研究者詳細 - 吉田　健文

論文 - 吉田　健文

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Unsupervised Machine Learning-Based Image Recognition of Raw Infrared Spectra: Toward Chemist-like Chemical Structural Classification and Beyond Numerical Data

Kentarou Fuku, Takefumi Yoshida (担当区分：最終著者,　責任著者 )

Journal of Chemical Information and Modeling ( American Chemical Society (ACS) ) 2025年03月 [査読有り]

DOI

First Encapsulation of Organometallic Single‐Molecule Magnet into Single‐Walled Carbon Nanotubes

Haitao Zhang, Ryo Nakanishi, Takefumi Yoshida, Masahiko Nishijima, Koji Harano, Yoji Horii, Masahiro Yamashita

Angewandte Chemie International Edition ( Wiley ) 2025年03月 [査読有り]

An air‐sensitive DyCp3 (Cp− = cyclopentadienyl) single‐molecule magnet (SMM) complex (1) was encapsulated into single‐walled carbon nanotubes (SWCNTs) to construct hybrid materials that are resistant to moisture and oxygen. The hybrid materials with independent slow‐magnetic‐relaxing centers are expected to become a key component of the next generation of information process devices based on spintronics. The resilience to moisture and oxygen further broadens its manufacturing methods and application scenarios. Furthermore, upon encapsulation into SWCNTs, DyCp3 exhibited clear ac frequency dependence in the ac magnetic susceptibility at a zero‐dc field. This indicates that the guest molecule's slow magnetic relaxation properties are preserved, which is crucial and necessary to realize SMMs‐based quantum information processing, by allowing a sufficient time window for quantum gate operations. Our result exemplifies that encapsulation of air‐sensitive organometallic SMMs into SWCNTs enhances their chemical stability and their magnetic relaxation time at a zero‐dc magnetic field, which provides a novel method for their further applications.

DOI

Double Core–Shell Semiconducting Molecular Chain Halogen-Bridged Metal Complexes with Ohmic Contact Heterojunctions

Masanori Wakizaka, Keisuke Ishiguro, Takefumi Yoshida, Hiroaki Iguchi, Takao Tsumuraya, Hiroshi Ito, Masahiro Yamashita, Shinya Takaishi

ACS Applied Materials & Interfaces ( American Chemical Society (ACS) ) 17 ( 9 ) 14322 - 14328 2025年02月 [査読有り]

DOI

Exploration of the synthesis, crystal structure, Hirshfeld surface analysis, binding properties, antibacterial activities, and molecular docking of a Schiff base nickel (II) Complex

A.B.M. Nazmul Isalm, Md. Ahsan Habib, Md. Mahadi Hasan, Md. Rafid Hasan, Kaykobad Md. Rezaul Karim, Md. Mahiuddin, Takefumi Yoshida, Md. Rabiul Karim, Shofiur Rahman, Hamad Albrithen, Abdullah N. Alodhayb, Paris E. Georghiou

Journal of Molecular Structure ( Elsevier BV ) 1322 140294 - 140294 2025年02月 [査読有り]

DOI

Transient Kinetic QXAFS Approach for Understanding the RDE–MEA Gap in Fuel Cell (Oxygen Reduction Reaction) Performances of Pt-Based Electrocatalysts

Takefumi Yoshida, Shinobu Takao, Hiroko Ariga-Miwa, Xiao Zhao, Gabor Samjeské, Takuma Kaneko, Tomoya Uruga, Yasuhiro Iwasawa (担当区分：筆頭著者 )

ACS Omega ( American Chemical Society (ACS) ) 2025年01月 [査読有り]

DOI

Hydrogen isotope separation at exceptionally high temperature using an unsaturated organometallic complex

Taku Kitayama, Tamon Yamauchi, Kaiji Uchida, Shunya Tanaka, Ryojun Toyoda, Hiroaki Iguchi, Ryota Sakamoto, Hao Xue, Naoki Kishimoto, Takefumi Yoshida, Tomoya Uruga, Shin-ichiro Noro, Shinya Takaishi

Dalton Transactions ( Royal Society of Chemistry (RSC) ) 2025年 [査読有り]

DOI

Tailoring Co site reactivity via Sr and Ni doping in LaCoO3 for enhanced water splitting performance

Saraswati Roy, Takefumi Yoshida, Amit Kumar, Seikh Mohammad Yusuf, Chanchal Chakraborty, Sounak Roy

Catalysis Today ( Elsevier BV ) 441 114885 - 114885 2024年11月 [査読有り]

DOI

Pyrolytic Depolymerization of Polyolefins Catalysed by Zirconium‐based UiO‐66 Metal–Organic Frameworks

Jerry Zhi Xiong Heng, Tristan Tsai Yuan Tan, Xin Li, Wei Wei Loh, Yuting Chen, Zhenxiang Xing, Zhiyan Lim, Jennet Li Ying Ong, Katherine Shiyun Lin, Yusuke Nishiyama, Takefumi Yoshida, Lili Zhang, Ken‐ichi Otake, Susumu Kitagawa, Xian Jun Loh, Enyi Ye, Jason Y. C. Lim

Angewandte Chemie International Edition ( Wiley ) 2024年09月 [査読有り]

Abstract

Polyolefins such as polyethylenes and polypropylenes are the most‐produced plastic waste globally, yet are difficult to convert into useful products due to their unreactivity. Pyrolysis is a practical method for large‐scale treatment of mixed, contaminated plastic, allowing for their conversion into industrially‐relevant petrochemicals. Metal–organic frameworks (MOFs), despite their tremendous utility in heterogeneous catalysis, have been overlooked for polyolefin depolymerization due to their perceived thermal instabilities and inability of polyethylenes and polypropylenes to penetrate their pores. Herein, we demonstrate the viability of UiO‐66 MOFs containing coordinatively‐unsaturated zirconium nodes, as effective catalysts for pyrolysis that significantly enhances the yields of valuable liquid and gas hydrocarbons, whilst halving the amounts of residual solids produced. Reactions occur on the Lewis‐acidic UiO‐66 nodes, without the need for noble metals, and yield aliphatic product distributions distinctly different from the aromatic‐rich hydrocarbons that can be obtained from zeolite catalysis. We also demonstrate the first unambiguous characterization of polyolefin penetration into UiO‐66 pores at pyrolytic temperatures, allowing access to the abundant Zr‐oxo nodes within the MOF interior for efficient C−C cleavage. Our work highlights the potential of MOFs as highly‐designable heterogeneous catalysts for depolymerisation of plastics, which can complement conventional catalysts in reactivity.

DOI

Unraveling High Chemoselectivity in Oxidative Dehydration of Glycerol into Acrylic Acid over a Bifunctional Metal–Organic Framework–Polyoxometalate Composite Catalyst

Paramita Koley, Subhash Chandra Shit, Takefumi Yoshida, Hiroko Ariga-Miwa, Tomoya Uruga, Tayebeh Hosseinnejad, Selvakannan Periasamy, Wooyul Kim, Dharmendra D. Mandaliya, Ravindra D. Gudi, Yasuhiro Iwasawa, Suresh K. Bhargava

ACS Catalysis ( American Chemical Society (ACS) ) 14 ( 16 ) 12110 - 12127 2024年07月 [査読有り]

DOI

Unsupervised Raw IR Spectra Images Recognition: Toward Chemist-Like Chemical Structure Classification

Kentarou Fuku, Takefumi Yoshida

ChemRxiv ( American Chemical Society (ACS) ) 2024年05月

DOI

Subnanometric Osmium Clusters Confined on Palladium Metallenes for Enhanced Hydrogen Evolution and Oxygen Reduction Catalysis

P Prabhu, Viet-Hung Do, Takefumi Yoshida, Yingtang Zhou, Hiroko Ariga-Miwa, Takuma Kaneko, Tomoya Uruga, Yasuhiro Iwasawa, Jong-Min Lee

ACS Nano ( American Chemical Society (ACS) ) 2024年03月 [査読有り]

DOI

Spin Dynamics Phenomena of a Cerium(III) Double-Decker Complex Induced by Intramolecular Electron Transfer

Keiichi Katoh, Kana Kobayashi, Michiyuki Suzuki, Tetsu Sato, Yoji Horii, Takefumi Yoshida, Brian. K. Breedlove, Masahiro Yamashita

