scholarly journals Lifetimes and Reaction Pathways of Guanine Radical Cations and Neutral Guanine Radicals in an Oligonucleotide in Aqueous Solutions

2012 ◽  
Vol 134 (10) ◽  
pp. 4955-4962 ◽  
Author(s):  
Yekaterina Rokhlenko ◽  
Nicholas E. Geacintov ◽  
Vladimir Shafirovich
Keyword(s):  
Aqueous Solutions ◽  
Radical Cations ◽  
Reaction Pathways

scholarly journals Spectral Probe for Electron Transfer and Addition Reactions of Azide Radicals with Substituted Quinoxalin-2-Ones in Aqueous Solutions

2021 ◽  
Vol 22 (2) ◽  
pp. 633
Author(s):  
Konrad Skotnicki ◽  
Slawomir Ostrowski ◽  
Jan Cz. Dobrowolski ◽  
Julio R. De la Fuente ◽  
Alvaro Cañete ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Aqueous Solutions ◽  
Absorption Spectra ◽  
Density Functional ◽  
Reduction Potential ◽  
Biological Significance ◽  
Radical Cations ◽  
Basis Sets ◽  
Double Bonds ◽  
Reduction Potentials

The azide radical (N3●) is one of the most important one-electron oxidants used extensively in radiation chemistry studies involving molecules of biological significance. Generally, it was assumed that N3● reacts in aqueous solutions only by electron transfer. However, there were several reports indicating the possibility of N3● addition in aqueous solutions to organic compounds containing double bonds. The main purpose of this study was to find an experimental approach that allows a clear assignment of the nature of obtained products either to its one-electron oxidation or its addition products. Radiolysis of water provides a convenient source of one-electron oxidizing radicals characterized by a very broad range of reduction potentials. Two inorganic radicals (SO4●−, CO3●−) and Tl2+ ions with the reduction potentials higher, and one radical (SCN)2●− with the reduction potential slightly lower than the reduction potential of N3● were selected as dominant electron-acceptors. Transient absorption spectra formed in their reactions with a series of quinoxalin-2-one derivatives were confronted with absorption spectra formed from reactions of N3● with the same series of compounds. Cases, in which the absorption spectra formed in reactions involving N3● differ from the absorption spectra formed in the reactions involving other one-electron oxidants, strongly indicate that N3● is involved in the other reaction channel such as addition to double bonds. Moreover, it was shown that high-rate constants of reactions of N3● with quinoxalin-2-ones do not ultimately prove that they are electron transfer reactions. The optimized structures of the radical cations (7-R-3-MeQ)●+, radicals (7-R-3-MeQ)● and N3● adducts at the C2 carbon atom in pyrazine moiety and their absorption spectra are reasonably well reproduced by density functional theory quantum mechanics calculations employing the ωB97XD functional combined with the Dunning’s aug-cc-pVTZ correlation-consistent polarized basis sets augmented with diffuse functions.

Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase

1998 ◽  
Vol 63 (9) ◽  
pp. 1498-1512 ◽  
Author(s):  
Ulf Mazurek ◽  
Detlef Schröder ◽  
Helmut Schwarz
Keyword(s):  
Gas Phase ◽  
Bond Activation ◽  
Branching Ratio ◽  
Radical Cations ◽  
Reaction Pathways ◽  
Ion Cyclotron Resonance ◽  
Ion Transfer ◽  
Consistent Picture ◽  
Anion Transfer ◽  
Chain Lengths

Gaseous chromium fluoride monocations CrFn+ (n = 1-4) can be prepared by sequential fluorine-atom transfer from nitrogen trifluoride, NF3, to chromium cation. In addition, formal F- anion transfer to CrFn+ (n = 2-4) to yield the corresponding neutral chromium fluorides CrFn+1 is observed. In conjunction with a re-evaluation of previous data, the present results provide a consistent picture of the thermochemistry of neutral and cationic chromium fluorides. The reactivity of the CrFn+ ions towards alkanes is investigated in a Fourier-transform ion cyclotron resonance mass spectrometer. While "bare" Cr+ does not react with alkanes, the chromium fluoride cations CrFn+ do; CrF3+ and CrF4+ are even capable of activating methane. With both increasing oxidation state of chromium and increasing chain lengths of the alkane, the branching ratio of the possible reaction pathways shifts from homolytic C-H and C-C bond activation to hydride- and methanide-ion transfer to yield carbocations, and finally electron transfer generating hydrocarbon radical cations.

scholarly journals Chemical and photochemical properties of chloroharmine derivatives in aqueous solutions

2016 ◽  
Vol 18 (2) ◽  
pp. 886-900 ◽  
Author(s):  
Federico A. O. Rasse-Suriani ◽  
M. Paula Denofrio ◽  
Juan G. Yañuk ◽  
M. Micaela Gonzalez ◽  
Ezequiel Wolcan ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Reaction Pathways ◽  
Photochemical Properties

In water, chloroharmines follow very distinctive thermal and photochemical pH- and O2-dependent-reaction pathways.

Structure and stability of radical cations from cyclic and open-chain dithia compounds in aqueous solutions

1979 ◽  
Vol 101 (18) ◽  
pp. 5322-5329 ◽  
Author(s):  
K. D. Asmus ◽  
D. Bahnemann ◽  
C. H. Fischer ◽  
D. Veltwisch
Keyword(s):  
Aqueous Solutions ◽  
Radical Cations ◽  
Open Chain ◽  
Structure And Stability

DFT studies of unique stereoelectronic effects of substituents on divergent reaction pathways of methylenecyclobutanone radical cations

Tetrahedron ◽  
2012 ◽  
Vol 68 (27-28) ◽  
pp. 5564-5571 ◽  
Author(s):  
Yusuke Kano ◽  
Futoshi Tanaka ◽  
Eisuke Ohta ◽  
Kazuhiko Mizuno ◽  
Hiroshi Ikeda
Keyword(s):  
Radical Cations ◽  
Reaction Pathways ◽  
Dft Studies ◽  
Stereoelectronic Effects

ChemInform Abstract: SULFUR-NITROGEN AND SULFUR-OXYGEN THREE-ELECTRON-BONDED RADICALS AND RADICAL CATIONS IN AQUEOUS SOLUTIONS

1985 ◽  
Vol 16 (37) ◽  
Author(s):  
K.-D. ASMUS ◽  
M. GOEBL ◽  
K.-O. HILLER ◽  
S. MAHLING ◽  
J. MOENIG
Keyword(s):  
Aqueous Solutions ◽  
Radical Cations
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