Silanation

Silanation is the term used for the introduction of a silicon-containing group into a molecule. In practice, it covers reactions that install silicon substituents via silane reagents to form silicon–carbon, silicon–oxygen, or silicon–nitrogen bonds. The term encompasses several distinct but related transformations used in organic synthesis, materials science, and surface chemistry.

In organic synthesis, silanation most commonly refers to the silylation of alcohols and phenols to produce silyl ethers. Reagents such as tert-butyldimethylsilyl chloride (TBSCl) or tert-butyldiphenylsilyl chloride (TBDPSCl) are employed, often with a base, to protect reactive hydroxyl groups during multi-step sequences. Silylation provides protection that can be removed later under specific conditions, typically fluoride sources.

Hydrosilylation is another major class of silanation, in which a silicon–hydrogen bond adds across carbon–carbon multiple bonds or carbonyls. This reaction is typically catalyzed by transition metals (such as Pt, Pd, Rh, Ni, or Ru) and yields organosilicon products with new C–Si bonds. Hydrosilylation is widely used to functionalize alkenes, alkynes, and carbonyl compounds.

Silanation on surfaces, or silanization, refers to forming covalent Si–O–Si or Si–C linkages between a substrate surface bearing hydroxyl groups and silane reagents. This creates self-assembled monolayers and enables functionalization or immobilization of molecules on glass, silica, or other oxide surfaces.

In addition, silanation underpins silicon-containing cross-coupling methodologies (for example, Hiyama couplings), which use organosilicon reagents in catalytic C–C bond formation.

Applications span pharmaceuticals, materials science, and polymer chemistry, reflecting its role in protection strategies, surface modification, and silicon-based synthesis.