Dalton Transactions ( Royal Society of Chemistry (RSC) ) 2024年 [査読有り]

DOI

Pd Nanoparticles on the Outer Surface of Microporous Aluminosilicates for the Direct Alkylation of Benzenes using Alkanes

Satoshi Misaki, Hiroko Ariga-Miwa, Takashi U. Ito, Takefumi Yoshida, Shingo Hasegawa, Yukina Nakamura, Shunta Tokutake, Moe Takabatake, Koichiro Shimomura, Wang-Jae Chun, Yuichi Manaka, Ken Motokura

ACS Catalysis ( American Chemical Society (ACS) ) 12281 - 12287 2023年09月 [査読有り]

DOI

Reversible Electrochromic/Electrofluorochromic Dual Switching in Zn(II)-Based Metallo-Supramolecular Polymer Films

Sanjoy Mondal, Dines Chandra Santra, Susmita Roy, Yemineni S. L. V. Narayana, Takefumi Yoshida, Yoshikazu Ninomiya, Masayoshi Higuchi

ACS Applied Materials & Interfaces ( American Chemical Society (ACS) ) 15 ( 36 ) 42912 - 42919 2023年08月 [査読有り]

DOI

Elucidation of Active Sites and Mechanistic Pathways of a Heteropolyacid/Cu-Metal–Organic Framework Catalyst for Selective Oxidation of 5-Hydroxymethylfurfural via Ex Situ X-ray Absorption Spectroscopy and In Situ Attenuated Total Reflection-Infrared Studies

Paramita Koley, Subhash Chandra Shit, Takefumi Yoshida, Hiroko Ariga-Miwa, Tomoya Uruga, Tayebeh Hosseinnejad, Selvakannan Periasamy, Su-Il In, Dharmendra D. Mandaliya, Ravindra D. Gudi, Yasuhiro Iwasawa, Suresh K. Bhargava

ACS Catalysis ( American Chemical Society (ACS) ) 13 ( 9 ) 6076 - 6092 2023年04月 [査読有り]

DOI

Data Mining from XANES Spectra of Nickel Complexes for Structure Estimation

Kentaro Fuku, Takefumi Yoshida, Tetsu Sato, Hiroaki Iguchi, Shinya Takaishi, Ryota Sakamoto, Hitoshi Abe

Chemistry Letters ( The Chemical Society of Japan ) 2023年03月 [査読有り]

DOI

Recent progress on unusual halogen-bridged Pd(III) chain compounds realized by weak ligand field and triple hydrogen bond approaches

Mohammad Rasel Mian, Masanori Wakizaka, Takefumi Yoshida, Hiroaki Iguchi, Shinya Takaishi, Masahiro Yamashita (担当区分：責任著者 )

Coordination Chemistry Reviews 475 ( 15 ) 214878 2023年01月 [査読有り]

The development of new halogen-bridged Pd chain complexes with molecular precision offers a promising strategy to stabilize Pd(III) ions, which are being considered as future optical, magnetic, dielectric, and conducting materials. More recently, uncommon and rare electronic states of Pd(III) ions in halogen-bridged chain complexes have been reported. In these systems, four different designed strategies have been adopted to stabilize Pd(III) oxidation states to date. This review focuses on the new strategies for the realization of Pd(III) halogen-bridged metal complexes (MX-Chains) using (1) weak ligand field and (2) triple hydrogen bond approaches. The resulting MX-Chains show clear evidence of the Pd(III) averaged-valence (AV) state rather than the conventional Pd(II)/Pd(IV) mixed-valence (MV) state. The relationships between the molecular structures, electronic states, and properties of these MX-Chains strongly depend on the in-plane ligands, counteranions and their surrounding environments. Furthermore, Pd(III) states have been found in the MX-Chains even above room temperature. Understanding and controlling the Pd(III) states in halogen-bridged chain complexes is a critical issue for development of next-generation devices, such as molecular electrical nano-wires. Overall, this review establishes halogen-bridged Pd(III) complexes as highly effective solid-state materials and provides detailed insight into their structure–property relationships, laying the groundwork for future developments in this new class of advanced materials.

DOI

Pd‐PdO Nanodomains on Amorphous Ru Metallene Oxide for High‐Performance Multifunctional Electrocatalysis

Viet‐Hung Do, P Prabhu, Vishal Jose, Takefumi Yoshida, Yingtang Zhou, Hiroko Miwa, Takuma Kaneko, Tomoya Uruga, Yasuhiro Iwasawa, Jong‐Min Lee

Advanced Materials ( Wiley ) 2208860 - 2208860 2023年01月 [査読有り]

Developing highly efficient multifunctional electrocatalysts is crucial for future sustainable energy pursuits, but remains a great challenge. Herein, a facile synthetic strategy is used to confine atomically thin Pd-PdO nanodomains to amorphous Ru metallene oxide (RuO2). The as-synthesized electrocatalyst (Pd(2)RuOx-0.5 h) exhibits excellent catalytic activity toward the pH-universal hydrogen evolution reaction (eta(10) = 14 mV in 1 m KOH, eta(10) = 12 mV in 0.5 m H2SO4, and eta(10) = 22 mV in 1 m PBS), alkaline oxygen evolution reaction (eta(10) = 225 mV), and overall water splitting (E-10 = 1.49 V) with high mass activity and operational stability. Further reduction endows the material (Pd(2)RuOx-2 h) with a promising alkaline oxygen reduction activity, evidenced by high halfway potential, four-electron selectivity, and excellent poison tolerance. The enhanced catalytic activity is attributed to the rational integration of favorable nanostructures, including 1) the atomically thin nanosheet morphology, 2) the coexisting amorphous and defective crystalline phases, and 3) the multi-component heterostructural features. These structural factors effectively regulate the material's electronic configuration and the adsorption of intermediates at the active sites for favorable reaction energetics.

DOI

Chemical pressure-induced PtIII–I Mott–Hubbard nanowire, [Pt(en)2I](Asp-Cn)2·H2O (13 ≤ n), detected via polarized infrared spectroscopy

Shohei Kumagai, Takefumi Yoshida, Hiroaki Iguchi, Masanori Wakizaka, Nobuto Funakoshi, Masahiro Yamashita, Shinya Takaishi

Chemical Communications ( Royal Society of Chemistry (RSC) ) 59 ( 95 ) 14118 - 14121 2023年 [査読有り]

DOI

Heterospin frustration in a metal-fullerene-bonded semiconductive antiferromagnet

Yongbing Shen, Mengxing Cui, Shinya Takaishi, Hideyuki Kawasoko, Kunihisa Sugimoto, Takao Tsumuraya, Akihiro Otsuka, Eunsang Kwon, Takefumi Yoshida, Norihisa Hoshino, Kazuhiko Kawachi, Yasuhiko Kasama, Tomoyuki Akutagawa, Tomoteru Fukumura, Masahiro Yamashita

Nature Communications ( Springer Science and Business Media LLC ) 13 ( 1 ) 2022年12月 [査読有り]

<title>Abstract</title>Lithium-ion-encapsulated fullerenes (Li+@C60) are 3D superatoms with rich oxidative states. Here we show a conductive and magnetically frustrated metal–fullerene-bonded framework {[Cu4(Li@C60)(L)(py)4](NTf2)(hexane)}<italic>n</italic> (<bold>1</bold>) (<italic>L</italic> = 1,2,4,5-tetrakis(methanesulfonamido)benzene, py = pyridine, NTf2− = bis(trifluoromethane)sulfonamide anion) prepared from redox-active dinuclear metal complex Cu2(L)(py)4 and lithium-ion-encapsulated fullerene salt (Li+@C60)(NTf2−). Electron donor Cu2(L)(py)2 bonds to acceptor Li+@C60 via eight Cu‒C bonds. Cu–C bond formation stems from spontaneous charge transfer (CT) between Cu2(L)(py)4 and (Li+@C60)(NTf2−) by removing the two-terminal py molecules, yielding triplet ground state [Cu2(L)(py)2]+(Li+@C60•−), evidenced by absorption and electron paramagnetic resonance (EPR) spectra, magnetic properties and quantum chemical calculations. Moreover, Li+@C60•− radicals (<italic>S</italic> = ½) and Cu2+ ions (<italic>S</italic> = ½) interact antiferromagnetically in triangular spin lattices in the absence of long-range magnetic ordering to 1.8 K. The low-temperature heat capacity indicated that compound <bold>1</bold> is a potential candidate for an <italic>S</italic> = ½ quantum spin liquid (QSL).

