Learn All about Cyanides and Isocyanides

As a hydrocyanic acid (HCN) derivative, cyanides and isocyanides are available in two isomeric forms. Replacement of the hydrogen atom in HCN by an alky or aryl group (RCN), where R represents the aryl or alkyl group, produces cyanides. Isocyanide is formed when the nitrogen atom of the –CN group is linked to an alkyl or aryl group. The functional isomers of cyanides and isocyanides are identical. An example of this terminology is “alkyl cyanides,” while an example of this nomenclature is “alkyl isocyanides.” Isocyanides, or carbylamines, are another name for isocyanides. Cyanides and isocyanides will be discussed in-depth in this article.

Overview of Cyanide Compounds

There are many types of cyanide RCN, which are potentially lethal and highly reactive. To make matters worse, cyanide impairs the cell’s ability to utilise oxygen. The isocyanide multicomponent reactions can be used to synthesise a wide range of organic compounds because of their functional group tolerance. Chemo-, stereo- and regioselective actions are all highly developed in them.

Cyanides can be used to synthesise amides, acids, and amines since they are an excellent synthetic pathway. When alkyl halides are converted to alkyl cyanide, a carbon atom is added to the chain, allowing cyanides to be employed as intermediates in organic processes. Industrial solvent acetonitrile is also employed in the production of textiles, nitriles, rubber, and other products. The fragrance of cyanides is pleasant, whereas that of isocyanides is revolting. Cyanide’s dipole moment is greater than that of isocyanides.

Cyanide is the name given to a chemical compound containing the –CN group. Known as the cyano group, this structure comprises one atom of carbon triple-bonded to an atom of nitrogen. Inorganic compounds contain the cyanide group as CN– anion. The acidification of cyanide salts yields hydrocyanic acid, often known as hydrogen cyanide (HCN), a highly volatile liquid manufactured on a considerable scale in the industry. Nitriles are organic cyanides in which the –CN group is connected to the carbon atom of the alkyl or aryl group via a covalent connection. For example, the cyanide group is linked to the methyl group in acetonitrile (CH3CN). However, cyanohydrins, formed when Nitriles are heated to high temperatures and exposed to air, release cyanide ions, making them quite poisonous.

Overview of Isocyanides Compounds

Isocyanide is an organic chemical containing the functional group –NC. As its name implies, it is an isomer of the closely related nitrile. The nitrogen atom connects the alkyl or aryl to the isocyanide group, not the carbon atom. The cyanide group can be connected to an alkyl or aryl group’s carbon atom via the carbon or nitrogen atom. An ambident group is a sort of group that can be linked through two different locations.

Cyanide and isocyanide Preparation

High molecular weight acid amides are dehydrated to produce the desired cyanide by heating to make cyanides. Grignard’s reagent and the Cyanogen chloride reaction are two of the most acceptable ways to make three alkyl cyanides. It is possible to make aryl nitrile from a diazonium salt using cuprous cyanide (KCN) and copper powder (DCCP). Here, you can find the chemical reaction used in this method. When aqueous ethanol solution is heated with an alkyl iodide and AgCN, it produces alkyl isocyanide.

Carbylamine Reaction

This reaction takes place by heating a mixture of primary amines and chloroform and ethanolic potassium hydroxide with ethanolic potassium hydroxide. For the reaction to occur, chloroform in an alkaline solution must first be converted into Dichloromethylene or dichloro carbene by elimination.

Cyanide and Isocyanide Chemistry

Water dissolves alkyl cyanides but not alkyl isocyanides because cyanides tend to form H–bonds with water, whereas isocyanides do not. Alkyl cyanides of lower molecular weights are soluble in water, but solubility declines with increasing molecular weight. The boiling temperatures of alkyl isocyanides are lower than those of the corresponding isomeric cyanides, which are toxic. Due to the lack of a pair of electrons available for hydrogen bonding, alkyl isocyanides (RNC) are not highly water-soluble.

Cyanide and Isocyanide Applications

During the Franco-Prussian War, cyanide was utilised as a chemical warfare agent. Cyanides are incredibly harmful to the body. Painting, shipbuilding, fire-fighting, electrical wire protection, cement, rubbers, and filaments are all common uses of isocyanides.

In organic synthesis, isocyanides are frequently utilised because of their excellent regioselectivity, chemoselectivity, stereoselectivity, and functional group tolerance. Several chemical reactions can be carried out using cyanides. When alkyl halides are converted to alkyl cyanide, a carbon atom is added to the chain, allowing cyanides to be employed as intermediates in organic processes. For example, the chemical formula (CH3CN) represents acetonitrile, while CH3NC is known as methyl carbylamine in IUPAC nomenclature. As a result, cyanides and isocyanides are functional groups that are identical in structure. 

Conclusion

To produce both cyanides and Isocyanides from HCN, an alkyl or aryl group must be substituted for one of the HCN hydrogen atoms, which is done by replacing the HCN group with an alkyl or aryl group. Isocyanide is formed when the nitrogen atom of the –CN group is linked to an alkyl or aryl group. Alkyl cyanides are the most common cyanide names in the naming system. Alkyl isocyanides and iso-nitriles are other names for isocyanides. Alkyl cyanide (RCN) is a highly reactive and poisonous chemical found in various forms.