Development of environmental stimuli-responsive functional molecules based on intramolecular electron transfer

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05079
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Osaka University
• Principal Investigator: HIRAO Yasukazu 大阪大学, 理学研究科, 講師 (50506392)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 電子移動 / 有機ラジカル / 刺激応答性分子 / 化学結合論 / クロミズム

Outline of Final Research Achievements

We synthesized a number of organic compounds coupling strong electron-donating and/or electron-accepting units, and analyzed them under various conditions using various physical techniques to evaluate their environmental stimulus responsiveness. The compounds connecting electron-donating and electron-accepting units became zwitterionic substances. With decreasing solvent polarity, the equilibrium shifted to the neutral biradical species corresponding to the product with intramolecular electron transfer. On the other hand, the compounds with dimerized bulky electron-donating units provided two conformational isomers. Their isomerization equilibrium constants depended on solvent viscosity. The stimuli-responsive properties and response mechanisms of the molecules developed in this project have not been reported before and are promising novel stimuli responsive material.

Free Research Field

構造有機化学

Academic Significance and Societal Importance of the Research Achievements

本研究課題で合成した有機化合物群は全て新規分子であり、その刺激応答性と応答機構は従来報告されていないものである。特に分子内の電子分布を変化可能な分子を開発したことにより、溶媒の極性や温度の変化に対して磁気的物性の変化で応答する分子を生み出すことができた。また、構造・物性が“ゆらぎやすい”分子を開発したことにより、従来とは全く異なる機構で溶媒粘度を感応する材料を創出することができた。これらの成果は刺激応答性材料の開発に新たな道を拓くものである。