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Статті в журналах з теми "Homolytic Cleavage"

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Автор: Grafiati

Опубліковано: 6 вересня 2023

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1

Verma, Piyush Kumar, Naresh Kumar Meher, and K. Geetharani. "Homolytic cleavage of diboron(4) compounds using diazabutadiene derivatives." Chemical Communications 57, no. 64 (2021): 7886–89. http://dx.doi.org/10.1039/d1cc02881b.

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Анотація:

Homolytic cleavage of diboron was achieved using diazabutadiene derivatives (DABs). The cleavage is accompanied by the formation of new π-bonds and the geometry of the product is highly dependent on the substituents on the DAB units.

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2

Nome, Faruk, Marcos Caroli Rezende, Claudia Maria Sabóia, and Arlindo Clemente Da Silva. "Kinetics of the thermolysis of para-substituted benzylcobalamins and derivatives." Canadian Journal of Chemistry 65, no. 9 (September 1, 1987): 2095–99. http://dx.doi.org/10.1139/v87-347.

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The thermolysis of five para-substituted benzylcobalamins was studied at different temperatures. In the presence of KCN the observed rates increase with the cyanide concentration until a constant value is attained at high [CN−]. In both series the homolytic cleavage of the Co—C bond is slightly dependent on the para-substituent of the benzyl moiety, with ρ values of −0.1 and −0.2 when 5,6-dimethylbenzimidazole (Bzm) and cyanide are the axial ligands respectively. The Co—C bond is weakened by electron-donating axial ligands and the homolytic cleavage rates increase in the order H2O < Bzm < CN.

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3

Bajaj, Ashima, Rishu Khurana, and Md Ehesan Ali. "Quantum interference and spin filtering effects in photo-responsive single molecule devices." Journal of Materials Chemistry C 9, no. 34 (2021): 11242–51. http://dx.doi.org/10.1039/d1tc02200h.

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4

Li, Yan, Kartik Chandra Mondal, Peter Stollberg, Hongping Zhu, Herbert W. Roesky, Regine Herbst-Irmer, Dietmar Stalke, and Heike Fliegl. "Unusual formation of a N-heterocyclic germylene via homolytic cleavage of a C–C bond." Chem. Commun. 50, no. 25 (2014): 3356–58. http://dx.doi.org/10.1039/c4cc00251b.

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5

Siegel, Marshall M., and Norman B. Colthup. "Molecular Orbital Study of Remote Charge Site Decompositions in the Collision-Induced Decomposition Mass Spectra of Fatty Acid Carboxylate Anions." Applied Spectroscopy 42, no. 7 (September 1988): 1214–21. http://dx.doi.org/10.1366/0003702884429887.

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Molecular orbital calculations were used to study the energetics of four different mechanisms used to explain the collision-induced decomposition mass spectra of saturated fatty acid carboxylate anions produced by fast atom bombardment and chemical ionization. The most abundant homologous series of anions, terminally unsaturated carboxylate anions, arose from the concerted cleavage of gauche segments of the hydrocarbon backbone via a sixatom transition state. A series of anions of lower abundance arose by homolytic cleavage of anti segments of the hydrocarbon backbone into two radical fragments. The loss of methane from the parent anion is produced by the concerted cleavage of the terminal methyl group via a four-atom transition state. The computed activation energies for the reaction mechanisms were in the following order: sixatom transition state < four-atom transition state ≪ homolytic cleavage of hydrocarbon backbone. Dehydration of the parent anion is rationalized to occur by loss of a carboxylate oxygen and two hydrogen atoms on the alpha carbon from the carboxylate carbon.

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6

Hosseini, Seyedeh Nargess, Jeffrey R. Johnston, and F. G. West. "Evidence for heterolytic cleavage of a cyclic oxonium ylide: implications for the mechanism of the Stevens [1,2]-shift." Chemical Communications 53, no. 94 (2017): 12654–56. http://dx.doi.org/10.1039/c7cc07716e.

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7

Hou, Bo, David Benito-Alifonso, Richard Webster, David Cherns, M. Carmen Galan, and David J. Fermín. "Rapid phosphine-free synthesis of CdSe quantum dots: promoting the generation of Se precursors using a radical initiator." J. Mater. Chem. A 2, no. 19 (2014): 6879–86. http://dx.doi.org/10.1039/c4ta00285g.