DOI

Macro- and atomic-scale observations of a one-dimensional heterojunction in a nickel and palladium nanowire complex

Masanori Wakizaka, Shohei Kumagai, Hashen Wu, Takuya Sonobe, Hiroaki Iguchi, Takefumi Yoshida, Masahiro Yamashita, Shinya Takaishi

Nature Communications ( Springer Science and Business Media LLC ) 13 ( 1 ) 2022年12月 [査読有り]

<title>Abstract</title>The creation of low-dimensional heterostructures for intelligent devices is a challenging research topic; however, macro- and atomic-scale connections in one-dimensional (1D) electronic systems have not been achieved yet. Herein, we synthesize a heterostructure comprising a 1D Mott insulator [Ni(chxn)2Br]Br2 (<bold>1</bold>; chxn = 1<italic>R</italic>-2<italic>R</italic>-diaminocyclohexane) and a 1D Peierls or charge-density-wave insulator [Pd(chxn)2Br]Br2 (<bold>2</bold>) using stepwise electrochemical growth. It can be considered as the first example of electrochemical liquid-phase epitaxy applied to molecular-based heterostructures with a macroscopic scale. Moreover, atomic-resolution scanning tunneling microscopy images reveal a modulation of the electronic state in the heterojunction region with a length of five metal atoms (~ 2.5 nm), that is a direct evidence for the atomic-scale connection of <bold>1</bold> and <bold>2</bold>. This is the first time that the heterojunction in the 1D chains has been shown and examined experimentally at macro- and atomic-scale. This study thus serves as proof of concept for heterojunctions in 1D electronic systems.

DOI

161Dy synchrotron-radiation-based Mössbauer absorption spectroscopy

Ryo Masuda, Shinji Kitao, Hiroyuki Tajima, Hiroki Taniguchi, Takaya Mitsui, Kosuke Fujiwara, Yoshitaka Yoda, Nobumoto Nagasawa, Daisuke Ishikawa, Alfred. Q. R. Baron, Takefumi Yoshida, Tetsu Sato, Keiichi Katoh, Hisao Kobayashi, Makoto Seto

Hyperfine Interactions ( Springer Science and Business Media LLC ) 243 ( 1 ) 2022年12月 [査読有り]

We demonstrate a measurement system for synchrotron-radiation-based Mössbauer absorption spectra with 161Dy using the 25.7 keV nuclear first excited state. Mössbauer spectra of DyF3, Dy metal and DyPc2 (Pc = phthalocyaninato) were obtained and the parameters for the hyperfine structure of 161Dy nuclei in them were evaluated to demonstrate the feasibility of this method. Isomer shifts showed that Dy atoms in all of them are in trivalent state although those in Dy metal was in the region of trivalent metal region. The magnetic hyperfine field of Dy metal of 569 ± 1 T agreed with the literature of the Mössbauer experiments. That of DyPc2 of 489 ± 1 T was reasonable because the ground state of DyPc2 were in the state of Jz = ±13/2. Considering the highly penetrative nature of the 25.7 keV incident radiation, it will be straightforward to apply this method for the study of materials under various conditions such as high pressure, high magnetic fields, and reactive atmospheres.

DOI

Porous Mn2+ Magnet with a Pt–Cl Framework: Correlation between Water Vapor Adsorption/Desorption and Slow Magnetic Relaxation

Hirotaka Nakajima, Kaiji Uchida, Takefumi Yoshida, Yoji Horii, Tetsu Sato, Zhang Luming, Satoshi Yamashita, Yasuhiro Nakazawa, Verdad C. Agulto, Makoto Nakajima, Brian K. Breedlove, Masahiro Yamashita, Hiroaki Iguchi, Shinya Takaishi (担当区分：責任著者 )

ChemPhysChem ( Wiley ) e202200618 2022年10月 [査読有り]

We report the water adsorption/desorption behavior and dynamic magnetic properties of the Pt-Cl chain complex [{[Pt(en)2 ][PtCl2 (en)2 ]}3 ][{(MnCl5 )Cl3 }2 ] ⋅ 12H2 O (1). Upon heating 1 in a vacuum, we obtained the dehydrated form [{[Pt(en)2 ][PtCl2 (en)2 ]}3 ][{(MnCl5 )Cl3 }2 ] (1DH). The framework structures of 1 and 1DH are identical, and both complexes underwent slow magnetic relaxation. However, the magnetic relaxation times for 1DH were shorter than those for 1, meaning that the dynamic magnetic properties were controlled upon water vapor adsorption/desorption. From detailed analyses of the dynamic magnetic behavior, a phonon-bottleneck effect contributes to the magnetic relaxation processes. We discuss the mechanism for the changes in the magnetic relaxation processes upon dehydration in terms of the heat capacity and thermal conductivity.

DOI

Hydrogen bonding propagated phase separation in quasi-epitaxial single crystals: a Pd-Br molecular insulator

Takefumi Yoshida, Shinya Takaishi, Laurent Guérin, Tatsuhiro Kojima, Hiroyoshi Ohtsu, Masaki Kawano, Tatsuya Miyamoto, Hiroshi Okamoto, Kenichi Kato, Masaki Takata, Yuka Hosomi, Shoji Yoshida, Hidemi Shigekawa, Hisaaki Tanaka, Shin-ichi Kuroda, Hiroaki Iguchi, Brian K. Breedlove, Zhao-Yang Li, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

Inorganic Chemistry ( American Chemical Society (ACS) ) 61 ( 35 ) 14067 - 14074 2022年09月

DOI

Ni(III) Mott–Hubbard-like State Containing High-Spin Ni(II) in a Semiconductive Bromide-Bridged Ni-Chain Compound

Masanori Wakizaka, Mohammad Rasel Mian, Takefumi Yoshida, Tetsu Sato, Hisaaki Tanaka, Tatsuya Miyamoto, Hiroshi Okamoto, Shinya Takaishi, Hiroaki Iguchi, Masahiro Yamashita

Inorganic Chemistry ( American Chemical Society (ACS) ) 61 ( 25 ) 9504 - 9513 2022年06月 [査読有り]

Halogen-bridged linear chain metal complexes (MX-Chains) are fascinating compounds that have a quasi-one-dimensional (1D) electronic system. In this study, we synthesized the first Ni-based MX-Chain compound having hydroxy groups, i.e., [Ni(dabdOH)2Br]Br2·[Ni(dabdOHx)2Br]0.5·(2-PrOH)0.25·(MeOH)0.25(1·solvent, x = ∼0.6, dabdOH = (2S,3S)-2,3-diaminobutane-1,4-diol). Single-crystal X-ray diffraction revealed that the MX-Chains in 1·solvent formed sheets and single-chain structures in the superlattice. It suggested an MH-like state, whereas the polarized reflection and Raman spectra suggested a CDW-like state. Magnetic and electron spin resonance measurements revealed that both high-spin Ni(II) (∼15%) and low-spin Ni(III) (∼85%) sites are present in the chain structures, i.e., the metal sites show mixed valency. Therefore, we concluded that 1·solvent adopts an intermediate state between the MH and CDW states. Moreover, a single crystal of 1·solvent exhibited semiconductive characteristics along the chain direction. This finding represents a new structural and electronic state of 1D electronic systems as well as MX-Chains.

