四苯基卟啉质子化结构变化的理论研究(Ⅱ)——五氟苯基及吡咯环上氟的取代基效应

Theoretical Studies on the Structural Change of the N-Protonated Tetraphenylporphyrin(Ⅱ) The Effects of the Substituting Groups Fluorines

卟啉的衍生物在 DNA螺旋中的嵌入并堆积具有高选择性 .为考察 5 ,1 0 ,1 5 ,2 0 -四 (五氟苯基 )卟啉(TF5PPH2 )和 2 ,3 ,7,8,1 2 ,1 3 ,1 7,1 8-八氟 -5 ,1 0 ,1 5 ,2 0 -四 (五氟苯基 )卟啉 (F2 8TPPH2 )中 F取代基对质子化卟啉结构的影响 ,在四苯基卟啉研究的基础上 ,用半经验的 AM1 MO方法 ,并进行合理的对称性限制 ,计算了 TF5PPH2 和 F2 8TPPH2 及其质子化二酸 (TF5PPH2 + 4)和 (F2 8TPPH2 + 4)的几种可能的构型 .结果表明 ,由于 F取代基的影响 ,质子化过程中的结构、键电荷布居和前线分子轨道均有明显的变化 。

With the symmetry being reasonably restricted, the semi empirical method of AM1 MO is used to calculate the geometries of 5,10,15,20 tetrakis(pentafluorophenyl)porphyrin(TF 5PPH 2) and 2,3,7,8,12, 13,17,18 octafluoro 5,10,15,20 tetrakis(pentafluorophenyl)porphyrin(F 28 TPPH 2) and their N protonated diacids(TF 5PPH 2+ 4 and F 28 TPPH 2+ 4) which all are kinds of important porphyrin derivatives. Moreover, the configurational change in protonation process and the probable influence to molecular aggregation conducted by the change are discussed by the means of structure analysis, population analysis and frontier orbital analysis.