para‐Quinodimethane‐Bridged Perylene Dimers and Pericondensed Quaterrylenes: The Effect of the Fusion Mode on the Ground States and Physical Properties |
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Authors: | Dr Soumyajit Das Sangsu Lee Minjung Son Xiaojian Zhu Dr Wenhua Zhang Dr Bin Zheng Pan Hu Dr Zebing Zeng Dr Zhe Sun Wangdong Zeng Prof Run‐Wei Li Prof Kuo‐Wei Huang Prof Jun Ding Prof Dongho Kim Prof Jishan Wu |
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Institution: | 1. Department of Chemistry, National University of Singapore, 3 Science Drive?3, 117543 Singapore, Fax: (+65)?6779‐1691;2. Department of Chemistry, Yonsei University, Seoul 120‐749 (Korea);3. Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China);4. Institute of Materials Research and Engineering, A*STAR, 3?Research Link, 117602 Singapore;5. Division of Physical Science and Engineering and KAUST Catalysis Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955‐6900 (Kingdom of Saudi Arabia);6. Department of Materials Science and Engineering, National University of Singapore, 119260 Singapore |
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Abstract: | Polycyclic hydrocarbon compounds with a singlet biradical ground state show unique physical properties and promising material applications; therefore, it is important to understand the fundamental structure/biradical character/physical properties relationships. In this study, para‐quinodimethane (p‐QDM)‐bridged quinoidal perylene dimers 4 and 5 with different fusion modes and their corresponding aromatic counterparts, the pericondensed quaterrylenes 6 and 7 , were synthesized. Their ground‐state electronic structures and physical properties were studied by using various experiments assisted with DFT calculations. The proaromatic p‐QDM‐bridged perylene monoimide dimer 4 has a singlet biradical ground state with a small singlet/triplet energy gap (?2.97 kcal mol?1), whereas the antiaromatic s‐indacene‐bridged N‐annulated perylene dimer 5 exists as a closed‐shell quinoid with an obvious intramolecular charge‐transfer character. Both of these dimers showed shorter singlet excited‐state lifetimes, larger two‐photon‐absorption cross sections, and smaller energy gaps than the corresponding aromatic quaterrylene derivatives 6 and 7 , respectively. Our studies revealed how the fusion mode and aromaticity affect the ground state and, consequently, the photophysical properties and electronic properties of a series of extended polycyclic hydrocarbon compounds. |
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Keywords: | aromaticity polycycles radicals rylene zethrene |
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