The chemical compound 1,2-dioxetanedione, or 1,2-dioxacyclobutane-3,4-dione, often called peroxyacid ester, is an unstable oxide of carbon (an oxocarbon) with formula C2O4. It can be viewed as a double ketone of 1,2-dioxetane (1,2-dioxacyclobutane), or a cyclic dimer of carbon dioxide.
Recently it has been found that a high-energy intermediate in one of these reactions (between oxalyl chloride and hydrogen peroxide in ethyl acetate), which is presumed to be 1,2-dioxetanedione, can accumulate in solution at room temperature (up to a few micromoles at least), provided that the activating dye and all traces of metals and other reducing agents are removed from the system, and the reactions are carried out in an inert atmosphere.
3D model (JSmol)
|Molar mass||88.018 g·mol−1|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
The chemical substance 1,2-dioxetane (1,2-dioxacyclobutane) is a heterocyclic organic compound with formula C2O2H4, containing a ring of two adjacent oxygen atoms and two adjacent carbon atoms. It is therefore an organic peroxide, and can be viewed as a dimer of formaldehyde (COH2).
In the 1960s, biochemists discovered that some derivatives of 1,2-dioxetane have a fleeting existence as intermediates in the reactions responsible for the bioluminescence in fireflies, glow-worms and other luminescent creatures. The hypothesis could not be proved because these four-membered cyclic peroxides are quite unstable. Then in 1968 the first example of a stable dioxetane derivative was made at the University of Alberta in Edmonton: 3,3,4-trimethyl-1,2-dioxetane, prepared as a yellow solution in benzene. When heated to 333 K, it decomposed smoothly (rather than explosively, as many peroxides do) to acetone and acetaldehyde with the emission of pale blue light.The second example of a dioxetane derivative was made shortly after: the symmetrical compound 3,3,4,4-tetramethyl-1,2-dioxetane, obtained as pale yellow crystals that sublimed even when kept in the refrigerator. Benzene solutions of this compound also decomposed smoothly with the emission of blue light. By adding compounds that normally fluoresce in UV light the colour of the emitted light could be altered.The luminescence of glowsticks and luminescent bangles and necklaces involves 1,2-dioxetanedione (C2O4), another dioxetane derivative that decomposes to carbon dioxide.Other dioxetane derivatives are used in clinical analysis, where their light emission (which can be measured even at very low levels) allows chemists to detect very low concentrations of body fluid constituents.3-Oxetanone
3-Oxetanone, also called oxetan-3-one or 1,3-epoxy-2-propanone, is a chemical compound with formula C3H4O2. It is the
ketone of oxetane, and an isomer of β-propiolactone.
3-Oxetanone is a liquid at room temperature, that boils at 140 °C. It is a specialty chemical, used for research in the synthesis of other oxetanes of pharmacological interest.
Oxetan-3-one also has been the object of theoretical studies.Bis(2,4-dinitrophenyl) oxalate
Bis (2,4-dinitrophenyl) oxalate (DNPO) is a source of 1,2-dioxetanedione, a chemical used in glow sticks. Other chemicals related to DNPO used in glow sticks include bis(2,4,6-trichlorophenyl)oxalate (TCPO) and bis(2,4,5-trichlorophenyl-6-carbopentoxyphenyl)oxalate (CPPO).C2O4
C2O4 may refer to:
Compounds sharing the molecular formula:
1,3-Dioxetanedione (1,3-dioxetane-2,4-dione)Dioxane tetraketone
Dioxane tetraketone (or 1,4-dioxane-2,3,5,6-tetrone) is an organic compound with the formula C4O6. It is an oxide of carbon (an oxocarbon), which can be viewed as the fourfold ketone of dioxane. It can also be viewed as the cyclic dimer of oxiranedione (C2O3), the hypothetical anhydride of oxalic acid.
