金属离子与腺嘌呤异构体复合物的稳定性

在B3LYP/6-311++G**//6-31+G*基组水平上结合PCM模型系统的优化了气相和液相环境中14种腺嘌呤异构体与四种金属离子(Na+,K+,Mg2+,Ca2+)形成的132个稳定复合物。通过能量对比，得到了所有复合物异构体在气液两相中的稳定性顺序及不同金属离子与同一异构体形成的复合物的能量排序，首次给出了液相中这些不同金属离子复合物的最稳定结构。结果发现溶剂效应导致了液相中的复合物稳定性顺序与气相中的相比发生了很大变化；同一异构体与不同金属离子形成的复合物其稳定性在排序中也变化很大。对于这些变化，本文分别从金属离子与腺嘌呤的复合物在气相中的结合能(EBE)及在液相中的溶质溶剂相互作用能(Epol)能等方面进行了系统的阐述

Stability of the Complexes Combined by Metal Ions and Adenine Base Isomers

132 stable complexes formed by metal ions(Na+，K+，Ca2+，Mg2+) and fourteen stable adenine tautomers in gas and aqueous phases were optimized at the B3LYP/6-311++G**//6-31+G* level in combination with the PCM models. By comparison, the stabilization ordering of all these stable complexes in aqueous phase is first obtained and the optimal binding site for a metal ion in a specific adenine tautomer is identified. Meanwhile, the differences of the ordering in the two different phases are analyzed systematically. Results indicate that it is solvent effect to induce different solute-solvent interaction and, as a result, lead to the stabilization ordering change from that in gas phase. It is the different metal ion effect to result in the different ordering of relative stability of a complex formed by different metal ion and identical adenine tautomer. For these changes, this article makes detailed analysis based on gas-phase binding energies (EBE) and aqueous phase polarized solute-solvent energies (Epol).