Introduction
Iodine monochloride is a chemical compound with the formula ICl.
Because of the difference in the electronegativity of iodine and
chlorine, ICl is highly polar and behaves as a source of I+.
Iodine monochloride is a low melting black or brownish-red solid
and widely available (usually in 97-98% purity).
It is soluble in alcohol, ether, CS2, acetic acid, acetone
and pyridine and hydrolyzes in water to HCl and IOH. ICl explodes
on contact with potassium metal, mixes with sodium metal, and it
can explode if impacted. Its reaction with PCl3 is extremely exothermic.
[¹]
Iodine monochloride can
be easily prepared by adding an aqueous solution of potassium iodate
to potassium iodate dissolved in concentrated HCl, in a closed vessel
to avoid the loss of chlorine.
[²]
Iodine
monochloride is a versatile reagent for the synthesis of a large
number of organic compounds being employed, for example, as a source
of electrophilic iodine in the synthesis of certain aromatic iodides.
[³]
It cleaves C-Si
bonds
[4]
and can be used in the electrophilic
addition to the double bond in alkenes leading to chloroiodoalkanes.
[5]
When iodine monochloride is reacted
with sodium azide in situ, the iodoazide product is obtained.
[6]
Other examples of synthetic applications
of this reagent also include electrophilic substitutions in Csp
[²]
and electrophilic cyclizations.
[7-9]
