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Journal articles on the topic 'Cationes radicales'

Author: Grafiati

Published: 17 September 2021

Last updated: 30 July 2025

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1

Ríos V., Luz Amalia, Rodrigo Paredes та William R. Dolbier Jr. "ESTUDIO DE LA REACTIVIDAD DE CATIONES RADICALES Α-AMONIO DISTÓNICOS EN SOLUCIÓN". Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales 23, № 89 (2024): 595–602. http://dx.doi.org/10.18257/raccefyn.23(89).1999.2858.

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Se estudiaron las reacciones de abstracción de hidrógeno, adición bimolecular y delación de varios cationes radicales distónicos (la-lla). Se midieron las constantes de velocidad absolutas para la delación de 6a y 7a y la constante de velocidad de abstracción de hidrógeno de 6a. Además, se realizó un estudio de Hammett, para lo cual se desarrollaron varios experimentos de competencia de una serie de radicales p-sustituidos (Sa-lla) obteniéndose los valores de las constantes de velocidad de los procesos de delación de cada sistema. También se presenta una posible explicación de la inesperada ba

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2

Zamora Guevara, José Alberto, Jorge Ricardo Campoverde Mori, William Johnny Jiménez Jiménez, and Walter Enrique Mariscal Santi. "Actividad Antioxidante de Pulpa, Semilla y Pericarpio de Mazorca del Theobroma Cacao." RECIAMUC 6, no. 3 (2022): 564–74. http://dx.doi.org/10.26820/reciamuc/6.(3).julio.2022.564-574.

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Un antioxidante es cualquier sustancia que al estar presente a bajas concentraciones respecto a las de un sustrato oxidable, retrasa o previene significativamente la oxidación de este sustrato. Entre los métodos desarrollados para medir la actividad anti radical, se mencionaran los más usados en las fuentes consultadas: método ABTS+: el ensayo decoloración de cationes radicales, el método ORAC la capacidad de absorción de radicales de oxígeno (ORAC) es un método que mide la inhibición antioxidante de los radicales peroxilo de oxidaciones inducidas y refleja la cadena radical clásica rompiendo

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3

Flores, Franklin D., and Juan F. Facetti M. "Sedimentos de fondo en los arroyos Tapiracuai y Cuarepotí." Revista de la Sociedad Científica del Paraguay 23, no. 2 (2019): 251–62. http://dx.doi.org/10.32480/rscp.2018-23-2.251-262.

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Los sedimentos de fondo de los cuerpos de agua constituyen un reservorio para los cationes metálicos, moléculas y otros productos que a lo largo de lapsos, cortos o largos, pueden constituirse en contaminantes, con efectos deletéreos para la biota; el conocimiento de su contenido es pues muy importante. En este trabajo se investigan en los sedimentos de los arroyos Tapiracuai y Cuarepoti los tenores de elementos de la serie 3d que por la presencia/acción de electrones desapareados pueden originar reacciones de radicales libres, así como otros tales como el Cd y el Pb de conocida toxicidad. Los

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4

Arnold, Donald R., та Xinyao Du. "The photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 5: methanol–monoterpenes (α- and β-pinene, tricyclene, and nopol), 1,4-dicyanobenzene". Canadian Journal of Chemistry 72, № 2 (1994): 403–14. http://dx.doi.org/10.1139/v94-062.

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The reactivity of the radical cations of α- and β-pinene (8 and 9), tricyclene (18), and nopol (23) has been studied. The radical ions were generated, in acetonitrile–methanol (3:1), by single electron transfer (set) to the singlet excited state of 1,4-di-cyanobenzene (1). Biphenyl (3) was used as a codonor. The cyclobutane rings of the initially formed radical cations of α- and β-pinene (8+• and 9+•) cleave to distonic radical cations that react as tertiary alkyl cations and allylic radicals. The results of ab initio molecular orbital calculations (STO-3G) are consistent with the observation

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5

Shea, Suzanne, Norman P. Schepp, Amy E. Keirstead, and Frances L. Cozens. "Dynamics of the transient species generated upon photolysis of diarylmethanes within zeolites Deprotonation and oxidation reactions." Canadian Journal of Chemistry 83, no. 9 (2005): 1637–48. http://dx.doi.org/10.1139/v05-208.

