A semiempirical study of 2,2′-dichlorodiethyl sulfide SN2 and neighboring group hydrolysis reaction mechanisms in the gas phase and in aqueous solution

1996 ◽  
Vol 370 (2-3) ◽  
pp. 209-220 ◽  
Author(s):  
William H. Donovan ◽  
William E. White
1987 ◽  
Vol 72 (3) ◽  
pp. 175-195 ◽  
Author(s):  
Oscar N. Ventura ◽  
Agust� Lled�s ◽  
Rosanna Bonaccorsi ◽  
Juan Bertr�n ◽  
Jacopo Tomasi

2005 ◽  
Vol 70 (11) ◽  
pp. 1769-1786 ◽  
Author(s):  
Luc A. Vannier ◽  
Chunxiang Yao ◽  
František Tureček

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.


Author(s):  
Branislav Milovanović ◽  
Jurica Novak ◽  
Mihajlo Etinski ◽  
Wolfgang Domcke ◽  
Nadja Doslic

Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy...


2003 ◽  
Vol 101 (13) ◽  
pp. 1945-1953 ◽  
Author(s):  
FRANCESCO AQUILANTE ◽  
MAURIZIO COSSI ◽  
ORLANDO CRESCENZI ◽  
GIOVANNI SCALMANI ◽  
VINCENZO BARONE

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