【摘要】 采用密度函数理论的B3LYP交换关联能泛函在6-311+G(2df,2p)基组水平上,对Ca2+、Mg2+与尿嘧啶(简称U)三种各互变异构体(简称U1、U2和U3)形成的复合物进行了优化计算,获得稳定复合物的构形,并对这些稳定复合物进行振动频率计算.分析计算结果发现由于离子的参与,单体分子振动的力常数和折合质量均会发生变化,导致红外振动谱线发生不同程度移动;进一步分析发现C-H和O-H键的氢原子作弯曲振动和伸缩振动的谱线移动不确定,直接与离子作用的氧原子参与的振动谱线会发生红移,不直接与离子作用的氧原子参与的振动谱线会发生蓝移.更多还原

【Abstract】 A density functional investigation of the interaction calcium and magnesium bivalent cations and uracil tautomers were performed to determine geometric coordinates for all possible stable isomers complexes at B3LYP/6-311+G(2df,2p) level.The stablest structures of the complexes were gained and were calculated to determine the characters of infrared vibrations.According to the results,the cations are found to be prone to act with the oxygen atoms and because cations take part in molecule’s vibrations the force constants and reduced masses are changed.In addtion,spectrum shifts were found when the cations interact with the uracil tautomers.the spectral lines belong to the vibration of C-O-M turn out redshift and the others turn out blueshift,expcept the vibrations of O-H and C-H.The characteristic infrared vibration frequencies of C-O-M are changed more obviously when tautomers act with the cations,which is mainly because cations act with the oxygen autom directly and change the force constants markedly.更多还原