Stable Expanded Porphycene‐Based Diradicaloid and Tetraradicaloid |
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| Authors: | Dr Anup Rana Yongseok Hong Dr Tullimilli Y Gopalakrishna Dr Hoa Phan Dr Tun Seng Herng Priya Yadav Prof Jun Ding Prof Dongho Kim Prof Jishan Wu |
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| Institution: | 1. Department of Chemistry, National University of Singapore, Singapore, Singapore;2. Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul, Korea;3. Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore |
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| Abstract: | The synthesis of a bithiophene‐bridged 34π conjugated aromatic expanded porphycene 1 and a cyclopentabithiophene bridged 32π conjugated anti‐aromatic expanded porphycene 2 by a McMurry coupling strategy is presented. Magnetic measurements and theoretical calculations reveal that both 1 and 2 exhibit an open‐shell singlet ground state with significant radical character (y0=0.63 for 1 ; y0=0.68, y1=0.18 for 2 ; y0: diradical character, y1: tetraradical character) and a small singlet–triplet energy gap (ΔES‐T=?3.25 kcal mol?1 for 1 and ΔES‐T=?0.92 kcal mol?1 for 2 ). Despite the open‐shell radical character, both compounds display exceptional stability under ambient air and light conditions owing to effective delocalization of unpaired electrons in the extended cyclic π‐conjugation pathway. |
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| Keywords: | diradicaloids expanded porphyrins octaphyrin polyradicaloids porphycene |
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