Kyushu University Academic Staff Educational and Research Activities Database
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SHUQI WU Last modified date:2023.12.06

Assistant Professor / Institute for Materials Chemistry and Engineering
Department of Fundamental Organic Chemistry
Institute for Materials Chemistry and Engineering

Graduate School

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 Reseacher Profiling Tool Kyushu University Pure
Academic Degree
Doctor of Science, Master of Science Tsinghua University (China), Bachelor of Science Tsinghua University (China)
Country of degree conferring institution (Overseas)
Yes Bachelor Master
Field of Specialization
Inorganic Chemistry, Physical Chemistry
ORCID(Open Researcher and Contributor ID)
Total Priod of education and research career in the foreign country
Research Interests
  • With the trend of miniaturization of electronic devices, molecular materials with multifunctionality are generally regarded as potential candidates for next-generation information technology. Controlling the magnetic and electronic states by external stimuli will play a central role in this aspect. In our study, we design and synthesize molecular crystals with the electronic structures lying at the boundary of different local minima on the potential energy surfaces, aiming at realizing the controllable switching behavior and synergistic electric and magnetic field effects. Currently, the pyroelectric effect from the pure molecular origin (e.g. intramolecular electron transfer) has been observed in polar valence tautomerism crystals. Future work involves the development of light- and field-responsive dynamic polar crystalline materials.
    keyword : Molecular Magnetism; Molecular Pyroelectricity; Magneto-electric Coupling; Electronic Structure
Academic Activities
1. Sheng-Qun Su, Shu-Qi Wu, Michael L. Baker, Peter Bencok, Nobuaki Azuma, Yuji Miyazaki, Motohiro Nakano, Soonchul Kang, Yoshihito Shiota, Kazunari Yoshizawa, Shinji Kanegawa, Osamu Sato, Quenching and Restoration of Orbital Angular Momentum through a Dynamic Bond in a Cobalt(II) Complex, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/jacs.0c02257, 142, 26, 11434-11441, 2020.07, Orbital angular momentum plays a vital role in various applications, especially magnetic and spintronic properties. Therefore, controlling orbital angular momentum is of paramount importance to both fundamental science and new technological applications. Many attempts have been made to modulate the ligand-field-induced quenching effects of orbital angular momentum to manipulate magnetic properties. However, to date, reported changes in the magnitude of orbital angular momentum are small in both molecular and solid-state magnetic materials. Moreover, no effective methods currently exist to modulate orbital angular momentum. Here we report a dynamic bond approach to realize a large change in orbital angular momentum. We have developed a Co(II) complex that exhibits coordination number switching between six and seven. This cooperative dynamic bond switching induces considerable modulation of the ligand field, thereby leading to substantial quenching and restoration of the orbital angular momentum. This switching mechanism is entirely different from those of spin-crossover and valence tautomeric compounds, which exhibit switching in spin multiplicity..
2. Shu-Qi Wu, Meijiao Liu, Kaige Gao, Shinji Kanegawa, Yusuke Horie, Genki Aoyama, Hajime Okajima, Akira Sakamoto, Michael L. Baker, Myron S. Huzan, Peter Bencok, Tsukasa Abe, Yoshihito Shiota, Kazunari Yoshizawa, Wenhuang Xu, Hui-Zhong Kou, Osamu Sato, Macroscopic Polarization Change via Electron Transfer in a Valence Tautomeric Cobalt Complex, NATURE COMMUNICATIONS, 10.1038/s41467-020-15988-1, 11, 1, 2020.04, Polarization change induced by directional electron transfer attracts considerable attention owing to its fast switching rate and potential light control. Here, we investigate electronic pyroelectricity in the crystal of a mononuclear complex, [Co(phendiox)(rac-cth)](ClO4).0.5EtOH (1.0.5EtOH, H(2)phendiox=9, 10-dihydroxyphenanthrene, rac-cth = racemic 5, 5, 7, 12, 12, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradecane), which undergoes a two-step valence tautomerism (VT). Correspondingly, pyroelectric current exhibits double peaks in the same temperature domain with the polarization change consistent with the change in dipole moments during the VT process. Time-resolved Infrared (IR) spectroscopy shows that the photo-induced metastable state can be generated within 150ps at 190K. Such state can be trapped for tens of minutes at 7K, showing that photo-induced polarization change can be realized in this system. These results directly demonstrate that a change in the molecular dipole moments induced by intramolecular electron transfer can introduce a macroscopic polarization change in VT compounds. Polarization change from directional electron transfer attracts considerable attention owing to its fast switching rate and potential light control. Here, the authors provide a proof-of-concept of electronic pyroelectricity induced by intramolecular electron transfer in the single crystal of a valence tautomeric compound..
