Photofunctional materials based on excited-state aromaticity

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H01952
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 32020:Functional solid state chemistry-related
• Research Institution: Kyoto University
• Principal Investigator: SAITO Shohei 京都大学, 理学研究科, 准教授 (30580071)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 羽ばたく分子 / 励起状態 / 芳香族性 / 蛍光粘度プローブ / 一重項分裂 / 接着 / 液晶 / 光剥離

Outline of Final Research Achievements

The following findings were obtained for the unique flapping molecules (FLAP). 1) FLAPs bearing tetracene or pentacene wings exhibit fast singlet fission; 2) FLAPs with bulky substituents act as flexible mechanophores and phase transitions in crystals can be visualized by fluorescence; 3) amphiphilic FLAPs with hydrophilic and hydrophobic groups form monolayers at the air-water interface and exhibit pressure response by molecular assembly; 4) FLAP bearing benzoperyleneimide wings exhibits remarkable photostability as a fluorescence viscosity probe that shows a sensitive response even in the extremely low viscosity range; 5) As a new method to design the shape of S1 energy profile, the excited state aromatic stabilization energy can be tuned by molecular design.

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Free Research Field

光化学、構造有機化学、有機材料化学

Academic Significance and Societal Importance of the Research Achievements

励起状態芳香族性は、通常のヒュッケル則に反して光励起状態の環状[4n]pi共役系で発現して分子骨格の平面化やエネルギー低下をもたらすことで知られ、近年注目が集まっているが、励起状態芳香族性の概念を光機能材料の設計指針として積極活用した例は申請時点ではほとんど報告がなかった。今回、研究代表者が独自に開発した多機能性の羽ばたく分子FLAPをプラットフォームとして、特に過去の報告が少ないS1芳香族性の発現条件を解明するとともに、その知見を光機能材料の設計として応用し、優れた蛍光粘度プローブや接着性の光応答液晶を開発することができた。