2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study
Many properties of 2,4-dichlorophenoxyacetic acid (2,4-D) depend on its molecular environment, such as whether it is an isolated molecule, a dimer, or in a crystalline state. The molecular geometry, conformational analysis, and vibrational spectrum of 2,4-D were theoretically calculated using Densit...
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2025-01-01
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| author | Claro Ignacio Sainz-Díaz Nelly L. Jorge Jorge M. Romero André Grand Alfonso Hernández-Laguna |
| author_facet | Claro Ignacio Sainz-Díaz Nelly L. Jorge Jorge M. Romero André Grand Alfonso Hernández-Laguna |
| author_sort | Claro Ignacio Sainz-Díaz |
| collection | DOAJ |
| description | Many properties of 2,4-dichlorophenoxyacetic acid (2,4-D) depend on its molecular environment, such as whether it is an isolated molecule, a dimer, or in a crystalline state. The molecular geometry, conformational analysis, and vibrational spectrum of 2,4-D were theoretically calculated using Density Functional Theory (DFT) methods. A new slightly more stable conformer was found, which is different to those previously reported. The most stable conformer shows a dimer by means of hydrogen bonds between the carboxylic groups of both molecules, which agrees with the experimental results. The crystal structure of 2,4-D was also calculated with 3D periodical boundary conditions at the DFT level. From the theoretical IR spectra, a vibrational analysis of this molecular species was accomplished, and the bands were reassigned. <sup>1</sup>H and <sup>13</sup>C NMR in the dissolution and solid states, respectively, showed intramolecular hydrogen bonds between carboxylic acid groups. The dimer is more stable than the isolated molecule. All these results indicated that the dimer can also exist in the solid state, which could explain the low solubility of this compound. In addition, the intercalation of 2,4-D into the confined interlayer space of montmorillonite was also calculated, and it was found that the adsorption is energetically favourable. This result was experimentally confirmed. These findings predicted that these natural clay minerals, which are found in the environment, can be excellent adsorbents for the 2,4-D pollutant. |
| format | Article |
| id | doaj-art-0984559c1cbb4aedad866e7ef4c72f04 |
| institution | Kabale University |
| issn | 1420-3049 |
| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-0984559c1cbb4aedad866e7ef4c72f042025-01-24T13:43:49ZengMDPI AGMolecules1420-30492025-01-0130236710.3390/molecules300203672,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical StudyClaro Ignacio Sainz-Díaz0Nelly L. Jorge1Jorge M. Romero2André Grand3Alfonso Hernández-Laguna4Instituto Andaluz de Ciencias de la Tierra (IACT-CSIC), Consejo Superior de Investigaciones Científicas, Av. de las Palmeras 4, 18100 Armilla, Granada, SpainLaboratorio de Investigaciones en Tecnología del Medio Ambiente, Área de Química Física, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad del Nordeste, Corrientes 3400, ArgentinaLaboratorio de Investigaciones en Tecnología del Medio Ambiente, Área de Química Física, Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad del Nordeste, Corrientes 3400, ArgentinaUniversité Grenoble Alpes, Commissariat à l’Energie Atomique, Centre National de la Recherche Scientifique, Institute for Nanoscience and Cryogenics, Systèmes Moléculaires et NanoMatériaux pour l’Énergie et la Santé, F-38000 Grenoble, FranceInstituto Andaluz de Ciencias de la Tierra (IACT-CSIC), Consejo Superior de Investigaciones Científicas, Av. de las Palmeras 4, 18100 Armilla, Granada, SpainMany properties of 2,4-dichlorophenoxyacetic acid (2,4-D) depend on its molecular environment, such as whether it is an isolated molecule, a dimer, or in a crystalline state. The molecular geometry, conformational analysis, and vibrational spectrum of 2,4-D were theoretically calculated using Density Functional Theory (DFT) methods. A new slightly more stable conformer was found, which is different to those previously reported. The most stable conformer shows a dimer by means of hydrogen bonds between the carboxylic groups of both molecules, which agrees with the experimental results. The crystal structure of 2,4-D was also calculated with 3D periodical boundary conditions at the DFT level. From the theoretical IR spectra, a vibrational analysis of this molecular species was accomplished, and the bands were reassigned. <sup>1</sup>H and <sup>13</sup>C NMR in the dissolution and solid states, respectively, showed intramolecular hydrogen bonds between carboxylic acid groups. The dimer is more stable than the isolated molecule. All these results indicated that the dimer can also exist in the solid state, which could explain the low solubility of this compound. In addition, the intercalation of 2,4-D into the confined interlayer space of montmorillonite was also calculated, and it was found that the adsorption is energetically favourable. This result was experimentally confirmed. These findings predicted that these natural clay minerals, which are found in the environment, can be excellent adsorbents for the 2,4-D pollutant.https://www.mdpi.com/1420-3049/30/2/3672,4-dichlorophenoxyacetic acidDFTintercalation in clay mineralsdimerIR assignmentNMR |
| spellingShingle | Claro Ignacio Sainz-Díaz Nelly L. Jorge Jorge M. Romero André Grand Alfonso Hernández-Laguna 2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study Molecules 2,4-dichlorophenoxyacetic acid DFT intercalation in clay minerals dimer IR assignment NMR |
| title | 2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study |
| title_full | 2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study |
| title_fullStr | 2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study |
| title_full_unstemmed | 2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study |
| title_short | 2,4-Dichlorophenoxyacetic Acid in the Gas and Crystal Phases and Its Intercalation in Montmorillonite—An Experimental and Theoretical Study |
| title_sort | 2 4 dichlorophenoxyacetic acid in the gas and crystal phases and its intercalation in montmorillonite an experimental and theoretical study |
| topic | 2,4-dichlorophenoxyacetic acid DFT intercalation in clay minerals dimer IR assignment NMR |
| url | https://www.mdpi.com/1420-3049/30/2/367 |
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