Hydrogen atom abstraction from carbon-, phosphorus-, silicon-, and tin-hydrogen bonds by the triplet excited state of the tetrakis(.mu.-pyrophosphito)diplatinum(II) tetraanion. Spectroscopic observation of the mixed-valence hydride complex Pt2(.mu.-P2O5H2)4H4-

1987 ◽  
Vol 109 (20) ◽  
pp. 6076-6079 ◽  
Author(s):  
D. Max Roundhill ◽  
Stephen J. Atherton ◽  
Zhong Ping Shen
Keyword(s):  
Excited State ◽  
Hydrogen Atom ◽  
Hydrogen Bonds ◽  
Mixed Valence ◽  
Spectroscopic Observation ◽  
Hydrogen Atom Abstraction ◽  
Triplet Excited State ◽  
Hydride Complex

scholarly journals Excited-state hydrogen atom abstraction initiates the photochemistry of β-2′-deoxycytidine

2015 ◽  
Vol 6 (3) ◽  
pp. 2035-2043 ◽  
Author(s):  
Rafał Szabla ◽  
Jesús Campos ◽  
Judit E. Šponer ◽  
Jiří Šponer ◽  
Robert W. Góra ◽  
...  
Keyword(s):  
Excited State ◽  
Hydrogen Atom ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Hydrogen Atom Abstraction ◽  
Nucleobase Loss

H–D exchange experiments and quantum-chemical calculations elucidate the mechanism of photoinduced anomerisation and nucleobase loss reactions observed in β-2′-deoxycytidine.

2-Deoxyribose Radicals in the Gas Phase and Aqueous Solution. Transient Intermediates of Hydrogen Atom Abstraction from 2-Deoxyribofuranose

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Atom ◽  
Gas Phase ◽  
Computational Study ◽  
Hydrogen Atom Abstraction ◽  
Oh Radical ◽  
Free Energies ◽  
Intramolecular Hydrogen ◽  
Solvation Free Energies ◽  
Transient Intermediates

A computational study at correlated levels of theory is reported to address the structures and energetics of transient radicals produced by hydrogen atom abstraction from C-1, C-2, C-3, C-4, C-5, O-1, O-3, and O-5 positions in 2-deoxyribofuranose in the gas phase and in aqueous solution. In general, the carbon-centered radicals are found to be thermodynamically and kinetically more stable than the oxygen-centered ones. The most stable gas-phase radical, 2-deoxyribofuranos-5-yl (5), is produced by H-atom abstraction from C-5 and stabilized by an intramolecular hydrogen bond between the O-5 hydroxy group and O-1. The order of radical stabilities is altered in aqueous solution due to different solvation free energies. These prefer conformers that lack intramolecular hydrogen bonds and expose O-H bonds to the solvent. Carbon-centered deoxyribose radicals can undergo competitive dissociations by loss of H atoms, OH radical, or by ring cleavages that all require threshold dissociation or transition state energies >100 kJ mol-1. This points to largely non-specific dissociations of 2-deoxyribose radicals when produced by exothermic hydrogen atom abstraction from the saccharide molecule. Oxygen-centered 2-deoxyribose radicals show only marginal thermodynamic and kinetic stability and are expected to readily fragment upon formation.

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