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arXiv · 1908.11158

On-surface synthesis of antiaromatic and open-shell indeno[2,1-b]fluorene polymers and their lateral fusion into porous ribbons

Marco Di Giovannantonio·Kristjan Eimre·Aliaksandr V. Yakutovich·Qiang Chen·Shantanu Mishra·José I. Urgel·Carlo A. Pignedoli·Pascal Ruffieux·Klaus Müllen·Akimitsu Narita·Roman Fasel
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Abstract

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 da-ta storage. However, the intrinsic instability of polyradical hydrocarbons severely limits de-tailed 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 non-benzenoid 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 non-contact atomic force microscopy, complemented by density-functional theory calculations. These polymers present a low band gap when adsorbed on Au(111). Moreover, their pro-nounced 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.

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Marco Di Giovannantonio, Kristjan Eimre, Aliaksandr V. Yakutovich, Qiang Chen, Shantanu Mishra, José I. Urgel, Carlo A. Pignedoli, Pascal Ruffieux, Klaus Müllen, Akimitsu Narita, Roman Fasel. 2019-08-29. On-surface synthesis of antiaromatic and open-shell indeno[2,1-b]fluorene polymers and their lateral fusion into porous ribbons. https://doi.org/10.1021/jacs.9b05335

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