Tert-Butyl isocyanide
Encyclopedia
tert-Butyl isocyanide is an organic compound
with the formula
Me3CNC (Me = methyl, CH3). It is an isocyanide
, commonly called isonitrile or carbylamine, as defined by the functional group
C≡N-R. tert-Butyl isocyanide, like most alkyl isocyanides, is a reactive colorless liquid with an extremely unpleasant odor. It forms stable complexes with transition metal
s and can insert into metal-carbon bonds
.
tert-Butyl isocyanide is prepared by a Hofmann carbylamine reaction
. In this conversion, a dichloromethane solution of tert-butylamine
is treated with chloroform
and aqueous sodium hydroxide in the presence of catalytic amount of the phase transfer catalyst
benzyltriethylammonium chloride
.
tert-Butyl isocyanide is isomeric with pivalonitrile
, also known as tert-butyl cyanide.
, isocyanides serves as ligands in coordination chemistry, especially with metals in the 0, +1, and +2 oxidation states. tert-Butyl isocyanide has been shown to stabilize metals in unusual oxidation states, such as Pd(I).
tert-Butyl isocyanide can form hepta-coordinate homoleptic
complexes, despite having a large t-Bu group, which is held far away from the metal
center because of the linearity of the M-C≡N-C linkages.
complexes, such as Fe2(CO)9 and Fe2(tBuNC)9. Although structurally similar, the analogous carbonyls differ in several ways, mainly because t-BuNC is a better donor ligand than CO. Thus, Fe(tBuNC)5 is easily protonated, whereas its counterpart Fe(CO)5 is not.
.
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...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
Me3CNC (Me = methyl, CH3). It is an isocyanide
Isocyanide
An isocyanide is an organic compound with the functional group -N≡C. It is the isomer of the related cyanide , hence the prefix iso....
, commonly called isonitrile or carbylamine, as defined by the functional group
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...
C≡N-R. tert-Butyl isocyanide, like most alkyl isocyanides, is a reactive colorless liquid with an extremely unpleasant odor. It forms stable complexes with transition metal
Transition metal
The term transition metal has two possible meanings:*The IUPAC definition states that a transition metal is "an element whose atom has an incomplete d sub-shell, or which can give rise to cations with an incomplete d sub-shell." Group 12 elements are not transition metals in this definition.*Some...
s and can insert into metal-carbon bonds
Chemical bond
A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction...
.
tert-Butyl isocyanide is prepared by a Hofmann carbylamine reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...
. In this conversion, a dichloromethane solution of tert-butylamine
Tert-Butylamine
tert-Butylamine is an organic chemical compound with the formula 3CNH2, and occurs as a colorless liquid. tert-Butylamine is one of the four isomeric amines of butane, the others being n-butylamine, sec-butylamine and isobutylamine.-Preparation:tert-Butylamine is commercially available...
is treated with chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
and aqueous sodium hydroxide in the presence of catalytic amount of the phase transfer catalyst
Phase transfer catalyst
In chemistry, a phase transfer catalyst or PTC is a catalyst that facilitates the migration of a reactant from one phase into another phase where reaction occurs. Phase transfer catalysis is a special form of heterogeneous catalysis. Ionic reactants are often soluble in an aqueous phase but...
benzyltriethylammonium chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
.
- Me3CNH2 + CHCl3 + 3 NaOH → Me3CNC + 3 NaCl + 3 H2O
tert-Butyl isocyanide is isomeric with pivalonitrile
Pivalonitrile
Pivalonitrile is a nitrile with the semi-structural formula 3CCN, abbreviated t-BuCN. This aliphatic organic compound is a clear, colourless liquid that is used as a solvent and as a labile ligand in coordination chemistry. Pivalonitrile is isomeric with tert-butyl isocyanide....
, also known as tert-butyl cyanide.
Coordination chemistry
By virtue of the lone electron pair on carbonCarbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
, isocyanides serves as ligands in coordination chemistry, especially with metals in the 0, +1, and +2 oxidation states. tert-Butyl isocyanide has been shown to stabilize metals in unusual oxidation states, such as Pd(I).
- Pd(dba)2 + PdCl2(C6H5CNBenzonitrileBenzonitrile is the chemical compound with the formula C6H5CN, abbreviated PhCN. This aromatic organic compound is colourless, with a sweet almond odour. It is prepared by the dehydration of benzamide, or by the reaction of sodium cyanide with bromobenzene....
)2 + 4 t-BuNC → [(t-BuNC)2PdCl]2 + 2 dba + 2 C6H5CN
tert-Butyl isocyanide can form hepta-coordinate homoleptic
Homoleptic
In inorganic chemistry, a homoleptic chemical compound is a metal compound with all ligands identical. The term uses a homo prefix to indicate that something is the same for all....
complexes, despite having a large t-Bu group, which is held far away from the metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
center because of the linearity of the M-C≡N-C linkages.
Similarity to metal carbonyls
tert-Butyl isocycanide forms complexes that are stoichiometrically analogous to certain binary metal carbonylCarbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups....
complexes, such as Fe2(CO)9 and Fe2(tBuNC)9. Although structurally similar, the analogous carbonyls differ in several ways, mainly because t-BuNC is a better donor ligand than CO. Thus, Fe(tBuNC)5 is easily protonated, whereas its counterpart Fe(CO)5 is not.
Insertion into metal-carbon bonds
Under certain circumstances, tert-butyl isocyanide has been shown to insert into metal-carbon bonds to form iminoacyls. The insertion of isocyanides into metal-carbon bonds is of potential relevance in organic synthesisOrganic synthesis
Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic molecules can often contain a higher level of complexity compared to purely inorganic compounds, so the synthesis of organic compounds has...
.