CATALMET · DESIGN OF CATALYSTS AND ALKENE METATHESIS
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2005-12-01 → 2007-11-30
- EU contribution
- €150,238
- Participants
- 1
- Scheme
- SCF
Lines connect the coordinator with its partners.
Results in brief
Final Activity Report Summary - CATALMET (Design of catalysts and alkene metathesis)
The project objectives aimed at the preparation of new metal catalysts for selective Catalytic combinations /transformations of molecules in order to contribute to greener aspects of chemistry and sustainable development via energy and atom economy. The main objectives focused on preparation of alkene metathesis catalysts and catalysis and related cross C-C bond formation reactions in order to selectively transform simple molecules and natural products into valuable compounds. The preparation of ruthenium catalysts was planned as the first target. Cationic nitrogen-heterocyclic carbene (NHC) containing Ru-complexes were prepared and activated to obtain in situ metathesis initiator for ring-closing metathesis. Their activity was in the range of that of phosphine containing complexes. Two types of polydentate ligands and related ruthenium complexes were prepared. hexakis(benzimidazolyl) ligand was prepared and allowed to bind six Ruthenium atoms. This complex was fully characterised and showed a spherical structure and its catalytic activity was studied in ring-closing metathesis and cross-metathesis reactions. The synthesis of new dendrimer-like ligands containing six benzimidazolium halide moieties was performed. They can serve as precursors for polycarbenes which were used to make polyruthenium intermediates with potential in alkene metathesis and cross C-C bond formation. A croos coupling reaction with unsaturated aminoacid derivative and long chain unsaturated ester was performed and needs developments toward surfactants for example. The polyimidazolium and polybenzimidazolium salts as NHC precursors were studied as well for direct C-C bond formation via C-H bond activation. Three important results were obtained: -The poly NHC-Ru catalysts perform direct C-C bond formation of phenylpyridine and heterocycles, -The (NHC)RuCl2 based systems are not the most efficient catalysts and the replacement of chlorides by carboxylates largely improves the ruthenium catalyst activity for C-C bond formation. -Simple ruthenium-carboxylate catalysts favour the direct arylation of heterocycles with arylchlorides with respect to arylbromides. Similar direct C-C bond formation via C-H bond functionalisation was performed with ligand free palladium-acetate in the direct arylation of heteroaromatics. It was demonstrated that low-loading (less than 0.1 mol %) of Pd(OAc)2 as catalyst precursor can be used in direct arylation via C-H bond activation of thiazoles, thiophenes and furans for a wide range of functions. However in that case the procedure is limited to more reactive electron-poor aryl bromides. Turnover numbers up to 10000 have been obtained for the coupling of activated aryl bromides.
Data: CORDIS, © European Union
Project objective
The presented project aims at the synthesis and development of new molecular ruthenium and rhenium catalysts for alkene metathesis. Their catalytic activity will be enhanced by the tuning of ligands. These complexes will be designed and used in the selecti ve transformation of unsaturated esters (derived from natural oils), terpenoid and aminoacid derivatives via ethenolysis and self-metathesis toward the production of useful high value chemicals. The target reactions on oils will offer access to linear mole cules that are key intermediates for the synthesis of cosmetics and surfactant type molecules. The terpenoids and aminoacid derivatives will offer access to chiral compounds and cyclic intermediates for pharmacy. The synthesis of catalysts will introduce i nnovations in organometallic synthesis by introducing new methods to produce new unsaturated vinylidene-, allenylidene-, alkenyl- and carbyne-complexes. The originality of the catalyst precursors also deals with their ionic character the profit of which wi ll be made to fix them on solids (silica) and polyanionic polymers. Thus catalytic systems will be modified to improve their stability and activity and to permit an efficient recycling as well as milder reaction conditions. These objectives will be achieve d by gathering of multidisciplinary competences: metal complex synthesis, organic synthesis, catalyst preparation, spectroscopic characterization and combinatorial High Throughput Experiments catalysis. Olefin metathesis in non volatile ionic liquids still need to be fully developed. Thus the objectives of this project would also contribute to the development of greener processes. Furthermore, recovery and recycling of the catalyst play an important role in decreasing the costs of a catalytic process. Europ ean industries are strongly interested in patenting efficient new catalysts for alkenes metathesis since the existing patents are under the control of USA.
Original text from CORDIS.
Participants
- UNIVERSITÉ DE RENNES 1 · RENNESCoordinatorFrance
Links
Data: CORDIS, © European Union