DOI

Hidden Heterometallic Interaction Emerging from Resonant Inelastic X-ray Scattering in Luminescent Tb–Pt Molecules

Takefumi Yoshida, Ahmed Shabana, David Chukwuma Izuogu, Kentaro Fuku, Tetsu Sato, Haitao Zhang, Yukina Yamamoto, Jun Kamata, Hitomi Ohmagari, Miki Hasegawa, Goulven Cosquer, Shinya Takaishi, Takuma Kaneko, Tomoya Uruga, Yasuhiro Iwasawa, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

J. Phys. Chem. C ( American Chemical Society ) 2022年04月 [査読有り]

DOI

A Novel π-d Conjugated Cobalt Tetraaza[14]annulene based Atomically Dispersed Electrocatalyst for Efficient CO Reduction

Zhifu Liang, Ting Zhang, Pengfei Cao, Takefumi Yoshida, Weiqiang Tang, Xiang Wang, Yong Zuo, Pengyi Tang, Marc Heggen, Rafal E. Dunin-Borkowski, Joan Ramon Morante, Andreu Cabot, Masahiro Yamashita, Jordi Arbiol

Chemical Engineering Journal ( Elsevier BV ) 136129 - 136129 2022年03月 [査読有り]

DOI

Elucidating 2D Charge‐Density‐Wave Atomic Structure in an MX–Chain by the 3D‐ΔPair Distribution Function Method**

Laurent Guérin, Takefumi Yoshida, Edoardo Zatterin, Arkadiy Simonov, Dmitry Chernyshov, Hiroaki Iguchi, Bertrand Toudic, Shinya Takaishi, Masahiro Yamashita (担当区分：責任著者 )

ChemPhysChem ( Wiley ) 23 ( 6 ) 2022年02月 [査読有り]

DOI

Insight into the Gd–Pt Bond: Slow Magnetic Relaxation of a Heterometallic Gd–Pt Complex

Takefumi Yoshida, Ahmed Shabana, Haitao Zhang, David Chukwuma Izuogu, Tetsu Sato, Kentaro Fuku, Hitoshi Abe, Yoji Horii, Goulven Cosquer, Norihisa Hoshino, Tomoyuki Akutagawa, Alex J. W. Thom, Shinya Takaishi, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

Bulletin of the Chemical Society of Japan ( The Chemical Society of Japan ) 95 ( 3 ) 513 - 521 2022年02月 [査読有り]

Lanthanide (Ln) compounds are common research targets in the field of magnetism and optics. Their properties arise from the electron localized in the f-orbital. Moreover, the effect of the covalency between lanthanide and ligands on magnetism attracted significant attention. We provided insight into the Gd–Pt bond (of the heterometallic Ln-Pt complexes: {[Pt(PhSAc)4]Ln[(PhSAc)4Pt]} NEt4·2DMF (Ln = Y(0), La(1), Gd(2); PhSAc = thiobenzoate, NEt4 = tetraethylammonium)); single-crystal polarized X-ray absorption near edge structure (XANES) reveal the electronic states around metal ion, where spectra of Gd-LIII edges show the Gd–Pt direction has the highest covalency (less ionic) around Gd ion in 2. In addition, calculating natural bonding (NBO) analysis, natural population analysis (NPA), LOL, and atoms in molecules (AIM), ab initio calculations reveal the role of metallic and organic ligands in the electronic and magnetic properties of Ln complexes. The slow magnetization relaxation of the Gd complex, which has not been reported previously in the Pt–Gd–Pt system, was observed up to 45K, the highest temperature reported to date among isolated Gd-complexes.

DOI

Electro-Oxidation Reaction of Methanol over La2–xSrxNiO4+δ Ruddlesden–Popper Oxides

Preetha Chandrasekharan Meenu, Pralok K. Samanta, Takefumi Yoshida, Niall J. English, Santanu Prasad Datta, Satyapaul A. Singh, Srikanta Dinda, Chanchal Chakraborty, Sounak Roy

ACS Applied Energy Materials ( American Chemical Society (ACS) ) 5 ( 1 ) 503 - 515 2022年01月 [査読有り]

DOI

Solid polymorphism and dynamic magnetic properties of dodecylated vanadyl-porphyrinato complex: Spin-lattice relaxations modulated by phase stabilisation

Yoji Horii, Momo Makino, Taro Yamamoto, Shoichi Tatsumi, Hal Suzuki, Mariko Noguchi, Takefumi Yoshida, Takashi Kajiwara, Zhaoyang Li, Masahiro Yamashita

Inorganic Chemistry Frontiers ( Royal Society of Chemistry (RSC) ) 2022年 [査読有り]

DOI

A Novel Π-D Conjugated Cobalt Tetraaza[14]Annulene Organic Framework for Efficient Electrocatalytic Co2 Reduction

Zhifu Liang, Ting Zhang, Pengfei Cao, Takefumi Yoshida, Weiqiang Tang, Xiang Wang, Pengyi Tang, Marc Heggen, Rafal E. Dunin-Borkowski, Joan Ramon Morante, andreu cabot, Masahiro Yamashita, Jordi Arbiol

SSRN Electronic Journal ( Elsevier BV ) 2022年

DOI

擬一次元ハロゲン架橋金属錯体における相転移及び相分離現象の解明

吉田健文 (担当区分：筆頭著者,　最終著者,　責任著者 )

熱測定 49 ( 4 ) 146 - 152 2022年 [査読有り] [招待有り]

Melamine-Induced Synthesis of a Structurally Perfect Kagomé Antiferromagnet

Yongbing Shen, Kunihisa Sugimoto, Satoshi Yamashita, Takefumi Yoshida, Yasuhiro Nakazawa, Brian. K. Breedlove, Haitao Zhang, Masahiro Yamashita

Chemical Communications ( Royal Society of Chemistry (RSC) ) 58 ( 23 ) 3763 - 3766 2022年 [査読有り]

DOI

フロギストン

熱測定 49 181 - 184 2022年

Ru(II)-Based Metallo-Supramolecular Polymer with Tetrakis(N-methylbenzimidazolyl)bipyridine for a Durable, Nonvolatile, and Electrochromic Device Driven at 0.6 V

Dines Chandra Santra, Sanjoy Mondal, Takefumi Yoshida, Yoshikazu Ninomiya, Masayoshi Higuchi

ACS Applied Materials & Interfaces ( American Chemical Society (ACS) ) 13 ( 26 ) 31153 - 31162 2021年06月 [査読有り]

Low-voltage operation, high durability, and long memory time are demanded for electrochromic (EC) display device applications. Metallo-supramolecular polymers (MSPs), composed of a metal ion and ditopic ligand, are one of the recently developed EC materials, and the ligand modification is expected to tune the redox potential of MSP. In order to lower the redox potential of MSP, tetrakis(N-methylbenzimidazolyl)bipyridine (L-Bip) was designed as an electronically rich ligand. Ru-based MSP (polyRu-LBip) was successfully synthesized by 1:1 complexation of RuCl2(DMSO)(4) with LBip. The molecular weight (M-w) was high (8.8 x 10(6) Da) enough to provide a simple H-1 NMR spectrum, of which the proton peaks could be assigned by the comparison with the spectrum of the corresponding mono-Ru complex. The redox potential (E-1/2) between Ru(II/III) was 0.51 V versus Ag/Ag+, which was much lower than the redox potential of previously reported Ru-based MSP with bis(terpyridyl)benzene (0.95 V vs Ag/Ag+). The polymer film exhibited reversible, distinct color changes between violet and light green-yellow upon applying very low potentials of 0 and 0.6 V vs Ag/Ag+, respectively. The appearance and disappearance of the metal-to-ligand charge transfer absorption by the electrochemical redox between Ru(II/III) were confirmed using in situ spectro-electrochemical measurement. A solid-state EC device with polyRu-L-Bip was revealed to have large optical contrast (Delta T 54%), fast response time (1.37 s for bleaching and 0.67 s for coloration), remarkable coloration efficiency (571 cm(2)/C), and high durability for the repeated color changes more than 20,000 cycles. The device also showed a long optical memory time of up to 19 h to maintain 40% to the initial contrast under the open circuit conditions. It is considered that the stabilization of the Ru(III) state by L-Bip suppressed the self-coloring to Ru(II) inside the device.

DOI

One-Step Synthesis of a Three-Dimensionally Hyperbranched Fe(II)-Based Metallo-Supramolecular Polymer Using an Asymmetrical Ditopic Ligand for Durable Electrochromic Films with Wide Absorption, Large Optical Contrast, and High Coloration Efficiency

Yemineni S. L. V. Narayana, Sanjoy Mondal, Utpal Rana, Yoshikazu Ninomiya, Dines Chandra Santra, Takefumi Yoshida, Masayoshi Higuchi

ACS Applied Electronic Materials ( American Chemical Society (ACS) ) 3 ( 5 ) 2044 - 2055 2021年04月 [査読有り]

For the development of durable electrochromic (EC) materials with wide absorption, large optical contrast, and high coloration efficiency, a three-dimensionally hyperbranched Fe(II)-based metallo-supramolecular polymer (polyFe3-D) was one-step synthesized by the complexation of an Fe(II) salt and an asymmetrical ditopic ligand (L) containing terpyridine (tpy) and phenanthroline (phen) moieties, according to the formation of a 1:2 complex of Fe(II) and tpys (Fe-tpys) and a 1:3 complex of Fe(II) and phens (Fe-phens). The formation of Fe-tpys and Fe-phens was confirmed by the appearance of two metal-to-ligand charge transfer (MLCT) absorptions in the visible area during the titration experiment. The molecular weight (M-w) of polyFe-3D was determined to 3.96 x 10(5) Da by a size-exclusion chromatography-viscometry measurement. PolyFe-3D with the two different Fe(II) complexes (Fe-typs and Fe-phens) exhibited a pair of redox waves for Fe(II/III) (E-1/2 = 0.74 V vs Ag/Ag+) reversibly in the cyclic voltammograms. The linear relationship between the peak current and the root of the scan rate during redox suggested a diffusion-controlled redox reaction. The spin-coated polymer film showed reversible EC changes between magenta and pale green, caused by the redox of Fe(II/III). A wide visible region from 430 to 640 nm was covered with the two MLCT absorptions of the Fe-tpys and Fe-phens moieties. The broad MLCT absorption disappeared upon applying 1.2 V vs Ag/Ag+ and reappeared at 0 V vs Ag/Ag+. The EC changes were revealed to have both a large transmittance change (Delta T) with 70% at 573 nm and a very high coloration efficiency (eta) with 689 cm(2)/C. The coloration efficiency exceeded those of the reported linear (one-dimensional), two-dimensional nanosheeted, and three-dimensional hyperbranched Fe(II)-based metallo-supramolecular polymers. A polyFe-3D film showed high durability for the EC changes of more than 1000 cycles. A solid-state simple device fabricated using polyFe-3D exhibited reversible EC changes of more than 1000 cycles without degradation.

DOI

Emergence of Metallic Conduction and Cobalt(II)-Based Single-Molecule Magnetism in the Same Temperature Range

Yongbing Shen, Hiroshi Ito, Haitao Zhang, Hideki Yamochi, Goulven Cosquer, Carmen Herrmann, Toshiaki Ina, Shinji K. Yoshina, Brian K. Breedlove, Akihiro Otsuka, Manabu Ishikawa, Takefumi Yoshida, Masahiro Yamashita

Journal of the American Chemical Society ( American Chemical Society (ACS) ) 143 ( 13 ) 4891 - 4895 2021年04月 [査読有り]

Single-molecule magnets exhibit magnetic bistabililties at the molecular level, making them promising for molecule-based spintronics due to high magnetic densities. The incorporation of SMM behavior and electrical conductivity in one compound is rare because these two physical properties often do not operate in the same temperature range, which further hinders their use in practical applications. Here we present an organic-inorganic molecular hybrid, β″-(BEDO-TTF)3[Co(pdms)2]·(MeCN)(H2O)2 (BO3) (BEDO-TTF = bis(ethylenedioxy)tetrathiafulvalene and H2pdms = 1,2-bis(methanesulfonamido)benzene), which manifests both metallic conduction (electrical conductivity up to 1000 S cm-1 at 12 K under 2.0 gigapascal pressure) and SMM behavior in the temperature range 12-26 K for the first time.

DOI

An unusual Pd(iii) oxidation state in the Pd–Cl chain complex with high thermal stability and electrical conductivity

Mohammad Rasel Mian, Masanori Wakizaka, Takefumi Yoshida, Hiroaki Iguchi, Shinya Takaishi, Unjila Afrin, Tatsuya Miyamoto, Hiroshi Okamoto, Hisaaki Tanaka, Shin-ichi Kuroda, Brian K. Breedlove, Masahiro Yamashita

Dalton Transactions ( Royal Society of Chemistry (RSC) ) 50 ( 5 ) 1614 - 1619 2021年 [査読有り]

DOI

Dual-Redox System of Metallo-Supramolecular Polymers for Visible-to-Near-IR Modulable Electrochromism and Durable Device Fabrication

Sanjoy Mondal, Dines Chandra Santra, Yoshikazu Ninomiya, Takefumi Yoshida, Masayoshi Higuchi

ACS Applied Materials & Interfaces ( American Chemical Society (ACS) ) 12 ( 52 ) 58277 - 58286 2020年12月 [査読有り]

Dual-redox metallo-supramolecular polymers with a zigzag structure (polyFe-N and polyRu-N) were successfully synthesized by 1:1 complexation of a redox-active Fe(II) or Ru(II) ion and 4,4-bis(2,2:6,2-terpyridinyl)phenyl-triphenylamine (L-TPA) as a redox-active ligand. The polymers had high solubility in methanol, and the polymer solutions showed dark brown (polyFe-N) or orange-red (polyRu-N) coloration. UV-vis spectra of the polymers displayed a strong metal-to-ligand charge transfer (MLCT) absorption in the visible region. Cyclic voltammograms of the polymer films exhibited two pairs of reversible redox waves. The first redox at similar to 0.5 V versus Ag/Ag+ was assigned to the redox in the triphenylamine (TPA) moiety of L-TPA, and the second redox at 0.8 V versus Ag/Ag+ (polyFe-N) or 0.9 V versus Ag/Ag+ (polyRu-N) was given to the redox of Fe(II)/(III) or Ru(II)/(III), respectively. Upon applying a positive potential of more than 0.5 V versus Ag/Ag+ to the polymer films, a new absorption at similar to 820 nm in the near-infrared (NIR) region appeared with wide tailing to the longer wavelength. It is considered that the new absorption in the NIR region is caused by the polaron band of the oxidized ligand in the polymers. When the applied potential was increased to 1.0 V versus Ag/Ag+ (polyFe-N) or 1.1 V versus Ag/Ag+ (polyRu-N), the maximum wavelength of the new absorption in the NIR region shifted to 885-900 nm and the absorbance was further enhanced with disappearance of the MLCT absorption. Eventually, the original colors of the polymers were faint to light green. This visible-to-NIR electrochromism was reversible, and maximum optical contrast (Delta T) reached 52% in the visible region and 80% in the NIR region. A prototype solid-state device with the polymer was fabricated for practical utilization, exhibiting excellent cycle stability of >4000 cycles with maintaining high optical contrast from the visible-to-NIR range.

DOI

Correction to: Synchrotron-radiation-based Mössbauer absorption spectroscopy with high resonant energy nuclides (Hyperfine Interactions, (2019), 240, 1, (120), 10.1007/s10751-019-1672-x)

Ryo Masuda, Kohei Kusada, Takefumi Yoshida, Shinji Michimura, Yasuhiro Kobayashi, Shinji Kitao, Hiroyuki Tajima, Takaya Mitsui, Hirokazu Kobayashi, Hiroshi Kitagawa, Makoto Seto

Hyperfine Interactions 241 ( 1 ) 2020年12月 [査読有り]

DOI

One-Pot Synthesis of Three-Dimensionally Hyperbranched Eu/Fe-Based Heterometallo-Supramolecular Polymers as Thermally Tough Proton-Conducting Nanoparticles

Yemineni S. L. V. Narayana, Utpal Rana, Chanchal Chakraborty, Takefumi Yoshida, Masayoshi Higuchi

ACS Applied Polymer Materials ( American Chemical Society (ACS) ) 2020年08月 [査読有り]

DOI

Ni(II)-Based Metallosupramolecular Polymer with Carboxylic Acid Groups: A Stable Platform for Smooth Imidazole Loading and the Anhydrous Proton Channel Formation

Yemineni S L V Narayana, Takefumi Yoshida, Manas Kumar Bera, Sanjoy Mondal, Masayoshi Higuchi

ACS Omega ( American Chemical Society (ACS) ) 5 ( 24 ) 14796 - 14804 2020年06月 [査読有り]

DOI

Dual-Branched Dense Hexagonal Fe(II)-Based Coordination Nanosheets With Red-to-Colorless Electrochromism and the Durable Device Fabrication

Sanjoy Mondal, Yoshikazu Ninomiya, Takefumi Yoshida, Taizo Mori, Manas Kumar Bera, Katsuhiko Ariga, Masayoshi Higuchi

ACS Applied Materials & Interfaces ( American Chemical Society (ACS) ) 12 ( 28 ) 31896 - 31903 2020年06月 [査読有り]

Highly dense hexagonal Fe(II)-based coordination nanosheets (CONASHs) were designed by dual-branching, at the metal-coordination moieties and the tritopic ligands, which successfully obtained a liquid/liquid interface by the complexation of Fe(II) ions and the tritopic bidentate ligands. The 1:1 complexation was confirmed by titration. The obtained Fe(II)-based nanosheets were fully characterized by small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). A monolayer of the sheets was obtained, employing the Langmuir-Blodgett (LB) method, and the determined thickness was similar to 2.5 nm. The polymer nanosheets exhibited red-to-colorless electrochromism because the electrochemical redox transformation between Fe(II) and Fe (III) ions controlled the appearance/disappearance of the metal (ion)-to-ligand charge-transfer (MLCT) absorption. The poor pi-conjugation in the tritopic ligands contributed to the highly colorless electrochromic state. A solid-state device, with the robust polymer film, exhibited excellent electrochromic (EC) properties, with high optical contrast (Delta T > 65%) and high durability after repeated color changes for >15 000 cycles, upon applying low-operating voltages (+1.5/0 V).