In 1998, Paolo Strazzolini and others synthesized this compound by reacting oxalyl chloride (COCl)2 or the bromide (COBr)2 with a suspension of silver oxalate (Ag2C2O4) in diethyl ether at −15 °C, followed by evaporation of the solvent at low temperature and pressure. The substance is stable when dissolved in ether and trichloromethane at −30 °C, but decomposes into a 1:1 mixture of carbon monoxide (CO) and carbon dioxide (CO2) upon heating to 0 °C. The stability and conformation of the molecule were also analyzed by theoretical methods.Dioxetanedione
Dioxetanedione may refer to:
In organic chemistry, enone–alkene cycloadditions are a version of the [2+2] cycloaddition This reaction involves an enone and alkene as substrates. Although the concerted photochemical [2+2] cycloaddition is allowed, the reaction between enones and alkenes is stepwise and involves discrete diradical intermediates.Glow stick
A glow stick is a self-contained, short-term light-source. It consists of a translucent plastic tube containing isolated substances that, when combined, make light through chemiluminescence, so it does not require an external energy source. The light cannot be turned off and can only be used once. Glow sticks are often used for recreation, but may also be relied upon for light during military, police, fire, or emergency medical services operations. They are also used by military and police to mark ‘clear’ areas.Oxalic anhydride
Oxalic anhydride or ethanedioic anhydride, also called oxiranedione, is a hypothetical organic compound with the formula C2O3, which can be viewed as the anhydride of oxalic acid or the two-fold ketone of ethylene oxide. It is an oxide of carbon (an oxocarbon).
The simple compound apparently has yet to be observed (as of 2009). In 1998, however, Paolo Strazzolini and others have claimed the synthesis of dioxane tetraketone (C4O6), which can be viewed as the cyclic dimer of oxalic anhydride.It has been conjectured to be a fleeting intermediate in the thermal decomposition of certain oxalates and certain chemoluminescent reactions of oxalyl chloride.Oxocarbon
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 (CO2) with IUPAC names carbon(II) oxide and carbon(IV) oxide respectively. Many other stable (practically if not thermodynamically) or metastable oxides of carbon are known, but they are rarely encountered, such as carbon suboxide (C3O2 or O=C=C=C=O) and mellitic anhydride (C12O9).
While textbooks will often list only the first three, and rarely the fourth, a large number of other oxides are known today, most of them synthesized since the 1960s. Some of these new oxides are stable at room temperature. Some are metastable or stable only at very low temperatures, but decompose to simpler oxocarbons when warmed. Many are inherently unstable and can be observed only momentarily as intermediates in chemical reactions or are so reactive that they can exist only in the gas phase or under matrix isolation conditions.
The inventory of oxocarbons appears to be steadily growing. The existence of graphene oxide and of other stable polymeric carbon oxides with unbounded molecular structures suggests that many more remain to be discovered.Oxocarbon anion
In chemistry, an oxocarbon anion is a negative ion consisting solely of carbon and oxygen atoms, and therefore having the general formula CxOn−y for some integers x, y, and n.
The most common oxocarbon anions are carbonate, CO2−3, and oxalate, C2O2−4. There is however a large number of stable anions in this class, including several ones that have research or industrial use. There are also many unstable anions, like CO−2 and CO−4, that have a fleeting existence during some chemical reactions; and many hypothetical species, like CO4−4, that have been the subject of theoretical studies but have yet to be observed.
Stable oxocarbon anions form salts with a large variety of cations. Unstable anions may persist in very rarefied gaseous state, such as in interstellar clouds. Most oxocarbon anions have corresponding moieties in organic chemistry, whose compounds are usually esters. Thus, for example, the oxalate moiety [–O–(C=O)2–O–] occurs in the ester dimethyl oxalate H3C–O–(C=O)2–O–CH3.Peroxyoxalate
Peroxyoxalates are esters initially formed by the reaction of hydrogen peroxide with oxalate diesters or oxalyl chloride, with or without base, although the reaction is much faster with base:
Peroxyoxalates are intermediates that will rapidly transform into 1,2-dioxetanedione, another high-energy intermediate. The likely mechanism of 1,2-dioxetanedione formation from peroxyoxalate in base is illustrated below:
1,2-Dioxetanedione will rapidly decompose into carbon dioxide (CO2). If there is no fluorescer present, only heat will be released. However, in the presence of a fluorescer, light can be generated (chemiluminescence).
