hydrosilylaatio

Hydrosilylaatio, or hydrosilylation in English, is a chemical transformation in which a silicon–hydrogen (Si–H) bond adds across an unsaturated carbon–carbon bond, most commonly a carbon–carbon double or triple bond found in alkenes and alkynes. The reaction forms a new carbon–silicon bond and a carbon–hydrogen bond, yielding organosilane products. The regiochemical outcome and stereochemistry of the addition depend on the substrate and the catalyst used.

Typical substrates include alkenes and alkynes, which after hydrosilylation give vinyl, alkyl, or allyl silanes, depending on the pattern of addition. Hydrosilylation is widely used to install silicon-containing functionality into organic molecules, providing handles for further transformation and enabling downstream applications in materials science and polymer chemistry.

Catalysts and mechanism are central to the reaction. Most practical hydrosilylations employ transition-metal catalysts, particularly platinum group metals. Common homogeneous catalysts include Karstedt’s catalyst (a platinum complex) and related Pt, Rh, or Pd systems. The reaction generally follows a Chalk–Harrod–type mechanism, involving activation of the Si–H bond at the metal center, insertion of the carbon–carbon multiple bond into a metal–silicon or metal–hydride fragment, and subsequent reductive elimination to form the C–Si bond while regenerating the active catalyst. The exact steps and the preferred pathway can vary with the catalyst, substrate, and reaction conditions.

Applications of hydrosilylation are extensive. It is a key method for synthesizing organosilanes, including vinylsilanes and alkylsilans, which serve as monomers, crosslinking agents, or functional groups in silicone polymers, coatings, adhesives, and electronic materials. It also enables surface modification and the preparation of silicon-containing intermediates for further transformations.