DOI

Electrochromic Fe(II)-Based Metallo-Supramolecular Polymers: Color Modulation by Spacer Modification in Bisterpyridine Ligand

Yoshikazu Ninomiya, Takefumi Yoshida, Masayoshi Higuchi

Chemistry Letters ( The Chemical Society of Japan ) 49 ( 9 ) 1003 - 1005 2020年05月 [査読有り]

We synthesized Fe(II)-based metallo-supramolecular polymers with bisterpyridines bearing ethynylene, phenylene, and durene as spacer (polyFeL1-3) and investigated the effect of the spacer modification on the electrochromic properties. We revealed the redox potential and MLCT absorption of polymers were greatly influenced by the spacer alteration. PolyFeL1-3 exhibited different colors; blue, bluish purple, and purple, respectively. Blue- and purple-colored electrochromic devices were successfully fabricated using polyFeL1 and polyFeL3. The electrochromic color changes were observed upon applying +3V for bleaching or -3V for coloring.

DOI

Transparent Supercapacitor Display with Redox-Active Metallo-Supramolecular Polymer Films

Sanjoy Mondal, Takefumi Yoshida, Subrata Maji, Katsuhiko Ariga, Masayoshi Higuchi

ACS APPLIED MATERIALS & INTERFACES ( AMER CHEMICAL SOC ) 12 ( 14 ) 16342 - 16349 2020年04月 [査読有り]

The use of metallo-supramolecular polymer (MSP) as a thin-film-based redox supercapacitor electrode material is reported for the first time. Fe(II)- and Ru(II)-based MSPs (polyFe and polyRu, respectively) were synthesized by complexation of appropriate metal salts with 4',4 ''-(1,4-phenylene)bis-2,2':6',2 ''-terpyridine, and thin films of these polymers were prepared by spray coating onto an indium tin oxide glass substrate. A study of the energy storage performances of the polyFe and polyRu films in a nonaqueous electrolyte system revealed volumetric capacitances of similar to 62.6 +/- 3 F/cm(3) for polyFe and 98.5 +/- 7 F/cm(3) for polyRu at a current density of 2 A/cm(3). To improve the energy storage performance over a wider potential range, asymmetric supercapacitor (ASC) displays were fabricated with suitable combinations of the MSPs as cathodic materials and Prussian blue as the anodic counter material in a sandwich configuration with a transparent polymeric ion gel as the electrolyte. The fabricated ASCs showed a maximum volumetric energy density (similar to 10-18 mW h/cm(3)) that was higher than that of lithium thin-film batteries and a power density (7 W/cm(3)) comparable to that of conventional electrolyte capacitors, with superb cyclic stability for 10 000 cycles. To demonstrate the practical use of the MSP, the illumination of a light-emitting diode bulb was powered by a laboratory-made device. This work should inspire the development of high-performance thin-film flexible supercapacitors based on MSPs as active cathodic materials.

DOI

Reversible four-color electrochromism triggered by the electrochemical multi-step redox of Cr-based metallo-supramolecular polymers

Takefumi Yoshida, Yoshikazu Ninomiya, Masayoshi Higuchi (担当区分：筆頭著者 )

RSC ADVANCES ( ROYAL SOC CHEMISTRY ) 10 ( 18 ) 10904 - 10909 2020年03月 [査読有り]

Four color electrochromism (yellow, magenta, blue, and navy) has been achieved in Cr(iii)-based metallo-supramolecular polymers (polyCr), which were synthesized by 1 : 1 complexation of Cr ions and 1,4-di[[2,2 ':6 ',2 ''-terpyridin]-4 '-yl]benzene (L). The polymer structure was determined by X-ray absorption fine structure (XAFS) measurement and X-ray photoelectron spectroscopy (XPS). The molecular weight of polyCr was calculated as 3.2 x 10(7) Da using right angle light scattering (RALS). The EXAFS fitting indicated that the bond distances of Cr-N are 2.020 angstrom and 2.208 angstrom. A film of polyCr shows multi-color electrochromism (EC) or absorption: a sharp peak at 380 nm at 0 V vs. Ag/Ag+ (yellow), a sharp peak at 510 nm and a broad peak at 800 nm at -0.6 V vs. Ag/Ag+ (magenta), a broad peak at 610 nm and between 700-900 nm at -1.2 V vs. Ag/Ag+ (blue), a broad peak between 450-900 nm at -1.8 V vs. Ag/Ag+ (navy). The transmittances change (Delta T), the switching times for coloring and bleaching (T-c, T-b) and the coloration efficiency (eta(c), eta(b)): [Delta T, (T-c, T-b), (eta(c), eta(b))] were [39.2%, (5.56 s, 1.39 s), (169 cm(2) C-1, 230 cm(2) C-1)] at 510 nm between -0.6 and 0.2 V vs. Ag/Ag+, [67.0%, (6.93 s, 2.52 s), (138 cm(2) C-1, 172 cm(2) C-1)] at 610 nm between -1.2 and 0.2 V vs. Ag/Ag+, [86.1%, (6.80 s, 3.03 s), (167 cm(2) C-1, 134 cm(2) C-1)] at 780 nm between -1.8 and 0.2 V vs. Ag/Ag+, respectively, during the cycles. The durability experiment indicates that polyCr shows an EC property for at least 100 cycles.

DOI

Proton Conductivity of Metallo-Supramolecular Polymer Boosted by Lithium Ions

Yemineni S. L. V. Narayana, Takefumi Yoshida, Chanchal Chakraborty, Manas Kumar Bera, Masayoshi Higuchi

ACS APPLIED POLYMER MATERIALS ( AMER CHEMICAL SOC ) 2 ( 2 ) 326 - 334 2020年02月 [査読有り]

This is a report to reveal the role of alkali metal ions on proton transfer in metallo-supramolecular polymers (MSPs). We successfully synthesized europium(III)-based MSPs with different counter cations (Li+, Na+, and K+) (polyEu-M+, M = Li, Na, and K, respectively) via 1:1 complexation of Eu(III) salt and tetracarboxylic acid-substituted bisterpyridine in the presence of metal hydroxide (MOH, M = Li, Na, and K). We found that the proton conductivity was dramatically changed by the countercation species of the polymer. Among the three polymers, polyEu-Li+ showed the highest proton conductivity (1.54 x 10(-2) S cm(-1)) at 95% relative humidity (RH) and 75 degrees C and also exhibited the lowest activation energy 0.14 eV at 95% RH. PolyEu-Li+ presented high water uptake (14.58), which was measured by the mass change (%) with respective reference mass, compared with polyEu-Na+ (13.08) and polyEu-K+ (11.50) at 95% RH. The results indicate that effective proton channels enabled by water molecules were formed in the presence of Li+.

