Control of organic molecule-based chiroptical properties by cyclic arrangement of dipolar units

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22528
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0501:Physical chemistry, functional solid state chemistry, organic chemistry, polymers, organic materials, biomolecular chemistry, and related fields
• Research Institution: Kyoto University
• Principal Investigator: Kato Kenichi 京都大学, 工学研究科, 助教 (10879406)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: キラル光学特性 / 環状有機分子 / 対称性 / 双極子 / 面不斉

Outline of Final Research Achievements

In the present work, we developed chiral cylindrical macrocycles bearing different substituents on upper and lower rims and evaluated their chiroptical properties. A series of aryl groups were introduced into a pillar[5]arene with bulky cyclohexylmethoxy substituents on one rim. When aryl group had an electron-withdrawing ester group, the pillar[5]arene showed explicit dipolar character and caused increase of the response wavelength and luminescence quantum yield and decrease of the dissymmetry factor for CD and CPL signals. Pyrene rings were also attached to the precursor pillar[5]arene via alkoxy linkers. Chiral information of chiral pillar[5]arene cores was effectively transmitted to pyrene clusters, leading to chiroptical response in visible region based on through-space interactions between pyrene planes.

Free Research Field

構造有機化学

Academic Significance and Societal Importance of the Research Achievements

有機分子系での優れたキラル光学特性の発現において、環状分子は近年高い注目を集めつつあるが、合成法の制約から上下対称な環状多量体と対称要素に乏しい分子の例が大多数を占めている。本研究のキラルかつ上下非対称な環状分子は欠落部を埋める点で重要であり、系統的な比較により環斜め方向に双極子を整列させた環状分子で分極の増大が非対称性因子の減少を引き起こすことを実験的に明らかにした。ピラーアレーンは強いCD応答にもかかわらずCPL材料への展開で他の分子系に遅れている現状があり、対称な分子修飾に着目することでピラーアレーン分子系の非対称性因子最大値を大きく更新した点も意義深い。