Web Release Date: June 16,
Intermolecular Proton Transfer in Anionic Complexes of Uracil with Alcohols
czyk,
and
Department of Chemistry, University of Gdask, Sobieskiego 18, 80-952 Gdask, Poland, and Chemical
Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218
Received: January 14, 2005
In Final Form: April 25, 2005
Abstract:
A series of 18 alcohols (ROH) has been designed with an enthalpy of deprotonation in the gas phase (HDP)
in the range 13.8-16.3 eV. The effects of excess electron attachment to the binary alcohol-uracil
(ROH···U) complexes have been studied at the density functional level with a B3LYP exchange-correlation
functional and at the second-order M
ller-Plesset perturbation theory level. The photoelectron spectra of
anionic complexes of uracil with 3 alcohols (ethanol, 2,2,3,3,3-pentafluoropropanol, and 1,1,1,3,3,3-hexafluoro-2-propanol) have been measured with 2.54 eV photons. For ROHs with deprotonation enthalpies larger than
14.8 eV, only the ROH···U- minimum exists on the potential energy surface of the anionic complex. For
alcohols with deprotonation enthalpies in the range 14.3-14.8 eV, two minima might exist on the anionic
potential energy surface, which correspond to the RO-···HU. and ROH···U- structures. For ROHs with
deprotonation enthalpies smaller than 14.3 eV, the excess electron attachment to the ROH···U complex always
induces a barrier-free proton transfer from the hydroxyl group of ROH to the O8 atom of U, with the product
being RO-···HU..
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