472:
is aptly referred to as the SOMO, or the Singly-Occupied
Molecular Orbital. For an electron-donating group, the SOMO interacts with the lower energy lone pair to form a new lower-energy filled bonding-orbital and a singly-filled new SOMO, higher in energy than the original. While the energy of the unpaired electron has increased, the decrease in energy of the lone pair forming the new bonding orbital outweighs the increase in energy of the new SOMO, resulting in a net decrease of the energy of the molecule. Therefore, electron-donating groups help stabilize radicals.
561:
508:
426:, when the R−H bond strength is weaker than the appropriate C−H bond of alkane." "Persistent should be used to describe a radical that has a lifetime that is significantly greater than methyl under the same condition." While relationships between thermodynamic stability and kinetic persistency is highly case-dependent, organic radicals can be generally stabilized by any or all of these factors: the presence of electronegativity, delocalization, and steric hindrance. The compound
422:
are known for their weak benzylic C−H bond strength, are thermodynamically stabilized due to resonance delocalization. However, these radicals are kinetically transient because they can undergo rapid, diffusion-limited dimerization, resulting in a lifetime that is less than a few nanoseconds. To avoid confusion, particularly for carbon-centered radicals, Griller and Ingold introduced the following definitions: "Stabilized should be used to describe a carbon-centered radical, R
491:. In radical chemistry, radicals are stabilized by hyperconjugation with adjacent alkyl groups. The donation of sigma (σ) C−H bonds into the partially empty radical orbitals helps to differentiate the stabilities of radicals on tertiary, secondary, and primary carbons. Tertiary carbon radicals have three σ C-H bonds that donate, secondary radicals only two, and primary radicals only one. Therefore, tertiary radicals are the most stable and primary radicals the least stable.
476:
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2304:, who won the Nobel prize for his research into the electron structure and geometry of radicals, suggested a looser definition of free radicals: "any transient (chemically unstable) species (atom, molecule, or ion)". The main point of his suggestion is that there are many chemically unstable molecules that have zero spin, such as C
2172:
451:
The delocalization of electrons across the structure of a radical, also known as its ability to form one or more resonance structures, allows for the electron deficiency to be spread over several atoms, minimizing instability. Delocalization usually occurs in the presence of electron-donating groups,
421:
The generation and reactivity of organic radicals are dependent on both their thermodynamic stability and kinetic stability, also known as the persistency. This distinction is necessary because these two types of stability do not always correlate with each other. For example, benzylic radicals, which
471:
as a lens, more specifically, by examining the intramolecular interaction of the unpaired electron with a donating group's pair of electrons or the empty π* orbital of an electron-withdrawing group in the form of a molecular orbital diagram. The HOMO of a radical is singly-occupied hence the orbital
544:
The stability of many (or most) organic radicals is not indicated by their isolability but is manifested in their ability to function as donors of H. This property reflects a weakened bond to hydrogen, usually O−H but sometimes N−H or C−H. This behavior is important because these H donors serve as
483:
With a group that is instead electron-withdrawing, the SOMO then interacts with the empty π* orbital. There are no electrons occupying the higher energy orbital formed, while a new SOMO forms that is lower in energy. This results in a lower energy and higher stability of the radical species. Both
386:
Radical elimination can be viewed as the reverse of radical addition. In radical elimination, an unstable radical compound breaks down into a spin-paired molecule and a new radical compound. Shown below is an example of a radical elimination reaction, where a benzoyloxy radical breaks down into a
442:
Electronegativity also factors into the stability of carbon atoms of different hybridizations. Greater s-character correlates to higher electronegativity of the carbon atom (due to the close proximity of s orbitals to the nucleus), and the greater the electronegativity the less stable a radical.
797:
of the material. Once the combustible material has been consumed, termination reactions again dominate and the flame dies out. As indicated, promotion of propagation or termination reactions alters flammability. For example, because lead itself deactivates radicals in the gasoline-air mixture,
438:
Organic radicals are inherently electron deficient thus the greater the electronegativity of the atom on which the unpaired electron resides the less stable the radical. Between carbon, nitrogen, and oxygen, for example, carbon is the most stable and oxygen the least stable.
1816:, which may act to regulate localized tissue inflammatory and/or healing responses, pain perception, and the proliferation of malignant cells. Radical attacks on arachidonic acid and docosahexaenoic acid produce a similar but broader array of signaling products.
2237:
was described as consisting of a methyl "radical" and a hydroxyl "radical". Neither are radicals in the modern chemical sense, as they are permanently bound to each other, and have no unpaired, reactive electrons; however, they can be observed as radicals in
198:
and their reaction products regulate many processes, such as control of vascular tone and thus blood pressure. They also play a key role in the intermediary metabolism of various biological compounds. Such radicals can even be messengers in a process dubbed
2416:
cleavage of the breaking bond is drawn with a "fish-hook" arrow to distinguish from the usual movement of two electrons depicted by a standard curly arrow. The second electron of the breaking bond also moves to pair up with the attacking radical electron.
258:
Some homolysis reactions are particularly important because they serve as an initiator for other radical reactions. One such example is the homolysis of halogens, which occurs under light and serves as the driving force for radical halogenation reactions.
1956:. They derive from molecular oxygen under reducing conditions. However, because of their reactivity, these same radicals can participate in unwanted side reactions resulting in cell damage. Excessive amounts of these radicals can lead to cell injury and
3078:
Floyd, R.A. (1999). "Neuroinflammatory processes are important in neurodegenerative diseases: An hypothesis to explain the increased formation of reactive oxygen and nitrogen species as major factors involved in neurodegenerative disease development".
3270:
Serpone, N; Salinaro, A; Emeline, AV; Horikoshi, S; Hidaka, H; Zhao, JC (2002). "An in vitro systematic spectroscopic examination of the photostabilities of a random set of commercial sunscreen lotions and their chemical UVB/UVA active agents".
2455:
reactions are those that result in a net increase in the number of radicals. They may involve the formation of radicals from stable species as in
Reaction 1 above or they may involve reactions of radicals with stable species to form more
370:, a radical adds to a spin-paired substrate. When applied to organic compounds, the reaction usually entails addition to an alkene. This addition generates a new radical, which can add to yet another alkene, etc. This behavior underpins
3140:
Rajamani
Karthikeyan; Manivasagam T; Anantharaman P; Balasubramanian T; Somasundaram ST (2011). "Chemopreventive effect of Padina boergesenii extracts on ferric nitrilotriacetate (Fe-NTA)-induced oxidative damage in Wistar rats".
2392:
2491:
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1638:
786:". This presents an additional barrier to the reaction. It also means molecular oxygen is relatively unreactive at room temperature except in the presence of a catalytic heavy atom such as iron or copper.
2033:
has been found to form radicals in sunlight, and therefore may be associated with cell damage as well. This only occurred when it was combined with other ingredients commonly found in sunscreens, like
247:
makes two new radicals from a spin-paired molecule by breaking a covalent bond, leaving each of the fragments with one of the electrons in the bond. Because breaking a chemical bond requires energy,
521:
Most simply, the greater the steric hindrance the more difficult it is for reactions to take place, and the radical form is favored by default. For example, compare the hydrogen-abstracted form of
3365:
Desvals, Arthur; Fortino, Mariagrazia; Lefebvre, Corentin; Rogier, Johann; Michelin, Clément; Alioui, Samy; Rousset, Elodie; Pedone, Alfonso; Lemercier, Gilles; Hoffmann, Norbert (2022-05-16).
