Study on Correlation between Magnetism and Electrical Conductivity in Electro-oxidized Actinide Phthalocyanine Complexes

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K14644
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 34010:Inorganic/coordination chemistry-related
• Research Institution: Japan Atomic Energy Agency (2022-2023); Kyoto University (2021)
• Principal Investigator: Tabata Chihiro 国立研究開発法人日本原子力研究開発機構, 原子力科学研究部門 原子力科学研究所 物質科学研究センター, 研究職 (60783496)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: アクチノイド / フタロシアニン / 結晶構造解析 / 磁性 / 第一原理計算

Outline of Final Research Achievements

The neutral and cationic species of the tetravalent uranium phthalocyanine complex UPc2, which is one of the uranium phthalocyanine complexes with a sandwich structure, were synthesised, their crystal structures were determined and the magnetic properties of the uranium ion as the central metal were clarified. The crystal structure of [UPc2][BF4], the cationic species of which has not been synthesised before, was determined for the first time, and a crystal field analysis of the measured magnetosensitivity of the neutral species revealed that it exhibits Curie paramagnetism down to low temperatures, which is derived from the pseudo-degenerate two levels. Furthermore, structural optimisation based on first-principles calculations suggested a highly curved structure in the cationic species from the molecular structure determined from X-ray structural analysis, indicating the existence of strong packing effects during crystallisation.

Free Research Field

固体物理学

Academic Significance and Societal Importance of the Research Achievements

フタロシアニン錯体に限らず、放射性物質の取扱の困難さからアクチノイド系化合物の研究例は少なく、継続的に研究を行っているグループは限られている。一方で、アクチノイド化合物の構造および磁性等の物性を支配する５f電子は、遷移金属のd電子や希土類金属の4f電子とは異なる独特かつ多彩な性質を示す。本研究では、物性物理学分野が得意とする詳細な物理量測定に基づく電子物性研究の手法と、物性化学分野が得意とする緻密で多彩な物質開発手法を組み合わせることで、錯体中の5f電子が示す磁性とその結晶構造を精密に解析・解明することに成功した。