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The oxidation of diarylmethanes is a multistep process involving initial formation of a radical cation, deprotonation of the radical cation to the radical, and oxidation of the radical to the carbocation. The dynamics and efficiency of the last two steps in this process, namely deprotonation and oxidation, in acidic zeolites and non-acid zeolites are examined in the present work as a function of the acidity of the diarylmethane radical cations and the oxidation potential of the diarylmethyl radicals. Our results indicate that rate constants for deprotonation strongly depend on the acidity of t

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6

Schepp, N. P., and Y. Rodríguez-Evora. "Generation and reactivity of the radical cations of coniferyl alcohol and isoeugenol in solution." Canadian Journal of Chemistry 81, no. 6 (2003): 799–806. http://dx.doi.org/10.1139/v03-075.

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Nanosecond laser flash photolysis of coniferyl alcohol and isoeugenol in acetonitrile leads to the formation of transient species that are identified as the corresponding radical cations. These radical cations decay with rate constants of ca. 1 × 106 s1 in dry acetonitrile. Both radical cations react rapidly with hydroxylic solvents like water and alcohols to give 4-vinylphenoxyl radicals, indicating that these reagents behave as bases rather than nucleophiles. In addition, anionic reagents (acetate, cyanide, and chloride) react rapidly with the radical cations with second-order rate constant

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7

G., R. Dey. "Radical cations and radicals of thiourea and its derivatives in n-butyl chloride solutions: A pulse radiolysis study." Journal of Indian Chemical Society Vol. 97, No. 11a, Nov 2020 (2020): 2233–41. https://doi.org/10.5281/zenodo.5653500.

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Radiation and Photochemistry Division, Homi Bhabha National Institute, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, India <em>E-mail</em>: grdey@barc.gov.in <em>Manuscript received online 10 October 2020, revised and accepted 31 November 2020</em> The formation of radical cations and radicals of thiourea and its derivatives such as thiosemicarbazide, diethylthiourea, phenylthiourea in <em>n</em>-butyl chloride solutions using pulse radiolysis technique is reported. Solute radical cations generated initially produce respective radicals on deprotonation. The yields of radicals of thes

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8

Yahya, Noha M., and Salim M. Khalil. "A Theoretical Study of Monosubstituted Cyclopropenyl System." Zeitschrift für Naturforschung A 47, no. 6 (1992): 768–74. http://dx.doi.org/10.1515/zna-1992-0609.

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AbstractMONDO-Forces calculations have been performed, with complete optimization of geometry on X-cyclopropenyl system (cations, radicals and anions), where X is H, O-, OH, CH3 , CN, NO2 , F and CF3 . All substituents prefer planar structure when substituted on both cations and radicals, while they prefer pyramidal structure in the case of anions except CF3 . The substituents O-, OH and F act as electron releasing, while CHO, NO2 and CF3 act as electron withdrawing when substituted on cyclopropenyl system. CH3 and CN show amphielectronic behaviour. They act as electron releasing on the cation

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9

Manley, David W., and John C. Walton. "Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis." Beilstein Journal of Organic Chemistry 11 (September 9, 2015): 1570–82. http://dx.doi.org/10.3762/bjoc.11.173.

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Heterogeneous semiconductor photoredox catalysis (SCPC), particularly with TiO2, is evolving to provide radically new synthetic applications. In this review we describe how photoactivated SCPCs can either (i) interact with a precursor that donates an electron to the semiconductor thus generating a radical cation; or (ii) interact with an acceptor precursor that picks up an electron with production of a radical anion. The radical cations of appropriate donors convert to neutral radicals usually by loss of a proton. The most efficient donors for synthetic purposes contain adjacent functional gro

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10

Adeniyi, Emmanuel, Matthias Zeller, and Sergiy V. Rosokha. "Crystal Engineering of Cation-Radical Salts with Weakly Coordinating Carbadodecaborate Anions." Crystals 13, no. 1 (2023): 99. http://dx.doi.org/10.3390/cryst13010099.

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An X-ray structural analysis revealed that the salts of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD), N-methylphenothiazine (MPTZ), and octamethylbiphenylene (OMB), with dodecamethyl- or hexabromo-substituted carbadodecaborate anions, comprise layers of the (partially) oxidized organic donors separated by sheets of the bulky counter-ions. The cationic layers comprise either well-separated TMPD+ or MPTZ+ cation radicals or π-stacks of partially oxidized OMB moieties consisting of more or less distinct (OMB)2+ units. Quantum mechanical calculations revealed that the formation of essentially i

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11

TEHRANI, ZAHRA ALIAKBAR, MARJAN JEBELI JAVAN, ALIREZA FATTAHI, and MOHAMMAD MAHMOODI HASHEMI. "EFFECT OF CATION RADICAL FORMATION ON REACTIVITY AND ACIDITY ENHANCEMENT OF CYTOSINE NUCLEOBASE: NATURAL BOND ORBITAL AND ATOM IN MOLECULE ANALYSIS." Journal of Theoretical and Computational Chemistry 11, no. 02 (2012): 313–27. http://dx.doi.org/10.1142/s0219633612500228.

