SATO Kazunobu


Search Institutional Repository



Laboratory location

Sugimoto Campus

Homepage URL

Degree 【 display / non-display

  •  -  Doctor of Science

Research Areas 【 display / non-display

Basic chemistry, Magnetic Resonance, Molecular Magnetism

Research Interests 【 display / non-display

Molecular spin quantum computer

Research Career 【 display / non-display

  • Molecular spin quantum computing by pulsed electron magnetic resonance

    (Individual) Project Year :


    Keyword in research subject:  ESR, quntum conputer, quantum information prosessing

  • Study of Organic high-spin Polycations and Polyanions

    (International Collaboration) Project Year :


    Keyword in research subject:  ESR, Polycation, Polyanion

  • Study of high-spin organic molecules by Electron Spin Magnetic Resonance

    (Collaboration in Japan) Project Year :


    Keyword in research subject:  High-spin organic molecule, ESR, ENDOR

  • Development of new methodology in magnetic resonance spectroscopy


    Keyword in research subject:  Pulsed ESR, Transient Nutation, Multiple Resonance

Association Memberships 【 display / non-display

  • Chemical Society of Japan

  • The Society of Electron Spin Science and Technology

  • American Chemical Society

  • International EPR Society

Committee Memberships 【 display / non-display

  • 2018.02

    The Society of Electron Spin Science and Technology   General Affairs

  • 2012.01

    Asia-Pacific EPR/ESR Society   Secretary Genreal

Current Career 【 display / non-display

  • Osaka City University   Graduate School of Science   Molecular Materials Science Course   Professor  

  • Osaka City University   Research Center for Artificial Photosynthesis (ReCAP)  

Graduate School 【 display / non-display


    Osaka City University  Graduate School, Division of Natural Science 

Graduating School 【 display / non-display


    Osaka City University   Faculty of Science  


Published Papers 【 display / non-display

  • Quantum Chemistry on Quantum Computers: A Method for Preparation of Multiconfigurational Wave Functions on Quantum Computers without Performing Post-Hartree-Fock Calculations

    Sugisaki Kenji, Nakazawa Shigeaki, Toyota Kazuo, Sato Kazunobu, Shiomi Daisuke, Takui Takeji

    ACS CENTRAL SCIENCE  5 ( 1 ) 167 - 175 2019.01  [Refereed]


  • Microscopic Behavior of Active Materials Inside a TCNQ-Based Lithium-Ion Rechargeable Battery by in Situ 2D ESR Measurements

    Kanzaki Yuki, Mitani Satoshi, Shiomi Daisuke, Morita Yasushi, Takui Takeji, Sato Kazunobu

    ACS APPLIED MATERIALS & INTERFACES  10 ( 50 ) 43631 - 43640 2018.12  [Refereed]


  • ESR analyses of picket fence Mn-II and 6th ligand coordinated Fe-III porphyrins (S=5/2) and a Co-II(hfac) complex (S=3/2) with sizable ZFS parameters revisited: a full spin Hamiltonian approach and quantum chemical calculations

    Yamane Takeshi, Sugisaki Kenji, Matsuoka Hideto, Sato Kazunobu, Toyota Kazuo, Shiomi Daisuke, Takui Takeji

    DALTON TRANSACTIONS  47 ( 46 ) 16429 - 16444 2018.12  [Refereed]

