Periodinanes also known as
λ5-
iodane
Iodane generally refers to any organic derivative of iodine. Without modifier, ''iodane'' is the systematic name for the parent hydride of iodine, HI. Thus, any organoiodine compound with general formula RI (e.g., iodomethane , or iodobenzene ) i ...
s are
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 ...
s with iodine in the +5 oxidation state. These compounds are described as
hypervalent
In chemistry, a hypervalent molecule (the phenomenon is sometimes colloquially known as expanded Octet rule, octet) is a molecule that contains one or more main group elements apparently bearing more than eight electrons in their valence shells. P ...
because the iodine center has more than 8
valence electrons
In chemistry and physics, a valence electron is an electron in the outer shell associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed. In a single covalent bond, a shared pair forms ...
.
Periodinane compounds
The λ
5-iodanes such as the
Dess-Martin periodinane have
square pyramidal
In molecular geometry, square pyramidal geometry describes the shape of certain compounds with the formula where L is a ligand. If the ligand atoms were connected, the resulting shape would be that of a pyramid with a square base. The point ...
geometry with 4 heteroatoms in basal positions and one apical phenyl group.
Iodoxybenzene or iodylbenzene, , is a known oxidizing agent.
Dess-Martin periodinane (1983) is another powerful oxidant and an improvement of the
IBX acid
2-Iodoxybenzoic acid (IBX) is an organic compound used in organic synthesis as an oxidizing agent. This periodinane is especially suited to oxidize alcohols to aldehydes. IBX is prepared from 2-iodobenzoic acid, potassium bromate, and sulfuric ...
already in existence in 1983. The IBX acid is prepared from 2-iodobenzoic acid and potassium
bromate
The bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (), and potassium bromate, ().
Bromates are formed many different ways in municipal drinki ...
and
sulfuric acid
Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...
and is insoluble in most solvents whereas the Dess-Martin reagent prepared from reaction of the IBX acid with
acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH3CO)2O. Commonly abbreviated Ac2O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis. It is a col ...
is very soluble. The oxidation mechanism ordinarily consists of a
ligand exchange reaction
In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...
followed by a
reductive elimination
Reductive elimination is an elementary step in organometallic chemistry in which the oxidation state of the metal center decreases while forming a new covalent bond between two ligands. It is the microscopic reverse of oxidative addition, and is ...
.
Uses
The predominant use of periodinanes is as oxidizing reagents replacing toxic reagents based on heavy metals.
[''Hypervalent iodine(V) reagents in organic synthesis'' Uladzimir Ladziata and Viktor V. Zhdankin ]Arkivoc
''Arkivoc'' (''Archive for Organic Chemistry'') is a peer-reviewed open access scientific journal covering all aspects of organic chemistry. It is published by the non-profit organization Arkat USA, which was established in 2000 through a personal ...
05-1784CR pp 26-58 2006''
Article
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See also
* Carbonyl oxidation with hypervalent iodine reagents
References
{{reflist
External links
Hypervalent Iodine Chemistry
*
Oxidizing agents