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8

Shu, Xing-Zhong, and Xiaobo Pang. "Titanium: A Unique Metal for Radical Dehydroxylative Functionalization of Alcohols." Synlett 32, no. 13 (March 4, 2021): 1269–74. http://dx.doi.org/10.1055/a-1406-0484.

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AbstractThe dehydroxylative functionalization of alcohols is synthetic appealing, but it remains a long-term challenge in the synthetic community. Low-valent titanium has shown the power to produce carbon radicals from alcohols via homolytic cleavage of the C–OH bonds and thus offers the potential to overcome this problem. In this perspective manuscript, we summarized the recent advance on radical dehydroxylative transformation of alcohols either promoted or catalyzed by titanium. The limitation and outlook of the studies in this field are also provided.1 Introduction2 Recent Developments in Dehydroxylative Functionalization of Alcohols2.1 Stoichiometric Titanium Complexes Mediated Homolysis of Alcohols2.2 Radical Dehydroxylative Functionalization of Alcohols by Ti Catalysis3 Summary and Outlook

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9

Tang, Wai-Kit, Chun-Ping Leong, Qiang Hao та Chi-Kit Siu. "Theoretical examination of competitive β-radical-induced cleavages of N–Cα and Cα–C bonds of peptides". Canadian Journal of Chemistry 93, № 12 (грудень 2015): 1355–62. http://dx.doi.org/10.1139/cjc-2015-0208.

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Selective cleavages of N–Cα and Cα–C bonds of β-radical tautomers of amino acid residues in radical peptides have been examined theoretically by means of the density functional theory at the M06-2X/6-311++G(d,p) level. The majority of the bond cleavages are homolytic via β-scission. Their energy barriers depend largely on the ability of the radical being stabilized in the transition structures and the availability of a mobile proton in the vicinity of the β-radical center. The N–Cα bond is less favorably cleaved than the Cα–C bond (except Ser and Thr) for systems without a mobile proton. It is because, firstly, the homolytic cleavage is less favorable for the more polar N–Cα bond than for the less polar Cα–C bond. Secondly, a less stable σ-radical localized on the amide nitrogen atom of the incipient N-terminal fragment is formed for the former, while a more stable radical delocalized in a π*(CO)-like orbital of the incipient C-terminal fragment is formed for the latter. In the presence of a mobile proton N-terminal to the β-radical center, some degrees of heterolytic cleavage character, as preferred by the polar N–Cα bond, are observed. Consequently, its barrier is reduced. If the mobile proton is located at the C-terminal amide oxygen of the β-radical center, the Cα–C bond cleavage will be significantly suppressed. It is because the radical in the incipient C-terminal fragment becomes more localized as a σ-radical on the carbon atom of its protonated amide group. With basic amino acid residues, the Cα–C bond cleavage can be reactivated. Heterolytic cleavage of the polar N–Cα bond can be largely facilitated if a mobile proton N-terminal to the β-radical center is available and the radical in the incipient C-terminal fragment is sufficiently stabilized, for instance, by the aromatic side chain of Trp and Tyr. Therefore, cleavages of the N–Cα bond induced by the β-radical tautomer of Trp and Tyr are often preferred as compared with cleavages of the Cα–C bond in peptide radical cations containing mobile protons.

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10

LIU, MIN HSIEN, and GEN FA ZHENG. "COMPUTATIONAL STUDY OF UNIMOLECULAR DECOMPOSITION MECHANISM OF RDX EXPLOSIVE." Journal of Theoretical and Computational Chemistry 06, no. 02 (June 2007): 341–51. http://dx.doi.org/10.1142/s0219633607002952.

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This study investigated the RDX (1,3,5-Trinitro-1,3,5-triazine) molecule to elucidate its possible decomposition species and the corresponding energies by performing the density-functional theory (DFT) calculations. Reasonable decomposition mechanisms are proposed based on the bond energy calculated using the differential overlap (INDO) program, which yields the weakest bonding site for reference and determines the site of easy cleavage. Computational results indicate that the activation energy of direct cis-form HONO elimination is lower than that of direct trans-form HONO elimination and that of a two-stage elimination of two forms of HONO ( N – N bond fission combined with C – H bond breaking) in the initial decomposition step, which are 213.9 kJ/mol and 93.8–101.8 kJ/mol, respectively. Two possible pathways are proposed; (1) N – N bond homolytic cleavage followed by elimination of cis-form HONO, and (2) N – N bond homolytic cleavage followed by elimination of trans-form HONO.

