

publié le , mis à jour le

Le Jeudi 12 Octobre 2017 à 14h
ENSCM, amphithéâtre Mousseron A (campus Balard, 240 av. Émile-Jeanbrau)

Since its discovery in the 1950s, olefin metathesis has evolved from a restricted use in petroleum cracking processes to the standard method for creating C–C double bonds. Progress has been driven by a range of increasingly advanced and well-defined olefin metathesis catalysts. Nevertheless, these developments have predominantly benefited preparative organic chemistry, and to a lesser extent, the synthesis of polymer materials. Many useful polymers such as poly(norbornene) or poly(dicyclopentadiene) can be prepared by ring-opening metathesis polymerization (ROMP), and have led to successful commercial applications. However, their implementation at industrial scale has been held back by the lack of ambient stability and processability of most late transition metal-based catalysts.[1] Designing ROMP catalysts in a way that allows the on-demand release of highly reactive alkylidene species is a very attractive goal to ease storage, handling and processing.[2] UV-vis radiation is certainly one of the most sought after activating stimuli because it enables, among other advantages, room-temperature process and spatial control.[3] So far, though, only radical and cationic chain-growth processes have enabled photopolymerization to be harnessed as a technology.[4] In an effort to improve ROMP photocatalyst performance, versatility, latency and ease of synthesis, we have designed an indirect activation method based on a metathesis inactive Ru complex converted into an active system by a photogenerator of N-heterocyclic carbene (NHC) ligand.[5] So far, all latent NHCs are triggered thermally or mechanically,[6] and the synthesis of an efficient photolatent NHCs is unprecedented. With this new photocatalytic system, full conversion of norbornene was achieved in less than 3 min.

References

1. S. Naumann, M.R. Buchmeiser, Macromol. Rapid Commun. 2014, 35, 682–701.
2. a) K.A. Ogawa, A.E. Goetz, A. J. Boydston, Synlett 2016, 27, 203–214 ; b) S. Monsaert, A.L. Vila, R. Drozdzak, P. Van Der Voort, F. Verpoort, Chem. Soc. Rev. 2009, 38, 3360–3372.
3. W. Schnabel, In : Polymers and Light, Wiley-VCH Verlag GmbH, 2007, pp. 273-304.
4. R. Schwalm, In : UV Coatings, Elsevier, Amsterdam, 2007, pp. 19-61.
5. B. K. Keitz, R.H. Grubbs, J. Am. Chem. Soc. 2009, 131, 2038–2039.
6. M. Fevre, J. Pinaud, Y. Gnanou, J. Vignolle, D. Taton, Chem. Soc. Rev. 2013, 42, 2142–2172.

Co-authors :
Julien Pinaud,[a] Thi Kim Hoang Trinh,[b] David Sauvanier,[a] Emeline Placet,[a] Patrick Lacroix-Desmazes,[a] Valérie Héroguez,[c] Jean-Michel Becht,[b] Bassam Tarablsi,[b] Jacques Lalevée,[b] Abraham Chemtob.[b]
a. Équipe IAM Ingénierie et Architectures Macromoléculaires, ICGM Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, Université de Montpellier, ENSCM.
b. IS2M Institut des Sciences des Matériaux de Mulhouse, UMR 7361 CNRS, Université de Haute-Alsace, Mulhouse.
c. LCPO Laboratoire de Chimie des Polymères Organiques, UMR 5629 CNRS, École Nationale Supérieure de Chimie Biologie Physique, Université de Bordeaux.

Contact local ICGM : Dr. Julien Pinaud (équipe IAM)

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