Catalytic Oxidation of Silanes by Carbon Nanotube-Gold Nanohybrids

摘要

The selective oxidation of silanes has attracted wide interest as silanols are key synthons for the production of silicon-containing materials and nucleophilic partners in organo-metallic cross-coupling reactions. Silanes are classically converted into silanols using strong oxidizing agents such as osmium tetroxide, permanganate, ozone, peracids, or peroxides. However, under these reaction conditions, significant amounts of siloxanes and toxic by-products are formed. To overcome these drawbacks, catalytic systems involving water and oxygen have been recently devised. They offer the advantage of cleanly producing silanols along with hydrogen gas as the only by-product. While initial catalytic silane oxidation studies relied on homogeneous transition metals, heterogeneous catalytic systems have emerged as very promising alternatives. Indeed, the latter are more efficient (high conversion rate), recyclable, selective (little to no siloxane by-product formation), and usually operate under milder conditions. Amongst heterogeneous catalysts for silane oxidation, recent elegant examples include nanoporous gold by Asao, Yamamoto, and co-workers, and hydroxya-patite-supported silver or gold nanoparticles by Kaneda and co-workers.