532:. TEMPO, or (2,2,6,6-Tetramethylpiperidin-1-yl)oxyl, is too sterically hindered by the additional methyl groups to react making it stable enough to be sold commercially in its radical form.
2316:
and so on. This definition is more convenient for discussions of transient chemical processes and astrochemistry; therefore researchers in these fields prefer to use this loose definition.
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products that serve as signaling molecules that may trigger responses that counter the tissue injury which caused their formation. ROS attacks other polyunsaturated fatty acids, e.g.
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2159:
and triplet excited state of a photosensitizer. Typical chemical transformations with this singlet dioxygen species involve, among others, conversion of cellulosic biowaste into new
1552:
1080:
2157:
2107:
1724:
837:
reactions are initiated by radicals. Polymerization involves an initial radical adding to non-radical (usually an alkene) to give new radicals. This process is the basis of the
262:
Another notable reaction is the homolysis of dibenzoyl peroxide, which results in the formation of two benzoyloxy radicals and acts as an initiator for many radical reactions.
579:
With regard to main group radicals, the most abundant radical in the universe is also the most abundant chemical in the universe, H. Most main group radicals are not however
2902:
Linde, C.; Åkermark, B.; Norrby, P.-O.; Svensson, M. (1999). "Timing is
Critical: Effect of Spin Changes on the Diastereoselectivity in Mn(Salen)-Catalyzed Epoxidation".
685:". The diradical state of oxygen also results in its paramagnetic character, which is demonstrated by its attraction to an external magnet. Diradicals can also occur in
553:). The tocopherol radical itself is insufficiently stable for isolation, but the parent molecule is a highly effective hydrogen-atom donor. The C−H bond is weakened in
2468:
reactions are those reactions resulting in a net decrease in the number of radicals. Typically two radicals combine to form a more stable species, for example:
443:
sp-hybridized carbons (50% s-character) form the least stable radicals compared to sp-hybridized carbons (25% s-character) which form the most stable radicals.
430:
illustrates the combination of all three factors. It is a commercially available solid that, aside from being magnetic, behaves like a normal organic compound.
1858:
Because radicals are necessary for life, the body has a number of mechanisms to minimize radical-induced damage and to repair damage that occurs, such as the
793:
of a given material strongly depends on the concentration of radicals that must be obtained before initiation and propagation reactions dominate leading to
3415:
Kharasch, M. S. (1933). "The
Peroxide Effect in the Addition of Reagents to Unsaturated Compounds. I. The Addition of Hydrogen Bromide to Allyl Bromide".
1788:
Radicals play important roles in biology. Many of these are necessary for life, such as the intracellular killing of bacteria by phagocytic cells such as
650: ° of +243 kJ/mol. For weak bonds, homolysis can be induced thermally. Strong bonds require high energy photons or even flames to induce homolysis.
2194:. The qualifier "free" was then needed to specify the unbound case. Following recent nomenclature revisions, a part of a larger molecule is now called a
2330:
2292:
In most fields of chemistry, the historical definition of radicals contends that the molecules have nonzero electron spin. However, in fields including
2324:
In chemical equations, radicals are frequently denoted by a dot placed immediately to the right of the atomic symbol or molecular formula as follows:
255:
associated with homolysis depends on the stability of a given compound, and some weak bonds are able to homolyze at relatively lower temperatures.
190:, and many other chemical processes. A majority of natural products are generated by radical-generating enzymes. In living organisms, the radicals
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2739:
2610:
215:
Radicals are either (1) formed from spin-paired molecules or (2) from other radicals. Radicals are formed from spin-paired molecules through
167:
are known to produce radicals. Radicals are intermediates in many chemical reactions, more so than is apparent from the balanced equations.
2218:
334:
generates radicals. To achieve this reaction, the C-H bond of the H-atom donor must be weak, which is rarely the case in organic compounds.
782:
between these must be overcome. This barrier can be overcome by heat, requiring high temperatures. The triplet-singlet transition is also "
536:-Hydroxypiperidine, however, does not have the four methyl groups to impede the way of a reacting molecule so the structure is unstable.
1839:, is typically associated with a constellation of free-radical-related symptoms including movement disorder, psychosis, skin pigmentary
1395:
2803:
1575:
1746:, especially since the chlorine radical is free to engage in another reaction chain; consequently, the use of chlorofluorocarbons as
3495:
3178:"Neuroprotecin D1: A docosahexanoic acid-derived docosatriene protects human retinal pigment epithelial cells from oxidative stress"
802:
was once commonly added to gasoline. This prevents the combustion from initiating in an uncontrolled manner or in unburnt residues (
294:. Typically one-electron reduced organic compounds are unstable. Stability is conferred to the radical anion when the charge can be
576:
A large variety of inorganic radicals are stable and in fact isolable. Examples include most first-row transition metal complexes.
3510:
2221:. A radical was then identified as the root base of certain acids (the Latin word "radix" meaning "root"). Historically, the term
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1759:
913:
of source molecules produces other radicals. In the lower atmosphere, important radical are produced by the photodissociation of
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2210:
2053:
1809:
3113:
An overview of the role of radicals in biology and of the use of electron spin resonance in their detection may be found in
2182:
Until late in the 20th century the word "radical" was used in chemistry to indicate any connected group of atoms, such as a
219:
of weak bonds or electron transfer, also known as reduction. Radicals are formed from other radicals through substitution,
3537:
2057:
1813:
35:
2000:
are also attributed to radical induced oxidation of cholesterol to 7-ketocholesterol. In addition radicals contribute to
2229:
was also used for bound parts of the molecule, especially when they remain unchanged in reactions. These are now called
2118:
686:
31:
701:
in their triplet state can be viewed as diradicals centred on the same atom, while these are usually highly reactive
2535:
2045:
1330:
1203:
1103:
3547:
2278:
846:
498:
The relative stabilities of tertiary, secondary, primary and methyl radicals can be explained by hyperconjugation
331:
2813:. Cyclic and Heterocyclic Thiazenes (section). Progress in Inorganic Chemistry. Vol. 36. pp. 299–391.
2191:
2114:
690:
623:
468:
252:
2693:
Monroe, Bruce M.; Weed, Gregory C. (1993). "Photoinitiators for free-radical-initiated photoimaging systems".
957:
3314:
Njie-Mbye, Ya Fatou; Kulkarni-Chitnis, Madhura; Opere, Catherine A.; Barrett, Aaron; Ohia, Sunny E. (2013).
3027:
Njie-Mbye, Ya Fatou; Kulkarni-Chitnis, Madhura; Opere, Catherine A.; Barrett, Aaron; Ohia, Sunny E. (2013).
2250:
2124:
2074:
1929:
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838:
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204:
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841:. The art of polymerization entails the method by which the initiating radical is introduced. For example,
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2038:
1894:
1870:
1820:
1661:
371:
3367:"Synthesis and characterization of polymethine dyes carrying thiobarbituric and carboxylic acid moieties"
2658:
Gridnev, Alexei A.; Ittel, Steven D. (2001). "Catalytic Chain
Transfer in Free-Radical Polymerizations".