     View Summary

    © The Royal Society of Chemistry. The fictitious spin-1/2 (effective spin-1/2) Hamiltonian approach has been the putative method to analyze the conventional fine-structure/hyperfine ESR spectra of high spin metallocomplexes with sizable zero-field splitting (ZFS) tensors since the early 1950s, and the approach gives salient principal geff-values far from g = 2 without explicitly affording their ZFS values in most cases. The experimental geff-values thus determined, however, never agree with those (gtrue-values) of the true principal g-tensors, which are obtainable from reliable quantum chemical calculations. We have recently derived exact or extremely accurate analytical expressions for the geff/gtrue relationships for the spin quantum number S's up to S = 7/2 (T. Yamane et al., Phys. Chem. Chem. Phys., 2017, 19, 24769-24791). In this work, we have removed the limitation of the collinearity between g- and ZFS tensors and derived the generalized geff/gtrue relationships. To illustrate the usefulness of the present approach, we have revisited important typical high spin systems with large ZFS values such as picket fence metalloporphyrins with MnII (S = 5/2) (Q. Yu et al., Dalton Trans., 2015, 44, 9382-9390), a 6th ligand coordinated porphyrin with FeIII (S = 5/2) (Y. Ide et al., Dalton Trans., 2017, 46, 242-249) and a pseudo-octahedral CoII (S = 3/2)(hfac)2 complex (D. V. Korchagin et al., Dalton Trans., 2017, 46, 7540-7548), completing the ESR spectral and magnetic susceptibility analyses and gaining significant physical insights into their electronic structures. The off-principal axis extra peaks overlooked in the documented spectra of the picket fence MnII porphyrins have fully been assigned, affording their accurate true g-, hyperfine and ZFS tensors, for the first time. For the CoII complex, the occurrence of the non-collinearity between the g- and ZFS tensors has been discussed by using the generalized geff/gtrue relationships. We have attempted to carry out reliable DFT-based and ab initio quantum chemical calculations of their magnetic tensors, in which spin-orbit couplings are incorporated, reproducing the experimental true tensors. We emphasize that the incorporation of multi-reference nature in the electron configuration is important to interpret the magnetic tensors for the CoII complex.

    DOI PubMed

  • Fe-transferrins or their homologues in ex-vivo mushrooms as identified by ESR spectroscopy and quantum chemical calculations: A full spin-Hamiltonian approach for the ferric sextet state with intermediate zero-field splitting parameters

    Nakazawa Shigeaki, Kanno Tomomi, Sugisaki Kenji, Kameya Hiromi, Matsui Miki, Ukai Mitsuko, Sato Kazunobu, Takui Takeji

    FOOD CHEMISTRY  266   24 - 30 2018.11  [Refereed]

     View Summary

    © 2018 Elsevier Ltd Fe-transferrins/their homologues in ex-vivo mushrooms were identified by ESR spectroscopy at liquid helium temperature, 4 K. The ESR fine-structure signals from Grifola frondosa were analyzed by spectral simulation with a full spin-Hamiltonian approach, determining the spin Hamiltonian parameters of the ferric iron species bound in the biological environment: S = 5/2, g = (2.045, 2.01, 2.235), |D| = 0.28 cm−1, |E/D| = 0.05. The zero-field splitting (ZFS) parameters, D- and E-values, are very close to the reported values, |D| = 0.25 cm−1and |E/D| = 0.06, for an Fe-transferrin with oxalate anion, and to |D| = 0.25 cm−1and |E/D| = 0.04 for one with malonate anion in human sera, suggesting that the Fe3+species are from Fe-transferrins or their homologues. Quantum chemical calculations of the ZFS tensors for Fe-transferrins were carried out. Fe-transferrins/homologues have been identified for all the mushrooms under study, suggesting that such Fe3+enzymes are widely distributed in mushrooms.


  • Reversible Solution pi-Dimerization and Long Multicenter Bonding in a Stable Phenoxyl Radical

    Bonanno Nico M., Poddutoori Prashanth K., Sato Kazunobu, Sugisaki Kenji, Takui Takeji, Lough Alan J., Lemaire Martin T.

    CHEMISTRY-A EUROPEAN JOURNAL  24 ( 56 ) 14906 - 14910 2018.10  [Refereed]

     View Summary

    © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Reversible solution π-dimerization is observed in the stable neutral phenoxyl radical 2,6-bis-(8-quinolylamino)-4-(tert-butyl)phenoxyl baqp and is spectroscopically characterized. This behavior, not previously observed for π-extended phenoxyl radicals, is relevant to the formation of long multicenter bonding in the π-dimer at low temperature akin to previously reported phenalenyl radicals. Our experimental data are supported in a quantitative manner by results from density functional theory (DFT) and ab initio molecular orbital theory calculations. Our theoretical results indicate that the solution dimer features strong bonding interactions between the two phenoxyl rings but that the stability of the dimer is also related to dispersion interactions between the flanking nearly parallel quinolyl rings.

