2022 Fiscal Year Research-status Report
Development of Multifunctional Photo-responsive Molecular Magnets
| Project/Area Number |
21K14582
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | Functional compounds / Low-frequency absorption / Luminescence / Molecular magnets / Nonlinear optics / Photomagnets / Switchable materials |
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| Outline of Annual Research Achievements |
In the second year of the project, 7 articles were published, and about 40 new transition metal complexes with different ligands were synthesized and characterized, with the most significant ones selected for further study on multifunctional photomagnetic materials. Among them, two new isostructural three-dimensional systems consisting of trinuclear triangle copper(II)-pyrazole and octacyanidometallates(IV) with strong antiferromagnetic interactions and spin frustration were synthesized, analyzed for their magnetic and optical properties, and described using theoretical calculations to improve the efficiency of the photomagnetic effect (Inorg. Chem. 2022, 61, 8930). Further studies on low-frequency THz absorption and Raman scattering (important for the development of fast wireless telecommunication), single-molecule magnet behavior (applicable in sophisticated high-density memory devices), and visible/near-infrared luminescence thermometric properties (used in bioimaging) in Ln(III)-(NCS/NCSe) and Ln(III)-[Au(SCN/CN)2] compounds for further implementation in photomagnetic systems have been studied (J. Mater. Chem. C 2023, 11, 1008; Adv. Opt. Mater. 2022, 10, 2201675; Int. J. Mol. Sci. 2022, 23, 6051). Due to the very promising results for lanthanide complexes, similar Fe(II)-[Hg(SCN)4] complexes were prepared and tested, obtaining paramagnetic materials exhibiting sub-terahertz absorption (Angew. Chem. Int. Ed. 2023, 62, e2022146) and non-linear optical effects observed in measurements of second harmonic generation and circular dichroism (Inorg. Chem. 2023, 62, 3278).
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
During Fiscal Year 2022, most of the planned activities were completed. This led to the development of new materials with chiral, luminescent, and conducting components, which were described using various spectroscopic, structural, and magnetic techniques. The database of previously studied materials from Fiscal Year 2021 was also updated with new promising photomagnetic materials. New research directions were also developed, including studies on Fe(II)-[Hg(SCN)4] systems that showed potential for constructing functional materials with low-frequency THz absorption and Raman scattering, nonlinear optical activity (circular dichroism and second harmonic generation), and magnetic properties (Angew. Chem. Int. Ed. 2023, 62, e2022146; Inorg. Chem. 2023, 62, 3278). New experimental methodologies were used to investigate these materials, which are currently being studied for their photomagnetic functionality.
Additionally, Cu(II) polynuclear clusters were combined with photoreactive [Mo(CN)8]4- anions (Inorg. Chem. 2022, 61, 8930), which led to the discovery of a new possible route for developing photomagnetic materials. Significant progress was made in studying the luminescence of lanthanide(III) complexes and their practical application in 10-300 K thermometry. Similar research is also being conducted on photoreactive Ln(III)/Cu(II)-[Mo(CN)8] systems. Finally, theoretical calculation tools were developed for each class of materials to better understand the observed effects.
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| Strategy for Future Research Activity |
In the next Fiscal Year 2023, particular attention will be given to the study of materials based on Fe(II)-[M(XCN)n] complexes, which can display non-trivial spin behavior and a photomagnetic effect resulting from light-induced spin-state trapping. Such a response of the system will be achieved by selecting appropriate organic ligands (e.g., chiral pyridine derivatives). At this stage, several potential candidates for multifunctional iron(II) photomagnets have been identified, and preliminary research is currently being conducted. In addition, research on chiral copper clusters, showing nonlinear optical activity, in combination with polycyanidometallates is being advanced. Materials with 4 or more connected Cu(II) centers, which are known to exhibit weaker antiferromagnetic interactions, making it difficult to observe the photomagnetic effect associated with charge transfer between Mo(IV) and Cu(II), are particularly expected. Further studies of systems with lanthanides(III), which have proven to be very promising in terms of practical application in fluorescent and Raman thermometric measurements, are also planned. Finally, conductivity measurements are projected for systems based on octacyanidometallate(IV) salts that can form photomagnetic systems with selected organic cations. Further actions in the development of density functional theory (DFT) methodology for the analysis of multifunctional materials will be continued.
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| Causes of Carryover |
The planned budget for the publication of scientific articles and hard-to-reach reagents needed for the research project was not used in the previous Fiscal Year 2022. It was decided that the funds would be allocated for the same purposes in the next Fiscal Year 2023. The allocation and use of these funds will ensure the timely implementation of the research project and the achievement of its goals.
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