3542:
2462:
reactions are those reactions involving radicals in which the total number of radicals remains the same.
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2413:
1969:
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865:
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818:
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are diradicals. Their chemical properties are distinct from the properties of their singlet analogues.
560:
3189:
2425:
2065:
1944:, commonly associated with cell damage. ROS form as a natural by-product of the normal metabolism of
1862:
2190:, whether it was part of a larger molecule or a molecule on its own. A radical is often known as an
507:
3557:
2508:
2016:
1905:
can act as antioxidants to help neutralize certain radicals. Bilirubin comes from the breakdown of
1844:
1797:
842:
813:
When a hydrocarbon is burned, a large number of different oxygen radicals are involved. Initially,
783:
522:
512:
299:
283:
68:
2202:, and "radical" now implies "free". However, the old nomenclature may still appear in some books.
789:
Combustion consists of various radical chain reactions that the singlet radical can initiate. The
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and alkyd paints harden due to radical crosslinking initiated by oxygen from the atmosphere.
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2724:, Lecture Notes in Chemistry, vol. 82, Berlin, Heidelberg: Springer, pp. 137–183,
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2301:
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1953:
1941:
1917:, which could eventually damage the central nervous system, while too much uric acid causes
914:
873:
869:
822:
694:
673:, the lowest-energy non-radical state of dioxygen, is less stable than the diradical due to
583:, despite their intrinsic stability. Hydrogen radicals for example combine eagerly to form H
488:
183:
122:
76:
53:
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459:
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2539:
1997:
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57:
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Reactive oxygen species are also used in controlled reactions involving singlet dioxygen
592:
3193:
931:
formation—and the photodissociation of ozone to give the excited oxygen atom O(1D) (see
129:), a molecule that has one unpaired electron on the oxygen atom. Two other examples are
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3342:
3315:
3055:
3028:
3004:
2979:
2955:
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2226:
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2001:
1948:
and have important roles in cell signaling. Two important oxygen-centered radicals are
1906:
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834:
779:
775:
771:
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729:
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639:
295:
179:
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130:
27:
Atom, molecule, or ion that has an unpaired valence electron; typically highly reactive
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64:
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3401:
2889:
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2286:
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1828:
1805:
884:
615:
347:
3316:"Lipid peroxidation: pathophysiological and pharmacological implications in the eye"
3300:
3162:
3029:"Lipid peroxidation: pathophysiological and pharmacological implications in the eye"
1764:
2436:
involving radicals can usually be divided into three distinct processes. These are
2293:
918:
900:
814:
790:
767:
681:
nature of the triplet-singlet transition required for it to grab electrons, i.e., "
588:
195:
187:
164:
2387:{\displaystyle \mathrm {Cl} _{2}\;\xrightarrow {UV} \;2{\mathrm {Cl} ^{\bullet }}}
390:
1881:
play a key role in these defense mechanisms. These are often the three vitamins,
1784:, which constitutes about 30% of plant matter. It is formed by radical reactions.
860:
Radical intermediates in the formation of polymethacrylate (plexiglas or perspex)
2757:
Griller, David; Ingold, Keith U. (1976). "Persistent carbon-centered radicals".
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2569:
2552:
2199:
1878:
1789:
1747:
1743:
807:
408:
236:
2995:
2404:
1776:
1294:
is an important source of radicals (see eq. 1 below). These reactions give the
48:
41:
This article is about free radicals. For radicals within larger molecules, see
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2030:
1993:
1989:
1949:
1933:
1848:
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888:
794:
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such as hydroxyl groups (−OH), ethers (−OR), adjacent alkenes, and amines (−NH
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343:
303:
191:
171:
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17:
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2009:
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Radicals may be generated in a number of ways, but typical methods involve
3490:
G. Herzberg (1971), "The spectra and structures of simple free radicals",
2600:
883:
reacts with many organic compounds to generate radicals together with the
3459:
2720:
Su, Wei-Fang (2013), Su, Wei-Fang (ed.), "Radical Chain
Polymerization",
2234:
2187:
1985:
1973:
1914:
1866:
1852:
1824:
1295:
677:. The relative stability of the oxygen diradical is primarily due to the
662:
479:
Molecular orbital diagram of a radical with an electron-withdrawing group
220:
99:
3428:
3117:
Toxicology of the Human
Environment – the critical role of free radicals
2770:
2706:
2527:
323:
3385:
2492:
Globally
Harmonized System of Classification and Labelling of Chemicals
2408:
Example of an arrow-pushing mechanism for an internal radical reaction.
2213:
introduced the phrase "radical" in 1785 and the phrase was employed by
2171:
1840:
909:
The most common radical in the lower atmosphere is molecular dioxygen.
713:
709:
705:
are known, with N-heterocyclic carbenes being the most common example.
698:
375:
335:
265:
3176:
Mukherjee, P.K.; Marcheselli, V.L.; Serhan, C.N.; Bazan, N.G. (2004).
2946:
2915:
2860:. Advances in Heterocyclic Chemistry. Vol. 62. pp. 137–247.
2671:
1286:
In the upper atmosphere, the photodissociation of normally unreactive
463:
Molecular orbital diagram of a radical with an electron-donating group
110:. With some exceptions, these unpaired electrons make radicals highly
3284:
2929:
Broderick, J.B.; Duffus, B.R.; Duschene, K.S.; Shepard, E.M. (2014).
2509:
ARC Centre of
Excellence for Free Radical Chemistry and Biotechnology
2401:
use single-headed arrows to depict the movement of single electrons:
2183:
1977:
1965:
1961:
1945:
1910:
1859:
1781:
868:. Variants include reversible addition-fragmentation chain transfer (
755:
734:
327:
Radical abstraction between a benzoyloxy radical and hydrogen bromide
2354:
1688:
1514:
1343:
1142:
980:
338:
and especiall doubly allylic C-H bonds are prone to abstraction by O
2403:
2170:
2012:
2005:
1957:
1855:
suggests that repeated exposure to radicals may extend life span.
1775:
1763:
1463:{\displaystyle {\ce {Cl^{\bullet }{}+O3->ClO^{\bullet }{}+O2}}}
1299:
855:
766:
of the electrons are parallel, this molecule is stable. While the
728:
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559:
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506:
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474:
458:
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322:
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47:
1633:{\displaystyle {\ce {O{}+ClO^{\bullet }->Cl^{\bullet }{}+O2}}}
269:
Homolysis of dibenzoyl peroxide producing two benzoyloxy radicals
2020:
1918:
95:
3444:"Radicals: Reactive Intermediates with Translational Potential"
2008:
damage, perhaps more than alcohol itself. Radicals produced by
1980:
are thought to be the result of reactions between radicals and
1843:
abnormalities, deafness, arthritis, and diabetes mellitus. The
1981:
1835:. The classic free-radical syndrome, the iron-storage disease
240:
Homolysis of a bromine molecule producing two bromine radicals
103:
591:(NO) is well known example of an isolable inorganic radical.
456:
or −NR), or electron-withdrawing groups, such as C=O or C≡N.
362:
Radical addition of a bromine radical to a substituted alkene
2599:
Clayden, Jonathan; Greeves, Nick; Warren, Stuart G. (2012).
