Synthesis of silicon-containing antiaromatic compounds, silaphenalene, and odd alternant hydrocarbons, silaphenalenyl

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K18954
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 33:Organic chemistry and related fields
• Research Institution: Shizuoka University
• Principal Investigator: Sakamoto Kenkichi 静岡大学, 理学部, 教授 (50187035)
• Project Period (FY): 2021-07-09 – 2023-03-31
• Keywords: シラフェナレン / ヘテロフェナレン / 奇交互炭化水素 / NICS / 反芳香族性 / 多環芳香族炭化水素 / 14族元素 / 常磁性環電流

Outline of Final Research Achievements

We have successfully established a synthetic method for hexahydrosilaphenalene, a molecule containing silicon at its center. Using a phenyl-substituted derivative as the starting material, we achieved the synthesis of phenylsilaphenalene, a compound with antiaromaticity, through selenium dioxide oxidation, acid-catalyzed dehydration, and DDQ oxidation. This compound exhibited prominent features of antiaromaticity in NMR analysis.
Furthermore, we applied the synthetic method of hexahydrosilaphenalene to germanium, tin, and phosphorus, successfully synthesizing the corresponding hexahydroheterophenalenes.
NICS calculations of neutral heterophenalenes and heterophenalenyls with various heteroatoms at the center have revealed a high correlation between the electronegativity and aromaticity of the central atom.

Free Research Field

有機典型元素化学

Academic Significance and Societal Importance of the Research Achievements

炭素原子による六員環構造が連なった多環芳香族炭化水素、さらにはグラフェンやカーボンナノチューブはユニークな電気的特性あるいは光学的特性などを示すことから新規な材料物質として盛んに研究されている。これらの化合物群の炭素原子の一部をケイ素のようなヘテロ原子に置き換えることが出来れば、その展望はさらに広がるであろう。本研究では、これまで全く類例のなかったシラフェナレン骨格の構築に初めて成功した。様々なヘテロ原子の導入にも成功しており、従来の多環芳香族炭化水素などの化学の進展に寄与したと考えている。