Crystalline Diradical Dianions of Pyrene-Fused Azaacenes |
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Authors: | Chao Chen Dr. Huapeng Ruan Zhongtao Feng Yong Fang Shuxuan Tang Dr. Yue Zhao Prof. Dr. Gengwen Tan Prof. Dr. Yuanting Su Prof. Dr. Xinping Wang |
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Affiliation: | 1. State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023 P. R. China;2. College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123 P. R. China |
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Abstract: | Although diradicals and azaacenes have been greatly attractive in fundamental chemistry and functional materials, the isolable diradical dianions of azaacenes are still unknown. Herein, we describe the first isolation of pyrene-fused azaacene diradical dianion salts [(18-c-6)K(THF)2]+[(18-c-6)K]+⋅ 1 2−.. and [(18-c-6)K(THF)]2+⋅ 2 2−.. by reduction of the neutral pyrene-fused azaacene derivatives 1 and 2 with excess potassium graphite in THF in the presence of 18-crown-6. Their electronic structures were investigated by various experiments, in conjunction with theoretical calculations. It was found that both dianions are open-shell singlets in the ground state and their triplet states are thermally readily accessible owing to the small singlet–triplet energy gap. This work provides the first examples of crystalline diradical dianions of azaacenes with considerable diradical character. |
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Keywords: | azaacenes crystal structure dianions diradicals pyrenes |
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