Exploration of the Properties of Nonbenzenoid Conjugated Systems based on Intermolecular Interaction and Novel Molecular Design

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01916
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Kyoto University
• Principal Investigator: Fukazawa Aiko 京都大学, 高等研究院, 教授 (70432234)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 非ベンゼン系共役電子系 / π共役 / 反芳香族 / ペンタレン / ジアザペンタレン / 電子受容体 / ペンタレン / フラーレン

Outline of Final Research Achievements

The intermolecular interactions of pentalenes and 1,4-diazapentalenes having thiophene as a fused ring moiety were analyzed and found to be capable of forming densely stacked structures by reducing exchange repulsion, although the formation of face-centered stacking structures that would manifest stacking aromaticity was not observed. During the course of the synthetic studies of a series of novel antiaromatic compounds, we selendipitiously found that benzothiophene-S,S-dioxide-fused pentalenes form stable complexes with nickel(0).
Furthermore, we have designed the π-conjugated oligomers of pentafulvalene and demonstrated their high electron affinity and robustness against multi-electron reduction close to that of fullerene C60, even in a flat one-dimensional conjugated system.

Free Research Field

構造有機化学

Academic Significance and Societal Importance of the Research Achievements

現在の有機光・電子機能性有機材料の基本構造はベンゼンや複素芳香環に依存している。これらの物性や機能の限界を打破する上で，異なる構造特性をもつ化合物群に対する物性の探究や機能開拓の試みは必要不可欠であり，本研究で得られた知見はその中でも分子設計や分子間相互作用に対する基礎的な理解を与えるものである。特に，フラーレンに迫る電子受容性を一次元炭化水素で実現できたことは，これまでの電子受容体の設計における常識を打破する成果であり，電子受容体の科学に新たな方向性を示すものといえる。