Calorimetric and computational study of 1,3- and 1,4-oxathiane sulfones
| Autor: | Manuel Temprado, Eusebio Juaristi, Rafael Notario, María Victoria Roux, Pilar Jiménez, Ramón Guzmán-Mejía |
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| Přispěvatelé: | Dirección General de Investigación Científica y Técnica, DGICT (España), Consejo Nacional de Ciencia y Tecnología (México) |
| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0022-3263 |
| Popis: | The enthalpies of formation in the condensed and gas states, ΔfH°m(cd) and ΔfH°m(g), of 1,3- and 1,4-oxathiane sulfones were derived from their respective enthalpies of combustion in oxygen, measured by a rotating bomb calorimeter and the variation of vapor pressures with temperatures determined by the Knudsen effusion technique. Standard ab initio molecular orbital calculations at the G2(MP2) and G3 levels were performed, and a theoretical study on molecular and electronic structure of the compounds has been carried out. Calculated ΔfH°m(g) values at the G3 level using atomization reactions agree well with the experimental ones. These experimental and theoretical studies support that the destabilization found in 1,3-oxathiane sulfone, 11.2 kJ mol-1 respecting to 1,4-oxathiane sulfone, is due to the electrostatic repulsion between the negative charges of the axial oxygen of the sulfone and the oxygen of the ring and apparently masks any stabilization originating from the hyperconjugative nO → σ*C-SO2 stereoelectronic interaction. The support of the Spanish DGI under Projects QU2003-05827 and FIS2004-02954-C03-01 is gratefully acknowledged. M.T. thanks MEC/SEUI, FPU AP2002-0603, Spain, for financial support. We are also grateful to Conacyt, Me´xico, for financial support via grant 45157-Q and to the reviewers for useful comment |
| Databáze: | OpenAIRE |
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