Cyanocarbon
Encyclopedia
Cyanocarbons are a chemical compound
s that contain several cyanide
groups
. Such substances generally are classified as organic compound
s, since they are formally derived from hydrocarbon
s by replacing one or more hydrogen
atom
s with a cyanide
. The parent member is C(CN)4. Organic chemists often refer to cyanides as nitrile
s.
In general, cyanide is an electronegative substituent. Thus, for example, cyanide-substituted carboxylic acid
s tend to be stronger than the parents. The cyanide group also stabilizes anions by delocalizing negative charge
as revealed by resonance
structures.
Important cyanocarbons:
with sodium tricyanomethanide in water (a reaction first tried by H. Schmidtmann in 1896 with inconclusive results ) is reported to result in the formation of de hydrate (NC)3C-H3O+ or the formation of (Z)-3-
amino-2-cyano-3-hydroxyacrylamide (H2N)(OH)C=C(CN)CONH2 depending on the precise conditions . The reaction of HCl gas with sodium tricyanomethanide dissolved in THF is reported to yield 1-chloro-1-amino-2,2-dicyanoethylene ((NC)2C=C(NH2)Cl) and its tautomer.
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s that contain several cyanide
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
groups
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
. Such substances generally are classified as organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
s, since they are formally derived from hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s by replacing one or more hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...
s with a cyanide
Cyanide
A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....
. The parent member is C(CN)4. Organic chemists often refer to cyanides as nitrile
Nitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...
s.
In general, cyanide is an electronegative substituent. Thus, for example, cyanide-substituted carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
s tend to be stronger than the parents. The cyanide group also stabilizes anions by delocalizing negative charge
Electric charge
Electric charge is a physical property of matter that causes it to experience a force when near other electrically charged matter. Electric charge comes in two types, called positive and negative. Two positively charged substances, or objects, experience a mutual repulsive force, as do two...
as revealed by resonance
Resonance (chemistry)
In chemistry, resonance or mesomerism is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis formula...
structures.
Definition and examples
Cyanocarbons are organic compounds bearing enough cyano functional groups to significantly alter their chemical properties.Important cyanocarbons:
- tetracyanoethyleneTetracyanoethyleneTetracyanoethylene is a clear colored organic compound consisting of ethylene with the four hydrogen atom replaced with cyano groups. It is an important member of the cyanocarbons.-Synthesis and reactions:...
, which readily reduces to a stable anion, unlike most ethene derivatives - Pentacyanocyclopentadiene, which forms a stable anion by ionization of the C-H bond.
- tetracyanoethylene oxide, an electrophilic epoxideEpoxideAn epoxide is a cyclic ether with three ring atoms. This ring approximately defines an equilateral triangle, which makes it highly strained. The strained ring makes epoxides more reactive than other ethers. Simple epoxides are named from the parent compound ethylene oxide or oxirane, such as in...
that undergoes ready scission of its C-C bond. - tetracyanoquinodimethanideTCNQTetracyanoquinodimethane is the organic compound with the formula 2CC6H4C2. This relative of para-quinone is an electron-acceptor that is used to prepare charge transfer salts, which are of interest in the area of molecular electronics....
, C6H4-1,4-(C(CN)2)2, a powerful electron acceptor.
Tricyanomethane
Tricyanomethane (NC)3CH is a hypothetical molecule that has thus far resisted all attempts at synthesis . It would rank as one of the most acidic of the carbon acids with an estimated Pka of -5. The reaction of sulfuric acidSulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
with sodium tricyanomethanide in water (a reaction first tried by H. Schmidtmann in 1896 with inconclusive results ) is reported to result in the formation of de hydrate (NC)3C-H3O+ or the formation of (Z)-3-
amino-2-cyano-3-hydroxyacrylamide (H2N)(OH)C=C(CN)CONH2 depending on the precise conditions . The reaction of HCl gas with sodium tricyanomethanide dissolved in THF is reported to yield 1-chloro-1-amino-2,2-dicyanoethylene ((NC)2C=C(NH2)Cl) and its tautomer.