尿嘧啶-巴比妥酸分子间相互作用的密度泛函理论研究

采用密度泛函理论(DFT)中的B3LYP方法,在6-311G**理论水平上研究了尿嘧啶(U)和巴比妥酸(B)分子间的相互作用,以期从理论上预测巴比妥酸类物质对核酸产生的影响。优化复合物构型得到5个B1-U、4个B2-U、4个B3-U稳定构型,经基组重叠误差和零点振动能校正后,比较各复合物的相互作用能,可以得出复合物的主要存在形式有B2-U-3、B2-U-1、B1-U-3和B1-U-1。从NBO的分析得知B1-U、B2-U、B3-U系列复合物的稳定性顺序与氢键强度一致,即氢键的强度决定了复合物的稳定性,分析自然键轨道能揭示相互作用的本质。

DENSITY FUNCTIONAL THEORY ON THE INTERACTION OF URACIL AND BARBITURIC ACID

In this paper the interaction between uracil（U） and barbituric acid（B） was studied by using the density functional theory （DFT） at the B3LYP/6-311G＊＊ level, for the purpose of further investigating the effect of barbituric acid on the structure of nucleic acid. The geometries were optimized and five B1-U, four B2-U and four B3-U stable complexes were obtained. Comparing the interaction energies after the correction of the basis set superposition error and zero point energies, it may show that the main form of the compound were B2-U-3, B2-U-1, B1-U-3 and B1-U-1. The stability of the series of complexes were consistent with the hydrogen bonding strength from the NBO analysis, namely hydrogen bonding strength determined the stability of the complexes, and natural bond orbital analysis could reveal the nature of interaction.