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The radical cations of DNA constituents generated by the ionizing radiation initiate an alteration of the bases, which is one of the main types of cytotoxic DNA lesions. These cation radical spices are known for their role in producing nucleic acid strand break. In this study, the gas-phase intrinsic chemical properties of the gaseous radical cations of cytosine and its base pair with guanine were examined by employing density functional theory (B3LYP) with the 6-311++G(d,p) basis set. Structures, geometries, adiabatic ionization energies, adiabatic electron affinities, charge distributions, m

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12

Webster, Richard D. "Electrochemical and Spectroscopic Characterization of Oxidized Intermediate Forms of Vitamin E." Molecules 27, no. 19 (2022): 6194. http://dx.doi.org/10.3390/molecules27196194.

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Vitamin E, a collection of lipophilic phenolic compounds based on chroman-6-ol, has a rich and fascinating oxidative chemistry involving a range of intermediate forms, some of which are proposed to be important in its biological functions. In this review, the available electrochemical and spectroscopic data on these oxidized intermediates are summarized, along with a discussion on how their lifetimes and chemical stability are either typical of similar phenolic and chroman-6-ol derived compounds, or atypical and unique to the specific oxidized isomeric form of vitamin E. The overall electroche

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13

Giffard, M., M. Sigalov, V. Khodorkovsky, A. Gorgues, and G. Mabon. "Ionic species derived from tetrathiafulvalenes (ttfs) : cation-radicals vs cations." Synthetic Metals 102, no. 1-3 (1999): 1713. http://dx.doi.org/10.1016/s0379-6779(98)00877-7.

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14

Shaik, Sason S., and Addy Pross. "Nucleophilic attack on cation radicals and cations. A theoretical analysis." Journal of the American Chemical Society 111, no. 12 (1989): 4306–12. http://dx.doi.org/10.1021/ja00194a023.

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15

Bogillo, V. I., and I. P. Gragerov. "Kinetics of the reduction of organic cations by cation radicals." Theoretical and Experimental Chemistry 21, no. 1 (1985): 42–48. http://dx.doi.org/10.1007/bf00524309.

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16

Tao, Xin, Constantin G. Daniliuc, Robert Knitsch, et al. "The special role of B(C6F5)3 in the single electron reduction of quinones by radicals." Chemical Science 9, no. 41 (2018): 8011–18. http://dx.doi.org/10.1039/c8sc03005g.

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In the presence of two molar equiv. of B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>p-benzoquinone reacts with persistent radicals TEMPO, trityl or decamethylferrocene by single electron transfer to give the doubly O-borylated benzosemiquinone radical anion with TEMPO<sup>+</sup>, trityl cation or ferrocenium counter cations.

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17

Arnold, Donald R., Xinyao Du, and Jing Chen. "The effect of meta- or para-cyano substitution on the reactivity of the radical cations of arylalkenes and alkanes. Radical ions in photochemistry, Part 34." Canadian Journal of Chemistry 73, no. 3 (1995): 307–18. http://dx.doi.org/10.1139/v95-042.

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The effect of electron-withdrawing substituents, meta- or para-cyano, on the reactivity of the radical cation of arylalkenes and alkanes has been determined. The radical cations were generated by single electron transfer (set) to an electron-accepting photosensitizer. Three reactions were studied: (i) the addition of nucleophile to the radical cation of arylalkenes, (ii) cleavage of the benzylic carbon–carbon bond of the radical cation of arylalkanes; and (iii) the deprotonation of the benzylic carbon–hydrogen bond of the radical cation of arylalkanes. The radical cations of 4-(1-phenylethenyl

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18

Wintgens, V., and J. C. Scaiano. "Photochemistry of dibenzylketone in Nafion membranes." Canadian Journal of Chemistry 65, no. 9 (1987): 2131–34. http://dx.doi.org/10.1139/v87-355.

