• Title/Summary/Keyword: Cation-radical

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Electron Spin Resonance and Electron Nuclear Double Resonance Studies on the Photoinduced Charge Separation of N-Methylphenothiazine in Phenyltriethoxysilane, Vinyltriethoxysilane and Methyltriethoxysilane Gel Matrices

  • Kang, Young-Soo;Park, Chan-Young
    • Journal of the Korean Magnetic Resonance Society
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    • v.4 no.2
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    • pp.91-102
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    • 2000
  • The photoproduced cation radical of N-methylphenothiazine doped in the different kind of matrices of phenyltriethoxysilane (PhiTEOS), vinyltriethoxysilane (VTEOS), and methyloiethoxysilane (METOS) was comparatively studied with electron spin resonance (ESR) and electron nuclear double resonance (ENDOR). The photoinduced charge separation efficiency was determined by integration of ESR spectra which correspond to the amount of photoproduced cation radical in the matrices. This was correlatively studied with the polarity and pore size of the gel matrices. The polarity of the matrices was comparatively determined by measuring λ$\sub$max/ values of PC$_1$ in the different matrices. The relative pore size among the matrices was determined by measuring relative proton matrix ENDOR line widths of the photoproduced cation radical of PCI. The decay kinetic constants of the cation radical of PCI in the different matrices was relatively studied with fitting the biexponential decay curves after exposure into the ambient condition. This is correlatively interpreted with the polarity and pore size of the matrices.

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Decarbonylation of the 2-Hydroxypyridine Radical Cation: A Computational Study

  • Choe, Joong Chul
    • Bulletin of the Korean Chemical Society
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    • v.35 no.10
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    • pp.3021-3024
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    • 2014
  • The potential energy surface (PES) for the dissociation of the 2-hydroxypyridine (2-HP) radical cation was determined from G3//B3LYP calculations, including the loss of CO, HCN, and HNC. The formation of the 1H-pyrrole radical cation by decarbonylation through a more stable tautomer, the 2-pyridone (2-PY) radical cation, was the most favorable dissociation pathway. Kinetic analysis by the Rice-Ramsperger-Kassel-Marcus model calculations was carried out based on the obtained PES. It is proposed that the dissociation occurs after a rapid tautomerization to 2-$PY^{{\cdot}+}$, and that most of the ions generated by ionization of 2-HP have the structure of 2-$PY^{{\cdot}+}$ at equilibrium above the tautomerization barrier.

Suppression of the Methyl Radical Loss from Acetone Cation within (CH3COCH3)n{CH3COCH3}+ Clusters

  • Lee, Yong-Hoon;Oh, Myoung-Kyu;Choi, Sung-Chul;Ko, Do-Kyeong;Lee, Jong-Min
    • Bulletin of the Korean Chemical Society
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    • v.29 no.8
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    • pp.1519-1524
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    • 2008
  • We have investigated the photophysics of the acetone radical cation in the vacuum ultraviolet energy region by multiphoton ionization combined with time-of-flight mass spectrometry in a cluster beam. We have found that the loss of methyl radical from the acetone radical cations is remarkably suppressed at 10.5 eV when they are solvated by a few neutral acetone molecules. The cluster ion mass spectra obtained by nanosecond and picosecond laser pulses reveal that there are intermolecular processes, occurring in several tens of picoseconds, which are responsible for the survival of the acetone cations in clusters. This remarkable solvation effect on the yield of the methyl radical loss from the acetone cation can be rationalized by the intracluster vibrational energy redistribution and the self-catalyzed enolization which compete with the methyl radical loss process.

Cation Radicals with 2-Phridylhydrazones in Nitrile Solvents s-Triazolo[4,3-a]pyridines by Thianthrene Cation Radical Perchlorate and 1-(2-Pyridyl)-1,2,4-Triazoles by Tris(2,4-Dibromophenyl)-aminium Hexachloroantimonate

  • 박균하;전건;신승림;오세화
    • Bulletin of the Korean Chemical Society
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    • v.18 no.6
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    • pp.604-608
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    • 1997
  • Reactions of arenealdehyde 2-pyridylhydrazones (1) with thianthrene cation radical ($Th^{+·}$) and tris(2,4-dibromophenyl)aminium hexachloroantimonate ($Ar_3N^{+·}SbCl_6^-$) were investigated. The major product was switched depending on the cation radical being used. That is, s-triazolo[4,3-α]pyridines (2), an intramolecular cyclization product, and 1-(2-pyridyl)-1,2,4-triazoles (3), an intermolecular cycloaddition product, were obtained as a major product when reacted with $Th^{+·}$ and $Ar_3N^{+·}$, respectively in nitrile solvents. The plausible mechanisms are proposed based on both the reduction potentials of $Th^{+·}$ and $Ar_3N^{+·}$ and control experiments.

Formation and Properties of Enyne Radical Cation

  • Kim, Bang-Duk;Shim, Sang-Chul;Noboyuki Ichinose;Sachiko Tojo;Tetsuro Majima
    • Journal of Photoscience
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    • v.8 no.2
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    • pp.67-69
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    • 2001
  • Radical cations of DPBEY and PPCB were generated by ${\gamma}$-radiolysis and pulse radiolysis in halogenated solvents. The radical cation PPCB+ shows 505 (shoulder) and 520 nm absorption peaks with 700 ns lifetime in agreement with the laser flash photolysis work and strongly support the exciplex mechanism proposed for the photoreaction of PPCB and dimethylfumarate.

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Radical Polymerization of Vinyl Monomers to Poly(vinyl)s having nBu3Sn end Groups with Biological Activity

  • Park, Jaeyoung;Lee, Beomgi;Kim, Seongsim;Cheong, Hyeonsook;Gwak, Gyeongja;Lee, Ki Bok;Woo, Hee-Gweon
    • Journal of Integrative Natural Science
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    • v.6 no.2
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    • pp.71-75
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    • 2013
  • $Bu_3Sn$-endded poly(vinyl)s with biological activity were obtained by the radical polymerization of vinyl monomers using thianthrene cation radical/$^nBu_3H$. Thianthrene cation and stannyl radicals promoted the homopolymerization and copolymerization of styrene and ethyl vinyl ether having number average molecular weights of 2000-3100. Tributyltin hydride functions as a chain transfer agent. Such polymereization by cationic thianthrene and stannyl radicals could provide some clues for the biological reaction in living animals. Plausible polymerization mechanisms were suggested.

Growth Behavial Couctive PolyanilineFilm on a Platinum Electrode by Electrochemical Oxidation (II) (전해산화에 의한 백금전극상 전도성 폴리아닐린 피막의 생장 거동(II))

  • 신성호;이주성
    • Journal of Surface Science and Engineering
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    • v.21 no.3
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    • pp.95-102
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    • 1988
  • The anodic oxidation of aniline in aqueous sulfuric acid solution on a platinum was studied. To examine of mechanism of this reaction, the date were obtained during controlled potential electrolysis, aided by computer system. The reaction mechanism was assumed the electrochemical-chemical-electrochemical(ECE) mechanism. We obtained the result that the intial charge transfer step proceeds through a radical cation, and this radical cation were bound cation led to may type of dimer in which p-aminodiphenylamine was de-electronated again to give the polymer.

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