Kang Soonchul, Hayashi Hironobu, Umeyama Tomokazu, Matano Yoshihiro, Tkachenko Nikolai V, Lemmetyinen Helge, Imahori Hiroshi
Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto (Japan).
Chem Asian J. 2008 Dec 1;3(12):2065-74. doi: 10.1002/asia.200800229.
Trifluoroacetic acid-catalyzed condensation of pyrrole with electron-deficient and sterically hindered 3,5-bis(trifluoromethyl)benzaldehyde results in the unexpected production of a series of meso-3,5-bis(trifluoromethyl)phenyl-substituted expanded porphyrins including [22]sapphyrin 2, N-fused [22]pentaphyrin 3, [26]hexaphyrin 4, and intact [32]heptaphyrin 5 together with the conventional 5,10,15,20-tetrakis(3,5-bis(trifluoromethyl)phenyl)porphyrin 1. These expanded porphyrins are characterized by mass spectrometry, (1)H NMR spectroscopy, UV/Vis/NIR absorption spectroscopy, and fluorescence spectroscopy. The optical and electrochemical measurements reveal a decrease in the HOMO-LUMO gap with increasing size of the conjugated macrocycles, and in accordance with the trend, the deactivation of the excited singlet state to the ground state is enhanced.
三氟乙酸催化吡咯与缺电子且位阻较大的3,5-双（三氟甲基）苯甲醛缩合，意外地生成了一系列中-3,5-双（三氟甲基）苯基取代的扩展卟啉，包括[22]蓝宝石卟啉2、N-稠合[22]五卟啉3、[26]六卟啉4和完整的[32]七卟啉5，以及传统的5,10,15,20-四（3,5-双（三氟甲基）苯基）卟啉1。这些扩展卟啉通过质谱、¹H NMR光谱、UV/Vis/NIR吸收光谱和荧光光谱进行表征。光学和电化学测量表明，随着共轭大环尺寸的增加，HOMO-LUMO能隙减小，并且根据这一趋势，激发单重态到基态的失活增强。
