BARRIERS TO METHYL GROUP ROTATION IN SOLID METHYLCHLOROSILANES
Loading...
Date
1973
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
Spin-lattice relaxation $T_{1}$ values have been measured in the temperature range $77^{\circ} K$ to $273^{\circ} K$ for protons in solid methylchlorosilanes by a pulsed nmr spectrometer operating at 28.0 MHz. In addition, line shapes and line widths for the corresponding proton nmr spectra have been recorded at 26.0 MHz by a rapid passage technique employing a Fabritek 1062 signal averager. Barriers to methyl group rotation were found to be 2.34 kcal/mole for $(CH_{3})_{3}SiCl$ (compared with 3.0 kcal/mole found spectroscopically by Durig, Carter and Li), 1.95 kcal/mole for $(CH_{3})_{2}SiCl_{2}$ and 1.66 kcal/mole for $CH_{3}SiCl_{3}$ (compared with 1.3 kcal/mole found by McIntyre and Johnson from $T_{1}$ measurements). The barrier for overall rotation of the $(CH_{3})_{3}Si$ group about the $C_{3}$ axis in trimethylchlorosilane was found to be 7.4 kcal/mole from both $T_{1}$ and linewidth measurements.
Description
Author Institution: Department of Physics, Queen's University