Bandeau SYMAC

Ionic liquids

To avoid conventional solvents, we use ionic liquids which offer the advantage of immobilizing the catalytic species and allow easy extraction of the reaction products, with a low metal content, interesting for obtaining products of pharmacy interest (Metallic nanoparticles in ionic liquids. Applications in catalysis, Chapter 5 in Nanomaterials in Catalysis, Eds. K. Philippot and P. Serp, Wiley, 2013).

With regard to the homogeneous systems (based on organometallic complexes), the enantioselective allylic substitution reaction (alkylation, amination and sulfonylation) catalysed by palladium in ionic liquids gave excellent TOF (> 20000 h-1), in the presence of chiral P-donor ligands (diphosphites containing carbohydrate skeletons and diamidophosphites ligands). When the solvent is a pyrrolidium salt, effective recycling with negligible palladium levels in the product are obtained (<0.1 ppm) (Chem. Commun. 2011, 47, 7869 ; Organometallics 2014, 33, 771). Remarkable activities and selectivities were observed for the allylic substitution reactions, with bidentate ligands (diphosphites) or ligands with a topology adapted to the medium (Tetrahedron 2011, 67, 421).

For molybdenum-based systems we have developed mono and bimetallic complex dioxomolybdène (VI) with oxazoline ligands, active in epoxidation reactions of substrates, allowing their immobilization in ILs environments (Appl. Catal. A 2011, 398, 88 ; Curr. Inorg. Chem. 2011, 1, 131). Only the bimetallic system induces excellent diastereoselectivity for the epoxidation of (R) -limonène. Mechanistic studies, including NMR-95Mo (Magn. Reson. Chem. 2009, 47, 573), helped to understand the metal-olefin interaction and lack of stereoselectivity in [BMI] [NTf2].

graphique 9

Hits: 635