Giribet Claudia G, Ruiz de Azúa Martín C
Facultad de Ciencias Exactas y Naturales, Departamento de Física, Universidad de Buenos Aires , 1428 Buenos Aires, Argentina.
Instituto de Física de Buenos Aires (IFIBA), CONICET, Universidad de Buenos Aires , 1428 Buenos Aires, Argentina.
J Phys Chem A. 2017 Apr 20;121(15):2960-2970. doi: 10.1021/acs.jpca.6b10059. Epub 2017 Apr 5.
The IPPP-CLOPPA method is applied to investigate the influence of a methyl group on the energy of the hydrogen bonds and the potential energy curve of the bridge protons in model compounds, which mimic the methylated and unmethylated cytosine-guanine base pairs. On the same grounds, this influence on the polarizability of the intermolecular hydrogen bonds of these compounds is also addressed, in order to determine whether this linear response property provides a significant proof of the electronic mechanisms that affect the stabilization of the hydrogen bonds. Results obtained show that the methyl electronic system delocalizes on the hydrogen bond region, and changes of these intermolecular hydrogen bonds are due to this effect of delocalization.
应用IPPP - CLOPPA方法研究甲基对模型化合物中氢键能量和桥质子势能曲线的影响，这些模型化合物模拟了甲基化和未甲基化的胞嘧啶 - 鸟嘌呤碱基对。基于同样的原因，还探讨了这种影响对这些化合物分子间氢键极化率的作用，以确定这种线性响应特性是否能为影响氢键稳定性的电子机制提供重要证据。所得结果表明，甲基电子体系在氢键区域发生离域，这些分子间氢键的变化归因于这种离域效应。
