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Cuesta SA, Torres FJ, Rincón L, Paz JL, Márquez EA, Mora JR. Effect of the Nucleophile's Nature on Chloroacetanilide Herbicides Cleavage Reaction Mechanism. A DFT Study. Int J Mol Sci 2021; 22:ijms22136876. [PMID: 34206795 PMCID: PMC8268095 DOI: 10.3390/ijms22136876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/21/2021] [Accepted: 06/23/2021] [Indexed: 11/16/2022] Open
Abstract
In this study, the degradation mechanism of chloroacetanilide herbicides in the presence of four different nucleophiles, namely: Br-, I-, HS-, and S2O3-2, was theoretically evaluated using the dispersion-corrected hybrid functional wB97XD and the DGDZVP as a basis set. The comparison of computed activation energies with experimental data shows an excellent correlation (R2 = 0.98 for alachlor and 0.97 for propachlor). The results suggest that the best nucleophiles are those where a sulfur atom performs the nucleophilic attack, whereas the other species are less reactive. Furthermore, it was observed that the different R groups of chloroacetanilide herbicides have a negligible effect on the activation energy of the process. Further insights into the mechanism show that geometrical changes and electronic rearrangements contribute 60% and 40% of the activation energy, respectively. A deeper analysis of the reaction coordinate was conducted, employing the evolution chemical potential, hardness, and electrophilicity index, as well as the electronic flux. The charge analysis shows that the electron density of chlorine increases as the nucleophilic attack occurs. Finally, NBO analysis indicates that the nucleophilic substitution in chloroacetanilides is an asynchronous process with a late transition state for all models except for the case of the iodide attack, which occurs through an early transition state in the reaction.
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Affiliation(s)
- Sebastián A. Cuesta
- Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador; (S.A.C.); (F.J.T.); (L.R.)
- Departamento de Ingeniería Química, Instituto de Simulación Computacional (ISC-USFQ), Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador
| | - F. Javier Torres
- Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador; (S.A.C.); (F.J.T.); (L.R.)
- Departamento de Ingeniería Química, Instituto de Simulación Computacional (ISC-USFQ), Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador
| | - Luis Rincón
- Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador; (S.A.C.); (F.J.T.); (L.R.)
- Departamento de Ingeniería Química, Instituto de Simulación Computacional (ISC-USFQ), Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador
| | - José Luis Paz
- Departamento Académico de Química Inorgánica, Facultad de Química e Ingeniería Química, Universidad Nacional Mayor de San Marcos, Cercado de Lima 15081, Peru;
| | - Edgar A. Márquez
- Grupo de Investigaciones en Química y Biología, Departamento de Química y Biología, Facultad de Ciencias Exactas, Universidad del Norte, Carrera 51B, Km 5, Vía Puerto Colombia, Barranquilla 081007, Colombia
- Correspondence: (E.A.M.); (J.R.M.)
| | - José R. Mora
- Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador; (S.A.C.); (F.J.T.); (L.R.)
- Departamento de Ingeniería Química, Instituto de Simulación Computacional (ISC-USFQ), Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170901, Ecuador
- Correspondence: (E.A.M.); (J.R.M.)
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Cuesta SA, Mora JR, Zambrano CH, Torres FJ, Rincón L. Comparative study of the nucleophilic attack step in the proteases catalytic activity: A theoretical study. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1705412] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Sebastián A. Cuesta
- Instituto de Simulación Computacional (ISM), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
- Departamento de Ingeniería Química – Grupo de Química Computacional y Teórica (QCT), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
| | - José R. Mora
- Instituto de Simulación Computacional (ISM), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
- Departamento de Ingeniería Química – Grupo de Química Computacional y Teórica (QCT), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
| | - Cesar H. Zambrano
- Instituto de Simulación Computacional (ISM), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
- Departamento de Ingeniería Química – Grupo de Química Computacional y Teórica (QCT), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
| | - F. Javier Torres
- Instituto de Simulación Computacional (ISM), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
- Departamento de Ingeniería Química – Grupo de Química Computacional y Teórica (QCT), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
| | - Luis Rincón
- Instituto de Simulación Computacional (ISM), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
- Departamento de Ingeniería Química – Grupo de Química Computacional y Teórica (QCT), Universidad San Francisco de Quito (USFQ), Quito, Ecuador
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Terán JE, Zambrano CH, Mora JR, Rincón L, Torres FJ. Theoretical investigation of the mechanism for the reductive dehalogenation of methyl halides mediated by the Co I-based compounds cobalamin and cobaloxime. J Mol Model 2018; 24:316. [PMID: 30338391 DOI: 10.1007/s00894-018-3844-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/17/2018] [Indexed: 11/30/2022]
Abstract
Theoretical calculations focusing on the cleavage of the C-X bond in methyl halides (CH3X; X = Cl, Br, I) as mediated by CoI-based systems have been carried out using the hybrid functional ωB97-XD together with the basis set 6-311++G(2d,2p). A total of seven CoI-based compounds were evaluated: cob[I]alamin (CoICbl) in its base-on form and cobaloxime (CoICbx) with either no ligand or different ligands (either pyridine (PYR), tributylphosphine (TBP), dimethyl sulfide (DMS), cyclohexylisocyanide (CI), or 5,6-dimethylbenzimidazole (DMB)) at the lower axial position. For the large CoICbl system, an ONIOM scheme was employed, where the high layer was described at the DFT level and the low layer was computed using the semi-empirical method PM6. A full DFT model was employed for the CoICbx cases. An SN2-like mechanism was evaluated in all cases. The intrinsic reaction coordinate profiles suggested early transition states with activation energies of ≈ 12 kcal/mol, ≈ 10 kcal/mol, and ≈ 5 kcal/mol for C-Cl, C-Br, and C-I cleavage, respectively, which is consistent with the leaving group abilities of these halides. The evolutions of the atomic charges in and the bond orders of Co-C and C-X were computed, and the results confirmed the existence of early transition states (δBav≈ 40%), where the polarization Cδ+-Xδ- (%Ev ≈ 43%) is the determining factor in the reaction process. Finally, a comparison of all the determined parameters showed that the reaction in the DMB-CoICbx system resembles the process that occurs in the larger CoICbl, suggesting that the former system could be a reliable model for the study of reductive dehalogenation mediated by vitamin B12, which is key to the anaerobic microbiological treatment of halocarbon contaminants.
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Affiliation(s)
- Julio E Terán
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
| | - Cesar H Zambrano
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
| | - Jose R Mora
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador. .,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.
| | - L Rincón
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
| | - F J Torres
- Universidad San Francisco de Quito, Instituto de Simulación Computacional (ISC-USFQ), Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador.,Universidad San Francisco de Quito, Grupo de Química Computacional y Teórica (QCT-USFQ), Departamento de Ingeniería Química, Diego de Robles y Vía Interoceánica, Quito, 17-1200-841, Ecuador
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