Calorimetric and Computational Study of 1,3- and 1,4-Oxathiane Sulfones

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• 作者：Mar&iacute ; a Victoria Roux ; Manuel Temprado ; Pilar Jimé ; nez ; Rafael Notario ; Ramó ; n Guzmá ; n-Mej&iacute ; a ; Eusebio Juaristi
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：February 16, 2007
• 年：2007
• 卷：72
• 期：4
• 页码：1143 - 1147
• 全文大小：133K
• 年卷期：v.72,no.4(February 16, 2007)
• ISSN：1520-6904

文摘

The enthalpies of formation in the condensed and gas states, _fH_m(cd) and _fH_m(g), of 1,3- and 1,4-oxathiane sulfones were derived from their respective enthalpies of combustion in oxygen, measured bya rotating bomb calorimeter and the variation of vapor pressures with temperatures determined by theKnudsen effusion technique. Standard ab initio molecular orbital calculations at the G2(MP2) and G3levels were performed, and a theoretical study on molecular and electronic structure of the compoundshas been carried out. Calculated _fH_m(g) values at the G3 level using atomization reactions agree wellwith the experimental ones. These experimental and theoretical studies support that the destabilizationfound in 1,3-oxathiane sulfone, 11.2 kJ mol^-1 respecting to 1,4-oxathiane sulfone, is due to the electrostaticrepulsion between the negative charges of the axial oxygen of the sulfone and the oxygen of the ring andapparently masks any stabilization originating from the hyperconjugative n_O *_C-SO2 stereoelectronicinteraction.