Conformational preferences on fluorine-containing molecules

• Grant number: 21/05095-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: August 01, 2021
• End date: January 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Claudio Francisco Tormena
• Grantee: Cassia Chiari
• 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
• Associated scholarship(s): 23/10448-0 - Measurement of JFH and JNF couplings in organic compounds: a conformational study, BE.EP.DD

Abstract

It is proposed to develop a new NMR pulse sequence base on Pure Shift approach to simultaneously determine the magnitude and sign of JFH couplings. The new pulse sequence will be based on combination of heteronuclear modulated echo, concatenated with zTOCSY and suitable Pure Shift elements. The compounds to be used in this study are in some cases commercially available, some are already prepared and the rest will be synthesised according established procedures described in the literature. The 1H, 13C, 1H{19F} and 19F NMR spectra will be obtained, as well as 2D experiments COSY, 1H-13C HSQC, 1H-15N HSQC and 1H-13C HMBC for the characterisation of the synthesised compounds. Besides those, 1H-19F hetero-COSY, 1H-19F HOESY and PSYCHEDELIC experiments will also be performed to measure JFH couplings as well as the new experiment which will be developed to measure simultaneously the magnitude and sign. The conformational search and the electronic structure calculations of the geometries of the most stable conformers will be accomplished, employing the Spartan16 and Gaussian16 software, respectively, and the interaction responsible for the conformational preference will be obtained through the NBO (Natural Bond Orbital) and NCI (Non-Covalent Interaction) calculations of the most stable conformations. The JHH and JFH coupling constants will be calculated and compared with experimental data. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

CHIARI, CASSIA; BATISTA, PATRICK R.; VIESSER, RENAN V.; SCHENBERG, LEONARDO A.; DUCATI, LUCAS C.; LINCLAU, BRUNO; TORMENA, CLAUDIO F.. Molecular dynamics and NMR reveal the coexistence of H-bond-assisted and through-space J_FH coupling in fluorinated amino alcohols. ORGANIC & BIOMOLECULAR CHEMISTRY, v. 22, n. 13, p. 16-pg., 2024-02-26. (21/05095-6, 17/20890-1, 19/18727-0, 17/17750-3, 19/18193-6, 23/00531-8, 21/09687-5, 20/10246-0, 18/02634-0, 15/08541-6, 22/10688-9)

CASSIA CHIARI; CLÁUDIO F. TORMENA. UMA NOVA ERA DA INCORPORAÇÃO DE ÁTOMO DE FLÚOR EM COMPOSTOS ORGÂNICOS: MÉTODOS MODERNOS E USO DA ESPECTROSCOPIA DE RESSONÂNCIA MAGNÉTICA DE 19F. Química Nova, v. 47, n. 4, 2024-02-29. (21/05095-6, 20/10246-0)