    DOI PubMed

display all >>

Books etc 【 display / non-display

  • Adiabatic Quantum Computing on Molecular Spin Quantum Computers

    S. Yamamoto, S. Nakazawa, K. Sugisaki, K. Sato, K. Toyota, D. Shiomi, and T. Takeji (Part: Joint Work )

    Electron Spin Resonance (ESR) Based Quantum Computing, Biological Magnetic Resonance, Vol. 31T. Takui, L. Berliner, and G. Hanson (Eds.), Springer-Verlag  2016

  • Molecular Spin Qubits: Molecular Optimization of Synthetic Spin Qubits, Molecular Spin AQC and Ensemble Spin Manipulation Technology

    S. Nakazawa, S. Nishida, K. Sato, K. Toyota, D. Shiomi, Y. Morita, K. Sugisaki, E. Hosseini, K. Maruyama, S. Yamamoto, M. Kitagawa, and T. Takui (Part: Joint Work )

    Principles and Methods of Quantum Information Technologies, in Lecture Notes in Physics 911, Y. Yamamoto, K. Semba (Eds.), Chapter 28, Springer Japan  2016

  • Novel Applications of ESR/EPR: Quantum Computing/Quantum Information Processing

    Kazunobu Sato, Shigeaki Nakazawa, Shinsuke Nishida, Robabeh D. Rahimi, Tomohiro Yoshino, Yasushi Morita, Kazuo Toyota, Daisuke Shiomi, Masahiro Kitagawa, and Takeji Takui (Part: Joint Work )

    EPR of Free Radicals in Solids II, Trends in Methods and Applications, A. Lund and M. Shiotani (eds.), Springer  2013

  • Quantum Chemical Calculation of the Zero-Field Splitting Tensors for Organic Spin Multiplets

    Kenji Sugisaki, Kazuo Toyota, Kazunobu Sato, Daisuke Shiomi, Masahiro Kitagawa, and Takeji Takui (Part: Joint Work )

    EPR of Free Radicals in Solids I, Trends in Methods and Applications, A. Lund and M. Shiotani (eds.), Springer  2013

  • Molecular-Based Exchange-Coupled High-Spin Clusters: Conventional, High-Field/High-Frequency and Pulse-Based Electron Spin Resonance of Molecule-Based Magnetically Coupled Systems

    Takeji Takui, Shigeaki Nakazawa, Hideto Matsuoka, Ko Furukawa, Kazunobu Sato, and Daisuke Shiomi (Part: Joint Work )

    EPR of Free Radicals in Solids II, Trends in Methods and Applications, A. Lund and M. Shiotani (eds.), Springer  2013

display all >>

Review Papers (Misc) 【 display / non-display

  • Molecular spin qubits: Molecular optimization of synthetic spin qubits, molecular spin AQC and ensemble spin manipulation technology

    Shigeaki Nakazawa, Shinsuke Nishida, Kazunobu Sato, Kazunobu Sato, Kazuo Toyota, Kazuo Toyota, Daisuke Shiomi, Daisuke Shiomi, Yasushi Morita, Kenji Sugisaki, Kenji Sugisaki, Elham Hosseini, Elham Hosseini, Koji Maruyama, Satoru Yamamoto, Masahiro Kitagawa, Masahiro Kitagawa, Takeji Takui, Takeji Takui

    Lecture Notes in Physics  911   605 - 624 2016.01  [Refereed]  [Invited]


  • Pyridine-substituted nitronyl nitroxide biradicals: A triplet (S = 1) ground state lasting out N-methylation

    Kenichi Hayakawa, Daisuke Shiomi, Daisuke Shiomi, Tomoaki Ise, Tomoaki Ise, Kazunobu Sato, Takeji Takui

    Journal of Materials Chemistry  16   4146 - 4154 2006.10  [Refereed]  [Invited]

