Thesis presented September 19, 2023
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Abstract:
Redox reactions are the most difficult to control. Their selectivity is often problematic, and the oxidants involved are highly polluting transition metals, even when used in catalytic proportions. Better than oxygen itself, hydrogen peroxide is the most controllable oxidant in fine chemistry, albeit only available in aqueous solution. A bio-inspired copper dimer complex has recently been shown to catalyze the conversion of oxygen to hydrogen peroxide (H₂O₂) in organic media, in the presence of a source of protons and electrons. These two types of reservoir (an amine and a polymethylated ferrocene) are difficult to remove from the organic medium, which is a major drawback that we aim to minimize.
Attaching these functionalities to a solid support that can be separated from the reaction medium is therefore a key issue. Among these functions, those concerning the storage of polymethylated ferrocenes present the greatest difficulty. Mesoporous silicas of the MCM-41 type were chosen as the support material, as their recent rapid microwave synthesis enables reproducible development of very large specific surface areas and enlarged pores. They lend themselves to grafting of multiple grafts with an alkoxysilane-type grafting function.
This thesis focuses on the preparation of hybrid materials containing octa- or nonamethylated ferrocenes. Their molecular grafts were synthesized and grafted, then compared with their unmethylated counterparts. They were then compared under catalytic conditions similar to those of homogeneous catalysis for the conversion of dioxygen to hydrogen peroxide, using a more suitable copper dimer complex. The solids were subjected to a range of techniques to characterize both the silica matrix and the grafted organometallic functions.

Keywords:
hydrogen peroxide controlled production, spectroscopy, copper complexes, dioxygene activation, mesoporous silica functionalization

On-line thesis. ​