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Structure, Conformation, and Thermochemistry of Dimesityl Methanethial S ‐oxide (Dimesityl Sulfine)
Author(s) -
Kappert Wilhelm,
Sander Wolfram,
Landgrafe Claudia
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719971214
Subject(s) - chemistry , mesityl oxide , ring (chemistry) , crystallography , stereochemistry , crystal structure , organic chemistry , acetone
The structure of dimesityl sulfine in solution and in the solid state was determined by NMR spectroscopy and X‐ray crystallography, respectively. In the crystal the two mesityl groups are twisted by approximately 60°, while in solution an averaged conformation with C s symmetry is observed, with the anti mesityl ring located in the CSO plane and the syn mesityl ring perpendicular to the CSO plane. From the coalescence temperature T c at 303 K, the free energy of activation for the rotation of the mesityl rings was estimated to be 14 ± 0.7 kcal/mol. At higher temperatures (140–185°C) dimesityl sulfine yields up to 95% 5,7‐dimethyl‐1‐mesityl‐benzo[ c ]thiophene.