Berdys-Kochańska Joanna, Kruszewski Jerzy, Skurski Piotr
Department of Chemistry, University of Gdańsk, Sobieskiego 18, 80-952 Gdańsk, Poland.
J Phys Chem A. 2005 Dec 22;109(50):11407-12. doi: 10.1021/jp053012l.
The possibility of an excess electron binding to canonical isomers of xanthine in the gas phase was studied at the coupled-cluster level with single and double excitations using the 6-31++G** basis sets supplemented with the 4(sp)3d set of diffuse functions. It was found that xanthine should exist in the gas phase as one canonical tautomer while all the other tautomers are not likely to be detected experimentally because of their significant thermodynamic instability. On the other hand, all canonical tautomers (except one) were found to be capable of forming electronically stable anionic states of dipole-bound nature. However, the only thermodynamically stable anion (with vertical electron binding energy estimated to be 0.041 eV) based on xanthine tautomers is the one supported by the most stable neutral species.
使用6-31++G**基组并补充4(sp)3d漫射函数集，在单双激发耦合簇水平上研究了气相中多余电子与黄嘌呤标准异构体结合的可能性。结果发现，黄嘌呤在气相中应以一种标准互变异构体形式存在，而所有其他互变异构体由于其显著的热力学不稳定性，不太可能通过实验检测到。另一方面，发现所有标准互变异构体（除一种外）都能够形成具有偶极束缚性质的电子稳定阴离子态。然而，基于黄嘌呤互变异构体的唯一热力学稳定阴离子（垂直电子结合能估计为0.041 eV）是由最稳定的中性物种支持的那种。