1992:
and potentially lead to malignancy. Some of the symptoms of
2858:
The Chemistry of Dithiadiazolylium and Dithiadiazolyl Rings
2242:
when broken apart by irradiation with energetic electrons.
487:
Another well-known albeit weaker form of delocalization is
484:
donating groups and withdrawing groups stabilize radicals.
3182:
Proceedings of the National Academy of Sciences of the USA
2205:
The term radical was already in use when the now obsolete
737:
torch showing excited molecular radical band emission and
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antioxidants in biology and in commerce. Illustrative is
30:"Free radical" redirects here. For the aging theory, see
849:(PMMA – Plexiglas or Perspex) via a repeating series of
2980:"Nitric oxide and peroxynitrite in health and disease"
2553:"Superoxide Ion: Generation and Chemical Implications"
1909:' contents, while uric acid is a breakdown product of
1897:. Furthermore, there is good evidence indicating that
394:
A radical elimination reaction of a benzoyloxy radical
2333:
2127:
2077:
2068:, to produce a similar series of signaling products.
1664:
1578:
1494:
1398:
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below). The net and return reactions are also shown (
630: °" are a measure of bond strength. Splitting H
467:
Delocalization effects can also be understood using
817:(HOO) are formed. These then react further to give
778:) state is available. For combustion to occur, the
614:Many radicals can be envisioned as the products of
3235:Lyons, MA; Brown, AJ (1999). "7-Ketocholesterol".
2386:
2151:
2101:
1718:
1632:
1546:
1462:
1366:
1262:
1174:
1074:
1002:
864:Newer radical polymerization methods are known as
2605:(2nd ed.). Oxford: Oxford University Press.
2277:proposed that free radicals were responsible for
669:) is an important example of a stable diradical.
1960:, which may contribute to many diseases such as
774:) diradical, an extremely reactive spin-paired (
607:radicals are known, despite limited extent of π
251:occurs under the addition of heat or light. The
3442:Yan, M; Lo, JC; Edwards, JT; Baran, PS (2016).
2551:Hayyan, M.; Hashim, M.A.; Anjkut, I.M. (2016).
2249:(carbon–containing) radical identified was the
1298:radical, Cl, which catalyzes the conversion of
1367:{\displaystyle {\ce {CFCS->Cl^{\bullet }}}}
1263:{\displaystyle {\ce {NO + O3 -> NO2 + O2}}}
1175:{\displaystyle {\ce {NO2 + O2 -> NO + O3}}}
661:are molecules containing two radical centers.
387:phenyl radical and a carbon dioxide molecule.
118:. Most organic radicals have short lifetimes.
3508:28th International Symposium on Free Radicals
2892:does not necessarily imply radical character.
2178:(1866–1947), the founder of radical chemistry
1847:of aging proposes that radicals underlie the
286:results from the lithium naphthanide radical.
8:
3273:Photochemical & Photobiological Sciences
2856:Rawson, J; Banister, A; Lavender, I (1995).
872:) and atom transfer radical polymerization (
770:of oxygen is this unreactive spin-unpaired (
227:Radical formation from spin-paired molecules
2023:. This process promotes the development of
2722:Principles of Polymer Design and Synthesis
2363:
2349:
1913:. Too much bilirubin, though, can lead to
1742:Such reactions cause the depletion of the
567:is an example of a robust organic radical.
290:Classically radicals form by one-electron
3467:
3341:
3331:
3211:
3201:
3054:
3044:
3003:
2954:
2789:Organic Chemistry of Stable Free Radicals
2729:
2568:
2377:
2369:
2367:
2343:
2335:
2332:
2143:
2138:
2131:
2129:
2126:
2093:
2088:
2081:
2079:
2076:
1711:
1706:
1701:
1683:
1679:
1674:
1669:
1665:
1663:
1625:
1620:
1611:
1605:
1592:
1583:
1579:
1577:
1539:
1534:
1509:
1505:
1500:
1495:
1493:
1455:
1450:
1441:
1435:
1424:
1419:
1410:
1404:
1399:
1397:
1357:
1338:
1334:
1332:
1255:
1250:
1239:
1234:
1223:
1218:
1207:
1205:
1167:
1162:
1137:
1133:
1128:
1117:
1112:
1107:
1105:
1067:
1062:
1051:
1046:
1035:
1033:
975:
971:
966:
961:
959:
3417:Journal of the American Chemical Society
2978:Pacher P, Beckman JS, Liaudet L (2007).
2904:Journal of the American Chemical Society
2300:, the definition is slightly different.
1003:{\displaystyle {\ce {NO2 -> NO + O}}}
634:into 2 H, for example, requires a Δ
2791:. London: Academic Press. pp. 1–6.
2519:
1547:{\displaystyle {\ce {O3 -> O + O2}}}
1075:{\displaystyle {\ce {O + O2 -> O3}}}
2931:"Radical S-Adenosylmethionine Enzymes"
2152:{\displaystyle {}^{3}\mathrm {O} _{2}}
2102:{\displaystyle {}^{1}\mathrm {O} _{2}}
1851:itself. Similarly, the process of mito
121:A notable example of a radical is the
60:shown, contains one unpaired electron.
1719:{\displaystyle {\ce {2O3 -> 3O2}}}
314:Radical formation from other radicals
152:) which have two unpaired electrons.
7:
2782:
2780:
2752:
2750:
2594:
2592:
2590:
2588:
1772:, a common biosynthetic intermediate
1655:
1569:
1485:
1389:
1324:
1197:
1097:
1025:
951:
845:(MMA) can be polymerized to produce
746:Combustion § Reaction mechanism
689:, lending themselves for studies of
203:. A radical may be trapped within a
2804:"Cyclic and Heterocyclic Thiazenes"
1976:and major disorders. Many forms of
762:, best represented by O–O. Because
675:Hund's rule of maximum multiplicity
595:(Potassium nitrosodisulfonate, (KSO
163:, heat, electrical discharges, and
2373:
2370:
2339:
2336:
2265:C. This species was discovered by
2139:
2089:
2015:are implicated in inactivation of
927:below), which plays a key role in
733:Spectrum of the blue flame from a
565:2,2,6,6-Tetramethylpiperidinyloxyl
428:2,2,6,6-tetramethylpiperidinyloxyl
25:
3081:Free Radical Biology and Medicine
1819:Radicals may also be involved in
1804:. For example, radical attack of
1318:
1312:
945:
939:
933:
923:
2121:) from natural triplet dioxygen
1760:Dioxygen in biological reactions
374:, technology that produces many
342:. This reaction is the basis of
298:. Examples include alkali metal
2811:Progress in Inorganic Chemistry
2320:Depiction in chemical reactions
2211:Louis-Bernard Guyton de Morveau
1810:13-hydroxyoctadecadienoic acids
750:A familiar radical reaction is
603:NO) is a related example. Many
3119:. London: Taylor and Francis.
2245:In a modern context the first
2054:13-hydroxyoctadecadienoic acid
1988:that can adversely affect the
1814:9-hydroxyoctadecadienoic acids
1598:
1428:
1227:
1055:
114:. Many radicals spontaneously
1:
3249:10.1016/s1357-2725(98)00123-x
3093:10.1016/s0891-5849(98)00293-7
2866:10.1016/S0065-2725(08)60422-5
2759:Accounts of Chemical Research
2058:9-hydroxyoctadecadienoic acid
866:living radical polymerization
404:Stability of organic radicals
223:, and elimination reactions.
