The reactions of CF 3 and CD 3 radicals with boron trimethyl

Hydrogen abstraction from boron trimethyl has been studied using the abstracting radicals CF 3 and CD 3 , from the photolysis of the corresponding ketones over the temperature range of 150° to 300°C. The following Arrhenius parameters were obtained:\documentclass{article}\pagestyle{empty}\begin{document}$$\begin{array}{l} {\rm (CD}_{\rm 3} {\rm + BME}_{\rm 3} {\rm); log }A{\rm = 11}{\rm .8, }E{\rm = 9}{\rm .98 kcal/mole} \\ {\rm (CF}_{\rm 3} {\rm + BMe}_{\rm 3} {\rm); log }A{\rm = 11}{\rm .6, }E{\rm = 6}{\rm .59 kcal/mole} \\ \end{array}$$\end{document}The difference E   CD   3– E   CF   3in the case of BMe 3 is considered due, in part, to polar effects. An exchange reaction is proposed for both CF 3 and CD 3 in collisions with BMe 3 :\documentclass{article}\pagestyle{empty}\begin{document}$${\rm R} + {\rm B}({\rm Me})_3 \to {\rm Me} + {\rm RBMe}_2$$\end{document}Radical combination of CF 3 and CH 2 BMe 2 leads to a hot molecule which undergoes a β‐fluoro rearrangement elimination process, or a stabilized molecule which can thermally decompose: