Chemical structure of a Trimethylsilyl group

A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. In Organic chemistry, functional groups are specific groups of Atoms within Molecules that are responsible for the characteristic Chemical reactions Organic chemistry is a discipline within Chemistry which involves the scientific study of the structure properties composition reactions, and preparation This group consists of three methyl groups bonded to a silicon atom [−Si(CH₃)₃], which is in turn bonded to the rest of a molecule. In Chemistry, a methyl group is a Hydrophobic Alkyl Functional group named after Methane (4 Silicon (ˈsɪlɪkən or /ˈsɪlɪkɒn/ silicium is the Chemical element that has the symbol Si and Atomic number 14 This structural group is characterized by chemical inertness and a large molecular volume which makes them useful in a number of applications. van der Waals surface area (abbreviated variously as vdWSA, VSA, WSA) also van der Waals surface or van der Waals envelope

A trimethylsilyl group bonded to a methyl group forms tetramethylsilane, which is abbreviated as TMS as well. Tetramethylsilane (abbreviated as TMS) is the Chemical compound with the formula Si(CH34 or SiMe4 (Me = CH3

Compounds with trimethylsilyl groups are not normally found in nature. Chemists sometimes use a trimethylsilylating reagent to derivatize rather non-volatile compounds such as certain alcohols, phenols, or carboxylic acids by substituting a trimethylsilyl group for a hydrogen in the hydroxyl groups on the compounds. A reagent or reactant is a substance or compound consumed during a Chemical reaction. In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon In Organic chemistry, phenols, sometimes called phenolics, are a class of Chemical compounds consisting of a Hydroxyl group (- Carboxylic acids are Organic acids characterized by the presence of a Carboxyl group, which has the formula -C(=OOH usually written -COOH or -CO2H Hydroxyl in Chemistry stands for a molecule consisting of an Oxygen atom and a Hydrogen atom connected by a Covalent bond. This way trimethylsiloxy groups are formed on the molecule. Silyl ethers are a group of Chemical compounds which contain a Silicon atom covalently bonded to an Alkoxy group Trimethylsilyl groups on a molecule have a tendency to make it more volatile, often making the compounds more amenable to analysis by gas chromatography or mass spectrometry. Gas-liquid chromatography (GLC, or simply gas chromatography (GC, is a type of Chromatography in which the mobile phase is a carrier gas usually an Inert Mass spectrometry is an analytical technique that identifies the chemical composition of a compound or sample based on the Mass-to-charge ratio of charged particles Such derivatizations are often done on a small scale in special vials.

When attached to certain functional groups in a reactant molecule, trimethylsilyl groups may also be used as temporary protecting groups during chemical synthesis or some other chemical reactions. A reagent or reactant is a substance or compound consumed during a Chemical reaction. A protecting group or protective group is introduced into a molecule by chemical modification of a Functional group in order to obtain Chemoselectivity In Chemistry, chemical synthesis is purposeful execution of Chemical reactions in order to get a product, or several products A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called

In an NMR spectrum, signals from atoms in trimethylsilyl groups in compounds will commonly have chemical shifts close to the tetramethylsilane reference peak at 0 ppm. Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is the name given to a technique which exploits the magnetic properties of certain nuclei Also compounds, such as high temperature silicone "stopcock" grease, which have polysiloxanes (often called silicones) in them will commonly show peaks from their methyl groups (attached to the silicon atoms) having NMR chemical shifts close to the tetramethylsilane standard peak, such as at 0. A stopcock is a Valve used to restrict or isolate the flow of a liquid or gas through a pipe. Although the word grease originally described the rendered fat of animals the term is now applied more broadly to mean a Lubricant of higher initial Viscosity Silicones are largely inert compounds with a wide variety of forms and uses 07 ppm in CDCl₃. ^[1]

Otherwise very reactive molecules can be isolated when enveloped by bulky trimethylsilyl groups. This effect can be observed in tetrahedranes. Tetrahedrane is a Platonic hydrocarbon with Chemical formula 44 and a tetrahedral structure

Super silyl groups

Related to trimethylsiliyl groups are so-called super silyl groups of which there exist two varieties: A silicon group connected to three trimethylsilyl groups makes a tri(trimethylsilyl)silyl group (TTMSS or TMS₃Si) and a silicon group connected to three tert-butyl groups. In Organic chemistry, butyl is a four- Carbon Alkyl substituent with Chemical formula -C4H9. The TTMSS group was proposed in 1993 by Hans Bock. With a van der Waals volume of up to 7 cubic angstrom it surpasses the related TIPS group (around 2) ^{[2] [3]} and one potential application is its use as a temporary substituent promoting asymmetric induction for example in this diastereoselective one-pot reaction involving two sequential Mukaiyama aldol reactions ^[4]:

See also

• Trimethylsilanol
• Tetramethylsilane

References