Trimethylsilyl cyanide is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

(CH₃)₃SiCN. This volatile liquid consists of a

cyanide Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...

group, that is CN, attached to a

trimethylsilyl A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom minus;Si(CH3)3 which is in turn bonded to the rest of a molecule. This structural group is ch ...

group. The molecule is used in

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

as the equivalent of

hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an ...

. It is prepared by the reaction of

lithium cyanide Lithium cyanide is an inorganic compound with the chemical formula LiCN. It is a toxic, white colored, hygroscopic, water-soluble salt that finds only niche uses. Preparation LiCN arises from the interaction of lithium hydroxide and hydrogen cyan ...

and trimethylsilyl chloride: :LiCN + (CH₃)₃SiCl → (CH₃)₃SiCN + LiCl

Structure

The molecule exhibits the expected structure of a nitrile-like compound. The compound exists in a facile equilibrium with a small amount of the

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. Iso ...

isocyanide An isocyanide (also called isonitrile or carbylamine) is an organic compound with the functional group –. It is the isomer of the related nitrile (–C≡N), hence the prefix is ''isocyano''.IUPAC Goldboo''isocyanides''/ref> The organic fragme ...

(CH₃)₃SiNC. By contrast, the nearly isostructural ''tert''-butyl nitrile does not readily isomerize to ''tert''-butyl isocyanide.

Reactions

Trimethylsilyl cyanide

hydrolyzes Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

to give

and

trimethylsilanol Trimethylsilanol (TMS) is an organosilicon compound with the formula (CH3)3SiOH. The Si centre bears three methyl groups and one hydroxyl group. It is a colourless volatile liquid.Paul D. Lickiss: ''The Synthesis and Structure of Organosilanols'', ...

: :(CH₃)₃SiCN + H₂O → (CH₃)₃SiOH + HCN In its principal application, it adds across carbon-oxygen double bonds, for example in an

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

, to form a new carbon-carbon bond: : + (CH₃)₃SiC≡N → N≡C–Si(CH₃)₃ The product is an ''O''-silylated

cyanohydrin In organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is , where R is H, alkyl, or aryl. Cyanohydrin ...

. One use of this reagent is to convert

pyridine Pyridine is a basic heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom. It is a highly flammable, weakly alkaline, water-miscible liquid with a d ...

-''N''-

oxide An oxide () is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula. "Oxide" itself is the dianion of oxygen, an O2– (molecular) ion. with oxygen in the oxidation state of −2. Most of the E ...

s into 2-cyanopyridine. This transformation is best done in

dichloromethane Dichloromethane (DCM or methylene chloride, methylene bichloride) is an organochlorine compound with the formula . This colorless, volatile liquid with a chloroform-like, sweet odour is widely used as a solvent. Although it is not miscible with ...

solution using dimethyl

carbamoyl chloride A carbamoyl chloride is the functional group with the formula R2NC(O)Cl. The parent carbamoyl chloride, H2NCOCl is unstable, but many N-substituted analogues are known. Most examples are moisture sensitive, colourless, and soluble in nonpolar orga ...

as the activating

electrophile In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively charged, have an atom that carries ...

. It is possible to use

benzoyl chloride Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula . It is a colourless, fuming liquid with an irritating odour, and consists of a benzene ring () with an acyl chloride () substituent. It is ...

but the yields and

regioselectivity In chemistry, regioselectivity is the preference of chemical bonding or breaking in one direction over all other possible directions. It can often apply to which of many possible positions a reagent will affect, such as which proton a strong base ...

of the addition of the cyano group are lower. Acetone cyanohydrin can be used to reversibly generate the cyanide anion. ''(4)'' CNAddScope1

Safety

This chemical is rated as "Fatal if swallowed, in contact with skin or if inhaled" as it hydrolyzes in the presence of moisture to give hydrogen cyanide gas. Disposal by using dilute solution of alkali hydroxide is recommended.MSDS of trimethylsilyl cyanide. (PDF)
Gelest. un 13, 2019/ref>

References

{{Cyanides Nitriles Trimethylsilyl compounds