Lemniscular Hexaphyrins as Examples of Aromatic and Antiaromatic Double-Twist Möbius Molecules

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• 作者：Henry S. Rzepa
• 刊名：Organic Letters
• 出版年：2008
• 出版时间：March 6, 2008
• 年：2008
• 卷：10
• 期：5
• 页码：949 - 952
• 全文大小：111K
• 年卷期：v.10,no.5(March 6, 2008)
• ISSN：1523-7052

文摘

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Two reported [26] and [28]hexaphyrins are analyzed via measured and computed geometries and NMR-shieldings as examples of respectively4n + 2 -electron aromatic and 4n -electron antiaromatic double-twist Möbius ring systems, adopting a lemniscular/figure-eight topologywith linking number L_K = 2. Values of local twist (T_W) and nonlocal writhe (W_R) derived from the relation L_k = T_w + W_R appear relativelyinsensitive to the aromatic/antiaromatic character. The [26]hexaphyrin may adopt differing solution and solid-state conformations.