Kishi Ryohei, Yamane Masaki, Sugiura Ryosuke, Yoshida Wataru, Shimizu Yosuke, Nakano Masayoshi
Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan
Center for Quantum Information and Quantum Biology (QIQB), Institute for Open and Transdisciplinary Research Initiatives, Osaka University 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan.
RSC Adv. 2020 Jul 7;10(43):25736-25745. doi: 10.1039/d0ra04787b. eCollection 2020 Jul 3.
In this study, we theoretically investigate the aromatic and open-shell characteristics of carbon nanobelts (CNBs) composed of five- and six-membered rings. We have designed nanobelts composed of indeno[1,2-]fluorene ([1,2-]IF) units, which are referred to as []IF-CNB (: the number of five-membered rings). The number of π-electrons, , in neutral []IF-CNB is 7, and thus depending on and charge states, can be 4 + 2 and 4. Quantum chemical calculations on neutral [6]IF-CNB and [8]IF-CNB and dicationic [8]IF-CNB have revealed that they are expected to exhibit unique aromatic and open-shell characteristics depending on , there are several analogies of the electronic structures in []IF-CNB to those in []annulene. Delocalized and intermediate open-shell electronic structures of []IF-CNB are also useful to drastically change the third-order nonlinear optical properties. These results suggest that theoretically designed []IF-CNB can be attractive and challenging targets of organic synthesis for realizing novel open-shell functional conjugated macrocycles.
在本研究中，我们从理论上研究了由五元环和六元环组成的碳纳米带（CNB）的芳香性和开壳层特性。我们设计了由茚并[1,2 - ]芴（[1,2 - ]IF）单元组成的纳米带，将其称为[]IF - CNB（：五元环的数量）。中性[]IF - CNB中的π电子数为7，因此根据和电荷状态，可为4 + 2和4。对中性[6]IF - CNB、[8]IF - CNB和二价阳离子[8]IF - CNB的量子化学计算表明，它们有望根据表现出独特的芳香性和开壳层特性，[]IF - CNB的电子结构与[]轮烯中的电子结构有若干相似之处。[]IF - CNB的离域和中间开壳层电子结构对于大幅改变三阶非线性光学性质也很有用。这些结果表明，理论设计的[]IF - CNB对于实现新型开壳层功能共轭大环化合物而言，可能是有机合成中具有吸引力且具有挑战性的目标。