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11

Mondol, Ranajit, and Edwin Otten. "Structure and bonding in reduced boron and aluminium complexes with formazanate ligands." Dalton Transactions 48, no. 37 (2019): 13981–88. http://dx.doi.org/10.1039/c9dt02831e.

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A comparison of structure and bonding in reduced formazanate B/Al complexes and their ligand-benzylated products is described. The kinetics of homolytic N–C(benzyl) bond cleavage in the latter compounds is studied.

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12

Weng, Zhiqiang, and Lai Yoong Goh. "Homolytic Cleavage and Aggregation Processes in Cyclopentadienylchromium Chemistry." Accounts of Chemical Research 37, no. 3 (March 2004): 187–99. http://dx.doi.org/10.1021/ar030003r.

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13

Ding, Lanlan, Wenrui Zheng, and Yingxing Wang. "Homolytic C–O Cleavage in Phosphates and Sulfonates." Journal of Physical Chemistry A 119, no. 14 (March 27, 2015): 3488–99. http://dx.doi.org/10.1021/acs.jpca.5b00569.

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14

Kampmeier, Jack A. "Regioselectivity in the Homolytic Cleavage of S-Adenosylmethionine." Biochemistry 49, no. 51 (December 28, 2010): 10770–72. http://dx.doi.org/10.1021/bi101509u.

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15

Kawamoto, Haruo, Takeshi Nakamura, and Shiro Saka. "Pyrolytic cleavage mechanisms of lignin-ether linkages: A study on p-substituted dimers and trimers." Holzforschung 62, no. 1 (January 1, 2008): 50–56. http://dx.doi.org/10.1515/hf.2008.007.

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Abstract Pyrolytic cleavage mechanisms of lignin-ether linkages were studied with some dimers and trimers which have various p-substituted Cα-phenoxy groups (-H, -OCH3, -Cl or -COCH3). Pyrolysis of these model compounds provides phenols and isoeugenol type products. To determine whether the reactions mechanisms are heterolytic or homolytic, the reactivities were compared based on Hammett's substituent constant (σ p ) and the ΔBDE parameter, namely the bond dissociation energy (BDE) reduction. The α-ether-linkages in phenolic forms are cleaved in a heterolytic mechanism, while in non-phenolic forms the α-ether linkages are cleaved homolytically. Cleavage of these α-ether linkages is the rate-determining step for the scission of the Cβ-O bond in trimers. The β-ether-linkages in the non-phenolic trimers are cleaved through the β-scission type reaction from the benzyl radical intermediates. On the other hand, quinone methide formation through heterolytic cleavage of the α-ether linkages is the key step for following homolysis of the Cβ-O bonds in the phenolic trimers. Electron attracting character of the quinone methide structure reduces the BDE of the Cβ-O bond.

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16

Ward, Antony J., Rebecca A. Lesic, Nicholas Proschogo, Anthony F. Masters, and Thomas Maschmeyer. "Strained surface siloxanes as a source of synthetically important radicals." RSC Advances 5, no. 122 (2015): 100618–24. http://dx.doi.org/10.1039/c5ra20399f.

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The calcination of pure amorphous silica at temperatures up to 850 °C results in the formation of strained siloxane rings which are capable of undergoing homolytic cleavage to generate radicals when in the presence of an appropriate substrate.

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17

Iguchi, Daniela, Rosa Erra-Balsells, and Sergio M. Bonesi. "Photo-Fries rearrangement of aryl acetamides: regioselectivity induced by the aqueous micellar green environment." Photochemical & Photobiological Sciences 15, no. 1 (2016): 105–16. http://dx.doi.org/10.1039/c5pp00349k.

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NMR spectroscopy shows the location of acetanilides within the shells and hydrophobic cores in micellar solutions. Irradiation of acetanilides in aqueous micellar solutions involves C–N homolytic cleavage to yield singlet radical pairs that selectively provide 2-aminoacetophenone derivatives.

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18

Zheng, Yue, Qianxiong Zhou, Wanhua Lei, Yuanjun Hou, Ke Li, Yongjie Chen, Baowen Zhang, and Xuesong Wang. "DNA photocleavage in anaerobic conditions by a Ru(ii) complex: a new mechanism." Chemical Communications 51, no. 2 (2015): 428–30. http://dx.doi.org/10.1039/c4cc06552b.

