Senthilkumar K, Kolandaivel P
Department of Physics, Bharathiar University, Coimbatore, India.
J Comput Aided Mol Des. 2002 Apr;16(4):263-72. doi: 10.1023/a:1020273219651.
Ab inito and density functional theory (DFT) methods were used to study the tautomers of barbituric acid in the gas phase and in a polar medium. In the gas phase, the tautomers were optimized at the HF/6-31G*, MP2/6-31G* and B3LYP/6-31G*, B3PW91/6-31G* levels of theory. The self-consistent reaction field theory (SCRF) at the HF/6-31G* level of theory has been used to optimize the tautomers in a polar medium. The relative stability of the tautomers was compared in the gaseous and polar mediums. The ability of maximum hardness principle to predict the stable tautomer has been studied. The 13C-NMR chemical shift for carbon atoms in the tautomers was calculated and the results are discussed.
采用从头算和密度泛函理论（DFT）方法研究了巴比妥酸在气相和极性介质中的互变异构体。在气相中，互变异构体在HF/6-31G*、MP2/6-31G以及B3LYP/6-31G、B3PW91/6-31G理论水平上进行了优化。在HF/6-31G理论水平上的自洽反应场理论（SCRF）被用于在极性介质中优化互变异构体。比较了互变异构体在气态和极性介质中的相对稳定性。研究了最大硬度原理预测稳定互变异构体的能力。计算了互变异构体中碳原子的13C-NMR化学位移并对结果进行了讨论。
