Original Gold-Alkyl complexes for coordination-insertion polymerization of olefins – POGO

A set of gold(III)-alkyl complexes will be prepared using two main synthetic strategies. The reactivity of selected complexes with model monomers such as ethylene and acrylonitrile will be explored by combining a set of experimental and theoretical techniques. Thorough mechanistic studies of the coordination-insertion reaction will be carried out to gain fundamental knowledge on the key parameters governing the reactivity and selectivity of these gold complexes.

At this stage of the project, we have developed a new synthetic strategy for the straigthforward preparartion of stable gold(III)-alkyle complexes, and we have shown for the first time a coordination-insertion of olefins with these gold(III) complexes.

The generality of the coordination-insertion process of olefins with these gold(III) complexes will be investigated. We will also seek to understand the influence of the steric and elecrtonic parameters of the ligand to establish the most promising complexes for polymerization studies.

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Initially considered as an inert metal, gold is now recognized as very powerful catalyst in organic synthesis. One very important area in homogenous catalysis for which gold complexes have not been considered yet, is the field of polymerization catalysis, particularly for the coordination-insertion polymerization of olefins. In contrast, late transition metal complexes such as Pd(II) and Ni(II) have been shown to be very good catalyst for the polymerization of olefins and the incorporation of polar monomers. However several limitations are still observed with these complexes, in particular for the copolymerization of olefins and polar monomers. Stimulated by the isolobal analogy between Au(III) and Pd(II) complexes, we propose in this project to prepare original bidentate Au(III)-alkyl complexes and investigate their behaviour in coordination-insertion polymerization of olefins. The main objective of this project is to shed light on a new facet of gold chemistry, we aim to thoroughly investigate the reactivity of gold towards olefins and to highlight that gold(III) complexes should be seriously considered for coordination-insertion polymerization catalysis. For that purpose, a set of gold(III)-alkyl complexes will be prepared using two main synthetic strategies. The reaction of selected complexes with model monomers such as ethylene and acrylonitrile will be explored by combining a set of experimental and theoretical techniques. In depth mechanistic studies of the coordination-insertion reaction will be carried out to gain fundamental knowledge on the key parameters governing the reactivity and selectivity of these gold complexes. Best representatives will be evaluated for ethylene and propylene polymerization and for copolymerization of ethylene with polar vinyl monomers.