Laboratoire de Chimie de Coordination.
Toulouse,
France

Outline

Fast reduction without apparent reducing agent! The basic compound Ru(CO)₂(PR₃)₃, archetype of reactive Ru(0) complex also known as an efficient catalyst for C-H/olefin coupling (the Murai reaction), is now available within minutes at 0°C from a common Ru(II) precursor such as Ru(CO)₃Cl₂(thf) via a simple cascade reaction using NEt₄OH as the only reagent and any phosphine as incoming ligand.

The observed reduction of the metal is the consequence of an oxidation of a CO ligand to CO₂ (recovered as CO₃^2-) taking place via the transient generation of a hydroxyl-carbonyl complex and its subsequent de-protonation. Identified as a simple acid/base reaction, such an intramolecular reductive pathway is favored at low temperature, due to its intrinsic kinetic preference over any other transformation susceptible to occur in the metal’s coordination sphere.

A complex caught in the act of CC bond formation. The above complex Ru(CO)₂(PPh₃)₃ was engaged in the following reaction sequence, which provides a suitable experimental model for the chelation-assisted hydro-acylation of diphenylacetylene with a tethered aldehyde.

Current research line

A new series of Ru(0) complexes incorporating functionalized N-heterocyclic carbenes is at the point to be disclosed.

Leading references

 S. Sentets, M. del Carmen Rodriguez Martinez, L. Vendier, B. Donnadieu, V. Huc, N. Lugan, G. Lavigne, J. Am. Chem. Soc. 2005, 127, 14554.
"Instant "Base-Promoted" Generation of Roper’s-type Ru(0) Complexes Ru(CO)₂(PR₃)₃ from a Simple Carbonylchlororuthenium(II) Precursor"

 L. Benhamou, V. César, N. Lugan, G. Lavigne, Organometallics 2007, 26, 4673.
“Snapshot of a Chelation-Assisted C-H/Alkyne Coupling: A Ruthenium Complex Caught in the Act of C-C Bond Formation.”