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Photoinduced homolytic cleavage of the Ru–O bond of a novel Ru(ii) complex leads to formation of ligand-based reactive radicals capable of breaking DNA in an oxygen-dependent manner and Ru fragments capable of binding DNA covalently.

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19

Foster, B., B. Gaillard, N. Mathur, A. L. Pincock, J. A. Pincock, and C. Sehmbey. "Substituent effects on homolytic versus heterolytic photocleavage of (1-naphthylmethyl)trimethylammonium chlorides." Canadian Journal of Chemistry 65, no. 7 (July 1, 1987): 1599–607. http://dx.doi.org/10.1139/v87-268.

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Singlet excited state rate constants have been measured for both the heterolytic and homolytic photocleavage of 3- and 4-methoxy and 3- and 4-cyano (1-naphthylmethyl)trimethylammonium chlorides, 6–10. The results are interpreted in terms of the meta effect or changes in charge distribution upon excitation and the competition between bond cleavage, electron transfer, and hydrogen atom transfer in the contact pairs resulting from the two types of cleavage.

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20

Li, Jing, Martin J. Lear та Yujiro Hayashi. "Autoinductive conversion of α,α-diiodonitroalkanes to amides and esters catalysed by iodine byproducts under O2". Chemical Communications 54, № 49 (2018): 6360–63. http://dx.doi.org/10.1039/c8cc03191f.

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Studies to convert nitroalkanes into amides and esters using I₂ and O₂ revealed in situ-generated iodine species facilitate the homolytic C–I bond cleavage of α,α-diiodonitroalkanes, arguably in an autoinductive or autocatalytic manner.

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21

Klepel, Florian, and Bart Jan Ravoo. "Dynamic covalent chemistry in aqueous solution by photoinduced radical disulfide metathesis." Organic & Biomolecular Chemistry 15, no. 18 (2017): 3840–42. http://dx.doi.org/10.1039/c7ob00667e.

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Photoinduced radical disulfide metathesis (PRDM) is a dynamic covalent reaction that requires UV light to induce the homolytic cleavage of the disulfide bond, thus offering the opportunity to construct dynamic covalent systems that are dormant and can be photo-activated on demand.

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22

Ragnar, Martin, Tord Eriksson, Torbjörn Reitberger, and Peter Brandt. "A New Mechanism in the Ozone Reaction with Lignin Like Structures." Holzforschung 53, no. 4 (July 1, 1999): 423–28. http://dx.doi.org/10.1515/hf.1999.070.

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Summary A new mechanism including a homolytic cleavage of a trioxide intermediate forming superoxide is suggested to be the main course of radical formation in reactions of ozone and lignin like structures. The suggested mechanism is supported by quantum chemical and thermochemical methods.

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23

Ji, Yu, Qiang Yao, Yueying Zhao, and Weihong Cao. "On the Origin of Alkali-Catalyzed Aromatization of Phenols." Polymers 11, no. 7 (July 2, 2019): 1119. http://dx.doi.org/10.3390/polym11071119.

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To gain an insight of the chemistry in the alkali-promoted aromatization of oxygen-containing heavily aromatic polymers or biomass; thermal degradations of sodium phenolates with different substituents have been investigated. The -ONa group strongly destabilizes the phenolates. The thermal stability of phenolates is largely in parallel with bond strengths of Ar substituents. De-substituents and the removal of aromatic hydrogens are dominant reactions in the main degradation step. CO is formed only at a very late stage. This degradation pattern is completely different from that of phenol. To account for this distinctive decomposition; a mechanism involving an unprecedented formation of an aromatic carbon radical anion generated from the homolytic cleavage of Ar substituent (or Ar–H) in keto forms has been proposed. The homolytic cleavage of Ar substituent (or Ar–H) is facilitated by the strong electron-donating ability of the oxygen anion. A set of free-radical reactions involved in the alkali-catalyzed aromatization have been established.

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24

Andrieux, C. P., F. Gonzalez, and J. M. Savéant. "Homolytic and heterolytic radical cleavage in the Kolbe reaction." Journal of Electroanalytical Chemistry 498, no. 1-2 (February 2001): 171–80. http://dx.doi.org/10.1016/s0022-0728(00)00365-x.

