Kano Koji, Nishiyabu Ryuhei, Yamazaki Tomoko, Yamazaki Iwao
Department of Molecular Science and Technology, Faculty of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan.
J Am Chem Soc. 2003 Sep 3;125(35):10625-34. doi: 10.1021/ja035055q.
A new methodology for preparing heteroporphyrin arrays in aqueous solution has been presented. The present method is based on the extremely strong ability of heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMe-beta-CD) to include 5,10,15,20-tetrakis(p-substituted-phenyl)porphyrins (Por) affording trans-type 1:2 complexes of the porphyrins and TMe-beta-CD. Two different Por-per-O-methylated beta-CD (per-Me-beta-CD) conjugates were synthesized. Conjugate 2 was prepared by an S(N)2 reaction of 5,10,15,20-tetrakis(p-hydroxyphenyl)porphyrin and per-O-methylated beta-cyclodextrin having one primary OTs group. Four per-Me-beta-CD moieties are attached to the meso positions of 2. Conjugate 3, synthesized from 5-(p-hydroxyphenyl)-10,15,20-tris(3,5-dicarboxyphenyl)porphyrin and monotosylated per-O-methylated beta-cyclodextrin, has one per-Me-beta-CD moiety at the periphery of the porphyrin. Conjugate 2 yields a stable 1:4 complex with the zinc complex of 5-phenyl-10,15,20-tris(3,5-dicarboxyphenyl)porphyrin (8) in the dissociated form. In this system, the energy transfer from photoexcited Zn-8 to free base 2 occurs with 85% efficiency. Conjugate 3 forms a very stable 1:1 complex with Zn-8 (K = (7.0 +/- 0.3) x 10(5) dm(3) mol(-1)) with an energy transfer efficiency (93%) larger than that obtained in the case of 2. The structure of the 3-Zn-8 complex, which can account for the efficient energy transfer, was deduced from (1)H NMR spectroscopy. Intramolecular fluorescence quenching of 2 and 3 by Fe(III)-8 also occurred through an electron-transfer process as the main quenching mechanism. The present method is a very simple and convenient means to construct various heteroporphyrin arrays in aqueous solution.
一种在水溶液中制备杂卟啉阵列的新方法已被提出。本方法基于七（2,3,6 - 三 - O - 甲基） - β - 环糊精（TMe - β - CD）对5,10,15,20 - 四（对 - 取代 - 苯基）卟啉（Por）极强的包合能力，可形成卟啉与TMe - β - CD的反式1:2配合物。合成了两种不同的Por - 全 - O - 甲基化β - 环糊精（全 - Me - β - CD）共轭物。共轭物2通过5,10,15,20 - 四（对 - 羟基苯基）卟啉与具有一个伯OTs基团的全 - O - 甲基化β - 环糊精的S(N)2反应制备。四个全 - Me - β - CD部分连接到2的中位。共轭物3由5 - （对 - 羟基苯基） - 10,15,20 - 三（3,5 - 二羧基苯基）卟啉和单甲苯磺酰化的全 - O - 甲基化β - 环糊精合成，在卟啉外围有一个全 - Me - β - CD部分。共轭物2与5 - 苯基 - 10,15,20 - 三（3,5 - 二羧基苯基）卟啉（8）的锌配合物以解离形式形成稳定的1:4配合物。在该体系中，从光激发的Zn - 8到游离碱2的能量转移效率为85%。共轭物3与Zn - 8形成非常稳定的1:1配合物（K = (7.0 ± 0.3) × 10(5) dm(3) mol(-1)），能量转移效率（93%）高于共轭物2的情况。通过(1)H NMR光谱推断出3 - Zn - 8配合物的结构，该结构可以解释高效的能量转移。Fe(III) - 8对2和3的分子内荧光猝灭也通过电子转移过程作为主要猝灭机制发生。本方法是在水溶液中构建各种杂卟啉阵列的非常简单方便的手段。
