Bioinspired metal-based oxidants: selectivity in catalytic hydroxylation of aliphatic c-h bonds and insight into the reactivity of oxoiron species

• Autores: Valeria Dantignana
• Directores de la Tesis: Miquel Costas Salgueiro (dir. tes.), Anna Company Casadevall (codir. tes.)
• Lectura: En la Universitat de Girona ( España ) en 2020
• Idioma: español
• Tribunal Calificador de la Tesis: Robertus J. M. Klein Gebbink (presid.), Anna Pla Quintana (secret.), Aidan Macdonald (voc.)
• Materias:
  • Química
• Enlaces
  • Tesis en acceso abierto en: TDX
• Resumen

  • Oxidation of alkyl C-H bonds is an important reaction in chemical synthesis, because it allows to convert readily available hydrocarbons into valuable compounds. To overcome the inert character of such bonds strong oxidants and harsh reaction conditions are usually required. Then, it is difficult to discriminate among the multiple C-H bonds contained in the substrate. Novel methods are required to achieve selective oxidations. To that purpose oxidations performed by iron-dependent oxygenases could be taken as inspiration. These enzymes selectively and efficiently catalyze oxidation reactions, under mild and environmental friendly conditions. Thus, model complexes that can mimic their reactivity have been synthetized. These bioinspired complexes act as catalysts in oxidation reactions, in combination with hydrogen peroxide as terminal oxidant. High-valent oxometal species have been identified as the active oxidants. Then, reactivity of synthetic high-valent oxometal compounds is currently studied by a number of research teams in order to gain fundamental mechanistic information in these reactions.

    In this context, this thesis aimed at investigating catalytic oxidation of unactivated C-H bonds and reactivity of well-defined high-valent oxoiron species. For the catalytic studies, bioinspired iron and manganese complexes bearing tetradentate aminopyridine ligands have been used. The solvent effect on the selectivity outcome has been explored in the oxidation of aliphatic C-H bonds. For the mechanistic studies, iron complexes bearing azamacrocyclic ligands have been used. First, the impact of the oxidation state of the iron center on the oxidative ability of high-valent oxoiron complexes has been studied. Subsequently, the reactivity of a series of oxoiron(IV) species bearing electronically tuned azamacrocyclic ligands has been compared.