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25

Hill, Nicholas S., Melinda J. Fule, Jason Morris, Jean-Louis Clément, Yohann Guillaneuf, Didier Gigmes, and Michelle L. Coote. "Mesolytic Versus Homolytic Cleavage in Photochemical Nitroxide-Mediated Polymerization." Macromolecules 53, no. 5 (February 26, 2020): 1567–72. http://dx.doi.org/10.1021/acs.macromol.0c00134.

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26

Arnett, Edward M., Sampath Venimadhavan, and Kalyani Amarnath. "Homolytic and heterolytic cleavage energies for carbon-nitrogen bonds." Journal of the American Chemical Society 114, no. 14 (July 1992): 5598–602. http://dx.doi.org/10.1021/ja00040a018.

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27

Mallorquin, Rocio Martinez, Guillaume Vincent, Etienne Derat, Max Malacria, Jean-Philippe Goddard, and Louis Fensterbank. "New Elements on the Behaviour of a Bissulfinylmethyl Radical." Australian Journal of Chemistry 66, no. 3 (2013): 346. http://dx.doi.org/10.1071/ch12545.

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In this article, we have studied the generation of a bissulfinylmethyl radical from the corresponding TEMPO and phenylselenyl bissulfoxide precursors. No univocal formation of the bissulfinylmethyl radical has been observed. Instead, complex mixtures have been obtained in thermal or photochemical conditions, showing prominent C–S homolytic bond cleavage.

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28

Arnold, B., L. Donald, A. Jurgens, and J. A. Pincock. "Homolytic versus heterolytic cleavage for the photochemistry of 1-naphthylmethyl derivatives." Canadian Journal of Chemistry 63, no. 11 (November 1, 1985): 3140–46. http://dx.doi.org/10.1139/v85-518.

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The photochemical cleavage of the 1-naphthylmethyl derivatives, 1–7, has been examined in methanol solvent under both direct and sensitized conditions. The competitition between homolytic and heterolytic cleavage as a function of multiplicity and leaving group has been studied in detail. Only substrates 1, 2, 3, and 7 react on sensitization with xanthone but evidence is presented that the resulting reactivity of 1, 2, and 3 may not be triplet energy transfer but rather exciplex formation. A semi-quantitative scale for photofugacities of the leaving groups from the excited singlet states has been established.

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29

Wang, Pengfei, Yuli Li, and Guangwei Wang. "Tetrahydroxydiboron-Initiated Atom-Transfer Radical Cyclization." Synthesis 53, no. 19 (April 19, 2021): 3555–63. http://dx.doi.org/10.1055/a-1485-4956.

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AbstractIn this work, the first diboron reagent initiated atom-transfer radical cyclization was reported, in which the boryl radicals were generated by the homolytic cleavage of a B–B single bond weakened by the coordination of Lewis base. To clarify the role of carbonate and DMF in the cleavage of B–B bond, we calculated the free energy diagram of two pathways by density functional theory (DFT) investigations. The DFT calculation showed that the presence of carbonate facilitates the B–B bond cleavage to form boron radicals, which can be further stabilized by DMF. Subsequent atom-transfer cyclization initiated by stabilized dihydroxyboron radical is also energetically favored.

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30

Morrow, GR, and ID Rae. "Thermal-Degradation of Polymers and Polymer Models. IV. Thermolysis of a Polymethacrylate Model With an Unsaturated End Group." Australian Journal of Chemistry 40, no. 8 (1987): 1477. http://dx.doi.org/10.1071/ch9871477.

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Thermal degradation of a model for the 'unsaturated end group' of poly(methyl methacrylate ) gives products which suggest that homolytic bond cleavage, and not a retro-ene reaction, is the major pathway. The diester (CH3)2C(COOCH3)CH2C(COOCH3)=CH2, when heated at 250-300�, gives up to 50 mole % of methyl 2-methylpropanoate (methyl isobutyrate ).

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31

Milne, Paul H., Danial D. M. Wayner, Dayal P. DeCosta, and James A. Pincock. "Substituent and charge distribution effects on the redox potentials of radicals. Thermodynamics for homolytic versus heterolytic cleavage in the 1-naphthylmethyl system." Canadian Journal of Chemistry 70, no. 1 (January 1, 1992): 121–27. http://dx.doi.org/10.1139/v92-021.

