中文摘要：

应用密度泛函理论的B3LYP／6-311＋G（d）方法研究了6-甲基-4-羟基嘧啶单体及二聚体质子转移的异构化反应．对反应势能面的研究发现，该化含物可能存在9种单体异构体，对其最稳定的单体构型进行分析．各单体间异构化反应的过渡态共有9种。反应的活化能最小为22．06kJ／mol，最大为356．55kJ／mol。最可能的反应路径在室温下即可进行．研究了2种二聚体及其异构化反应的过渡态，发现二聚体均比其对应的单体稳定，而且质子转移所需要的活化能仅为20．13kJ／mol，比单体低很多．氢键在这种变化中起了主要作用，由单体和二聚体的总能量计算了氢键的键能.

英文摘要：

Density Functional Theory（DFr） of quantum chemistry method was used to investigate the proton transfer reactions of 6-methyl-4-hydroxy pyrimidine monomer and dimer. By studying the potential energy surface of the isomefization, it was found that there were 9 monomer isomers and 9 transition states in possible reaction pathways. The most stable structure of monomers was analyzed. The lowest and largest reaction activation energy were 22. 06 and 356. 55 kJ/mol, respectively. The most possible reaction pathways could proceed at room temperature. Two dimers and their transition states were also investigated and it was found that all dimer were more stable than the corresponding monomers. The reaction activation energy of the dimer tautomefization was less than that of the corresponding monomer. Hydrogen bond played an sticking role in those changes and the energies of hydrogen bond were calculated from the total energies of monomers and dimers.