DOI

Precise Synthesis of Alternate Fe(II)/Os(II)‐Based Bimetallic Metallo‐Supramolecular Polymer

Manas K. Bera, Yoshikazu Ninomiya, Takefumi Yoshida, Masayoshi Higuchi

Macromol. Rapid Commun. ( WILEY-V C H VERLAG GMBH ) 41 ( 1 ) 2020年01月 [査読有り]

A novel terpyridine-based bimetallic metallo-supramolecular polymer (polyFeOs) containing alternately complexed Fe(II) and Os(II) ions is synthesized. For precise synthesis of the polymer, a new three-step synthetic pathway is developed to obtain a high yield (%) of product in each step. The first step is the synthesis of dibromo terpyridine-Os(II) complex in 87% yield, the second step is the synthesis of bisterpyridine ligand containing Os(II) (OsL1) in 74% yield, and the last step is the synthesis of polyFeOs in 90% yield. The polyFeOs exhibits high thermal stability with two degradation temperatures at around 390 and 690 degrees C, which indicate thermal evaporation of the counter anions (Cl- and BF4-) and degradation of the coordination bonds, respectively. The combination of two different metal ions in polyFeOs results in an enlarged optical window (lambda = 315-675 nm) and two highly stable reversible redox states, which can be of huge interest for potential optical, electro-optical, and electrochemical applications.

DOI

Electrochromic Os-based metallo-supramolecular polymers: electronic state tracking by in situ XAFS, IR, and impedance spectroscopies

Takefumi Yoshida, Manas Kumar Bera, Yemineni S. L. V. Narayana, Sanjoy Mondal, Hitoshi Abe, Masayoshi Higuchi

RSC Advances ( Royal Society of Chemistry (RSC) ) 10 ( 41 ) 24691 - 24696 2020年 [査読有り]

DOI

An Organic‐Inorganic Hybrid Exhibiting Electrical Conduction and Single‐Ion‐Magnetism

Yongbing Shen, Goulven Cosquer, Hiroshi Ito, David Chukwuma Izuogu, Alex J.W. Thom, Toshiaki Ina, Tomoya Uruga, Takefumi Yoshida, Shinya Takaishi, Brian K. Breedlove, Zhao-Yang Li, Masahiro Yamashita

Angew. Chem. Ed. Int. 59 2399 - 2406 2020年 [査読有り]

DOI

Ionic-Caged Heterometallic Bismuth–Platinum Complex Exhibiting Electrocatalytic CO2 Reduction

Yoshida Takefumi, Ahsan Md. Habib, Haitao Zhang, David Chukwuma Izuogu, Hitoshi Abe, Hiroyoshi Ohtsu, Tadashi Yamaguchi, Brian K. Breedlove, Alexander James William Thom, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

Dalton Trans. 2020年 [査読有り]

DOI

Simultaneous manifestation of metallic conductivity and single-molecule magnetism in a layered molecule-based compound

Yongbing Shen, Hiroshi Ito, Haitao Zhang, Hideki Yamochi, Seiu Katagiri, Shinji K. Yoshina, Akihiro Otsuka, Manabu Ishikawa, Goulven Cosquer, Kaiji Uchida, Carmen Herrmann, Takefumi Yoshida, Brian K. Breedlove, Masahiro Yamashita

Chemical Science ( Royal Society of Chemistry (RSC) ) 11 ( 41 ) 11154 - 11161 2020年 [査読有り]

DOI

Emergence of electrical conductivity in a flexible coordination polymer by using chemical reduction

Kentaro Fuku, Momoka Miyata, Shinya Takaishi, Takefumi Yoshida, Masahiro Yamashita, Norihisa Hoshino, Tomoyuki Akutagawa, Hiroyoshi Ohtsu, Masaki Kawano, Hiroaki Iguchi

Chemical Communications ( Royal Society of Chemistry (RSC) ) 56 ( 61 ) 8619 - 8622 2020年 [査読有り]

DOI

Periodicity of Single‐Molecule Magnet Behaviour of Heterotetranuclear Lanthanide Complexes Across the Lanthanide Series: A Compendium

David Chukwuma Izuogu, Yoshida Takefumi, Goulven Cosquer, Jonnie N. Asegbeloyin, Haitao Zhang, Alex J. W. Thom, Masahiro Yamashita

Chem. Eur. J. 2020年 [査読有り]

DOI

Conductive zigzag Pd(III)–Br chain complex realized by multiple-hydrogen-bond approach

Mohammad Rasel Mian, Unjila Afrin, Hiroaki Iguchi, Shinya Takaishi, Takefumi Yoshida, Tatsuya Miyamoto, Hiroshi Okamoto, Hisaaki Tanaka, Shin-ichi Kuroda, Masahiro Yamashita

CrystEngComm 22 ( 23 ) 3999 - 4004 2020年 [査読有り]

DOI

Electrochromic devices using Fe (II)‐based metallo‐supramolecular polymer: Introduction of ionic liquid as electrolyte to enhance the thermal stability

Sanjoy Mondal, Takefumi Yoshida, Masayoshi Higuchi

J. Soc. Inf. Display ( WILEY ) 27 ( 11 ) 661 - 666 2019年11月 [査読有り] [招待有り]

DOI

Thermally stable electrochromic devices using Fe(II)-based metallo-supramolecular polymer

Sanjoy Mondal, Takefumi Yoshida, Utpal Rana, Manas Kumar Bera, Masayoshi Higuchi

SOLAR ENERGY MATERIALS AND SOLAR CELLS ( ELSEVIER ) 200 110000 2019年09月 [査読有り] [招待有り]

A solid-state electrochromic (EC) device with high thermal durability was successfully fabricated by the combination of Fe(II)-based metallo-supramolecular polymer (polyFe) as a cathodically coloring EC layer, a poly (methyl methacrylate)-based solid-state electrolyte layer, and Prussian blue (PB) as an anodically coloring EC layer between two indium tin oxide (ITO)-coated glass conducting substrates. Spray coating technique was used to make polyFe film on ITO-glass. Counter materials were investigated to improve the long-term durability and performance of solid state devices. The polyFe layer thickness was optimized at 240 +/- 50 nm, resulting in better electrochromic performance of the fabricated device with transmittance change of similar to 54% and 95% cyclic stability after 1000 cycles with a short response time by applying voltages of +2.7 V and -1.3 V reversibly. Importantly, the thermal stability of the fabricated solid device was also explored, and we achieved maximum temperature stability at 100 degrees C with 50% retention of device properties in this study.

DOI

Construction of Coordination Nanosheets Based on Tris(2,2 '-bipyridine)-Iron-(Fe2+) Complexes as Potential Electrochromic Materials

Manas Kumar Bera, Taizo Mori, Takefumi Yoshida, Katsuhiko Ariga, Masayoshi Higuchi

ACS APPLIED MATERIALS & INTERFACES ( AMER CHEMICAL SOC ) 11 ( 12 ) 11893 - 11903 2019年03月 [査読有り]

The coordination nanosheets (CONASHs) are emerging as a new class of functional two-dimensional materials, which are one of the most active research areas of chemistry and physics in this decade. Despite the success of various structural and functional CONASHs, the development of a new molecular structure to discover alluring functional CONASHs remains challenging. Herein, we report successful preparation of two novel CONASHs (NBP1 and NBP2) through coordination between one of the unexplored molecular frameworks of bis(2,2'-bipyridine)-based ligands (BP1 and BP2) and Fe2+ ions. Using a liquid-liquid interface as a platform, large-scale thin films of multilayer CONASHs have been prepared without any support, which can be deposited onto any desired substrate. Detailed characterization of the CONASHs using various microscopic and spectroscopic techniques reveals homogeneous and flat morphology of nanometer thickness with the quantitative formation of tris(2,2'-bipyridine)-Fe2+ complex motifs in the nanosheet frameworks. The color of the films has been tuned from blue to magenta by the suitable molecular design of the ligands. Owing to the insolubility of the CONASH films in any solvent and the presence of redox-active Fe2+, we explore the functionality of these nanostructured thin films deposited on indium tin oxide as electrochromic materials. The CONASHs exhibit color-to-colorless and color-to-color electrochromic transitions with attractive response times, switching stabilities, and coloration efficiencies. Finally, we demonstrate solid-state electrochromic devices of the CONASHs operated at a potential range of +2.5 to -2.5 V, which are electrochemically stable for several switching cycles, suggesting that these CONASHs are potential electrochromic materials for next-generation display applications.