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Анотація:

The electrochemical oxidation and reduction potentials of a number of substituted 1-methylnaphthalenes (1a-l) and 1-naphthylmethyl radicals (2a-l•) as well as 2-methylnaphthalene (3) and the 2-naphthylmethyl radical (4•) have been measured by cyclic voltammetry and photomodulation voltammetry. The oxidation potentials correlate with σ+ (ρ+ = −7.1 and −8.4 for 1 and 2• respectively) while the reduction potentials correlate with σ− (ρ− = 10.1 and 13.0 for 1 and 2• respectively). The relative magnitude of the ρ values can be rationalized when the charge density distribution in these systems is considered. This leads to the interesting conclusion that even though a full charge is placed in the π-system of 1 when it is oxidized or reduced, the fraction of the charge that accumulates at C4 is actually less than in 2+ or 2− where only 50–70% of the charge is delocalized into the ring. A correlation between ρ for the redox reactions of 1, 2•, benzyl, diphenylmethyl, and cumyl and the calculated (AM1) charge density at C4 is established, implying that the sensitivity of the corresponding ions to substituent effects increases as the fraction of charge at that site increases. The redox data have been used in thermochemical cycles in order to estimate the substituent effect on the homolytic, mesolytic, and heterolytic cleavage reactions of 1 and its corresponding radical ions. The implication of these results on the C—C cleavage versus deprotonation of radical cations and on the photochemical homolysis versus heterolysis of naphthylmethyl halides and acetates is discussed. Keywords: electrochemistry, homolysis, heterolysis, naphthylmethyl, substituent effect.

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32

Ben Amor, N., and C. Daniel. "Spin–orbit ab initio investigation of the UV photoinduced bond cleavage in iodotrimethylstannane." Canadian Journal of Chemistry 87, no. 7 (July 2009): 1006–12. http://dx.doi.org/10.1139/v09-064.

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The photoinduced homolytic cleavage of the Sn–I bond in iodotrimethylstannane (CH3)3SnI, observed after UV irradiation, is investigated by means of spin–orbit ab initio calculations based on CASSCF (complete active space self-consistent field) and MS-CASPT2 (multi-state complete active space 2nd order perturbation theory) methods. The absorption electronic spectrum is characterized by ten low-lying 1,3A′ and 1,3A″ spin eigenstates corresponding to py(I),px(I) → σ*SnI; σSnI → σ*SnI and py(Sn), px(Sn) → σ*SnI, where σSnI and σ*SnI are the bonding and anti-bonding orbitals of the Sn–I bond along the pz axis. From the 1A′ electronic ground state and these ten spin eigenstates, 21 spin–orbit states are generated leading to various deactivation channels of (CH3)3SnI, corresponding to the formation of radicals (CH3)3Sn• and •I and to the ionic species (CH3)3Sn+ and I–. Irradiation into the upper band at 175 nm should lead to the heterolytic cleavage of the Sn–I bond to form the ionic primary products exclusively, whereas absorption into the shoulder at 250 nm induces the homolytic breaking with formation of the radical products.

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33

Wang, Lele, Wenzhao Qiu, Hongge Shao, and Rusheng Yuan. "Photoinduced C-C Cross-Coupling of Aryl Chlorides and Inert Arenes." International Journal of Photoenergy 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/5632613.

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Here we report a facile, efficient, and catalyst-free method to realize C-C cross-coupling of aryl chlorides and inert arenes under UV light irradiation. The aryl radical upon homolytic cleavage of C-Cl bond initiated the nucleophilic substitution reaction with inert arenes to give biaryl products. This mild reaction mode can also be applied to other synthetic reactions, such as the construction of C-N bonds and trifluoromethylated compounds.

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34

Dohi, Toshifumi, Shohei Ueda, Kosuke Iwasaki, Yusuke Tsunoda, Koji Morimoto, and Yasuyuki Kita. "Selective carboxylation of reactive benzylic C–H bonds by a hypervalent iodine(III)/inorganic bromide oxidation system." Beilstein Journal of Organic Chemistry 14 (May 16, 2018): 1087–94. http://dx.doi.org/10.3762/bjoc.14.94.