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Photolysis of dibenzyl ketone in vacuum-dried Nafion membranes leads to the detection of fluorescence from the protonated ketone and formation of modest yields of benzyl cations characterized using laser photolysis techniques. Exchange of the acid sites in Nafion by cationic surfactants leads to decreased environmental polarity and a change in mechanism towards the benzyl radical chemistry which is common in organic solvents. The decay of benzyl radicals in Nafion membranes shows magnetic field dependence which indicates that geminate processes play an important role.

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19

Rhodes, Christopher J. "Studies of Radio-Labelled Free Radicals Derived from a VOC (Volatile Organic Compound), Benzaldehyde, Adsorbed in Cation-Exchanged Zeolite X." Progress in Reaction Kinetics and Mechanism 31, no. 3 (2006): 139–58. http://dx.doi.org/10.3184/146867806x197106.

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Radio-labelled free radicals were formed by the addition of muonium-a radioactive hydrogen atom with a positive muon as its nucleus-to benzaldehyde, as adsorbed in cation-exchanged zeolite X. PhCHOMu• radicals were the major species formed and the activation parameters associated with their reorientational motion were measured using longitudinal-field muon spin relaxation (LF-MuSRx). Two distinct adsorbed fractions were detected in each of the samples containing Li+, Na+, K+, Ca2+, Sr2+ and Ba2+ cations, believed to be from (1) an effectively bulk benzaldehyde component with an almost common a

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20

Vianello, Robert, and Zvonimir B. Maksić. "A Combined ab initio and Density Functional Study of the Electronic Structure of Thymine and 2-Thiothymine Radicals." Collection of Czechoslovak Chemical Communications 68, no. 12 (2003): 2322–34. http://dx.doi.org/10.1135/cccc20032322.

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The electronic and energetic properties of thymine (1) and 2-thiothymine (2) and their neutral and positively charged radicals are considered by a combined ab initio and density functional theory approach. It is conclusively shown that ionization of 1 and 2 greatly facilitates deprotonation of the formed radical cations thus making the proton transfer between charged and neutral precursor species thermodynamically favourable. The adiabatic ionization potential of 1 and 2 are analysed. It appears that ADIP(1) is larger than ADIP(2) by 10 kcal/mol, because of greater stability of the highest occ

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21

Zhang, Hongguang, Aiguo Wang, Ruixuan Zhao та Jinguang Hu. "Cation-mediated acid-base pairs for mild oxidative cleavage of lignocellulosic β-1,4-glycosidic bonds". BioResources 19, № 2 (2024): 2736–48. http://dx.doi.org/10.15376/biores.19.2.2736-2748.

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Solar-driven lignocellulosic biomass photoreforming holds significant promise for the production of value-added chemicals and fuels. The cleavage of the β-1,4-glycosidic bond is crucial for the effective conversion of lignocellulosic biomass. Polymeric carbon nitride (PCN) with acid-base pairs (M-C sites) is developed through heteroatomic carbon incorporation and cation insertion. It can be used for the gentle oxidation of cellobiose to monosaccharides, bypassing the formation of organic acids such as gluconic acid and glucaric acid. A series of different alkaline/alkaline-earth cation for reg

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22

Nomura, Shigeki, Yotaro Morishima, Toshihiro Koremoto, and Mikiharu Kamachi. "Cationic polymerization of vinyl monomers initiated by 10-methylphenothiazine cation radicals." Journal of Polymer Science Part A: Polymer Chemistry 32, no. 9 (1994): 1703–10. http://dx.doi.org/10.1002/pola.1994.080320912.

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23

Arnold, Donald R., Mary S. W. Chan, and Kimberly A. McManus. "Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction, Part 12. Factors controlling the regiochemistry of the reaction with alcohol as the nucleophile." Canadian Journal of Chemistry 74, no. 11 (1996): 2143–66. http://dx.doi.org/10.1139/v96-243.

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The photo-NOCAS reaction that combines methanol, serving as the nucleophile, and the radical cation of 4-methyl-1,3-pentadiene (14+•), substituting on the 1,4-dicyanobenzene radical anion (1−•), yields (E)-1-(4-cyanophenyl)-4-methoxy-4-methyl-2-pentene (15) as the major product. This regioisomer arises from bonding of methanol to C-4, the more heavily alkyl-substituted carbon of the diene, giving the less alkyl-substituted allylic radical. All previous examples of the photo-NOCAS reaction have yielded major adduct(s) having regiochemistry consistent with the anti-Markovnikov rule; the more hea

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24

Qin, Ling, G. N. R. Tripathi, and Robert H. Schüler. "Radiation Chemical Studies of the Oxidation of Aniline in Aqueous Solution." Zeitschrift für Naturforschung A 40, no. 10 (1985): 1026–39. http://dx.doi.org/10.1515/zna-1985-1009.

