A Study on the Reducing Abilities of Tris(alkylthio)Silanes

Authors:

• Chryssostomos Chatgilialoglu,
• M. Guerra,
• A. Guerrini,
• G. Seconi,
• K.B. Clark,
• D. Griller,
• J. Kanabus-Kaminska,
• J.A. Martinho-Simões

Abstract

Tris(methylthio)silane and tris(isopropylthio)silane effectively reduce a variety of organic substrates via free radical mechanisms. These silanes can also be used as hydrosilylating agents for alkenes having electron-donating substituents. The bond dissociation energy of the Si-H bonds have been measured by photoacoustic calorimetry and found to be around 83 kcal mol ⁻¹ . The absolute rate constants for the reaction of the tert-butoxyl radical with (RS) ₃ SiH have been measured by a laser flash photolysis technique and the optical absorption spectra of the corresponding radicals have been obtained. Multiple scattering X _α calculations showed that the dominant absorption detected in the UV-vis region was due to σ _Si-S (e) → SOMO and SOMO →σ ^*_Si-S (e) transitions. © 1992, American Chemical Society. All rights reserved.