Ethylene dione or ethylenedione, also called dicarbon dioxide, Carbon peroxide, ethenedione, or ethene-1,2-dione, is a
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with the
formula or . It is an
oxide of
carbon
Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
(an
oxocarbon
In chemistry, an oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen. The simplest and most common oxocarbons are carbon monoxide (CO) and carbon dioxide (). Many other stable (practically if not thermodynamica ...
), and can be described as the carbon-carbon covalent
dimer
Dimer may refer to:
* Dimer (chemistry), a chemical structure formed from two similar sub-units
** Protein dimer, a protein quaternary structure
** d-dimer
* Dimer model, an item in statistical mechanics, based on ''domino tiling''
* Julius Dimer ...
of
carbon monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
.
It can also be thought of as the
dehydrated
In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
form of
glyoxylic acid
Glyoxylic acid or oxoacetic acid is an organic compound. Together with acetic acid, glycolic acid, and oxalic acid, glyoxylic acid is one of the C2 carboxylic acids. It is a colourless solid that occurs naturally and is useful industrially.
...
(), or a
ketone of
ethenone
In organic chemistry, ethenone is the formal name for ketene, an organic compound with formula or . It is the simplest member of the ketene class. It is an important reagent for acetylations.
Properties
Ethenone is a highly reactive gas (at ...
.
Synthesis attempts
The existence of ethylenedione was first suggested in 1913.
[H. Staudinger, E. Anthes, ''Ber. Dtsch. Chem. Ges.'' 1913, 46, 1426.] However, for over a century the compound had eluded all attempts to synthesize and observe it, and it came to be considered a purely hypothetical compound, or at best an "exceedingly coy molecule".
In 2015, a research group reported the creation of ethylenedione — by using
laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The fi ...
light to eject an
electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family,
and are generally thought to be elementary particles because they have no ...
from the corresponding stable singly-charged
anion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
— and its spectroscopic characterization. However, the reported spectrum was later found to match that of the oxyallyl diradical, , formed by rearrangement or disproportionation under the high-energy experimental conditions rather than simple electron loss.
[Katharine G. Lunny, Yanice Benitez, Yishai Albeck, Daniel Strasser, John F. Stanton, Robert E. Continetti (2018): "Spectroscopy of Ethylenedione and Ethynediolide: A Reinvestigation". ''Angewandte Chemie, International Edition'', volume 57, issue 19, pages 5394-5397.]
Theoretical investigations
Despite the existence of the
closed-shell Kekulé structure, O=C=C=O, the lowest bound state of ethyledione is a
triplet. It would then be a
diradical
In chemistry, a diradical is a molecular species with two electrons occupying molecular orbitals (MOs) which are degenerate. The term "diradical" is mainly used to describe organic compounds, where most diradicals are extremely reactive and i ...
, with an
electronic structure
In quantum chemistry, electronic structure is the state of motion of electrons in an electrostatic field created by stationary nuclei. The term encompasses both the wave functions of the electrons and the energies associated with them. Electr ...
motif similar to the
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
molecule. However, when the molecule is distorted away from its equilibrium geometry, the potential surfaces of the triplet and
singlet state
In quantum mechanics, a singlet state usually refers to a system in which all electrons are paired. The term 'singlet' originally meant a linked set of particles whose net angular momentum is zero, that is, whose overall spin quantum number s=0. A ...
s intersect, allowing for
intersystem crossing Intersystem crossing (ISC) is an isoenergetic radiationless process involving a transition between the two electronic states with different spin multiplicity.
Excited Singlet and Triplet States
When an electron in a molecule with a singlet ground ...
to the singlet state, which is unbound and dissociates to two ground-state CO molecules. The timescale of the intersystem crossing was predicted to be 0.5
ns, making triplet ethylenedione a transient, yet spectroscopically long-lived molecule.
On the other hand, the mono
anion
An ion () is an atom or molecule with a net electrical charge.
The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...
of ethylenedione, OCCO
−, as well as the dianion , called
acetylenediol
Acetylenediol, or ethynediol, is a chemical substance with formula HO−C≡C−OH (an ynol). It is the diol of acetylene. Acetylenediol is unstable in the condensed phase, although its tautomer glyoxal (CHO)2 is well known.
Detection
Acetyl ...
ate, are both stable.
Recent theoretical computations suggest that the ''in situ'' preparation and characterization of ethylenedione may be possible through low-energy free-electron induced single-molecule engineering.
[
]
Koch's glyoxylide
In the 1940s, Detroit
Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at t ...
physician William Frederick Koch claimed that he had synthesized this compound, which he called glyoxylide, and that it was an antidote
An antidote is a substance that can counteract a form of poisoning. The term ultimately derives from the Greek term φάρμακον ἀντίδοτον ''(pharmakon) antidoton'', "(medicine) given as a remedy". Antidotes for anticoagulants are s ...
to the toxins that caused a long list of ailments, including diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...
and cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
. The claims were false and the drug was classified as a fraud by the FDA
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
.
See also
* Cyclohexanehexone C6O6, also called triquinoyl, formally a trimer of ethylene dione.
*Oxocarbons
In chemistry, an oxocarbon or oxide of carbon is a chemical compound consisting only of carbon and oxygen. The simplest and most common oxocarbons are carbon monoxide (CO) and carbon dioxide (). Many other stable (practically if not thermodynamica ...
References
{{Inorganic compounds of carbon
Oxocarbons
Heterocumulenes
Conjugated ketones
Hypothetical chemical compounds