3. Wei Huang, Shuqi Wu, Xiangwei Gu, Yao Li, Atsushi Okazawa, Norimichi Kojima, Shinya Hayami, Michael L. Baker, Peter Bencok, Mariko Noguchi, Yuji Miyazaki, Motohiro Nakano, Takumi Nakanishi, Shinji Kanegawa, Yuji Inagaki, Tatsuya Kawae, Gui-Lin Zhuang, Yoshihito Shiota, Kazunari Yoshizawa, Dayu Wu, Osamu Sato, Temperature dependence of spherical electron transfer in a nanosized [Fe-14] complex, NATURE COMMUNICATIONS, 10.1038/s41467-019-13279-y, 10, 2019.12, The study of transition metal clusters exhibiting fast electron hopping or delocalization remains challenging, because intermetallic communications mediated through bridging ligands are normally weak. Herein, we report the synthesis of a nanosized complex, [Fe(Tp) (CN)(3)](8)[Fe(H2O)(DMSO)](6) (abbreviated as [Fe-14], Tp(-)hydrotris(pyrazolyl)borate; DMSO, dimethyl sulfoxide), which has a fluctuating valence due to two mobile d-electrons in its atomic layer shell. The rate of electron transfer of [Fe-14] complex demonstrates the Arrhenius-type temperature dependence in the nanosized spheric surface, wherein high-spin centers are ferromagnetically coupled, producing an S=14 ground state. The electronhopping rate at room temperature is faster than the time scale of Mossbauer measurements (
4. Michael L. Baker, Shu-Qi Wu, Soonchul Kang, Satoshi Matsuzawa, Marie-Anne Arrio, Yasuo Narumi, Takumi Kihara, Tetsuya Nakamura, Yoshinori Kotani, Osamu Sato, Hiroyuki Nojiri, Electron-Transfer Activity in a Cyanide-Bridged Fe-42 Nanomagnet, INORGANIC CHEMISTRY, 10.1021/acs.inorgchem.9b01216, 58, 15, 10160-10166, 2019.08, The ability to switch a molecule between different magnetic states is of considerable importance for the development of new molecular electronic devices. Desirable properties for such applications include a large-spin ground state with an electronic structure that can be controlled via external stimuli. Fe-42 is a cyanide-bridged stellated cuboctahedron of mixed-valence Fe ions that exhibits an extraordinarily large S = 45 spin ground state. We have found that the spin ground state of Fe(42 )can be altered by controlling the humidity and temperature. Dehydration results in a 15 mu B reduction of the saturation magnetization that can be partially recovered upon rehydration. The complementary use of UV-vis, IR, L-2,L-3-edge X-ray absorption spectroscopy and X-ray magnetic circular dichroism is applied to uncover the mechanism for the observed dynamic behavior. It is identified that dehydration is concurrent with metal-to-metal electron transfer between Fe pairs via a cyanide pi hybridization. Upon dehydration, electron transfer occurs from low-spin {Fe-II(Tp)(CN)(3)} sites to high-spin Fe-III centers. The observed reduction in magnetization upon dehydration of Fe-42 is inconsistent with a ferrimagnetic ground state and is proposed to originate from a change in zero-field splitting at electron-reduced high-spin sites..
5. Juan Yuan, Shu-Qi Wu, Mei-Jiao Liu, Osamu Sato, Hui-Zhong Kou, Rhodamine 6G-Labeled Pyridyl Aroylhydrazone Fe(II) Complex Exhibiting Synergetic Spin Crossover and Fluorescence, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/jacs.8b00103, 140, 30, 9426-9433, 2018.08, Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe(II) complex 1 for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN4O2 coordination environment, and intermolecular pi---pi contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic susceptibility measurements on complex 1 show that three-step SCO takes place in the temperature range of 120-350 K, and its desolvated form 1-d exhibits SCO around room temperature (T-c up arrow = 343 K and T-c down arrow = 303 K) with a wide hysteresis loop of 40 K. Moreover, complex 1-d displays light-induced excited spin-state trapping phenomenon. Intriguingly, the fluorescence intensity of the maximum emission at 560 nm for complex 1-d displays discontinuous variation in the range of 250-400 K, indicative of the occurrence of synergetic fluorescence and SCO..
Educational Activities
Teaching the physical concepts in molecular magnetism and theoretical calculations; discussing experimental plans and providing suggestions and comments to students.