Tetrametüülsilaan

Tetrametüülsilaan, often abbreviated as TMS, is an organosilicon compound with the chemical formula Si(CH3)4. It is a colorless, volatile liquid at room temperature. TMS is structurally similar to methane, with a silicon atom at the center bonded to four methyl groups. This symmetrical arrangement contributes to its relatively low boiling point and high vapor pressure.

Tetrametüülsilaan is primarily known for its use as a standard in nuclear magnetic resonance (NMR) spectroscopy. In both 1H and 13C NMR, TMS is added to the sample in small quantities. The silicon-carbon bonds in TMS are very stable, and the methyl protons are highly shielded, resulting in a signal at a chemical shift of 0 parts per million (ppm). This reference point allows chemists to accurately determine the chemical shifts of other protons and carbons in their samples. TMS is chosen because its signal is typically at a high field (upfield) compared to most organic compounds, meaning it does not overlap with most other signals, and it is easily removed from the sample by evaporation if necessary.

Industrially, tetrametüülsilaan is produced through the direct process, reacting silicon metal with methyl chloride in the presence of a copper catalyst. It serves as a precursor in the synthesis of other organosilicon compounds and silicones. Its volatility and non-polar nature make it a useful solvent in certain applications, though its use in this capacity is less common than its role as an NMR standard. TMS is generally considered to have low toxicity.