| Full text | |
| Author(s): |
Barbosa, Thais M.
[1]
;
Viesser, Renan V.
[1]
;
Martins, Lucas G.
[1]
;
Rittner, Roberto
[1]
;
Tormena, Claudio F.
[1]
Total Authors: 5
|
| Affiliation: | [1] Univ Campinas UNICAMP, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil
Total Affiliations: 1
|
| Document type: | Journal article |
| Source: | ChemPhysChem; v. 19, n. 11, p. 1358-1362, JUN 5 2018. |
| Web of Science Citations: | 1 |
| Abstract | |
The long-range scalar coupling constant between proton and fluorine nuclei, (5)J(HF), is observed to be larger than (3)J(HF) in the pyrimidinyl moiety of voriconazole. A set of smaller molecules is chosen (fluorobenzene, N-methyl-2-fluoropyridine, N-methyl-3-fluoropyridine, 3-fluoropyridine, 5-pyrimidine, and 2-fluoropyridine) to evaluate the influence of the nitrogen atom in the experimental J(HF) values. Spectral aliased pure shift heteronuclear single quantum coherence spectroscopy (SAPS-HSQC) is applied to determine the relative sign between the J(CF) and J(HF) scalar couplings. Theoretical calculations show that the (3)J(HF) and (5)J(HF) coupling constants can be described mainly by a Fermi contact (FC) transmission mechanism. A decomposition analysis of J(HF) in terms of localized molecular orbital (LMO) contributions allows us to determine that the interaction involving the nitrogen lone pair (LPN) is the main reason for the larger (5)J(HF) compared to (3)J(HF). Our analysis indicates that delocalization of LPN has a positive contribution to the long-range coupling, while a negative one is observed for (3)J(HF). (AU) | |
| FAPESP's process: | 16/24109-0 - Conformational Analysis of Some Aliphatic Esters Bearing a Nitrogen Atom as a Substituent |
| Grantee: | Roberto Rittner Neto |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 15/08541-6 - Nuclear magnetic resonance spectroscopy: beyond molecular structure assignment |
| Grantee: | Claudio Francisco Tormena |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 14/12776-6 - Development and application of NMR techniques to analyse complex mixtures |
| Grantee: | Thaís Mendonça Barbosa |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 17/20890-1 - Evaluation of shielding and transmission mechanisms of 1H, 13C and 19F NMR |
| Grantee: | Renan Vidal Viesser |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |