Fused Dibenzo[a,m]rubicene: A New Bowl-Shaped Subunit of C70 Containing Two Pentagons

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• 作者：Junzhi Liu ; Silvio Osella ; Ji Ma ; Reinhard Berger ; David Beljonne ; Dieter Schollmeyer ; Xinliang Feng ; Klaus Müllen
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：July 13, 2016
• 年：2016
• 卷：138
• 期：27
• 页码：8364-8367
• 全文大小：338K
• 年卷期：0
• ISSN：1520-5126

文摘

Total synthetic approaches of fullerenes are the holy grail for organic chemistry. So far, the main attempts have focused on the synthesis of the buckminsterfullerene C₆₀. In contrast, access to subunits of the homologue C₇₀ remains challenging. Here, we demonstrate an efficient bottom-up strategy toward a novel bowl-shaped polycyclic aromatic hydrocarbons (PAH) C34 with two pentagons. This PAH represents a subunit for C₇₀ and of other higher fullerenes. The bowl-shaped structure was unambiguously determined by X-ray crystallography. A bowl-to-bowl inversion for a C₇₀ fragment in solution was investigated by dynamic NMR analysis, showing a bowl-to-bowl inversion energy (ΔG^⧧) of 16.7 kcal mol^–1, which is further corroborated by DFT calculations.