Barrier-free intermolecular proton transfer in the uracil-glycine complex induced by excess electron attachment

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• 作者：M. Gutowski ; I. Dabkowska ; J. Rak ; S. Xu ; J.M. Nilles ; D. Radisic and K.H. Bowen Jr
• 关键词：PACS. 31.10.+z Theory of electronic structure ; electronic transitions ; and chemical binding – 33.80.Eh Autoionization ; photoionization ; and photodetachment – 36.40.Wa Charged clusters
• 刊名：The European Physical Journal D - Atomic, Molecular and Optical Physics
• 出版年：2002
• 出版时间：September 2002
• 年：2002
• 卷：20
• 期：3
• 页码：431-439
• 全文大小：1,709 KB
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Atoms, Molecules, Clusters and Plasmas
  Nanotechnology
  Quantum Physics
  Quantum Computing, Information and Physics
  Complexity
  Solid State Physics and Spectroscopy
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1434-6079

文摘

The photoelectron spectra (PES) of anions of uracil-glycine and uracil-phenylalanine complexes reveal broad features with maxima at 1.8 and 2.0 eV. The results of ab initio density functional B3LYP and second order M?ller-Plesset theory calculations indicate that the excess electron occupies a π* orbital localized on uracil. The excess electron attachment to the complex can induce a barrier-free proton transfer (BFPT) from the carboxylic group of glycine to the O8 atom of uracil. As a result, the four most stable structures of the anion of uracil-glycine complex can be characterized as the neutral radical of hydrogenated uracil solvated by the anion of deprotonated glycine. The similarity between the PES spectra for the uracil complexes with glycine and phenylalanine suggests that the BFPT is also operative in the case of the latter anionic species. The BFPT to the O8 atom of uracil may be related to the damage of nucleic acid bases by low energy electrons because the O8 atom is involved in a hydrogen bond with adenine in the standard Watson-Crick pairing scheme.