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Titolo:
Thermodynamic, spectroscopic, and computational evidence for the irreversible conversion of beta- to alpha-endosulfan
Autore:
Schmidt, WF; Bilboulian, S; Rice, CP; Fettinger, JC; McConnell, LL; Hapeman, CJ;
Indirizzi:
Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA Univ Maryland College Pk MD USA 20742 & Biochem, College Pk, MD 20742 USA USDA ARS, Environm Qual Lab, Beltsville, MD 20705 USA USDA ARS BeltsvilleMD USA 20705 ironm Qual Lab, Beltsville, MD 20705 USA
Titolo Testata:
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
fascicolo: 11, volume: 49, anno: 2001,
pagine: 5372 - 5376
SICI:
0021-8561(200111)49:11<5372:TSACEF>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
POLYCHLORINATED-BIPHENYLS; ATMOSPHERIC CONCENTRATIONS; ORGANOCHLORINE PESTICIDES; CONFORMATIONS; DEPOSITION; AIR;
Keywords:
alpha- and beta-endosulfan; conformation; NMR; volatility; eutectic mixture; computational chemistry;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Life Sciences
Citazioni:
23
Recensione:
Indirizzi per estratti:
Indirizzo: Hapeman, CJ Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA Univ Maryland College Pk MD USA 20742 ollege Pk, MD 20742 USA
Citazione:
W.F. Schmidt et al., "Thermodynamic, spectroscopic, and computational evidence for the irreversible conversion of beta- to alpha-endosulfan", J AGR FOOD, 49(11), 2001, pp. 5372-5376

Abstract

Previous studies have provided unequivocal evidence for the symmetry of beta -endosulfan and the corresponding asymmetry of alpha -endosulfan; the conversion of beta -endosulfan to alpha -endosulfan was identified. In this study, evidence from differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) experiments combined with computational chemistry calculations was used to propose a molecular mechanism for the corresponding conformational changes that occur in this process. DSC and NMR data of mixtures indicated that both isomers can influence the conformer populations in the solid, solution, and vapor phase. Computational chemistry demonstrated that the relative S=O configuration between alpha- and beta -isomers can bethe intermediate state through which the conformations of alpha- and beta -isomers affect each other. Furthermore, calculations for mixtures indicated that the asymmetrical conformation of the sulfite in alpha -endosulfan can induce asymmetry in beta -endosulfan, and conversion to alpha -endosulfanoccurs from this transition state.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/10/20 alle ore 00:02:02