| Full text | |
| Author(s): |
Obeid, Guilherme
;
Moraes, Gustavo O.
;
Penna, Tatiana C.
;
Schenberg, Leonardo A.
;
Ducati, Lucas C.
;
Correra, Thiago C.
Total Authors: 6
|
| Document type: | Journal article |
| Source: | Journal of Chemical Physics; v. 158, n. 5, p. 12-pg., 2023-02-07. |
| Abstract | |
Glyphosate is a widely used herbicide, and its protonation and deprotonation sites are fundamental to understanding its properties. In this work, the sodiated, protonated, and deprotonated glyphosate were evaluated in the gas phase by infrared multiple photon dissociation spectroscopy to determine the exact nature of these coordination, protonation, and deprotonation states in the gas phase. In this context, Natural Bond Orbital analyses were carried out to unravel interactions that govern glyphosate (de)protonation states in the gas phase. The solvent effect on the protonation/deprotonation equilibria was also investigated by implicit (Solvation Model Based on Density and polarizable continuum models) and explicit solvation models (Monte Carlo and Molecular Dynamics simulations). These results show that glyphosate is protonated in the phosphonate group in the gas phase because of the strong hydrogen bond between the carboxylic oxygen (O7) and the protonated phosphonate group (O8-H19), while the most stable species in water is protonated at the amino group because of the preferential interaction of the NH2+ group and the solvent water molecules. Similarly, deprotonated glyphosate [Glyp-H](-) was shown to be deprotonated at the phosphonate group in the gas phase but not in solution, also because of the preferential solvation of the NH2+ group present in the other deprotomers. Therefore, these results show that the stabilization of the protonated amino group by the solvent molecules is the governing factor of the (de)protonation equilibrium of glyphosate in water. (AU) | |
| FAPESP's process: | 20/10246-0 - Nuclear magnetic resonance spectroscopy: from pulse sequences to structural assignments |
| Grantee: | Claudio Francisco Tormena |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 19/12808-9 - Glyphosate protonation and metal coordination sites |
| Grantee: | Guilherme Obeid |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| FAPESP's process: | 17/20262-0 - Unraveling electrochemical reaction intermediates by mass spectrometry coupled to ion vibrational spectroscopy |
| Grantee: | Tatiana Casselli Penna |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 17/17750-3 - Solvent Effect in NMR Parameters by ab initio Molecular Dynamics |
| Grantee: | Lucas Colucci Ducati |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 15/08539-1 - Multi-User Equipment approved in grant 2014/15962-5: ion trap mass spectrometer modified to perform infrared vibrational spectroscopy (IRMPD) |
| Grantee: | Thiago Carita Correra |
| Support Opportunities: | Multi-user Equipment Program |
| FAPESP's process: | 19/18727-0 - Study of 199Hg organometallic compounds in solution by ab initio molecular dynamics and relativistic NMR calculations |
| Grantee: | Leonardo Araujo Schenberg |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 19/25634-9 - Real-time reaction analysis in complex matrices by advanced mass spectrometry techniques |
| Grantee: | Thiago Carita Correra |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 20/08894-4 - Mechanistic characterization of organometallic reactions by nonconventional sampling techniques in mass spectrometry |
| Grantee: | Guilherme Obeid |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 21/06726-0 - Investigation of reactive intermediates in complex chemical and biochemical processes |
| Grantee: | Thiago Carita Correra |
| Support Opportunities: | Research Grants - Young Investigators Grants - Phase 2 |
| FAPESP's process: | 14/15962-5 - Reaction mechanism of asymmetric catalysts by mass spectrometry and gas-phase vibrational ion spectroscopy |
| Grantee: | Thiago Carita Correra |
| Support Opportunities: | Research Grants - Young Investigators Grants |