A Stable Saddle‐Shaped Polycyclic Hydrocarbon with an Open‐Shell Singlet Ground State

作者：Ji Ma, Junzhi Liu, Martin Baumgarten, Yubin Fu, Yuan‐Zhi Tan, Karl Sebastian Schellhammer, Frank Ortmann, Gianaurelio Cuniberti, Hartmut Komber, Reinhard Berger, Kläus Müllen, Xinliang Feng · 发表于：Angewandte Chemie International Edition · 年份：2017 · DOI：10.1002/anie.201611689 · 被引用次数：111 · 研究领域：Synthesis and Properties of Aromatic Compounds、Fullerene Chemistry and Applications、Organic Electronics and Photovoltaics

Abstract Diindeno‐fused bischrysene, a new diindeno‐based polycyclic hydrocarbon (PH), was synthesized and characterized. It was elucidated in detailed experimental and theoretical studies that this cyclopenta‐fused PH possesses an open‐shell singlet biradical structure in the ground state and exhibits high stability under ambient conditions (t1/2=39 days). The crystal structure unambiguously shows a novel saddle‐shaped π‐conjugated carbon skeleton due to the steric hindrance of the central cove‐edged bischrysene unit. UV/Vis spectral measurements revealed that the title molecule has a very narrow optical energy gap of 0.92 eV, which is consistent with the electrochemical analysis and further supported by density functional theory (DFT) calculations.