Peroxyoxalate chemiluminescence (CL) was first reported by Rauhut in 1967  in the reaction of diphenyl oxalate. The emission is generated by the reaction of an oxalate ester with hydrogen peroxide in the presence of a suitably fluorescent energy acceptor. This reaction is used in glow sticks.
The three most widely used oxalates are bis(2,4,6-trichlorophenyl)oxalate (TCPO), Bis(2,4,5-trichlorophenyl-6-carbopentoxyphenyl)oxalate (CPPO) and bis(2,4-dinitrophenyl) oxalate (DNPO). Other aryl oxalates have been synthesized and evaluated with respect to their possible analytical applications . Divanillyl oxalate, a more eco-friendly or "green" oxalate for chemiluminescence, decomposes into the nontoxic, biodegradable compound vanillin and works in nontoxic, biodegradable triacetin  . Peroxyoxalate CL is an example of indirect or sensitized chemiluminescence in which the energy from an excited intermediate is transferred to a suitable fluorescent molecule, which relaxes to the ground state by emitting a photon. Rauhut and co-workers have reported that the intermediate responsible for providing the energy of excitation is 1,2-dioxetanedione [1,3]. The peroxyoxalate reaction is able to excite many different compounds, having emissions spanning the visible and infrared regions of the spectrum [3,4], and the reaction can supply up to 440 kJ mol-1, corresponding to excitation at 272 nm . It has been found, however, that the chemiluminescence intensity corrected for quantum yield decreases as the singlet excitation energy of the fluorescent molecule increases . There is also a linear relationship between the corrected chemiluminescence intensity and the oxidation potential of the molecule . This suggests the possibility of an electron transfer step in the mechanism, as demonstrated in several other chemiluminescence systems [7-10]. It has been postulated that a transient charge transfer complex is formed between the intermediate 1,2-dioxetanedione and the fluorescer , and a modified mechanism was proposed involving the transfer of an electron from the fluorescer to the reactive intermediate . The emission of light is thought to result from the annihilation of the fluorescer radical cation with the carbon dioxide radical anion formed when the 1,2-dioxetanedione decomposes . This process is called chemically induced electron exchange luminescence (CIEEL).
Chemiluminescent reactions are widely used in analytical chemistry [14, 15]Woodward–Hoffmann rules
The Woodward–Hoffmann rules (or the pericyclic selection rules), devised by Robert Burns Woodward and Roald Hoffmann, are a set of rules used to rationalize or predict certain aspects of the stereochemistry and activation energy of pericyclic reactions, an important class of reactions in organic chemistry. The Woodward–Hoffmann rules are a consequence of the changes in electronic structure that occur during a pericyclic reaction and are predicated on the phasing of the interacting molecular orbitals. They are applicable to all classes of pericyclic reactions (and their microscopic reverse 'retro' processes), including (1) electrocyclizations, (2) cycloadditions, (3) sigmatropic reactions, (4) group transfer reactions, (5) ene reactions, (6) cheletropic reactions, and (7) dyotropic reactions. Due to their elegance, simplicity, and generality, the Woodward–Hoffmann rules are credited with first exemplifying the power of molecular orbital theory to experimental chemists.Woodward and Hoffmann developed the pericyclic selection rules by examining correlations between reactant and product orbitals (i.e., how reactant and product orbitals are related to each other by continuous geometric distortions that are functions of the reaction coordinate). They identified the conservation of orbital symmetry as a crucial theoretical principle that dictates the outcome (or feasibility) of a pericyclic process. Other theoretical approaches that lead to the same selection rules have also been advanced. Hoffmann was awarded the 1981 Nobel Prize in Chemistry for elucidating the importance of orbital symmetry in pericyclic reactions, which he shared with Kenichi Fukui. Fukui developed a similar set of ideas within the framework of frontier molecular orbital (FMO) theory. Because Woodward had died two years before, he was not eligible to win what would have been his second Nobel Prize in Chemistry.
|Compounds derived from oxides|