화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.109, No.27, 13383-13391, 2005
Intermolecular proton transfer in anionic complexes of uracil with alcohols
A series of 18 alcohols (ROH) has been designed with an enthalpy of deprotonation in the gas phase (H-DP) in the range 13.8-16.3 eV. The effects of excess electron attachment to the binary alcohol-uracil ((ROHU)-U-...) complexes have been studied at the density functional level with a B3LYP exchange-correlation functional and at the second-order Moller-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 (ROHU-)-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 (ROHU.)-U-... structures. For ROHs with deprotonation enthalpies smaller than 14.3 eV, the excess electron attachment to the (ROHU)-U-... complex always induces a barrier-free proton transfer from the hydroxyl group of ROH to the 08 atom of U, with the product being (RO-...HU.).