论文部分内容阅读
本文报导用半经验方法研究N_1-氢-4-氨基-2-羰基胞嘧啶与4-亚氨基-2-羰基胞嘧啶异构化反应。用MINDO/3能量梯度法优化了孤立体系的全部自由度,计算结果表明氨型比亚氨型稳定,△E=33.85 kJ mol~(-1);限定分子体系在同一平面,用Powell法优化过渡态几何构型,计算所得正反应活化势垒为168.87 kJ mol~(-1),逆反应活化势垒为135.02 kJ mol~(-1)。从IRC途径分析了该异构化反应的物理实质。
This paper reports the semi-empirical method for the isomerization of N 1 -hydroxy-4-amino-2-carbonylcytosine and 4-imino-2-carbonylcytosine. The full degree of freedom of the isolated system was optimized by the MINDO / 3 energy gradient method. The calculated results show that the ammonia type is more stable than the iminoform, △ E = 33.85 kJ mol -1. The molecular system is defined on the same plane and optimized by the Powell method For the transition state geometry, the calculated positive reaction activation barrier is 168.87 kJ mol -1, and the reverse reaction activation barrier is 135.02 kJ mol -1. The physical nature of this isomerization reaction was analyzed from the IRC pathway.