Molecular systems with external field induced state conversions

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K19088
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 34:Inorganic/coordination chemistry, analytical chemistry, and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: Oshio Hiroki 筑波大学, 数理物質系(名誉教授), 名誉教授 (60176865)
• Co-Investigator(Kenkyū-buntansha): 大谷 亮 九州大学, 理学研究院, 准教授 (30733729)
• Project Period (FY): 2018-06-29 – 2023-03-31
• Keywords: 錯体化学 / 分子磁性 / 外場応答性分子

Outline of Final Research Achievements

This study aimed to construct spin crossover (SCO) and mixed valence (ET) complexes showing the external field-induced electronic state conversion.
(1) SCO complexes with di-basic/acid ligands were synthesized, and it was shown that the protonation of the ligands could convert the spin state. (2) Cyanide ion-bridged mixed-valence complexes were synthesized. The complexes exhibited that the intermolecular ππ interactions produce stresses on the coordination structure, resulting in significant differences in the external field-induced phase transition temperature. (3) In two-dimensional SCO complexes, we realized a system in which the SCO and the dielectric response are coupled by the coupling between the SCO and the rotation of the pyrazole group in the bridging ligand.

Free Research Field

錯体化学

Academic Significance and Societal Importance of the Research Achievements

金属酸化物は強い電子相関に基づく強磁性・強誘電・電気伝導性を示し、これら物性を光・電場・磁場で制御するマルチフェロイックシステムが実現しつつある。一方、分子性化合物においては柔軟な構造・電子状態をもつにもかかわらず，その酸化状態・スピン状態の組合せに基づく光物性・磁性・電気的性質が強く結合する系は極めて少なく、高効率で高速な物性変換分子システムの構築が必要である。本研究では、スピンクロスオーバ錯体や混合原子価錯体集合体に、配位子のプロトン脱離・付加や分子間相互作用の導入により、将来の分子デバイスの基盤となる高度な物性変換システムシステムを構築することができた。