![BobbitSalt](https://upload.wikimedia.org/wikipedia/commons/8/8c/BobbitSalt.png)
''N''-Oxoammonium salts are a class of
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...
s with the formula
1R2=O">1R2=O−. The cation
1R2=O">1R2=Ois of interest for the dehydrogenation of alcohols. Oxoammonium salts are diamagnetic, whereas the nitroxide has a doublet ground state. A prominent nitroxide is prepared by oxidation of
(2,2,6,6-tetramethylpiperidin-1-yl)oxyl, commonly referred to as
EMPOsup>+. A less expensive analogue is
Bobbitt's salt.
Structure and bonding
Oxoammonium cations are isoelectronic with
carbonyl
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. A compound containing a ...
s and structurally related to
aldoxime
In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substitute ...
s (hydroxylamines), and
aminoxyl
Aminoxyl denotes a radical functional group with general structure R2N–O•. It is commonly known as a nitroxyl radical or a nitroxide, however IUPAC discourages the use of these terms, as they erroneously suggest the presence of a nitro group. ...
(nitroxide) radicals, with which they can interconvert via a series of
redox
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction ...
steps. According to
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
, the N–O distance in
EMPOF
4 is 1.184 Å, 0.1 Å shorter than the N–O distance of 1.284 Å in the charge-neutral TEMPO. Similarly, the N in
EMPOsup>+ is nearly planar, but the O moves 0.1765 Å out of the plane in the neutral TEMPO.
![RedoxNitroxide](https://upload.wikimedia.org/wikipedia/commons/b/b9/RedoxNitroxide.png)
The ''N''-oxoammonium salts are used for oxidation of
alcohol
Alcohol most commonly refers to:
* Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom
* Alcohol (drug), an intoxicant found in alcoholic drinks
Alcohol may also refer to:
Chemicals
* Ethanol, one of sev ...
s to
carbonyl
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. A compound containing a ...
groups,
as well as other forms of
oxoammonium-catalyzed oxidation
Oxoammonium-catalyzed oxidation reactions involve the conversion of organic substrates to more highly oxidized materials through the action of an N-oxoammonium species. Nitroxides may also be used in catalytic amounts in the presence of a stoichi ...
s. The nitroxyl
TEMPO
In musical terminology, tempo (Italian, 'time'; plural ''tempos'', or ''tempi'' from the Italian plural) is the speed or pace of a given piece. In classical music, tempo is typically indicated with an instruction at the start of a piece (often ...
reacts via its ''N''-oxoammonium salt.
[
]
See also
*
Nitrone – structurally related, the ''N''-oxide of an imine
References
{{DEFAULTSORT:Oxoammonium Salt, N-
Functional groups
Oxycations