Metal-free catalysis for the Markovnikov hydrosilylation of styrene.

An external electric field (EEF), as a metal-free catalyst, catalyzing the Markovnikov hydrosilylation of styrene was studied for the first time. As compared to the field-free situation, the barrier height was almost halved upon the application of EEF with a field strength of 180 × 10−4 a.u. in the direction perpendicular to the "bond axis". Therefore, the use of EEF not only resolved the questions of the separation of homogeneous catalysts from the reaction mixture, but also facilitated the reaction by decreasing its barriers. Furthermore, we found that the lower the energy of the transition state (TSX) and the higher the energy of the HOMO of the reactant (R1′), the lower the barrier height of hydrosilylation. Hopefully, this study can provide guidance toward experiments involving an external electric field. [ABSTRACT FROM AUTHOR]