Construction of Conjugated Macrocycles Based on Knot Theory and the Circularly Polarized Luminescence Behaviors

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K18967
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 33:Organic chemistry and related fields
• Research Institution: Kwansei Gakuin University
• Principal Investigator: Morisaki Yasuhiro 関西学院大学, 生命環境学部, 教授 (60332730)
• Project Period (FY): 2021-07-09 – 2024-03-31
• Keywords: 面性不斉 / 円偏光発光 / 大環状分子 / 三葉結び目 / シクロファン

Outline of Final Research Achievements

The results we achieved in this work are as follows. (1) We have focused on the construction of a pi-conjugated chiral trefoil knot using optically active [2.2]paracyclophane and reached the remaining two steps. (2) We have successfully prepared conjugated oligomers in which 2~4 pi-electron systems are stacked. (3) In addition, pi-conjugated chiral macrocycles were also synthesized. They emitted circularly polarized luminescence (CPL) with high anisotropy factors and CPL brightness values. (4) We synthesized one-handed ortho-oligophenylene-stacked molecules emitting CPL with high anisotropy factors. It is the first report that ortho-oligophenylenes emit CPL. (5) We synthesized triphenylene-stacked molecule and revealed their structure and physical properties in detail.

Free Research Field

有機合成化学

Academic Significance and Societal Importance of the Research Achievements

キラルな三葉結び目を共役系で構築した環状分子の合成例は皆無であり、合成に挑戦し円偏光発光を評価する円偏光発光輝度値（B_CPL値）で世界最高値を目指す本研究は学術的意義がある。本研究では結び目をもたない環状分子の合成にも成功した。特に＃型環状四量体は10^-3の桁の良好な異方性因子（g値）を示し、B_CPL値も約200 M^-1cm^-1 と良好な値を示した。また、環状A型分子はその値を凌駕する優れた円偏光発光体であった（10^-2の桁のg値と300 M^-1cm^-1超のB_CPL値）。これらを通して優れた円偏光発光特性を示す分子の設計指針を提案できたことは学術的社会的意義が大きい。