Chiroptical properties based on the assembly of achiral phenylacetylene macrocycles (PAMs)

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05069
• 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: Hokkaido University
• Principal Investigator: KATOONO RYO 北海道大学, 理学研究院, 助教 (60432142)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: フェニルアセチレンマクロサイクル / キラリティ / テレフタルアミド

Outline of Final Research Achievements

Newly-designed chiral molecules and their chiroptical properties were studied.　Here, two achiral rings create chirality through the assembly, such as stacking, mechanical linking, or merging. As an achiral ring, a phenylacetylene macrocycle ([6]PAM) was used for the creation of multiple chiral molecules. Site-specific modification of PAMs was suitable for bridging of the two rings at arbitrary positions.
Regarding the chiroptical properties, the specific optical rotation of a mechanical bound molecule was outstanding (>±1000), and also molar CDs (Δε) exceeded at most ±1000 in the CD spectroscopy. It is interesting to note that another mechanical bound molecule, with the same component but bridged at different positions, showed only halves of those activities. For [11]PAM, these activities were worse. These results shows that chiroptical properties could be modulated by the shape of a molecule.

Free Research Field

キラル化学

Academic Significance and Societal Importance of the Research Achievements

カテナンやロタキサンを主題とする従来の研究では、その設計において、通常異性体が生じないような工夫がなされる。本研究では、それとは逆に、構造多様性を創出する足場として利用した点が独創的である。ここでは、二分子の[6]PAMを集積させて多様なキラル構造を創り出す。全く同一の構成要素を基に、異なる形状の分子からそれぞれ固有の光学活性を創り出すことができた。環拡大した[12]PAMもまた集積の一形態とみなし、標的とした。[12]PAM構造は、合成例だけでも一例しか報告がなく、キラリティに関する報告は皆無であったが、本研究で初めて[12]PAMに基づくキロプティカル特性を示すことができた。