Structure, Conformation, and Thermochemistry of Dimesityl MethanethialS-oxide (Dimesityl Sulfine)

✍ Scribed by Kappert, Wilhelm ;Sander, Wolfram ;Landgrafe, Claudia

• Book ID: 102902815
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 582 KB
• Volume: 1997
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199719971214

✦ Synopsis

Abstract

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 CSO plane and the syn mesityl ring perpendicular to the CSO 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.