Laboratoire de Chimie de Coordination.
Toulouse,
France

Outline

In-situ generated catalysts. Inspired by Grubbs III type olefin metathesis catalysts, where bromo-pyridine ligands are acting as leaving groups, we have designed a series of “user-friendly”pyridine-functionalized phosphine complexes of Ru(II) of general formula RuCl₂(R₂PCH₂(C₅H₂R’R”N))(PPh₃). Such complexes are seen to function as ROMP initiators for norbornene upon in situ activation by a commercial carbene source.

During the course of tests aimed at rationalizing such a behavior, we were led to observe that a typical carbene source like ethyl diazoacetate acts as a phosphine scavenger to create a 14 electrons organometallic fragment, further reacting with two equivalents of the carbene to produce diethyl maleate, intercepted here as a coordinated ligand.

The same phosphino-pyridine complexes are also seen to rank amongst the fastest transfer hydrogenation catalysts reported so far.

Advanced fine-tuning of Hoveyda-Grubbs olefin metathesis catalysts .
A European Marie Curie project in collaboration with Karol Grela has led to the development of a new class of Hoveyda Grubbs catalysts. These are incorporating a poly-chelating carbene ligand bearing a weakly donating ester group as a terminal substituent of the ether. Such complexes are air stable and can be recycled. They allow to reach the optimum balance between stability, activity and selectivity in a number of challenging RCM and cross-metathesis reactions.

 
 
 
 
 
Current research line

Our research is now oriented toward the design of zwitterionic olefin metathesis catalysts based on anionic N-heterocyclic carbenes, which have been independently synthesized in our group.

Leading references

 M. Bieniek, R. Bujok, M. Cabaj, N. Lugan, G. Lavigne, D. Artl, K. Grela, J. Am. Chem. Soc. 2006, 128, 13652.
"Advanced fine-tuning of Grubbs/Hoveyda olefin metathesis catalysts: a further step toward an optimum balance between antinomic properties"

 E. Mothes, S. Sentets, M. A. Luquin, R. Mathieu, N. Lugan, G. Lavigne, Organometallics 2008, 27, 1193.
“New insight into the reactivity of pyridine-functionalized phosphine complexes of Ru(II) with respect to olefin metathesis and transfer hydrogenation.”