Cross-bridging reaction of 5,20-diethynyl substituted hexaphyrins to vinylene-bridged hexaphyrins.
Cross-bridging reaction of 5,20-diethynyl substituted hexaphyrins to vinylene-bridged hexaphyrins.
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DOI：
10.1021/ja067102v
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发表时间：
2007-01
影响因子：
15
通讯作者：
Masaaki Suzuki;A. Osuka
中科院分区：
文献类型：
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作者：
Masaaki Suzuki;A. Osuka
5，20-二乙炔基取代的[26]己卟啉（1.1.1.1.1）可能通过强烈折叠构象进行热或自发交联反应，以提供反式亚乙烯基桥接的[26]己卟啉。乙烯基桥连的六卟啉的芳族-反芳族转换已经在两电子氧化还原过程中得到证实。奇怪的是，亚乙烯桥连的六卟啉的共振贡献者被认为是[16]diazaannuleno[16] diazaannulene，但由于桥的垂直几何形状，它的贡献应该是次要的。亚乙烯基桥连的六卟啉作为一个有效的配体，使用中心亚乙烯基双键以η2-方式与三个吡咯氮原子一起沿着配位两个锌（II）离子。
5,20-Diethynyl substituted [26]hexaphyrins(1.1.1.1.1.1) undergo a thermal or spontaneous cross-bridging reaction to provide trans-vinylene-bridged [26]hexaphyrins, probably through strongly folded conformations. Facile aromatic−antiaromatic switching of vinylene-bridged hexaphyrins has been demonstrated upon two-electron redox processes. Curiously, a resonance contributor of the vinylene-bridged hexaphyrins is regarded as [16]diazaannuleno[16]diazaannulene but its contribution should be minor because of the perpendicular geometry of the bridge. Vinylene-bridged hexaphyrin serves as an effective ligand that coordinates two zinc(II) ions using the central vinylene double bond in a η2-fashion along with the three pyrrolic nitrogen atoms.