On-Surface Synthesis of Antiaromatic and Open-Shell Indeno[2,1-b]fluorene Polymers and Their Lateral Fusion into Porous Ribbons
On-Surface Synthesis of Antiaromatic and Open-Shell Indeno[2,1-b]fluorene Polymers and Their Lateral Fusion into Porous Ribbons
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DOI：
10.1021/jacs.9b05335
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发表时间：
2019-08-07
影响因子：
15
通讯作者：
Fasel, Roman
中科院分区：
文献类型：
--
作者：
Di Giovannantonio, Marco;Eimre, Kristjan;Fasel, Roman
多环烃由于其在有机电子学中的潜在作用而受到极大的关注，对于具有未成对电子密度的开壳层系统，在自旋电子学和数据存储中也是如此。然而，多自由基碳氢化合物固有的不稳定性严重限制了对其电子结构的详细研究。在这里，我们报告的表面合成共轭聚合物组成的茚并[2，1-B]芴单元，这是反芳族和开壳双自由基。所观察到的反应产物，其中还包括一个nonbenzenoid多孔带所产生的未受保护的茚并[2，1-B]芴链的横向融合，其特征在于通过低温扫描隧道显微镜/光谱和非接触原子力显微镜，辅以密度泛函理论计算。当吸附在Au（111）上时，这些聚合物呈现低的带隙。此外，他们的显着antiaromaticity和自由基的字符，阐明从头计算，使他们有前途的候选人在电子学和自旋电子学的应用。此外，它们为探索低维有机纳米材料中的磁性提供了丰富的游乐场。
Polycyclic hydrocarbons have received great attention due to their potential role in organic electronics and, for open-shell systems with unpaired electron densities, in spintronics and data storage. However, the intrinsic instability of polyradical hydrocarbons severely limits detailed investigations of their electronic structure. Here, we report the on-surface synthesis of conjugated polymers consisting of indeno[2,1-b]fluorene units, which are antiaromatic and open-shell biradicaloids. The observed reaction products, which also include a nonbenzenoid porous ribbon arising from lateral fusion of unprotected indeno[2,1-b]fluorene chains, have been characterized via low-temperature scanning tunneling microscopy/spectroscopy and noncontact atomic force microscopy, complemented by density-functional theory calculations. These polymers present a low band gap when adsorbed on Au(111). Moreover, their pronounced antiaromaticity and radical character, elucidated by ab initio calculations, make them promising candidates for applications in electronics and spintronics. Further, they provide a rich playground to explore magnetism in low-dimensional organic nanomaterials.