36:Free radical (disambiguation)
2219:Traité Élémentaire de Chimie
2119:triplet-triplet annihilation
1780:An approximate structure of
879:Being a prevalent radical, O
32:Free-radical theory of aging
2802:Oakley, Richard T. (1988).
2731:10.1007/978-3-642-38730-2_7
2570:10.1021/acs.chemrev.5b00407
2420:Radicals also take part in
1984:, potentially resulting in
1932:or ROS are species such as
1796:. Radicals are involved in
626:, usually abbreviated as "Δ
3574:
3237:Int. J. Biochem. Cell Biol
2996:10.1152/physrev.00029.2006
2046:polyunsaturated fatty acid
1823:, senile and drug-induced
1757:
898:
743:
624:bond dissociation energies
616:breaking of covalent bonds
170:Radicals are important in
40:
29:
3155:10.1007/s10811-010-9564-0
2819:10.1002/9780470166376.ch4
2279:anti-Markovnikov addition
847:Poly(methyl methacrylate)
806:) or premature ignition (
412:The radical derived from
108:unpaired valence electron
3374:New Journal of Chemistry
3333:10.3389/fphys.2013.00366
3046:10.3389/fphys.2013.00366
2787:Forrester, A.R. (1968).
2497:Hofmann–Löffler reaction
2167:History and nomenclature
691:spin forbidden reactions
646:into two Cl requires a Δ
469:molecular orbital theory
253:bond dissociation energy
3553:Environmental chemistry
3320:Frontiers in Physiology
3203:10.1073/pnas.0402531101
3033:Frontiers in Physiology
2251:triphenylmethyl radical
1930:Reactive oxygen species
1925:Reactive oxygen species
1895:polyphenol antioxidants
609:resonance stabilization
557:(trityl) derivatives.
207:or be otherwise bound.
2529:radical (free radical)
2430:reactive intermediates
2409:
2388:
2179:
2153:
2103:
2052:, to form a series of
2039:octyl methoxycinnamate
1871:glutathione peroxidase
1785:
1773:
1720:
1634:
1548:
1464:
1368:
1264:
1176:
1076:
1004:
917:to an oxygen atom and
861:
839:radical chain reaction
819:organic hydroperoxides
741:
720:Occurrence of radicals
568:
518:
499:
480:
464:
418:
395:
372:radical polymerization
368:free-radical additions
363:
328:
287:
270:
241:
106:that has at least one
79:
61:
34:. For other uses, see
2503:Free radical research
2407:
2389:
2174:
2154:
2104:
1970:myocardial infarction
1875:glutathione reductase
1808:produces a series of
1779:
1770:deoxyadenosyl radical
1767:
1750:has been restricted.
1721:
1635:
1549:
1465:
1369:
1292:ultraviolet radiation
1265:
1177:
1077:
1005:
859:
758:molecule is a stable
732:
563:
510:
497:
478:
462:
411:
393:
361:
326:
281:
268:
239:
176:atmospheric chemistry
67:
51:
3538:Biological processes
3460:10.1021/jacs.6b08856
3115:Rhodes C.J. (2000).
2426:radical substitution
2331:
2125:
2075:
2066:docosahexaenoic acid
1863:superoxide dismutase
1800:processes, known as
1662:
1576:
1492:
1396:
1331:
1306:, thus facilitating
1204:
1104:
1032:
958:
895:Atmospheric radicals
815:hydroperoxyl radical
642:, while splitting Cl
540:Facile H-atom donors
332:Hydrogen abstraction
3454:(39): 12692–12714.
3429:10.1021/ja01333a041
3194:2004PNAS..101.8491M
2771:10.1021/ar50097a003
2707:10.1021/cr00017a019
2639:polymerdatabase.com
2399:reaction mechanisms
2361:
2017:alpha 1-antitrypsin
1845:free-radical theory
1821:Parkinson's disease
1714:
1695:
1682:
1628:
1542:
1521:
1508:
1458:
1427:
1350:
1288:chlorofluorocarbons
1258:
1242:
1226:
1170:
1149:
1136:
1120:
1070:
1054:
987:
974:
843:methyl methacrylate
821:that break up into
703:persistent carbenes
687:metal-oxo complexes
284:lithium naphthalene
282:The deep colour of
112:chemically reactive
69:Lewis dot structure
3513:2007-07-16 at the
3386:10.1039/D2NJ00684G
2635:"Diacyl Peroxides"
2538:2017-03-02 at the
2410:
2384:
2271:Morris S. Kharasch
2180:
2149:
2099:
1786:
1774:
1716:
1702:
1670:
1630:
1616:
1544:
1530:
1496:
1460:
1446:
1415:
1364:
1260:
1246:
1230:
1214:
1172:
1158:
1124:
1108:
1072:
1058:
1042:
1000:
962:
905:Ozone-oxygen cycle
862:
742:
572:Inorganic radicals
569:
526:-hydroxypiperidine
519:
516:-hydroxypiperidine
500:
481:
465:
419:
396:
364:
329:
288:
271:
242:
161:ionizing radiation
90:, also known as a
80:
75:ion compared to a
62:
43:Moiety (chemistry)
3380:(19): 8971–8980.
3126:978-0-7484-0916-7
3087:(9–10): 1346–55.
2947:10.1021/cr4004709
2916:10.1021/ja9809915
2875:978-0-12-020762-6
2828:978-0-470-16637-6
2741:978-3-642-38730-2
2672:10.1021/cr9901236
2666:(12): 3611–3660.
2612:978-0-19-927029-3
2602:Organic chemistry
2362:
2269:in 1900. In 1933
2240:mass spectrometry
2231:functional groups
2215:Antoine Lavoisier
2117:energy transfer (
2109:known as type II
1938:hydrogen peroxide
1768:Structure of the
1740:
1739:
1705:
1696:
1673:
1654:
1653:
1619:
1604:
1591:
1582:
1568:
1567:
1533:
1526:
1522:
1499:
1484:
1483:
1449:
1434:
1418:
1403:
1388:
1387:
1356:
1351:
1337:
1284:
1283:
1249:
1233:
1217:
1210:
1196:
1195:
1161:
1154:
1150:
1127:
1111:
1096:
1095:
1061:
1045:
1038:
1024:
1023:
998:
992:
988:
965:
949:, respectively).
911:Photodissociation
823:hydroxyl radicals
638: ° of +435
434:Electronegativity
16:(Redirected from
3565:
3548:Chemical bonding
3518:
3505:
3499:
3488:
3482:
3481:
3471:
3439:
3433:
3432:
3423:(6): 2468–2496.
