Near‐Infrared Light‐Induced Spin‐State Switching Based on Fe(II)−Hg(II) Spin‐Crossover Network
The development of molecular switches with tunable properties has garnered considerable interest over several decades. A novel spin-crossover (SCO) material based on iron(II) complexes incorporating 4-acetylpyridine (4-acpy) and [Hg(SCN)<sub>4</sub>]<sup>2-</sup> anions was synthesized and formulated as [Fe(4-acpy)<sub>2</sub>][Hg(μ-SCN)<sub>4</sub>] (1). Compound 1 is crystallized in a three-dimensional network in the non-centrosymmetric orthorhombic space group Pna2<sub>1</sub> with two octahedral [Fe(4-acpy)<sub>2</sub>(NCS)<sub>4</sub>] entities featuring two distinct Fe centers (Fe1 and Fe2). Crystallographic, magnetic, and Mössbauer measurements reveal an incomplete SCO exclusively at Fe2, with transition temperature T<sub>1/2</sub>≈102 K. Photomagnetic studies conducted at 10 K with lasers ranging from 405 to 1310 nm evidence light-induced excited spin-state trapping (LIESST) and reverse-LIESST effects, with a unique near-infrared-responsive LIESST phenomenon at 1064 and 1310 nm. Advanced photocrystallographic studies at 40 K provide precise structural evidence for these metastable states. The optical and vibrational properties consistently corroborate with magnetic and photomagnetic studies. Additionally, temperature- and light-dependent terahertz (THz) absorptions are associated with phonon vibrations around Fe2 centers, through SCO behavior, as supported by ab initio calculation. The Fe(II)-Hg(II) systems can be promising benchmarks for exploring synergistic switching effects in structural, magnetic, and spectroscopic properties.
Authors
- Guillaume Chastanet (ORCID: https://orcid.org/0000-0001-6829-4066)
- Asuka Namai (ORCID: https://orcid.org/0000-0001-6200-6326)
- Kevin Tran (ORCID: https://orcid.org/0000-0003-3693-4537)
- Franz Renz (ORCID: https://orcid.org/0000-0003-1494-1242)
- Kenta Imoto (ORCID: https://orcid.org/0000-0002-6764-2484)
- Kunal Kumar (ORCID: https://orcid.org/0000-0002-2626-0615)
- Sumit Ranjan Maity (ORCID: https://orcid.org/0000-0002-8168-8024)
- Laurent Guérin (ORCID: https://orcid.org/0000-0002-0509-8444)
- Maximilian Seydi Kilic (ORCID: https://orcid.org/0009-0007-7173-1459)
- Koji Nakabayashi (ORCID: https://orcid.org/0000-0002-5946-944X)
- Guanping Li (ORCID: https://orcid.org/0000-0001-5168-7998)
- Yuiga Nakamura (ORCID: https://orcid.org/0000-0003-3696-0997)
- Shin‐ichi Ohkoshi (ORCID: https://orcid.org/0000-0001-9359-5928)
- Olaf Stefańczyk (ORCID: https://orcid.org/0000-0003-0955-5646)
- Kosei Okuzono
Institutions
- Leibniz University Hannover (DE)
- Centre National de la Recherche Scientifique (FR)
- Université de Bordeaux (FR)
- University of Manchester (GB)
- SPring-8 (JP)
- Institut de Physique de Rennes (FR)
- Institut de Chimie de la Matière Condensée de Bordeaux (FR)
- Japan Synchrotron Radiation Research Institute (JP)
- Institut Polytechnique de Bordeaux (FR)
- Université de Rennes (FR)
- The University of Tokyo (JP)
Publication Details
- Journal
- Angewandte Chemie International Edition
- Published
- 2024-12-11
- DOI
- https://doi.org/10.1002/anie.202423095
- Citations
- 7
- Primary Topic
- Quantum and electron transport phenomena
- Type
- article
- Field-Weighted Citation Impact
- 2.36
Funders
- Ministry of Education, Culture, Sports, Science and Technology
- University of Tokyo
- Universidade de Macau
- Centre National de la Recherche Scientifique
- Iketani Science and Technology Foundation
- Japan Society for the Promotion of Science