Jérémy Chaignon

Silica-grafted manganese complexes for catechol oxidation
Jérémy Chaignon

The excess of pesticides used in agriculture requires special and expensive treatments to keep waters clean. Lots of them present substituted aromatic rings, thus we decided to design materials based on a family of enzymes called MndD (for Manganese-dependent Dioxygenase). Those enzymes perform the extradiol cleavage of catechol derivatives, using molecular dioxygen as a cheap and non-polluting oxidant.
Manganese complexes were synthesized to mimic the first coordination sphere of the enzymatic catalytic site. Moreover, we designed those complexes to be grafted in mesoporous silica through click chemistry. Those molecular complexes show an oxidative activity when put together in catalytic quantities with catechol derivatives and base. We aim at better results with silica-grafted complexes, due to the confined space provided by the mesopores that would get closer to the enzymatic active site.
We report here the structural and spectroscopic characterization of those molecular complexes along with their silica-supported version. The first catalysis results will also be presented, varying reaction conditions such as substrate, base and reaction time.