Conjugated Polymers Based on Tautomeric Units: Regulation of Main-Chain Conjugation and Expression of Aggregation Induced Emission Property via Boron-Complexation

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• 作者：Ryousuke Yoshii ; Kazuo Tanaka ; Yoshiki Chujo
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：April 8, 2014
• 年：2014
• 卷：47
• 期：7
• 页码：2268-2278
• 全文大小：730K
• 年卷期：v.47,no.7(April 8, 2014)
• ISSN：1520-5835

文摘

To understand the contribution of the tautomeric units to the 蟺-conjugation through the polymer main-chain, the characteristics of the conjugated polymers containing the ketoimine moiety were investigated. Though the ketoimine skeleton usually forms the enaminoketone structure, the electronic structure in the ketoimine units can be fixed in enolimine form by boron complexation. By employing this fixing effect, we sought to regulate the electronic structure and evaluate the change in degree of main-chain conjugation. The polymerization was executed in Suzuki鈥揗iyaura coupling reactions with the ketoimine or the boron ketoiminate monomers. The characterization and the determination of the structures of the products were performed with NMR spectrometry. The optical and electrochemical properties were examined by UV鈥搗is absorption spectroscopy, photoluminescence spectroscopy, and cyclic voltammetry. The degree of main-chain conjugation was evaluated from the peak shifts in the absorption and emission bands. Initially, it was observed that the conjugated system intrinsically extended even through the enaminoketone structure in which the main-chain conjugation should be inhibited. In addition, as we expected, it was indicated that the boron complexation to the ketoimine units can contribute to the extension of 蟺-conjugation through the main-chain. Furthermore, it was found that the boron ketoiminate polymers exhibited aggregation-induced emission properties.