3412:
3406:
3405:
3371:
3362:
3356:
3355:
3345:
3335:
3311:
3305:
3304:
3285:10.1039/b206338g
3267:
3261:
3260:
3232:
3226:
3225:
3215:
3205:
3173:
3167:
3166:
3137:
3131:
3130:
3111:
3105:
3104:
3075:
3069:
3068:
3058:
3048:
3024:
3018:
3017:
3007:
2975:
2969:
2968:
2958:
2935:Chemical Reviews
2926:
2920:
2919:
2899:
2893:
2886:
2880:
2879:
2853:
2847:
2846:
2844:
2843:
2837:
2831:. Archived from
2808:
2799:
2793:
2792:
2784:
2775:
2774:
2754:
2745:
2744:
2733:
2717:
2711:
2710:
2695:Chemical Reviews
2690:
2684:
2683:
2660:Chemical Reviews
2655:
2649:
2648:
2646:
2645:
2631:
2625:
2624:
2596:
2583:
2582:
2572:
2548:
2542:
2526:IUPAC Gold Book
2524:
2422:radical addition
2393:
2391:
2390:
2385:
2383:
2382:
2381:
2376:
2350:
2348:
2347:
2342:
2302:Gerhard Herzberg
2283:hydrogen bromide
2196:functional group
2158:
2156:
2155:
2150:
2148:
2147:
2142:
2136:
2135:
2130:
2113:reactions after
2111:photooxygenation
2108:
2106:
2105:
2100:
2098:
2097:
2092:
2086:
2085:
2080:
2062:arachidonic acid
1954:hydroxyl radical
1942:hydroxyl radical
1734:
1725:
1723:
1722:
1717:
1715:
1713:
1710:
1703:
1697:
1684:
1681:
1678:
1671:
1656:
1648:
1639:
1637:
1636:
1631:
1629:
1627:
1624:
1617:
1612:
1610:
1609:
1602:
1597:
1596:
1589:
1584:
1580:
1570:
1562:
1553:
1551:
1550:
1545:
1543:
1541:
1538:
1531:
1524:
1523:
1510:
1507:
1504:
1497:
1486:
1478:
1469:
1467:
1466:
1461:
1459:
1457:
1454:
1447:
1442:
1440:
1439:
1432:
1426:
1423:
1416:
1411:
1409:
1408:
1401:
1390:
1382:
1373:
1371:
1370:
1365:
1363:
1362:
1361:
1354:
1352:
1339:
1335:
1325:
1290:(CFCs) by solar
1278:
1269:
1267:
1266:
1261:
1259:
1257:
1254:
1247:
1241:
1238:
1231:
1225:
1222:
1215:
1208:
1198:
1190:
1181:
1179:
1178:
1173:
1171:
1169:
1166:
1159:
1152:
1151:
1138:
1135:
1132:
1125:
1119:
1116:
1109:
1098:
1090:
1081:
1079:
1078:
1073:
1071:
1069:
1066:
1059:
1053:
1050:
1043:
1036:
1026:
1018:
1009:
1007:
1006:
1001:
999:
996:
990:
989:
976:
973:
970:
963:
952:
915:nitrogen dioxide
851:radical addition
695:transition metal
622:. The homolytic
528:to the molecule
511:Radical form of
503:Steric hindrance
489:hyperconjugation
151:
150:
149:
123:hydroxyl radical
77:hydroxyl radical
54:hydroxyl radical
21:
3573:
3572:
3568:
3567:
3566:
3564:
3563:
3562:
3523:
3522:
3521:
3515:Wayback Machine
3506:
3502:
3489:
3485:
3441:
3440:
3436:
3414:
3413:
3409:
3369:
3364:
3363:
3359:
3313:
3312:
3308:
3269:
3268:
3264:
3243:(3–4): 369–75.
3234:
3233:
3229:
3188:(22): 8491–96.
3175:
3174:
3170:
3143:J. Appl. Phycol
3139:
3138:
3134:
3127:
3114:
3112:
3108:
3077:
3076:
3072:
3026:
3025:
3021:
2977:
2976:
2972:
2941:(8): 4229–317.
2928:
2927:
2923:
2910:(21): 5083–84.
2901:
2900:
2896:
2887:
2883:
2876:
2855:
2854:
2850:
2841:
2839:
2835:
2829:
2806:
2801:
2800:
2796:
2786:
2785:
2778:
2756:
2755:
2748:
2742:
2719:
2718:
2714:
2692:
2691:
2687:
2657:
2656:
2652:
2643:
2641:
2633:
2632:
2628:
2613:
2598:
2597:
2586:
2550:
2549:
2545:
2540:Wayback Machine
2525:
2521:
2517:
2483:
2474:
2434:Chain reactions
2368:
2334:
2329:
2328:
2322:
2315:
2311:
2307:
2264:
2260:
2256:
2233:. For example,
2217:in 1789 in his
2209:was developed.
2169:
2137:
2128:
2123:
2122:
2087:
2078:
2073:
2072:
2044:ROS attack the
1998:atherosclerosis
1927:
1907:red blood cells
1877:. In addition,
1837:hemochromatosis
1802:redox signaling
1798:cell signalling
1762:
1756:
1732:
1660:
1659:
1646:
1601:
1588:
1574:
1573:
1560:
1490:
1489:
1476:
1431:
1400:
1394:
1393:
1380:
1353:
1329:
1328:
1308:ozone depletion
1305:
1276:
1202:
1201:
1188:
1102:
1101:
1088:
1030:
1029:
1016:
956:
955:
907:
897:
882:
831:
804:engine knocking
800:tetraethyl lead
748:
727:
722:
668:
656:
645:
633:
602:
598:
586:
574:
555:triphenylmethyl
542:
505:
455:
449:
436:
406:
401:
384:
356:
341:
321:
316:
276:
234:
229:
213:
201:redox signaling
157:redox reactions
148:
145:
144:
143:
141:
135:triplet carbene
58:Lewis structure
46:
39:
28:
23:
22:
15:
12:
11:
5:
3571:
3569:
3561:
3560:
3555:
3550:
3545:
3540:
3535:
3525:
3524:
3520:
3519:
3500:
3483:
3434:
3407:
3357:
3306:
3279:(12): 970–81.
3262:
3227:
3168:
3132:
3125:
3106:
3070:
3019:
2990:(1): 315–424.
2970:
2921:
2894:
2881:
2874:
2848:
2827:
2794:
2776:
2746:
2740:
2712:
2685:
2650:
2626:
2611:
2584:
2563:(5): 3029–85.
