Band Gap of Carbon鈥揝ulfur [n]Helicenes

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• 作者：Makoto Miyasaka ; Maren Pink ; Arnon Olankitwanit ; Suchada Rajca ; Andrzej Rajca
• 刊名：Organic Letters
• 出版年：2012
• 出版时间：June 15, 2012
• 年：2012
• 卷：14
• 期：12
• 页码：3076-3079
• 全文大小：302K
• 年卷期：v.14,no.12(June 15, 2012)
• ISSN：1523-7052

文摘

Asymmetric synthesis of (鈭?-[9]helicene, as well as preparation of its lower homologues, completes the series of carbon鈥搒ulfur [5]-, [7]-, [9]-, and [11]helicenes. Spectroscopic and electrochemical studies of this series provide an absorption onset-based band gap, E_g = 3.40 eV, for a cross-conjugated (C₂S)_n helix; this value may be compared to E_g = 3.59 eV obtained from TD-DFT computed excitation energies for a series of dimethyl-substituted [n]helicenes (n 鈮?31).