| 研究課題/領域番号 |
21K14582
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| 研究機関 | 東京大学 |
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研究代表者 |
ステファンチック オラフ 東京大学, 大学院理学系研究科(理学部), 特任助教 (00822503)
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| 研究期間 (年度) |
2021-04-01 – 2024-03-31
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| キーワード | Functional compounds / Switchable materials / Molecular magnets / Photomagnets / Advanced materials / Luminescence / Nonlinear optics |
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| 研究実績の概要 |
In the first year of research, more than 50 new d- and f-block metal complexes with diverse organic ligands were synthesized. Most of the materials were structural and physicochemical characterized, allowing the determination of the relevant materials for future research on multifunctional photomagnetic materials. Part of the results were published as seven scientific articles. Special attention was focused on Fe(II) complexes showing two new cross-effects of the desolvation-assisted spin-crossover and light-induced excited spin-state trapping, switching between two magnetic states upon external stimuli (Inorg. Chem. Front. 2021, 8, 3210; highlighted on the back cover). This discovery will be important for designing humidity-switchable materials. Moreover, the newly prepared chiral Ln(III)-[W(CN)8], Ln = Gd-Lu, molecular magnets were investigated to determine the influence of the applied Ln(III) ion on the intensity of the effect of nonlinear optics - second harmonic generation (SHG) (Inorg. Chem. 2021, 60, 12009). Next, the effect of anion substitution on the SHG phenomenon, low-frequency Raman scattering, and luminescence thermometric properties was investigated for Yb(III)-(NCS/NCSe) and Ln(III)-[Au(SCN)2] compounds (Adv. Opt. Mater. 2022, 10, 2101721; Angew. Chem. Int. Ed. 2022, 61, e202201265). These results pave the way to introduce these properties into photomagnetic materials. Finally, four Cu(II)-[Mo(CN)8] systems were experimentally and theoretically investigated, confirming their photomagnetic properties of diverse origins (Inorg. Chem. Front. 2022, 9, 771).
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The majority of activities planned for the Fiscal Year 2021 were successfully realized, resulting in the design, synthesis, and comprehensive structural, spectroscopic, and magnetic characterization of new transition metal complexes with chiral, luminescent, and conducting components. As a result of the work, an extensive database of potential photomagnetic materials was developed. Among them, two classes of compounds have been distinguished as particularly promising: salts and coordination networks based on spin-crossover active Fe(II) cations (Inorg. Chem. Front. 2021, 8, 3210) or [Mo(CN)8]4- anions (Inorg. Chem. Front. 2022, 9, 771), and charge transfer polynuclear coordination polymers based on lanthanide/transition metals and octacyanidometallates, e.g. Ln(III)/Cu(II)-[M(CN)8], M = Mo and W systems (Inorg. Chem. 2021, 60, 12009). Significant advances in the development of chiral photomagnets were achieved by using chiral ions for the crystallization of noncentrosymmetric Fe(II) complexes and [Mo(CN)8] salts, and enantiopure ligands to form hybrid bimetallic networks. The most progress was made in the elaboration of luminescent photomagnets for Ln(III)-based luminescence compounds, as well as composites based on photoreactive complexes and luminescent organic ligands. Finally, the first steps towards achieving a photomagnetic conductive material were made by the synthesis of Cu(II)-[Mo(CN)8] systems containing protonated organic ligands capable of showing ionic conductivity.
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| 今後の研究の推進方策 |
In the Fiscal Year 2022, detailed photomagnetic measurements of the most promising samples to determine the effectiveness of this phenomenon are planned. Then, depending on the expected additional properties, nonlinear optics (NLO) measurements for chiral samples, luminance measurements for samples with appropriate components, and impedance measurements for samples with potentially conductive ions will be conducted. Chiral photomagnetic systems will be investigated by means of circular dichroism spectroscopy, second harmonic generation spectroscopy, and ferroelectricity measurements to confirm NLO effects. Based on the previous results (Inorg. Chem. 2021, 60, 12009; Adv. Opt. Mater. 2022, 10, 2101721), particular attention will be paid to enhancing the effects of NLO, taking into account the effects of substitution of building elements (e.g. metal centers, ligands, and anions). Luminescence properties will be determined in the range of 10-300 K utilizing a spectrofluorometer equipped with a cryogenic cooling system, while room-temperature conductivity will be conducted with an impedance analyzer. Additionally, further synthesis and basic research to develop the next functional photomagnetic materials and to improve the observed effects will also be continued. Finally, density functional theory (DFT) periodic calculations will be conducted to better understand the observed phenomena.
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