Study of the mechanism of chemical and photochemical reactions through in situ monitoring by Nuclear Magnetic Resonance.

• Grant number: 24/20732-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2025
• End date: July 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Claudio Francisco Tormena
• Grantee: João Pedro Brussolo da Silva
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 20/10246-0 - Nuclear magnetic resonance spectroscopy: from pulse sequences to structural assignments, AP.TEM

Abstract

Nuclear Magnetic Resonance (NMR) is a spectroscopic technique that stands out for its spectra' wealth of structural information. It has recently been used in reaction monitoring, aiming to elucidate reaction mechanisms by obtaining kinetic profiles, since its understanding is fundamental for the improvement of industrial processes and understanding of biological systems. Reaction monitoring can be performed directly in the NMR tube (on-line NMR) or pumped by a pneumatic unit directly from its reaction system coupled in flow to the equipment (on-flow NMR). The study of chemical reactions that still lack mechanistic elucidation, such as boronic acid catalysis, will be the object of study in this project, since the species involved in the stages of this reaction have not yet been identified, as well as the lack of a quantitative evaluation between the impact of the volume of the ligands in the catalyst. Thus, based on this class of reactions, the project aims to apply a flow system to propose new monitoring approaches through NMR and to help elucidate the limiting steps of the reactions. Palladium-based photoredox reactions, such as the Heck cross-coupling reaction, will also be studied to determine the catalytic role of light in the activation of palladium, as well as the influence of different ligands (phosphines) on the reactivity. By capturing intermediates existing only under irradiation conditions and innovative monitoring approaches, such as diffusion experiments, we intend to answer these gaps. To this end, the project also aims to implement the LED-NMR methodology through in situ irradiation systems in reaction monitoring.