Synthesis of pi-Extended Helical Aromatic Compounds and Investigation on Their Chiral Molecular Functions

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05077
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Kyoto University
• Principal Investigator: Hirose Takashi 京都大学, 化学研究所, 准教授 (30626867)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: ヘリセン / π拡張 / キラリティー / 円二色性 / 分子バネ / 単結晶構造解析 / 量子化学計算

Outline of Final Research Achievements

In this study, we have synthesized π-extended helical compounds and investigated their characteristic molecular functions derived from their chiral molecular structure.
The homogeneously π-extended helicenes, that is the helical analog of hexabenzocoronene, tend to have small HOMO-LUMO gap that is significantly decreases with increasing the helical length of the π-extended helicenes. We have also succeeded in the synthesis of π-expanded helical compounds with large helical diameter, which behave as a soft molecular spring with a small molecular spring constant that is ca. one-tenth of that of conventional helicenes.

Free Research Field

物理有機化学

Academic Significance and Societal Importance of the Research Achievements

本研究では、π拡張型およびπ伸長型らせん状化合物にユニークな物性の一般性を実験的に示すことができ、分子構造とキラルならせん構造に由来する物性との関係性についての新たな知見を得ることができた。具体的には、均一にπ拡張したらせん状分子は「世界最高レベルの優れた円偏光応答性」を示し、π伸長型らせん状分子は「高い柔軟性を持つナノスケールの分子ばね材料」としての応用が期待できることを明らかにした。