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A Stable Saddle‐Shaped Polycyclic Hydrocarbon with an Open‐Shell Singlet Ground State
Author(s) -
Ma Ji,
Liu Junzhi,
Baumgarten Martin,
Fu Yubin,
Tan YuanZhi,
Schellhammer Karl Sebastian,
Ortmann Frank,
Cuniberti Gianaurelio,
Komber Hartmut,
Berger Reinhard,
Müllen Klaus,
Feng Xinliang
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201611689
Subject(s) - singlet state , density functional theory , steric effects , conjugated system , ground state , open shell , hydrocarbon , molecule , chemistry , saddle point , computational chemistry , band gap , photochemistry , materials science , atomic physics , stereochemistry , organic chemistry , physics , polymer , excited state , geometry , optoelectronics , mathematics
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 ( t 1/2 =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.