Harańczyk Maciej, Rak Janusz, Gutowski Maciej, Radisic Dunja, Stokes Sarah T, Bowen Kit H
Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland.
J Phys Chem B. 2005 Jul 14;109(27):13383-91. doi: 10.1021/jp050246w.
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 (ROH...U) complexes have been studied at the density functional level with a B3LYP exchange-correlation functional and at the second-order Møller-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*.
设计了一系列18种醇（ROH），其在气相中的去质子化焓（H(DP)）范围为13.8 - 16.3 eV。利用B3LYP交换相关泛函在密度泛函理论水平以及在二阶Møller - Plesset微扰理论水平上研究了过量电子附着到二元醇 - 尿嘧啶（ROH...U）络合物上的影响。用2.54 eV光子测量了尿嘧啶与3种醇（乙醇、2,2,3,3,3 - 五氟丙醇和1,1,1,3,3,3 - 六氟 - 2 - 丙醇）的阴离子络合物的光电子能谱。对于去质子化焓大于14.8 eV的ROH，在阴离子络合物的势能面上仅存在ROH...U - 最小值。对于去质子化焓在14.3 - 14.8 eV范围内的醇，在阴离子势能面上可能存在两个最小值，它们分别对应于RO -...HU和ROH...U - 结构。对于去质子化焓小于14.3 eV的ROH，过量电子附着到ROH...U络合物上总是会引发从ROH的羟基到U的O8原子的无障碍质子转移，产物为RO -...HU。