2543:
2518:
2516:
2513:
2512:
2511:
2505:
2504:
2500:
2499:
2494:
2489:
2482:
2479:
2478:
2477:
2476:
2475:
2472:
2463:
2457:
2395:
2394:
2380:
2375:
2372:
2366:
2360:
2357:
2353:
2346:
2341:
2338:
2321:
2318:
2313:
2309:
2305:
2298:astrochemistry
2262:
2258:
2254:
2235:methyl alcohol
2227:radical theory
2207:radical theory
2168:
2165:
2146:
2141:
2134:
2096:
2091:
2084:
2035:titanium oxide
1926:
1923:
1755:
1752:
1738:
1737:
1728:
1726:
1709:
1700:
1694:
1691:
1687:
1677:
1668:
1652:
1651:
1642:
1640:
1623:
1615:
1608:
1600:
1595:
1587:
1566:
1565:
1556:
1554:
1537:
1529:
1520:
1517:
1513:
1503:
1482:
1481:
1472:
1470:
1453:
1445:
1438:
1430:
1422:
1414:
1407:
1386:
1385:
1376:
1374:
1360:
1349:
1346:
1342:
1303:
1282:
1281:
1272:
1270:
1253:
1245:
1237:
1229:
1221:
1213:
1194:
1193:
1184:
1182:
1165:
1157:
1148:
1145:
1141:
1131:
1123:
1115:
1094:
1093:
1084:
1082:
1065:
1057:
1049:
1041:
1022:
1021:
1012:
1010:
995:
986:
983:
979:
969:
896:
893:
880:
835:polymerization
830:
829:Polymerization
827:
780:energy barrier
744:Main article:
726:
723:
721:
718:
679:spin-forbidden
671:Singlet oxygen
666:
655:
652:
643:
631:
600:
596:
584:
573:
570:
541:
538:
504:
501:
453:
448:
447:Delocalization
445:
435:
432:
405:
402:
400:
397:
383:
380:
355:
352:
339:
320:
317:
315:
312:
275:
272:
233:
230:
228:
225:
212:
209:
180:polymerization
146:
131:triplet oxygen
26:
24:
14:
13:
10:
9:
6:
4:
3:
2:
3570:
3559:
3556:
3554:
3551:
3549:
3546:
3544:
3541:
3539:
3536:
3534:
3533:Free radicals
3531:
3530:
3528:
3516:
3512:
3509:
3504:
3501:
3497:
3496:0-486-65821-X
3493:
3487:
3484:
3479:
3475:
3470:
3465:
3461:
3457:
3453:
3449:
3448:J Am Chem Soc
3445:
3438:
3435:
3430:
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3422:
3418:
3411:
3408:
3403:
3399:
3395:
3391:
3387:
3383:
3379:
3375:
3368:
3361:
3358:
3353:
3349:
3344:
3339:
3334:
3329:
3325:
3321:
3317:
3310:
3307:
3302:
3298:
3294:
3290:
3286:
3282:
3278:
3274:
3266:
3263:
3258:
3254:
3250:
3246:
3242:
3238:
3231:
3228:
3223:
3219:
3214:
3209:
3204:
3199:
3195:
3191:
3187:
3183:
3179:
3172:
3169:
3164:
3160:
3156:
3152:
3149:(2): 257–63.
3148:
3144:
3136:
3133:
3128:
3122:
3118:
3110:
3107:
3102:
3098:
3094:
3090:
3086:
3082:
3074:
3071:
3066:
3062:
3057:
3052:
3047:
3042:
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3023:
3020:
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3011:
3006:
3001:
2997:
2993:
2989:
2985:
2981:
2974:
2971:
2966:
2962:
2957:
2952:
2948:
2944:
2940:
2936:
2932:
2925:
2922:
2917:
2913:
2909:
2905:
2898:
2895:
2891:
2890:paramagnetism
2885:
2882:
2877:
2871:
2867:
2863:
2859:
2852:
2849:
2838:on 2015-09-23
2834:
2830:
2824:
2820:
2816:
2812:
2805:
2798:
2795:
2790:
2783:
2781:
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2747:
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2732:
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2686:
2681:
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2627:
2622:
2618:
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2514:
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2498:
2495:
2493:
2490:
2488:
2487:Electron pair
2485:
2484:
2480:
2470:
2469:
2467:
2464:
2461:
2458:
2454:
2451:
2450:
2449:
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2344:
2327:
2326:
2325:
2319:
2317:
2303:
2299:
2295:
2290:
2288:
2287:allyl bromide
2284:
2280:
2276:
2272:
2268:
2267:Moses Gomberg
2252:
2248:
2243:
2241:
2236:
2232:
2228:
2224:
2220:
2216:
2212:
2208:
2203:
2201:
2197:
2193:
2189:
2185:
2177:
2176:Moses Gomberg
2173:
2166:
2164:
2162:
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2120:
2116:
2112:
2094:
2082:
2069:
2067:
2063:
2059:
2055:
2051:
2050:linoleic acid
2047:
2042:
2040:
2036:
2032:
2028:
2026:
2022:
2018:
2014:
2011:
2007:
2003:
1999:
1995:
1991:
1987:
1983:
1979:
1975:
1971:
1967:
1963:
1959:
1955:
1951:
1947:
1943:
1939:
1935:
1931:
1924:
1922:
1920:
1916:
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1900:
1896:
1892:
1888:
1884:
1880:
1876:
1872:
1868:
1864:
1861:
1856:
1854:
1850:
1849:aging process
1846:
1842:
1838:
1834:
1830:
1829:schizophrenia
1826:
1822:
1817:
1815:
1811:
1807:
1806:linoleic acid
1803:
1799:
1795:
1791:
1783:
1778:
1771:
1766:
1761:
1753:
1751:
1749:
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935:
930:
926:
925:
920:
916:
912:
906:
902:
894:
892:
890:
886:
885:hydroperoxide
877:
875:
871:
867:
858:
854:
852:
848:
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840:
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824:
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704:
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692:
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680:
676:
672:
664:
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653:
651:
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625:
621:
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612:
610:
606:
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577:
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558:
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552:
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537:
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515:
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502:
496:
492:
490:
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473:
470:
461:
457:
446:
444:
440:
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431:
429:
425:
417:
416:
410:
403:
398:
392:
388:
381:
379:
377:
373:
369:
360:
353:
351:
350:derivatives.
349:
348:linoleic acid
345:
337:
333:
325:
318:
313:
311:
309:
305:
304:anthracenides
301:
297:
293:
285:
280:
273:
267:
263:
260:
256:
254:
250:
246:
238:
231:
226:
224:
222:
218:
210:
208:
206:
202:
197:
193:
189:
185:
181:
177:
173:
168:
166:
162:
158:
153:
140:
136:
132:
128:
124:
119:
117:
113:
109:
105:
101:
97:
93:
89:
85:
78:
74:
70:
66:
59:
55:
50:
44:
37:
33:
19:
18:Free Radicals
3543:Biomolecules
3503:
3486:
3451:
3447:
3437:
3420:
3416:
3410:
3377:
3373:
3360:
3323:
3319:
3309:
3276:
3272:
3265:
3240:
3236:
3230:
3185:
3181:
3171:
3146:
3142:
3135:
3116:
3109:
3084:
3080:
3073:
3036:
3032:
3022:
2987:
2984:Physiol. Rev
2983:
2973:
2938:
2934:
2924:
2907:
2903:
2897:
2884:
2857:
2851:
2840:. Retrieved
2833:the original
2810:
2797:
2788:
2762:
2758:
2721:
2715:
2698:
2694:
2688:
2663:
2659:
2653:
2642:. Retrieved
2638:
2629:
2601:
2560:
2556:
2546:
2528:
2522:
2465:
2459:
2452:
2445:
2441:
2437:
2419:
2411:
2396:
2323:
2294:spectroscopy
2291:
2244:
2222:
2204:
2184:methyl group
2181:
2070:
2043:
2029:
1928:
1879:antioxidants
1857:
1818:
1790:granulocytes
1787:
1748:refrigerants
1741:
1730:
1644:
1558:
1474:
1378:
1317:
1311:
1285:
1274:
1186:
1086:
1014:
944:
938:
932:
922:
919:nitric oxide
908:
901:Oxygen cycle
878:
863:
832:
812:
791:flammability
788:
768:ground state
749:
707:
682:
657:
647:
635:
627:
613:
593:Fremy's salt
589:Nitric oxide
580:
578:
575:
547:α-tocopherol
543:
533:
523:
520:
513:
486:
482:
466:
450:
441:
437:
423:
420:
415:α-tocopherol
413:
385:
365:
330:
300:naphthenides
289:
261:
257:
243:
214:
205:solvent cage
196:nitric oxide
188:biochemistry
169:
165:electrolysis
154:
138:
126:
120:
92:free radical
91:
87:
81:
2701:: 435–448.
