儿茶素-胞嘧啶分子间相互作用的密度泛函研究

Density functional theory study on the interaction between catechin and cytosine

采用密度泛函理论的B3LYP方法,在6-31+G*基组水平上研究了儿茶素-胞嘧啶分子间相互作用机制,得到稳定的儿茶素-胞嘧啶复合物11个.计算结果表明氢键对于复合物的稳定性起着重要的作用,并且当复合物形成2个或更多的氢键时,氢键的类型及强度共同决定着复合物的稳定性.我们还应用了分子中的原子(AIM)理论和自然键轨道(NBO)理论对这11种复合物中氢键的性质和特征进行了分析.通过研究发现,所有的氢键复合物进行基组重叠误差(BSSE)校正后的相互作用能为-17.35～-43.27kJ/mol,相互作用能主要由氢键所贡献.振动分析显示,氢键的形成使相对应键的对称伸缩振动频率减小,说明这些复合物中形成的氢键都是正常的红移型氢键,与实验结果相一致.

The interacting patterns and mechanism of the catechin and cytosine have been investigated using the density functional theory B3LYP method with 6-31＋G＊basis set.Eleven stable structures for the catechin-cytosine complexes have been found respectively.The results indicated that the complexes are mainly stabilized by the hydrogen bonding interactions.Theories of atoms in molecules（AIM）and natural bond orbital（NBO）have been utilized to investigate the hydrogen bonds involved in all the systems.The interaction energies of all the complexes were corrected for basis set superposition error（BSSE）,are from？17.35 to？43.27 kJ/mol.The results showed that the hydrogen bonding contribute to the interaction energies dominantly.The corresponding bonds stretching motions in all the complexes are red-shifted relative to that of the monomer,which is in good agreement with experimental results.