     View Summary

    A 3,5-pyridine-substituted biradical of nitronyl nitroxide (1) has been designed, synthesized and the magnetic properties fully characterized. The ground-state spin multiplicity of 1 has been found to be triplet (S = 1) with a singlet-triplet energy gap of 2J/kB= 40 K from magnetic susceptibility measurements on a magnetically diluted system dispersed in organic polymer films. The 3,5-substituted pyridine 1 has a hydrogen-accepting site which is more accessible to hydrogen donors than previously known biradicals with sterically hindered 2,6-pyridine frameworks. N-Methylation of 1 has yielded a stable cationic species in a trifluoromethanesulfonate salt (2+·TfO-). The ground state of the cation 2+has been found to be triplet as well with 2J/kB= 32 K from magnetic susceptibility measurements for magnetically diluted films. The magnetic susceptibility of neat crystalline solids of 1 and 2+·TfO-has been explained by Heisenberg exchange coupling models based on their X-ray crystal structures. It is well known that the energy preference of a high-spin ground state for m-phenylene, or m-xylylene, coupling units is disturbed in such cases as the π-conjugation is affected by heteroatomic substitution, an ionic charge, or molecular conformation. The present experimental results show that the high-spin preference in 1 and 2+is little influenced by the heterocycle or the ionic charge. Intermolecular noncovalent bonds such as hydrogen bonding and electrostatic interactions are a driving force for crystallization of open-shell molecules in a controllable manner. The ground-state triplet biradicals serve as building blocks for molecule-based magnets of S > 1/2 based on intermolecular noncovalent bonding architecture. © The Royal Society of Chemistry 2006.


  • Multidimensional networks of π-conjugated oligomers: Crystal structures of 4,4′:2′,2″:4″,4‴-quaterimidazole in hydrate, protonated salt, and dinucleic copper complexes

    Tsuyoshi Murata, Yasushi Morita, Yasushi Morita, Kozo Fukui, Yumi Yakiyama, Kazunobu Sato, Daisuke Shiomi, Takeji Takui, Kazuhiro Nakasuji

    Crystal Growth and Design  6   1043 - 1047 2006.04  [Refereed]  [Invited]

     View Summary

    Hydrogen-bonded networks of 4,4′:2′,2″:4″, 4‴-quaterimidazole, a new molecular building block for supramolecular assemblies based on π-conjugated oligomers, are investigated in tetrahydrate, hydroiodic acid salt, and dinucleic copper complexes. We emphasize that multidimensional networks are constructed by taking advantage of a two-directional nature of hydrogen-bonding interactions inherent in the imidazole-ring system. In the crystal structure of the tetrahydrate, hydrogen-bonding interactions through water molecules construct a three-dimensional network including a π-stacking columnar structure. The hydroiodic acid salt forms a one-dimensional tape-like structure by double hydrogen bondings across the iodide anions and solvent molecules. The dicopper complex of quaterimidazole exhibits intra- and intermolecular hydrogen bondings to construct a one-dimensional chain by N-H⋯O⋯H-N hydrogen bonding through water molecules. These hydrogen-bonding modes of the quaterimidazole system are discussed in view of a structural relationship with 2,2′- and 4,4′-biimidazole systems. © 2006 American Chemical Society.


  • Ground-state triplet biradicals of nitronyl nitroxide containing a nucleobase substituent as synthons for bio-inspired organic magnets

    H. Tanaka, T. Ise, T. Ise, D. Shiomi, D. Shiomi, K. Sato, T. Takui

    Journal of Low Temperature Physics  142   605 - 608 2006.02  [Refereed]  [Invited]

     View Summary

    An organic nitronyl nitroxide biradical substituted with a nucleobase of cytosine was designed and synthesized. The molecular ground state of the biradical was found to be triplet (S = 1) with a singlet-triplet energy gap of 2J/k B = 50.6 K from magnetic susceptibility measurements. The ground-state triplet biradical serves as an S = 1 building block for bio inspired molecule-based magnets with hydrogen-bonded nucleobase pairings. © 2007 Springer Science+Business Media, Inc.


