ED Sciences Chimiques
Rational design of materials for selective transformations of enantiomers and biomass
by Wanmai SRISUWANNO (Institut des Sciences Moléculaires)
The defense will take place at 13h00 - M136 Vidyasirimedhi Institute of Science and Technology 555 Moo 1 Payupnai, Wangchan, Rayong 21210, Thailand
in front of the jury composed of
- Siriporn JUNGSUTTIWONG - Professor - Ubon Ratchathani University - Rapporteur
- Xiaonan SUN - Ingénieure de recherche - Université Paris Cité - Rapporteur
- Supawadee NAMUANGRUK - Directrice de recherche - National Nanotechnology Center - Examinateur
- Chularat WATTANAKIT - Associate Professor - Vidyasirimedhi Institute of Science and Technology - CoDirecteur de these
- Alexander KUHN - Professor - Institut des Sciences Moléculaire, Bordeaux INP - Directeur de these
Molecular chirality is crucial in drug design because of its essential role in enabling precise and effective interactions with receptor molecules. Therefore, the development of efficient enantioselective synthesis methods is essential for the successful and scalable production of pharmaceuticals. We propose in this thesis to explore alternative concepts based on the generation of microscopic chiral features on metal surfaces or in the bulk of porous metal structures, which enable enantioselective recognition and asymmetric synthesis. As described in the first chapter, surfaces with chiral features can be simply obtained via the shear stress generated during the mechanical torsion of a wire in either clockwise or counterclockwise directions, allowing the formation of chiral high-Miller-index crystallographic planes. Enantioselective recognition is facilitated by the twisted metal structures, with a performance depending on both, the angle and direction of the twist. Furthermore, the twisted metal surfaces are able to induce a certain degree of enantioselectivity during the electrosynthesis of a chiral compound, whereas the non-twisted metal surfaces produce a racemic mixture. By following another approach, we have successfully designed mesoporous chiral-encoded metals as catalysts for the synthesis of a chiral enantiomer via electrochemical and chemical approaches. In this thesis, we describe the first example of autonomous self-propelled chiral objects, using zinc wires and plates coated with a chiral metal, for the spontaneous redox synthesis of a chiral compound from a prochiral precursor without utilizing external stirring. As can be seen in chapters 2 and 3, two types of objects have been used involving different propulsion mechanisms: i) bubble propulsion due to the spontaneous proton reduction and ii) self-electrophoresis coupled with a magnetic field, facilitating the formation of a magnetohydrodynamic vortex. The driving force relies on the spontaneous oxidation of zinc, initiating an electron transfer to the chiral-encoded surfaces, allowing the enantioselective reduction of a prochiral precursor. The autonomous self-propulsion enhances the mass transport of the prochiral compound from the bulk solution to the surface of the electrode, leading to an increased yield of product with a certain degree of enantioselectivity. Finally, we extend the design of porous materials beyond chiral metals to include another class of materials—hierarchical zeolites. We demonstrate the first example of bifunctional hafnium (Hf)-isomorphously substituted zeolites as heterogeneous catalysts for the production of biosourced chemicals. Spectroscopic investigation demonstrates that the active Hf centers are incorporated selectively into the crystalline frameworks of Beta zeolites. The presence of the isolated Hf species in the aluminosilicate matrice reveals distinct Lewis acid and Brønsted acid properties, selectively and efficiently promoting glucose isomerization and fructose dehydration to produce 5-hydroxymethylfurfural (HMF). The one-pot HMF synthesis with a yield of 63.2 ± 2.0% and glucose conversion of 95.4 ± 1.1% is carried out under mild conditions. In addition, the isolated Hf species are highly stable in the Beta zeolite framework. In conclusion, this thesis highlights the custom design of non-porous and porous inorganic materials for sustainable chemical processes, ranging from enantioselective recognition and asymmetric catalytic synthesis of a chiral compound to sugar upgrading.