四吡啶基卟啉质子化结构变化的理论研究

Theoretical Studies on the Structural Change of the N - Protonated Tetrapyridylporphine

为考察m-吡啶基对质子化卟啉结构的影响,用半经验的AMI MO方法,并进行合理的对称性限制,计算了一类重要的卟啉衍生物——四吡啶基卟啉(TP_yPH_2)及其质子化二酸(TP_yPH_4^(2+))的构型.通过结构分析,电荷布居分析和前沿轨道分析,讨论了质子化过程中的构型变化以及这种变化对分子堆积可能带来的影响.

Various substituting groups of porphyrin derivatives have great influence on the molecular intercalation and aggregation in DNA helix. In order to investigate the effects of meso ?pyridyls on the structure of N - protonated porphyrin, the geometries of tetrapyridylporphine and its diacid were calculated by using AM1 MO method and symmetry restriction. The results show that the method and the symmetry restriction are reasonable and the molecular shape is favorable to the aggregation after the protonation. Meanwhile, the reasons of the configurational change and the selectivity of the aggregation were discussed by means of structure analysis, population analysis and frontier orbital analysis.