  • Magnetic properties of a nitronyl nitroxide triradical as a model for single-component molecule-based ferrimagnets

    Y. Kanzaki, T. Ise, T. Ise, D. Shiomi, D. Shiomi, K. Sato, T. Takui

    Journal of Low Temperature Physics  142   597 - 600 2006.02  [Refereed]  [Invited]

     View Summary

    Two kinds of organic triradicals consisting of a nitronyl nitroxide biradical with S = 1 and a monoradical with S = 1/2 were synthesized as model molecules for single-component organic ferrimagnets. The intramolecular exchange interactions of the triradicals were examined from magnetic susceptibility. The results indicate that the triradicals have potential as building blocks for single-component organic molecule-based ferrimagnets. © 2007 Springer Science+Business Media, Inc.


display all >>

Conference Activities & Talks 【 display / non-display

  • Quantum Chemical Calculations of Open Shell Molecules on Quantum Com-puters: Efficient Construction Methods of the Open Shell Wave Functions

    Kenji Sugisaki, Satoru Yamamoto, Shigeaki Nakazawa, Kazuo Toyota, Kazunobu Sato, Daisuke Shiomi, and Takeji Takui

    The Third Joint Conference of the Asia-Pacific EPR/ESR Society and The International EPR (ESR) Society (IES) Symposium  2018.09 

  • Spin Manipulation by Arbitrary Microwave Excitation for Molecular Quantum Control

    Kazunobu Sato, Satoru Yamamoto, Taiki Shibata, Rei Hirao, Keigo Tanimoto, Kenji Sugisaki, Shigeaki Nakazawa, Elham Hosseini, Koji Maruyama, Kazuo Toyota, Daisuke Shiomi, Konstantin Ivanov, Yasushi Morita, and Takeji Takui

    The Third Joint Conference of the Asia-Pacific EPR/ESR Society and The International EPR (ESR) Society (IES) Symposium  2018.09 

  • Molecular Spin Manipulations by Arbitrary Microwave Excitation Technology for Optimal Quantum

    K. Sato, S. Yamamoto, T. Shibata, R. Hirao, K. Tanimoto, K. Sugisaki, S. Nakazawa, E. Hosseini, K. Maruyama, K. Toyota, D. Shiomi, K. Ivanov, Y. Morita, and T. Takui  [Invited]

    XII Russian-Japanese workshop “OPEN SHELL COMPOUNDS AND MOLECULAR SPIN DEVICES”  2018.09 

  • Selective Spin Inversion by Utilizing Chirp Pulses for Molecular Spin Quantum Computation

    Rei Hirao, Satoru Yamamoto, Kazunobu Sato, Shigeaki Nakazawa, Kazuo Toyota, Daisuke Shiomi, Konstantin Ivanov, Takeji Takui

    XII Russian-Japanese workshop “OPEN SHELL COMPOUNDS AND MOLECULAR SPIN DEVICES”  2018.09 

  • Molecular Spin Technology based on Arbitrary Microwave Excitations for Quantum Control

    Kazunobu Sato, Satoru Yamamoto, Taiki Shibata, Rei Hirao, Keigo Tanimoto, Kenji Sugisaki, Shigeaki Nakazawa, Elham Hosseini, Koji Maruyama, Kazuo Toyota, Daisuke Shiomi, Konstantin Ivanov, Yasushi Morita, and T. Takui  [Invited]

    The III International Conference “Spin physics, spin chemistry and spin technology” (SPCT-2018)  2018.09 

display all >>

Grant-in-Aid for Scientific Research 【 display / non-display

  • Quantum Control based on NMR Paradigm ESR Methodology

    Project/Area Number : 17H03012  Grant-in-Aid for Scientific Research(B) Representative

    Project Year :


  • Development of pulsed electron-electron multiple resonance spectroscopy for quantum state manipulation

    Project/Area Number : 23350011  Grant-in-Aid for Scientific Research(B) Representative

    Project Year :


    Partaker : NAKAZAWA Shigeaki, SUGISAKI Kenji, TOYOTA Kazuo

     View Summary

    We have applied pulsed ESR spectroscopy to weakly exchange-coupled molecular bi- and tri-radicals to discuss electron-spin transient nutation (ESTN) phenomena in the spin states. General understandings of the ESTN phenomena in the two or three-spin systems are achieved. It helps us to implement the quantum spin manipulation quantum.
    In addition, we have developed electron spin technology by the use of arbitrary wave generators (AWG) in order to precisely manipulate molecular spins. We showed a phase rotation for transient spin nutation experiments using the arbitrary microwaves, indicating that the electron spin state is controlled on the Bloch sphere without any limitations. Hole-burning experiments with coherent-multiple microwave frequencies were also demonstrated. The AWG-based spin technology is applicable to quantum information science/quantum computers as well as high-sensitivity ESR spectroscopy.

