Shimizu Soji, Aratani Naoki, Osuka Atsuhiro
Department of Chemistry, Graduate School of Science, Kyoto University, Japan.
Chemistry. 2006 Jun 14;12(18):4909-18. doi: 10.1002/chem.200600158.
A series of meso-trifluoromethyl-substituted expanded porphyrins, including N-fused [24]pentaphyrin 3, [28]hexaphyrin 4, [32]heptaphyrin 5, [46]decaphyrin 6, and [56]dodecaphyrin 7, were synthesized by means of an acid-catalyzed one-pot condensation reaction of 2-(2,2,2-trifluoro-1-hydroxyethyl)pyrrole (1) as the first examples bearing meso-alkyl substituents. Besides these products, porphyrin 2 and two calix[5]phyrins 8 and 9 were also obtained. [28]Hexaphyrin 4 was quantitatively oxidized to [26]hexaphyrin 14 with MnO(2). These expanded porphyrins have been characterized by mass spectrometry, (1)H and (19)F NMR spectroscopy, and UV/Vis spectroscopy. The single-crystal structures have been determined for 3, 4, 6, 7, and 14. The N-fused [24]pentaphyrin 3 displays a distorted structure containing a tricyclic fused moiety that is similar to those of meso-aryl-substituted counterparts, whereas 8 and 9 are indicated to take roughly planar conformations with an inverted pyrrole opposite to the sp(3)-hybridized meso-carbon atom. Both [28]- and [26]hexaphyrins 4 and 14 have figure-of-eight structures. Solid-state structures of the decaphyrin 6 and dodecaphyrin 7 are remarkable, exhibiting a crescent conformation and an intramolecular two-pitch helical conformation, respectively.
通过2-(2,2,2-三氟-1-羟乙基)吡咯(1)的酸催化一锅缩合反应，合成了一系列中-三氟甲基取代的扩展卟啉，包括N-稠合[24]五卟啉3、[28]六卟啉4、[32]七卟啉5、[46]十卟啉6和[56]十二卟啉7，它们是首批带有中-烷基取代基的实例。除了这些产物外，还得到了卟啉2以及两个杯[5]卟啉8和9。[28]六卟啉4用MnO₂定量氧化为[26]六卟啉14。这些扩展卟啉已通过质谱、¹H和¹⁹F NMR光谱以及UV/Vis光谱进行了表征。已测定了3、4、6、7和14的单晶结构。N-稠合[24]五卟啉3呈现出一种扭曲结构，包含一个三环稠合部分，这与中-芳基取代的类似物相似，而8和9显示出大致平面的构象，其中一个吡咯与sp³杂化的中碳原子相对。[28]和[26]六卟啉4和14均具有8字形结构。十卟啉6和十二卟啉7的固态结构很显著，分别呈现出新月形构象和分子内双螺距螺旋构象。