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Oxidation of aniline in aqueous solution by ·OH radicals proceeds predominantly via addition to the ring followed by elimination of OH- on the microsecond time scale to form the aniline radical cation. Direct oxidation by electron transfer accounts for less than 4% of the ·OH reactions. The different hydroxycyclohexadienyl isomers produced by ·OH addition decay at different rates with this decay catalyzed both by protons and phosphate. In basic solution the resultant radical cation deprotonates to form the anilino radical. The p Ka for the equilibrium between the acidic and basic forms of this

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25

Shukla, D., N. P. Schepp, N. Mathivanan, and L. J. Johnston. "Generation and spectroscopic and kinetic characterization of methoxy-substituted phenoxyl radicals in solution and on paper." Canadian Journal of Chemistry 75, no. 12 (1997): 1820–29. http://dx.doi.org/10.1139/v97-615.

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A number of methoxy-substituted phenoxyl radicals have been generated and characterized by laser flash photolysis techniques in solution and on paper. The radicals have been produced by three routes in solution: hydrogen abstraction from phenols by tert-butoxyl radical, photolysis of α-aryloxyacetophenones, and direct excitation of phenols. Most of the phenoxyl radicals studied have a characteristic absorption near 400 nm; the ortho-substituted radicals have an additional broad absorption in the visible in non-hydroxylic solvents (e.g., 650 nm for 2-methoxyphenoxyl radical). The relative inten

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26

Ikeh, Mélanie A. C., Stavroula L. Kastora, Alison M. Day, et al. "Pho4 mediates phosphate acquisition inCandida albicansand is vital for stress resistance and metal homeostasis." Molecular Biology of the Cell 27, no. 17 (2016): 2784–801. http://dx.doi.org/10.1091/mbc.e16-05-0266.

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During interactions with its mammalian host, the pathogenic yeast Candida albicans is exposed to a range of stresses such as superoxide radicals and cationic fluxes. Unexpectedly, a nonbiased screen of transcription factor deletion mutants revealed that the phosphate-responsive transcription factor Pho4 is vital for the resistance of C. albicans to these diverse stresses. RNA-Seq analysis indicated that Pho4 does not induce stress-protective genes directly. Instead, we show that loss of Pho4 affects metal cation toxicity, accumulation, and bioavailability. We demonstrate that pho4Δ cells are s

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27

Bai, Zhikun. "The spatial and temporal distribution of cationic and anionic radicals in early embryo implantation." Open Chemistry 18, no. 1 (2020): 1075–79. http://dx.doi.org/10.1515/chem-2020-0136.

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AbstractThe main objective of this study is to obtain some knowledge of cationic and anionic radicals in early embryo implantation in mice. The method used in this study is known as histochemical staining, in which Xylidine ponceau was used at pH 2.5 and toluidine blue was used at pH 4.0. We detected the change in glycosaminoglycans and total proteins in the endometrial stroma during the preimplantation of mice. This study revealed that the distribution patterns of cationic radicals and anionic radicals are similar on days 4 and 5 of pregnancy. However, there was a distinct difference between

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Sailer, Christian F., and Eberhard Riedle. "Photogeneration and reactions of benzhydryl cations and radicals: A complex sequence of mechanisms from femtoseconds to microseconds." Pure and Applied Chemistry 85, no. 7 (2013): 1487–98. http://dx.doi.org/10.1351/pac-con-13-04-01.

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Benzhydryl radicals and cations are reactive intermediates central to the understanding of organic reactivity. They can be generated from benzhydryl halides by UV irradiation. We performed transient absorption (TA) measurements over the range from femtoseconds to microseconds to unravel the complete reaction scheme. The 290–720-nm probe range allows the unambiguous monitoring of all fragments. The appearance of the radical is delayed to the optical excitation, the onset of the cation signal is found even later. Ab initio calculations show that this non-rate behavior in the 100 fs range is due

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Arnold, Donald R., and Kimberly A. McManus. "Photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction: methanol, beta-myrcene, and 1,4-dicyanobenzene. Intramolecular cyclization of an ene-diene radical cation." Canadian Journal of Chemistry 76, no. 9 (1998): 1238–48. http://dx.doi.org/10.1139/v98-156.