2466:Termination
2460:Propagation
2446:termination
2442:propagation
2200:substituent
2161:poylmethine
1833:Alzheimer's
1794:macrophages
1744:ozone layer
889:Drying oils
808:preignition
697:chemistry.
382:Elimination
344:drying oils
319:Abstraction
296:delocalized
186:chemistry,
3558:Senescence
3527:Categories
2842:2011-03-31
2644:2020-12-08
2515:References
2453:Initiation
2438:initiation
2275:Frank Mayo
2031:Oxybenzone
1990:cell cycle
1950:superoxide
1934:superoxide
1758:See also:
1754:In biology
899:See also:
795:combustion
752:combustion
739:Swan bands
725:Combustion
659:Diradicals
654:Diradicals
346:, such as
292:reductions
192:superoxide
172:combustion
3402:248165785
3394:1369-9261
2888:However,
2765:: 13–19.
2621:761379371
2557:Chem. Rev
2471:2 Cl → Cl
2456:radicals.
2414:homolytic
2379:∙
2025:emphysema
2010:cigarette
2004:-induced
1986:mutations
1903:uric acid
1899:bilirubin
1891:vitamin E
1887:vitamin C
1883:vitamin A
1693:ν
1607:∙
1599:⟶
1594:∙
1519:ν
1437:∙
1429:⟶
1406:∙
1359:∙
1348:ν
1228:⟶
1147:ν
1056:⟶
985:ν
887:radical.
784:forbidden
760:diradical
620:homolysis
551:vitamin E
399:Stability
274:Reduction
249:homolysis
245:Homolysis
232:Homolysis
217:homolysis
211:Formation
84:chemistry
73:Hydroxide
3511:Archived
3478:27631602
3352:24379787
3301:27248506
3293:12661594
3257:10224662
3222:15152078
3163:27537163
3101:10381209
3065:24379787
3014:17237348
2965:24476342
2680:11740917
2579:26875845
2536:Archived
2481:See also
2397:Radical
2352:→
2188:carboxyl
1996:such as
1974:diabetes
1915:jaundice
1867:catalase
1853:hormesis
1825:deafness
1686:→
1512:→
1341:→
1322:below).
1296:chlorine
1140:→
978:→
714:nitrenes
710:carbenes
708:Triplet
699:Carbenes
663:Dioxygen
581:isolable
376:plastics
354:Addition
221:addition
116:dimerize
100:molecule
94:, is an
3469:5054485
3343:3863722
3326:: 366.
3190:Bibcode
3056:3863722
3039:: 366.
3005:2248324
2956:4002137
2247:organic
2223:radical
2192:R group
2019:in the
2002:alcohol
1911:purines
1860:enzymes
1841:melanin
1733:eq. 2.5
1647:eq. 2.4
1561:eq. 2.3
1477:eq. 2.2
1381:eq. 2.1
1319:eq. 2.4
1313:eq. 2.2
1277:eq. 1.4
1189:eq. 1.3
1089:eq. 1.2
1017:eq. 1.1
946:eq. 1.4
940:eq. 1.3
934:eq. 1.2
924:eq. 1.1
853:steps:
776:singlet
772:triplet
683:oxidize
605:thiazyl
336:Allylic
88:radical
3494:
3476:
3466:
3400:
3392:
3350:
3340:
3299:
3291:
3255:
3220:
3213:420421
3210:
3161:
3123:
3099:
3063:
3053:
3012:
3002:
2963:
2953:
2872:
2825:
2738:
2678:
2619:
2609:
2577:
2444:, and
2163:dyes.
2115:Dexter
1978:cancer
1966:stroke
1962:cancer
1946:oxygen
1940:, and
1831:, and
1782:lignin
825:(HO).
756:oxygen
754:. The
735:butane
640:kJ/mol
308:ketyls
306:, and
184:plasma
3398:S2CID
3370:(PDF)
3297:S2CID
3159:S2CID
2836:(PDF)
2807:(PDF)
2186:or a
2013:smoke
2006:liver
1994:aging
1958:death
1300:ozone
921:(see
833:Many
764:spins
530:TEMPO
102:, or
71:of a
3492:ISBN
3474:PMID
3390:ISSN
3348:PMID
3289:PMID
3253:PMID
3218:PMID
3121:ISBN
3097:PMID
3061:PMID
3010:PMID
2961:PMID
2870:ISBN
2823:ISBN
2736:ISBN
2676:PMID
2617:OCLC
2607:ISBN
2575:PMID
2424:and
2412:The
2312:, CH
2296:and
2273:and
2253:, (C
2064:and
2056:and
2037:and
2021:lung
1952:and
1919:gout
1901:and
1893:and
1889:and
1873:and
1812:and
1792:and
1336:CFCS
1302:to O
943:and
929:smog
903:and
874:ATRP
870:RAFT
712:and
194:and
133:and
96:atom
86:, a
52:The
3464:PMC
3456:doi
3452:138
3425:doi
3382:doi
3338:PMC
3328:doi
3281:doi
3245:doi
3208:PMC
3198:doi
3186:101
3151:doi
3089:doi
3051:PMC
3041:doi
3000:PMC
2992:doi
2951:PMC
2943:doi
2939:114
2912:doi
2908:121
2862:doi
2815:doi
2767:doi
2726:doi
2703:doi
2668:doi
2664:101
2565:doi
2561:116
2533:PDF
2428:as
2308:, C
2285:to
2281:of
2225:in
2198:or
1982:DNA
1590:ClO
1433:ClO
876:).
810:).
693:in
618:by
366:In
125:(HO
104:ion
82:In
3529::
3472:.
3462:.
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2988:87
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2959:.
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2937:.
2933:.
2906:.
2868:.
2821:.
2809:.
2779:^
2761:.
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2699:93
2697:.
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2662:.
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2615:.
2587:^
2573:.
2559:.
2555:.
2448:.
2440:,
2432:.
2289:.
2048:,
2041:.
2027:.
1972:,
1968:,
1964:,
1936:,
1921:.
1885:,
1869:,
1865:,
1827:,
1603:Cl
1402:Cl
1355:Cl
1232:NO
1209:NO
1153:NO
1110:NO
991:NO
964:NO
665:(O
611:.
587:.
378:.
310:.
302:,
182:,
178:,
174:,
159:,
142:CH
98:,
56:,
3517:.
3498:.
3480:.
3458::
3431:.
3427::
3404:.
3384::
3354:.
3330::
3324:4
3303:.
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3067:.
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2306:2
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1690:h
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1220:3
1216:O
1212:+
1191:)
1187:(
1164:3
1160:O
1156:+
1144:h
1130:2
1126:O
1122:+
1114:2
1091:)
1087:(
1064:3
1060:O
1048:2
1044:O
1040:+
1037:O
1019:)
1015:(
997:O
994:+
982:h
968:2
881:2
667:2
648:H
644:2
636:H
632:2
628:H
601:2
599:)
597:3
585:2
549:(
534:N
524:N
514:N
454:2
424:·
340:2
147:2
139:꞉
137:(
127:·
45:.
38:.
20:)
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