Determination of electronic properties in heterocyclic rings through NMR parameters

• Grant number: 23/13801-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2024
• End date: February 29, 2028
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Claudio Francisco Tormena
• Grantee: Giulia Saneti Grandini
• 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

Heterocyclic rings constitute a large part of the vital molecules for life, participating directly in the formation of DNA and RNA, or participating in the maintenance of life through the incorporation of these rings in the structure of molecules with pharmacological properties. Among them, the purine, pyrimidine and pyridine rings stand out, which have several applications to be explored according to structural changes. In the literature, it is possible to find several studies that point out that the presence of heavy atoms, such as halogens and chalcogens, can cause changes in reactivity and spectroscopic characteristics due to the spin-orbit coupling observed for these atoms. In order to understand and evaluate these effects, Nuclear Magnetic Resonance spectroscopy can be applied to measure the spin-spin coupling constant and the shielding tensor, where both parameters are related electronic properties of the molecules. In addition to the experimental technique of Nuclear Magnetic Resonance, it can also be studied from a theoretical point of view, where the components of spin-spin coupling and the shielding tensor can be decomposed into the molecular orbitals involved. For this, a relativistic quantum description of the substituted rings of interest is employed.