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The photochemical nucleophile-olefin combination, aromatic substitution (photo-NOCAS) reaction of methanol, 7-methyl-3-methylene-1,6-octadiene ( β-myrcene, 1), and 1,4-dicyanobenzene yields five 1:1:1 adducts:cis-2-(4-cyanophenyl)-4-(1-methoxy-1-methylethyl)-1-methylenecyclohexane (15), trans-2-(4-cyanophenyl)-4-(1-methoxy-1-methylethyl)-1-methylenecyclohexane (16), 1-(4-cyanophenylmethyl)-4-(1-methoxy-1-methylethyl)cyclohexene (17), 4-[4-methoxy-3,3-dimethylcyclohex-(E)-1-ylidenyl]methylbenzonitrile (18), and 4-(1-vinyl-4-trans-methoxy-3,3-dimethylcyclohexyl)benzonitrile (19). All of these ad

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30

Piatkivskyi, Andrii, Justin Kai-Chi Lau, Giel Berden, et al. "Hydrogen atom transfer in the radical cations of tryptophan-containing peptides AW and WA studied by mass spectrometry, infrared multiple-photon dissociation spectroscopy, and theoretical calculations." European Journal of Mass Spectrometry 25, no. 1 (2018): 112–21. http://dx.doi.org/10.1177/1469066718802547.

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Two types of radical cations of tryptophan—the π-radical cation and the protonated tryptophan-N radical—have been studied in dipeptides AW and WA. The π-radical cation produced by removal of an electron during collision-induced dissociation of a ternary Cu(II) complex was only observed for the AW peptide. In the case of WA, only the ion corresponding to the loss of ammonia, [WA–NH3] •+, was observed from the copper complex. Both protonated tryptophan-N radicals were produced by N-nitrosylation of the neutral peptides followed by transfer to the gas phase via electrospray ionization and subsequ

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31

Glass, Richard S., A. M. Radspinner, and W. P. Singh. "Sulfur cation radicals." Pure and Applied Chemistry 68, no. 4 (1996): 853–58. http://dx.doi.org/10.1351/pac199668040853.

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32

Hildenbrand, Knut. "The SO4·̄induced Oxidation of 2′-Deoxyuridine-5′-phosphate, Uridine-5′-phosphate and Thymidine-5′-phosphate. An ESR Study in Aqueous Solution." Zeitschrift für Naturforschung C 45, no. 1-2 (1990): 47–58. http://dx.doi.org/10.1515/znc-1990-1-210.

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Abstract Reactions of photolytically generated SO4·̄ with 2′-deoxyuridine-5′-phosphate (5′-dUMP), uridine-5′-phosphate (5′-UMP) and thymidine-5′-phosphate (5′-dTMP) were studied by ESR spectroscopy in aqueous solution under anoxic conditions. From 5′-dUMP and 5′-UMP the 5′,5-cyclicphosphate-6-yl radicals 10 and 11 were generated (pH 2 -11) whereas from 5′-dTMP at pH 3 -8 the 5,6-dihydro-6-hydroxy-5-yl radical 14 and at pH 7 -1 1 the 5-methylene-2′-deoxyuridine-5′-phosphate radical 15 was produced. In the experiments with 5′-UMP in addition to radical 11 the signals of sugar radicals 12 and 13

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33

Shevchenko, D. "Synthesis methods, structure and applications of cyanoaurate complexes with organic cation radicals and onium cations: a review." Bulletin of the South Ural State University series "Chemistry" 16, no. 2 (2024): 14–36. http://dx.doi.org/10.14529/chem240202.

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Cyanoaurate complexes represent a wide class of compounds with diverse structures and many potential practical applications, including such areas as microelectronics, nanotechnology, materials science, medicine. In contrast to metal cyanoaurates, complexes with only organic radical cations and onium/inium cations do not have a coordination polymeric structure; their crystal organization is determined only by noncovalent interactions between the structural units. The absence of well-defined coordination centers for ordering cyanoaurate anions imposes some restrictions on the ability of syntheti

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34

Pincock, J. A., and I. S. Young. "The photochemistry of indenyl alcohols and esters: Substituent effects on the competition between ion- and radical-derived products." Canadian Journal of Chemistry 81, no. 10 (2003): 1083–95. http://dx.doi.org/10.1139/v03-131.

