Ab initio study of the conformational equilibrium of trimethylene cyclic sulfite

Citation
Jg. Contreras et St. Madariaga, Ab initio study of the conformational equilibrium of trimethylene cyclic sulfite, J PHYS ORG, 13(4), 2000, pp. 187-191
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
ISSN journal
0894-3230 → ACNP
Volume
13
Issue
4
Year of publication
2000
Pages
187 - 191
Database
ISI
SICI code
0894-3230(200004)13:4<187:AISOTC>2.0.ZU;2-B
Abstract
Ab initio calculations, in the frame of MO theory, were carried out on both most stable (chair) conformers of trimethylene cyclic sulfite. Optimized g eometries derived at the HF/6-31G* level reveal that both conformers posses s a rigid chair conformation with the S=O group located either axially (con former I) or equatorially (conformer II). Energy calculations at the MP2/6- 311++G**//HF/6-31G* level indicates that conformer I is ca 4.6 kcal. mol(-1 ) more stable than II. The I = II interconversion was studied in the gas ph ase at different temperatures and in solutions of low- and high-polarity so lvents. The calculations reveal that in the gas phase and in solutions of l ow-polarity solvents the conversion of I into II does not occur. In medium- high-polarity solvents, such as acetonitrile and dimethyl sulfoxide, II is present at ca 12%. Copyright (C) 2000 John Wiley & Sons, Ltd.