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An oxidation system comprising phenyliodine(III) diacetate (PIDA) and iodosobenzene with inorganic bromide, i.e., sodium bromide, in an organic solvent led to the direct introduction of carboxylic acids into benzylic C–H bonds under mild conditions. The unique radical species, generated by the homolytic cleavage of the labile I(III)–Br bond of the in situ-formed bromo-λ3-iodane, initiated benzylic carboxylation with a high degree of selectivity for the secondary benzylic position.

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35

Lesimple, Alain, Yves Le Bigot, Michel Delmas, and Joseph Banoub. "Electron ionization mass spectrometry of difurfuryl diamines." Spectroscopy 14, no. 3 (2000): 109–14. http://dx.doi.org/10.1155/2000/453723.

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Electron impact mass spectrometry (ei-ms) has aided the structural characterization of a novel series of synthetic difuranic diamines and permitted the comparison with a previous study employing electrospray ionization mass spectrometry. As expected, the molecular radical ion was inexistant in this series of compounds and the fragmentation routes of the molecular radical ion were governed either by homolytic cleavage of the radical R2•or by heterolytic loss of NH3to give their respective base peaks.

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36

Paul, Ganesh Chandra, Samir Ghorai, and Chandan Mukherjee. "Monoradical-containing four-coordinate Co(iii) complexes: homolytic S–S and Se–Se bond cleavage and catalytic isocyanate to urea conversion under sunlight." Chemical Communications 53, no. 57 (2017): 8022–25. http://dx.doi.org/10.1039/c7cc03486e.

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37

Bracker, Mario, Lucas Helmecke, Martin Kleinschmidt, Constantin Czekelius, and Christel M. Marian. "Visible Light-Induced Homolytic Cleavage of Perfluoroalkyl Iodides Mediated by Phosphines." Molecules 25, no. 7 (April 1, 2020): 1606. http://dx.doi.org/10.3390/molecules25071606.

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In an effort to explain the experimentally observed variation of the photocatalytic activity of t Bu 3 P, n Bu 3 P and (MeO) 3 P in the blue-light regime [Helmecke et al., Org. Lett. 21 (2019) 7823], we have explored the absorption characteristics of several phosphine– and phosphite–IC 4 F 9 adducts by means of relativistic density functional theory and multireference configuration interaction methods. Based on the results of these computational and complementary experimental studies, we offer an explanation for the broad tailing of the absorption of t Bu 3 P-IC 4 F 9 and (MeO) 3 P-IC 4 F 9 into the visible-light region. Larger coordinate displacements of the ground and excited singlet potential energy wells in n Bu 3 P-IC 4 F 9 , in particular with regard to the P–I–C bending angle, reduce the Franck–Condon factors and thus the absorption probability compared to t Bu 3 P-IC 4 F 9 . Spectroscopic and computational evaluation of conformationally flexible and locked phosphites suggests that the reactivity of (MeO) 3 P may be the result of oxygen lone-pair participation and concomitant broadening of absorption. The proposed mechanism for the phosphine-catalyzed homolytic C–I cleavage of perfluorobutane iodide involves S1 ← S0 absorption of the adduct followed by intersystem crossing to the photochemically active T 1 state.

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38

Costentin, Cyrille, Marc Robert, and Jean-Michel Savéant. "Activation Barriers in the Homolytic Cleavage of Radicals and Ion Radicals." Journal of the American Chemical Society 125, no. 1 (January 2003): 105–12. http://dx.doi.org/10.1021/ja027287f.

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39

Cao, Levy L., and Douglas W. Stephan. "Homolytic Cleavage Reactions of a Neutral Doubly Base Stabilized Diborane(4)." Organometallics 36, no. 16 (August 9, 2017): 3163–70. http://dx.doi.org/10.1021/acs.organomet.7b00522.

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40

Vagánek, Adam, Ján Rimarčík, Michal Ilčin, Peter Škorňa, Vladimír Lukeš, and Erik Klein. "Homolytic N–H bond cleavage in anilines: Energetics and substituent effect." Computational and Theoretical Chemistry 1014 (June 2013): 60–67. http://dx.doi.org/10.1016/j.comptc.2013.03.027.

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41

LEVITIN, J. YA, A. K. YATSIMIRSKII, and M. E. VOL'PIN. "ChemInform Abstract: Mechanisms of the Homolytic Cleavage of Organo-Cobalt Complexes." ChemInform 22, no. 18 (August 23, 2010): no. http://dx.doi.org/10.1002/chin.199118312.