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The photochemistry of the indenyl acetates 1 and pivalates 2, substituted with X = H, 5-CH3O, and 6-CH3O, have been examined in both methanol and cyclohexane. The precursor alcohols 3 were also found to be photoreactive. Although only radical-derived products were obtained in cyclohexane, both ion- and radical-derived products were formed in methanol. The absence of significant fluorescence emission from any of the substrates 1, 2, and 3 indicates that the excited singlet states are highly reactive. A mechanism is proposed for the ion-derived products that proceeds through direct heterolytic c

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35

Li, Lijuan, Richard E. Perrier, Donald R. Eaton, and Michael J. McGlinchey. "The reactions of nitrosoarenes with cationic cyclohexadienyl complexes of iron tricarbonyl: an ESR study." Canadian Journal of Chemistry 67, no. 11 (1989): 1868–77. http://dx.doi.org/10.1139/v89-290.

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The reactions of nitrosoarenes with the (cyclohexadienyl)Fe(CO)3 cation have been investigated by using electron spin resonance spectroscopy. The radicals produced are nitroxides of the type (OC)3Fe(C6H7)(Ar)N—O• but, in some cases, disproportionation and loss of the metal carbonyl fragment leads to the corresponding C6H5(Ar)N—O• radical. With bulky nitrosoarenes, such as C6Me5NO, isomers are observed in which the aryl ring rotation is slow on the ESR time scale. The analogous reactions with the cyclohexadienyl cation derived from the B ring of (ergosteryl acetate)Fe(CO)3 lead to initial attac

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36

Rozanowska, Malgorzata, Ruth Edge, Edward J. Land, Suppiah Navaratnam, Tadeusz Sarna та T. George Truscott. "Scavenging of Retinoid Cation Radicals by Urate, Trolox, and α-, β-, γ-, and δ-Tocopherols". International Journal of Molecular Sciences 20, № 11 (2019): 2799. http://dx.doi.org/10.3390/ijms20112799.

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Retinoids are present in human tissues exposed to light and under increased risk of oxidative stress, such as the retina and skin. Retinoid cation radicals can be formed as a result of the interaction between retinoids and other radicals or photoexcitation with light. It has been shown that such semi-oxidized retinoids can oxidize certain amino acids and proteins, and that α-tocopherol can scavenge the cation radicals of retinol and retinoic acid. The aim of this study was to determine (i) whether β-, γ-, and δ-tocopherols can also scavenge these radicals, and (ii) whether tocopherols can scav

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ROECK, M., та M. SCHMITTEL. "ChemInform Abstract: Enol Cation Radicals in Solution. Part 5. Controlled Oxidation of Enolates to α-Carbonyl Radicals and α-Carbonyl Cations." ChemInform 25, № 13 (2010): no. http://dx.doi.org/10.1002/chin.199413096.

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Rathore, Rajendra, Sergey V. Lindeman, and Sameh H. Abdelwahed. "Design, Synthesis, Electronic Properties, and X-ray Structural Characterization of Various Modified Electron-Rich Calixarene Derivatives and Their Conversion to Stable Cation Radical Salts." Molecules 27, no. 18 (2022): 5994. http://dx.doi.org/10.3390/molecules27185994.

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We have designed and synthesized electron-rich calixarene derivatives, which undergo reversible electrochemical oxidation in a well-accessible potential range that allows the ready preparation and isolation of the corresponding cation radicals. Preparation of mono- or tetra-radical cation can be achieved by using stable aromatic cation-radical salts such as MA+•, MB+•, and NAP+• as selective organic oxidants. The cation radicals of calixarenes are stable indefinitely at ambient temperatures and can be readily characterized by UV-vis-NIR spectroscopy. These cation radicals bind a single molecul

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Schröder, Detlef, Héloïse Soldi-Lose, and Helmut Schwarz. "Unimolecular Rearrangements of Transient Carboxy Radicals and Cations." Australian Journal of Chemistry 56, no. 5 (2003): 443. http://dx.doi.org/10.1071/ch02265.

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Charge reversal (CR) and neutralization–reionization (NR) mass spectra of aliphatic carboxylate ions RCOO– provide insight into the behaviour of the transient neutral carboxy radicals RCOO• as well as the short-lived RCOO+ cations. For the neutral radicals, a novel hydrogen rearrangement is proposed, which might explain the sometimes only modest yields in the Hunsdiecker reaction of carboxylic acids in the condensed phase.

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Wright, Michael E., and Myung Jong Jin. "Polymer-supported cation radicals." Journal of Organic Chemistry 54, no. 4 (1989): 965–68. http://dx.doi.org/10.1021/jo00265a043.

