hexametyldisilansiini

Hexamethyldisilazane, often abbreviated as HMDS, is an organosilicon compound with the chemical formula [(CH3)3Si]2NH. It is a colorless liquid with a characteristic ammoniacal odor. HMDS is widely used as a silylating agent in organic chemistry and as a precursor in the synthesis of silicon-containing materials. Its primary function is to introduce trimethylsilyl groups (TMS) into molecules, which can alter their properties or protect functional groups during chemical reactions.

In organic synthesis, HMDS is particularly useful for derivatizing compounds containing hydroxyl, amino, or thiol groups. The resulting trimethylsilyl ethers, amines, or thioethers are often more volatile, making them suitable for gas chromatography analysis, or they can be more soluble in organic solvents. The TMS group can also serve as a protecting group, preventing unwanted reactions at these functional sites, and can be easily removed later.

Beyond its role in laboratory synthesis, HMDS finds applications in industrial processes. It is employed in the semiconductor industry as an adhesion promoter for photoresists on silicon wafers. This application relies on HMDS's ability to react with hydroxyl groups on the silicon dioxide surface, creating a hydrophobic layer that improves the adherence of the photoresist material. Furthermore, HMDS is used in the production of silicone oils and resins, contributing to their unique properties. It is a flammable liquid and should be handled with appropriate safety precautions.