Oligomérisation sélective de l'éthylène avec des complexes de chrome : étude théorique et expérimentale combinée - et extensions à d'autres métaux

Abstract

The selective catalytic oligomerization of ethylene to alpha-olefins constitutes a process of significant scientific as well as economic interest both in industry and academics. The present thesis gives both experimental and theoretical contributions to the catalyzed selective tri- and tetramerization with chromium coordination complexes. Important aspects of the mechanism of this reaction are adressed, including the oxidation state of the active species, the origin of cyclic secondary products, as well as the influence of the ligand steric bulk, are comprehensively adressed. A number of alternative bidentate ligands have been evaluated in the oligomerization reaction. Another part of this thesis concerns the selective ethylene dimerization with nickel(II) complexes bearing mixed heteroatomic iminophosphorane (N,O), (N,S), and (N,P) ligands. The synthesis of these new ligands, their coordination to Ni(II), as well as the catalytic evaluation of the obtained complexes are reported. The last part of this work concerns the preparation of two new phosphatitanocenes and catalytic evaluation in the ethylene oligomerization/polymerization reaction