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41

Tabakovic, Ibro, Toshihide Maki, Larry L. Miller, and Yuan Yu. "Persistent thiophene cation radicals." Chemical Communications, no. 16 (1996): 1911. http://dx.doi.org/10.1039/cc9960001911.

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42

Galinato, Mary Grace I., Dariusz Niedzwiedzki, Cailin Deal, Robert R. Birge, and Harry A. Frank. "Cation radicals of xanthophylls." Photosynthesis Research 94, no. 1 (2007): 67–78. http://dx.doi.org/10.1007/s11120-007-9218-5.

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43

Molski, Matthias J., Monther A. Khanfar, Hashem Shorafa, and Konrad Seppelt. "Halogenated Benzene Cation Radicals." European Journal of Organic Chemistry 2013, no. 15 (2013): 3131–36. http://dx.doi.org/10.1002/ejoc.201201691.

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Molski, Matthias J., Doreen Mollenhauer, Sebastian Gohr, et al. "Halogenated Benzene Cation Radicals." Chemistry - A European Journal 18, no. 21 (2012): 6644–54. http://dx.doi.org/10.1002/chem.201102960.

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Soualmi, Saida, Luba Ignatovich, and Viatcheslav Jouikov. "Cation radicals of organogermatranes." Applied Organometallic Chemistry 24, no. 12 (2010): 865–71. http://dx.doi.org/10.1002/aoc.1710.

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Pirisi, Katalin, Lipsa Nag, Zsuzsanna Fekete, et al. "Identification of the vibrational marker of tyrosine cation radical using ultrafast transient infrared spectroscopy of flavoprotein systems." Photochemical & Photobiological Sciences 20, no. 3 (2021): 369–78. http://dx.doi.org/10.1007/s43630-021-00024-y.

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AbstractTryptophan and tyrosine radical intermediates play crucial roles in many biological charge transfer processes. Particularly in flavoprotein photochemistry, short-lived reaction intermediates can be studied by the complementary techniques of ultrafast visible and infrared spectroscopy. The spectral properties of tryptophan radical are well established, and the formation of neutral tyrosine radicals has been observed in many biological processes. However, only recently, the formation of a cation tyrosine radical was observed by transient visible spectroscopy in a few systems. Here, we as

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Araki, Mitsunori, Pawel Cias, Alexey Denisov, Jan Fulara, and John P. Maier. "Electronic spectroscopy of the nonlinear carbon chains C4H4+ and C8H4+." Canadian Journal of Chemistry 82, no. 6 (2004): 848–53. http://dx.doi.org/10.1139/v04-013.

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The electronic spectrum of a nonlinear carbon chain radical C4H4+ was observed after mass-selective deposition in a 6 K neon matrix. The corresponding gas-phase spectra of C4H4+ and C4D4+ have been observed in the 512 to 513 nm region and at 710 nm for C8H4+. These were detected in direct absorption by cavity ringdown spectroscopy through a supersonic planar discharge. The electronic transition energies of these nonlinear carbon chain radicals correlate well with those of the polyacetylene cations HCnH+ (n = 4, 6, 8). The observed profiles are reproduced with rotational constants obtained by a

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Chen, Yuan, Xiguang Liu, Xueqi Sun, et al. "Synthesis and Antioxidant Activity of Cationic 1,2,3-Triazole Functionalized Starch Derivatives." Polymers 12, no. 1 (2020): 112. http://dx.doi.org/10.3390/polym12010112.

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In this study, starch was chemically modified to improve its antioxidant activity. Five novel cationic 1,2,3-triazole functionalized starch derivatives were synthesized by using “click” reaction and N-alkylation. A convenient method for pre-azidation of starch was developed. The structures of the derivatives were analyzed using FTIR and 1H NMR. The radicals scavenging abilities of the derivatives against hydroxyl radicals, DPPH radicals, and superoxide radicals were tested in vitro in order to evaluate their antioxidant activity. Results revealed that all the cationic starch derivatives (2a–2e

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Hioe, Johnny, Davor Šakić, Valerije Vrček, and Hendrik Zipse. "The stability of nitrogen-centered radicals." Organic & Biomolecular Chemistry 13, no. 1 (2015): 157–69. http://dx.doi.org/10.1039/c4ob01656d.

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Bogillo, V. I., and I. P. Gragerov. "Reactions of Free Radicals with Organic Cations." Russian Chemical Reviews 57, no. 1 (1988): 29–40. http://dx.doi.org/10.1070/rc1988v057n01abeh003332.

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