Photoinduced catalyst based on photoreactions

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K19006
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 35:Polymers, organic materials, and related fields
• Research Institution: Nara Institute of Science and Technology
• Principal Investigator: KAWAI TSUYOSHI 奈良先端科学技術大学院大学, 先端科学技術研究科, 教授 (40221197)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 光反応 / ルイスペア / ポリエステル

Outline of Final Research Achievements

In this study, we investigated the photoinduced Lewis pair generation through photochromic reactions, resulting in the ion dissociation of Lewis base and Lewis acid units. Given that ion pairs possess high reactivity, their activation of small molecules is effective, and the photogeneration of sterically hindered FLPs (Frustrated Lewis Pairs) represents a significant impact in uncharted territory. Anticipating the dissociation of alkoxy groups accompanying the photochromic reaction, we synthesized compounds A, B, and C. Compound C, with a structure alleviating steric hindrance, exhibited three distinctive absorption bands in the visible region during the photoreaction, indicating the formation of a carbocation and a stable Lewis pair. Furthermore, using this compound C, we successfully achieved the photo-driven polymerization of cyclic ester monomers.

Free Research Field

光機能材料

Academic Significance and Societal Importance of the Research Achievements

生分解性ポリマーなど環境負荷の小さいポリマー材料や、抗血栓性など生体親和性の高いポリマー材料のためポリエステル系樹脂が検討されきた。これらの光形成においては側鎖に導入されたビニル基を利用した光架橋、光架橋が活用されてきたが、これは本来の機能と相反する。エステルモノマーの光重合のためには高反応活性のルイス塩基やＦＬＰを光形成する必要がある。本研究で提示された光駆動型のルイスペア発生剤は、学術的には従来にないイオン対型のルイスペアをもたらし、さらにポリエステル系フォトポリマーにつながり、格段の社会的なインパクトが期待される。