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A computational study of the conformational stability, vibrational spectra, and thermochemical properties of 2,6-dichlorobenzamide, 2-(trifluoromethyl)benzamide, 2-(trifluoromethyl)benzoic acid, and 3-chloro-5-(trifluoromethyl)pyridine-2-carboxylic acid
Article
Date:
2023Publishing House and Editing Place:
OLDENBOURG VERLAGMagazine:
Zeitschrift für Physikalische Chemie, vol. 237 (pp. 1575-1616) OLDENBOURG VERLAGSummary
2,6-Dichlorobenzamide (BAM), 2-(trifluoromethyl)benzamide (TBAM), 2-(trifluoromethyl)benzoic acid (TBA), and 3-chloro-5-(trifluoromethyl)pyridine2-carboxylic acid (PCA) are degradation by-products of fluopicolide and fluopyram fungicides. In this work, a detailed theoretical study of their different molecular, spectroscopic and thermochemical properties was carried out with different formulations of the density functional theory and high-level model chemistries. The mean values of ?146.0 ± 6.3, ?763.2 ± 6.3, ?949.0 ± 6.3, and ?919.4 ± 6.3 kJ mol?1 for the standard enthalpies of formation of BAM, TBAM, TBA and PCA, respectively, were derived for the first time at the G3MP2//DFT and G4MP2//DFT levels of theory (DFT = B3LYP, BMK, and B98). Additionally, a good agreement between formation enthalpies derived from isodesmic reaction approach and from Benson’s group additivity method was obtained.Key Words
2,6-DICHLOROBENZAMIDEFUNGICIDE3-CHLOROFLUORINATED PESTICIDE2-(TRIFLUOROMETHYL)BENZOIC ACIDDEGRADATION BY-PRODUCTS2-(TRIFLUOROMETHYL)BENZAMIDE2-CARBOXYLIC ACIDCHLORINATED PESTICIDEQUANTUM-CHEMICAL CALCULATIONS5-(TRIFLUOROMETHYL)PYRIDINE