  • Molecular spin quantum control

    Project/Area Number : 21102004  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area) Partaker / Other

    Project Year :


    Partaker : TAKUI Takeji, SATO Kazunobu, MORITA Yasushi, KAGAWA Akinori

     View Summary

    We have demonstrated precise spin controls for quantum information processing by numerical optimization of pulse waveform and pulse compensation for transient phenomenon in a resonator. Using regioselectively isotope labeled molecules, we have realized nuclear polarization of 34 % at room temperature and spin amplification. We have developed Ku-band pulse ESR spectrometer with an arbitrary wave form generator and stripline resonator and succeeded in pulse ESR experiments at 150 mK.
    We have designed molecules with electron spins and nuclear spins (molecular spins) which have desirable electromagnetic property for quantum control by means of magnetic resonance and characterized them.

  • Molecular-Spin Quantum Manipulation by Pulsed Electron-Nuclear Multiple Resonance Technique

    Project/Area Number : 18350015  Grant-in-Aid for Scientific Research(B) Representative

    Project Year :


  • Molecular Spinics of Sub-Micron Scale Super Lattices composed of Ferromagnetic Thin Films and Gigantic Single Molecules with Open-Shell Structure

    Project/Area Number : 15087209  Grant-in-Aid for Scientific Research on Priority Areas Partaker / Other

    Project Year :


    Partaker : SATO Kazunobu, SHIOMI Daisuke, TOYATAA Kazuo

     View Summary

    The project "Molecular Spinics of Sub-Micron Scale Super Lattices composed of Ferromagnetic Thin Films and Gigantic Single Molecules with Open-Shell Structure" aims to develop electron-spin mediated exotic functionalities and to characterize their features in terms of microscopic details, emphasizing (1) the introduction of novel magnetic materials or entities such as super lattices fabricated from ferromagnetic thin films in semi-microscopic scale and (2) gigantic single molecules featuring exotic molecular spin properties. The main line of the research is intended to connect with the extension of electron-spin mediated spin science and spin technology, particularly introducing molecular spin quantum computers as the latest application of molecular spins from the viewpoint of materials challenge and the establishment of "true" spin manipulation technology.
    Referred to spin dynamics of the super lattices composed of ferromagnetic thin films, we have for the first time found a "lateral Walker mode" and "Gigantic Dioplar Spin Wave" as novel quantum spin waves from the super lattice. Both waves intrinsically originate from ferromagnetic super lattice structures of the thin film. The former arises also from a single square wire fabricated of the ferromagnetic thin film in a micron scale. Remarkable angular dependence of the ferromagnetic resonance spectra from the single wire was analyzed at X-band and ambient temperature, yielding the magnetic tensor parameters relevant to electron-dipolar long-range interactions in microscopic scale. Our results agree with those from the Brilloun scattering experiments. Notably, the appearance of the gigantic dipolar spin wave phenomena depends on the number of the assemblies of the super lattice cells aligned in one or two dimension, suggesting the existence of thresholds for super lattice structures and their intrinsic spin properties. Assuming the quantization conditions, we have calculated the appearance conditions of the dipolar spin wave as a function of the number with the help of the experimentally acquired magnetic data. Pant's theory has been invoked to interpret the experimentally derived magnetic parameters, enabling us to calculate magnetic dipolar interactions in one dimension. Interestingly, the dipolar spin wave reveals non-linear behavior with increased microwave power on resonance. calculating, in which. made ESR spectrometer
    We have developed and established microwave and radiofrequency spin manipulation technology by implementing molecular spin quantum computers. This technology includes the manipulation of quantum phases of molecular electron spin and nuclear spins in Bloch space, which enables us to establish quantum entanglement between the spins : Establishment of the entanglement is the central issue of quantum computers and quantum information processing. From the experimental side, we have created bipartite entanglement and pseudo tripartite one by the use of extremely stable organic open-shell entities, in which particular nucleus is isotope-labeled. Our spin manipulation technology invokes time proportional phase incrementation for both electron spin and nuclear spin, simultaneously. In this project, we have for the first time shown the spinor intrinsic to electron spin, explicitly from the experimental side.

display all >>