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42

Arantes, Guilherme M., Anirban Bhattacharjee, and Martin J. Field. "Homolytic Cleavage of FeS Bonds in Rubredoxin under Mechanical Stress." Angewandte Chemie 125, no. 31 (June 18, 2013): 8302–4. http://dx.doi.org/10.1002/ange.201303462.

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43

Arantes, Guilherme M., Anirban Bhattacharjee, and Martin J. Field. "Homolytic Cleavage of FeS Bonds in Rubredoxin under Mechanical Stress." Angewandte Chemie International Edition 52, no. 31 (June 18, 2013): 8144–46. http://dx.doi.org/10.1002/anie.201303462.

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44

Tran, Dat Phuc, Yuki Sato, Yuki Yamamoto, Shin-ichi Kawaguchi, Shintaro Kodama, Akihiro Nomoto, and Akiya Ogawa. "Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions." Beilstein Journal of Organic Chemistry 17 (April 20, 2021): 866–72. http://dx.doi.org/10.3762/bjoc.17.72.

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The homolytic cleavage of the PV(O)–PIII bond in tetraphenyldiphosphine monoxide simultaneously provides both pentavalent and trivalent phosphorus-centered radicals with different reactivities. The method using V-40 as an initiator is successfully investigated for the regio- and stereoselective phosphinylphosphination of terminal alkynes giving the corresponding trans-isomers of 1-diphenylphosphinyl-2-diphenylthiophosphinyl-1-alkenes in good yields. The protocol can be applied to a wide variety of terminal alkynes including both alkyl- and arylalkynes.

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45

Yi, Hong, Guanghui Zhang, Jie Xin, Yi Deng, Jeffrey T. Miller, Arthur J. Kropf, Emilio E. Bunel, et al. "Homolytic cleavage of the O–Cu(ii) bond: XAFS and EPR spectroscopy evidence for one electron reduction of Cu(ii) to Cu(i)." Chemical Communications 52, no. 42 (2016): 6914–17. http://dx.doi.org/10.1039/c6cc01413e.

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In this work, we demonstrate that the ^tBuO⁻ anion serves not only as the base but also as a mediator to promote the reduction of Cu(ii) to Cu(i) in copper catalysis. XAFS and EPR spectroscopy evidence the [Cu(O^tBu)₃]⁻ ate complex as the key intermediate which undergoes homolytic cleavage of the O–Cu(ii) bond generating [Cu(O^tBu)₂]⁻ ate complex.

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46

Ding, Lanlan, Wenrui Zheng, and Yingxing Wang. "Theoretical study on homolytic C(sp2)–O cleavage in ethers and phenols." New Journal of Chemistry 39, no. 9 (2015): 6935–43. http://dx.doi.org/10.1039/c5nj01354b.

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47

Barroso, J., A. R. Pierna, T. C. Blanco, E. Morallón, and F. Huerta. "Homolytic cleavage C–C bond in the electrooxidation of ethanol and bioethanol." Journal of Power Sources 196, no. 9 (May 2011): 4193–99. http://dx.doi.org/10.1016/j.jpowsour.2010.09.087.

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48

Groves, John T., and Yoshihito Watanabe. "Heterolytic and homolytic oxygen-oxygen bond cleavage reactions of acylperoxomanganese(III) porphyrins." Inorganic Chemistry 25, no. 27 (December 1986): 4808–10. http://dx.doi.org/10.1021/ic00247a006.

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49

Vagánek, Adam, Ján Rimarčík, Vladimír Lukeš, and Erik Klein. "On the energetics of homolytic and heterolytic OH bond cleavage in flavonoids." Computational and Theoretical Chemistry 991 (July 2012): 192–200. http://dx.doi.org/10.1016/j.comptc.2012.04.014.

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50

Murphy, Barry E., Sergey A. Krasnikov, Natalia N. Sergeeva, Attilio A. Cafolla, Alexei B. Preobrajenski, Alexander N. Chaika, Olaf Lübben, and Igor V. Shvets. "Homolytic Cleavage of Molecular Oxygen by Manganese Porphyrins Supported on Ag(111)." ACS Nano 8, no. 5 (April 30, 2014): 5190–98. http://dx.doi.org/10.1021/nn501240j.

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