Knot-Isomers of Mbius Cyclacene: How Does the Number of Knots Influence the Structure and First Hyperpolarizability?

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• 作者：Hong-Liang Xu ; Zhi-Ru Li ; Zhong-Min Su ; Shabbir Muhammad ; Feng Long Gu ; Kikuo Harigaya
• 刊名：Journal of Physical Chemistry C
• 出版年：2009
• 出版时间：August 27, 2009
• 年：2009
• 卷：113
• 期：34
• 页码：15380-15383
• 全文大小：243K
• 年卷期：v.113,no.34(August 27, 2009)
• ISSN：1932-7455

文摘

Four knot-isomers of Mbius cyclacene are composed of 15 nitrogen-substituted benzo rings. They are non-Mbius cyclacenes without a knot (0), Mbius cyclacenes with a knot (1), non-Mbius cyclacenes with two knots (2), and Mbius cyclacenes with three knots (3). Their structures and nonlinear optical properties are systematically studied. The order of first hyperpolarizability (β₀) is 4693 (0) < 10484 (2) < 25419 (3) < 60846 au (1). The β₀ values of the knot-isomers with knot(s) are larger than that of the knot-isomer without a knot. It shows that the β₀ value can be dramatically increased (13 times) by twisting the knot(s) to the cyclacene. Two noticeable relationships between the number of knots and the first hyperpolarizability have been observed: (i) the β₀ values of one surface Mbius cyclacene (1 and 3) with an odd number of knots are larger than that of two-surface non-Mbius cyclacenes (0 and 2) with an even number of knots. (ii) For the one-surface Mbius cyclacenes, the β₀ value for 1 with one knot is larger than that for 3 with three knots. On the other hand, the largest component of β₀ is alternated for the four knot-isomers. The largest components are β_z for the 0 and β_y for the 1 and 2. The largest component turns back to the β_z for the 3.