Synthesis of Novel Near-infrared Fluorescence Analytical Reagents Using Aggregation-induced Emission (AIE) by Organic Fluorescent Dyes

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K05518
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34020:Analytical chemistry-related
• Research Institution: Hirosaki University
• Principal Investigator: Kawakami Jun 弘前大学, 理工学研究科, 教授 (60261426)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 蛍光分析試薬 / 有機蛍光色素 / 凝集誘起発光 / 近赤外 / トリプタンスリン

Outline of Final Research Achievements

Most fluorescence analysis reagents using organic fluorescent dyes have a planar structure and show strong fluorescence in dilute solutions, but in concentrated solutions, they form aggregate structures in which molecules are stacked, causing aggregation-caused quenching (ACQ).
In this study, by introducing bulky substituents that allow rotational movement into the molecule, we aimed to construct new near-infrared fluorescence analysis reagents using aggregation-induced emission (AIE), in which the non-radiative process with thermal radiation prevails in dilute solution, but the fluorescence intensity increases in concentrated solution or in an aggregated state due to suppression of rotational movement and difficulty in forming integrated structures. Several model molecules were successfully synthesised and interesting findings were obtained.

Free Research Field

有機光化学，超分子化学

Academic Significance and Societal Importance of the Research Achievements

従来の蛍光分析試薬は，平面構造の有機蛍光色素を用いたものが多く，希薄溶液中では強い蛍光を示すが，濃度の増大により分子が積み重なった集積構造を形成して凝集起因消光を起こすため，検出感度や定量性に問題があった。
本研究で合成された，分子内電荷移動型の蛍光性トリプタンスリンに回転可能な嵩高い置換基を導入した系は，希薄溶液中では熱放射を伴う無輻射過程が勝り無蛍光であるが，高濃度溶液中や凝集状態では回転運動と積み重なった集積構造の抑制により生体蛍光プローブとして最適な近赤外領域での凝集誘起発光を示すものである。よって，今後の蛍光分析試薬開発において学術的・社会的に意義のある成果と言える。