Iodobenzene is an

organoiodine compound Organoiodine compounds are organic compounds that contain one or more carbon–iodine bonds. They occur widely in organic chemistry, but are relatively rare in nature. The thyroxine hormones are organoiodine compounds that are required for he ...

consisting of a

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms, ...

ring substituted with one

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

atom. It is useful as a synthetic intermediate in

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; ...

. It is a volatile colorless liquid, although aged samples appear yellowish.

Preparation

Iodobenzene is commercially available, but it can be prepared in the laboratory from

aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine In organic chemistry, an aromatic amine is an organic compound consisting of an aroma ...

via the Diazotization Reaction. In the first step, the

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituen ...

functional group is diazotized with

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

and

sodium nitrite Sodium nitrite is an inorganic compound with the chemical formula NaNO2. It is a white to slightly yellowish crystalline powder that is very soluble in water and is hygroscopic. From an industrial perspective, it is the most important nitrite ...

. Potassium iodide is added to the resultant phenyldiazonium chloride, causing

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

gas to evolve. The product is separated by steam distillation. : Synthesis Iodobenzene

Alternatively, it can be produced by refluxing

and

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...

with benzene.

Reactions

Since the C–I bond is weaker than C–Br or C–Cl, iodobenzene is more reactive than

bromobenzene Bromobenzene is an aryl halide, C6H5Br. It is a colourless liquid although older samples can appear yellow. It is a reagent in organic synthesis. Synthesis and reactions Bromobenzene is prepared by the action of bromine on benzene in the presen ...

or chlorobenzene. Iodobenzene reacts readily with

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

to form the

Grignard reagent A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide ...

, phenylmagnesium iodide. Phenylmagnesium iodide, like the bromide analog, is a synthetic equivalent for the phenyl anion synthon. Iodobenzene reacts with chlorine to give the complex,

iodobenzene dichloride Iodobenzene dichloride (PhICl2) is a complex of iodobenzene with chlorine. As a reagent for organic chemistry, it is used as an oxidant and chlorinating agent. Chemical structure Single-crystal X-ray crystallography has been used to determine ...

,{{OrgSynth , title = Iodobenzene dichloride , author = H. J. Lucas and E. R. Kennedy , prep = cv3p0482 , collvol = 3 , collvolpages = 482 which is used as a solid source of chlorine. Iodobenzene can also serve as a substrate for the

Sonogashira coupling The Sonogashira reaction is a cross-coupling reaction used in organic synthesis to form carbon–carbon bonds. It employs a palladium catalyst as well as copper co-catalyst to form a carbon–carbon bond between a terminal alkyne and an aryl or vi ...

Heck reaction The Heck reaction (also called the Mizoroki–Heck reaction) is the chemical reaction of an unsaturated halide (or triflate) with an alkene in the presence of a base and a palladium catalyst (or palladium nanomaterial-based catalyst) to form a s ...

, and other metal-catalyzed couplings. These reactions proceed via the oxidative addition of iodobenzene.

Preparation

Reactions

See also

References

Further reading