Push鈥揚ull Type Oligo(N-annulated perylene)quinodimethanes: Chain Length and Solvent-Dependent Ground States and Physical Properties

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• 作者：Zebing Zeng ; Sangsu Lee ; Minjung Son ; Kotaro Fukuda ; Paula Mayorga Burrezo ; Xiaojian Zhu ; Qingbiao Qi ; Run-Wei Li ; Juan T. L贸pez Navarrete ; Jun Ding ; Juan Casado ; Masayoshi Nakano ; Dongho Kim ; Jishan Wu
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：July 8, 2015
• 年：2015
• 卷：137
• 期：26
• 页码：8572-8583
• 全文大小：748K
• ISSN：1520-5126

文摘

Research on stable open-shell singlet diradicaloids recently became a hot topic because of their unique optical, electronic, and magnetic properties and promising applications in materials science. So far, most reported singlet diradicaloid molecules have a symmetric structure, while asymmetric diradicaloids with an additional contribution of a dipolar zwitterionic form to the ground state were rarely studied. In this Article, a series of new push鈥損ull type oligo(N-annulated perylene)quinodimethanes were synthesized. Their chain length and solvent-dependent ground states and physical properties were systematically investigated by various experimental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device, Raman spectroscopy, and electrochemistry. It was found that with extension of the chain length, the diradical character increases while the contribution of the zwitterionic form to the ground state becomes smaller. Because of the intramolecular charge transfer character, the physical properties of this push鈥損ull system showed solvent dependence. In addition, density functional theory calculations on the diradical character and Hirshfeld charge were conducted to understand the chain length and solvent dependence of both symmetric and asymmetric systems. Our studies provided a comprehensive understanding on the fundamental structure鈥?and environment鈥損roperty relationships in the new asymmetric diradicaloid systems.