Construction of novel 4npi-electron systems and creation of weak pi-bonds through tailor-made control of pi-conjugated circuits

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05464
• 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: Osaka University
• Principal Investigator: Konishi Akihito 大阪大学, 大学院工学研究科, 助教 (10756480)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 開殻性 / 反芳香族性 / 非交互炭化水素 / クムレン / キャリア輸送能

Outline of Final Research Achievements

Open-shell molecules have been studied extensively from both basic and applied perspectives. Although the design guideline based on the Clar's sextet rule is one of the most powerful strategies, expanding molecular size is not avoidable, which causes instability and handling issues. To overcome this situation, I have performed to develop and understand the open-shell property in the smallest molecular system by utilizing a 4nπ-electron system. I have achieved (1) the development of molecules with open-shell and anti-aromatic characteristics as functional materials, (2) synthesis and characterization of bisperiazulene, and (3) conversion of the conjugated cumulenes as a synthetic precursor into a highly condensed 4nπ-conjugated system. Through the execution of this project, I have established efficient construction methods of 4nπ-electron systems and experimentally elucidated the mechanism of the open-shell nature in 4nπ-conjugated systems.

Free Research Field

構造有機化学

Academic Significance and Societal Importance of the Research Achievements

国内外で反芳香族性や開殻性に着目した実験的・理論的研究は幅広く行われている。しかし、各々の性質解明、応用展開に特化したものに限られている。両者の特性を活かし、4nπ骨格に着目した新たな開殻性発現の指針を得たことが本研究の大切な点であり、これまでの報告例とは大きく異なる。さらに、ホール輸送能の評価を通じ、本申請における特殊な電子状態をもつ分子系が材料応用展開の高い可能性を秘めていることをあきらかにした。本申請で確立した4nπ電子系の効率構築法とあわせ、これらの分子系が新たな材料としての活用できる可能性を強く見出すことができた。