DOI

Ln-Pt Electron Polarization Affected Slow Magnetic Relaxation with Heterometallic Er, Ho-Pt Complexes

Takefumi Yoshida, David C. Izuogu, Hai-Tao Zhang, Goulven Cosquer, Hitoshi Abe, Wolfgang Wernsdorfer, Brian K. Breedlove, Masahiro Yamashita

Dalton Trans. 48 7144 - 7149 2019年 [査読有り] [招待有り]

DOI

Observation of charge bistability in quasi-one-dimensional halogen-bridged palladium complexes by X-ray absorption spectroscopy

Takefumi Yoshida, Shinya Takaishi, Shohei Kumagai, Hiroaki Iguchi, Rasel Mian Mohamad, Masahiro Yamashita (担当区分：筆頭著者 )

Dalton Trans. 48 11628 - 11631 2019年 [査読有り]

DOI

Porous Molecular Conductor: Electrochemical Fabrication of Through-Space Conduction Pathways among Linear Coordination Polymers

L. Qu, H. Iguchi, S. Takaishi, F. Habib, C. F. Leong, D. M.D'Alessandro, T. Yoshida, H. Abe, E. Nishibori, M. Yamashita

J. Am. Chem. Soc. 141 6802 - 6806 2019年 [査読有り]

DOI

Synchrotron-radiation-based Mössbauer Absorption Spectroscopy with High Resonant Energy Nuclides

R. Masuda, K. Kusada, T. Yoshida, S. Michimura, Y. Kobayashi, S. Kitao, H. Tajima, T. Mitsui, H. Kobayashi, H. Kitagawa, M. Seto

Hyperfine Interactions ( SPRINGER INTERNATIONAL PUBLISHING AG ) 240 ( 1 ) 120 2019年 [査読有り]

We successfully observed the synchrotron-radiation-based Mossbauer absorption spectra with Gd-158 and Ru-99. Their nuclear resonant energies were 79.5 keV and 89.6 keV, respectively, and they are factually the highest energy which energy region synchrotron radiation covers with sufficient intensity as the incident X-rays for Mossbauer spectroscopy. Although the low recoilless fraction owing to these high resonant energy, Mossbauer energy spectra of GdPd3 to (Gd2O3)-Gd-158 and fcc-Ru nanoparticles to bulk hcp-Ru-99 metal were obtained with natural samples of the former compounds with sufficient amount, because of the high transparency of these high energy X-rays(to electronic scattering). In spite of large statistical errors, we can evaluate the hyperfine parameters when the spectrum includes simple 1-site profile. Ru-99 and Gd-158 SR-based Mossbauer absorption spectra of various complex materials including somewhat complex structures will be available with the improvements to the measurement system; More detector elements for larger solid angle subtended to the scatterer sample will yields more counting rates and improvement higher recoilless fraction by arranging more appropriate chemical specimen as the scatterer yields deeper absorption profile.

DOI

Slow magnetic relaxation in a Tb(III)-based coordination polymer

Takefumi Yoshida, Yemineni S. L. V. Narayana, Hitoshi Abe, Masayoshi Higuchi (担当区分：筆頭著者 )

DALTON TRANSACTIONS ( ROYAL SOC CHEMISTRY ) 47 ( 45 ) 16066 - 16071 2018年12月 [査読有り]

A Tb(III)-based coordination polymer (polyTb) was synthesized by complexation of Tb(NO3)(3)center dot(6H(2)O) and 4',4 ''''-[1,1'-biphenyl]-4,4'-diylbis[6,6 ''-bis(ethoxycarbonyl)2':6',2 ''-terpyridine](L). The polymer structure was determined by Job's plots, DFT calculation, and X-ray absorption fine structure (XAFS) measurement. Job's plots indicated that the mole ratio (Tb ion:L) is 1:1. The optimized model structures suggested a La model: the LaN6 center dot center dot center dot(O=C)(2) model. The bond distances of La-O and La-N are similar to 2.80 angstrom and 2.60 angstrom, respectively. The EXAFS fitting indicated that the bond distances of Tb-O and Tb-N are 2.65 angstrom and 2.95 angstrom, respectively. polyTb shows field-induced magnetic relaxation in the solid and solution state. The luminescence of polyTb, originating from an f-f transition, was observed (phi = 6.9%). polyTb formed a porous structure on a Si substrate, whereas a fibrous complex structure was formed on glass. polyTb chains are orientated on glass, which were determined by XRD.

DOI

Modulation of a coordination structure in a europium(III)-based metallo-supramolecular polymer for high proton conduction

Yemineni S. L. V. Narayana, Chanchal Chakraborty, Utpal Rana, Yoshikazu Ninomiya, Takefumi Yoshida, Masayoshi Higuchi

RSC ADVANCES ( ROYAL SOC CHEMISTRY ) 8 ( 65 ) 37193 - 37199 2018年 [査読有り]

Developing high proton conducting solid materials is significant in the field of fuel cells. A europium(III)based metallo-supramolecular polymer with uncoordinated carboxylic acids (PolyEu-H) was successfully synthesized by modifying the synthesis conditions. The proton conductivity was enhanced with increasing the relative humidity (RH) from 30 to 95% RH. PolyEu-H showed about 104 times higher proton conductivity than the polymer with coordinated carboxylic acids (PolyEu) and about 400 times higher than the polymer without carboxylic acids (PolyEu-2). The proton conductivity of PolyEu-H reached 4.45 x 10(-2) S cm(-1) at 95% RH and 25 degrees C and 5.6 x 10(-2) S cm(-1) at 75 degrees C. The activation energy, Ea was ultralow (0.04 eV), which indicates proton conduction based on the Grotthuss mechanism. The results indicate that efficient proton conduction occurs through proton channels formed by moisture in PolyEu-H.

DOI

Diversity in Design of Electrochromic Devices with Metallo-Supramolecular Polymer: Multi-Patterned and Tube-Shaped Displays

Takefumi Yoshida, Masayoshi Higuchi (担当区分：筆頭著者 )

JOURNAL OF PHOTOPOLYMER SCIENCE AND TECHNOLOGY ( TECHNICAL ASSOC PHOTOPOLYMERS,JAPAN ) 31 ( 3 ) 343 - 347 2018年 [査読有り]

As newly designed electrochromic devices (ECDs), we fabricated a multi-patterned display (MPD) and a tube-shaped display (TSD) with Fe(II)-based metallo-supramolecular polymer (polyFe) and/or Ru(II)-based polymer (polyRu). The MPD was fabricated by staking three independent ECDs. The device thickness was less than 5 mm using both-sides-coated ITO glasses. The MPD presented eight different images with high contrast and fast response. The bleaching and coloring times (T-b and T-c) were 1.7 and 2.0 s at 500 nm, in which the absorption attributed to polyRu appears, respectively, and 3.6 and 1.8 s at 600 nm, in which the absorption attributed to polyFe appears, respectively. The TSD was successfully fabricated using two flexible ITO-PET films and two tube-shaped glasses. The TSD also showed good electrochromic behavior (T-b: 22 s and T-c: 3.6 s). These results guarantee the achievement of the further application for new design of architecture or appliance.

DOI

Slow Magnetic Relaxation in a Palladium‐Gadolinium Complex Induced by Electron Density Donation from the Palladium Ion

David Chukwuma Izougu, Takefumi Yoshida, Haitao Zhang, Goulven Cosquer, Keiichi Katoh, Shuhei Ogata, Miki Hasekawa, Hiroyuki Nojiri, Marko Damjanović, Wolfgang Wernsdorfer, Tomoya Uruga, Toshiaki Ina, Brian K. Breedlove, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

Chem. Eur. J. 24 9285 - 9294 2018年 [査読有り]

DOI

Multiple Magnetic Relaxation Pathways and Dual-Emission Modulated by a Heterometallic Tb-Pt Bonding Environment

Takefumi Yoshida, David Chukwuma Izougu, Daichi Iwasawa, Shuhei Ogata, Miki Hasegawa, Brian K. Breedlove, Goulven Cosquer, Wolfgang Wernsdorfer, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

CHEMISTRY-A EUROPEAN JOURNAL ( WILEY-V C H VERLAG GMBH ) 23 ( 44 ) 10527 - 10531 2017年08月 [査読有り]

A heterometallic Tb-Pt complex, [Tb2Pt3(SAc)(12)(H2O)(2)] (SAc = thioacetate), was synthesized. Dual emission was modulated by the presence of a heterometallic Tb-Pt bonding environment. The heterometallic Tb-Pt bond lowers the symmetry of the Tb ion and enhanced the emission efficiency. In addition, the Tb-Pt complex shows field-induced multiple magnetic relaxation pathways. Furthermore, it served as an antenna for the observed dual emission. In other words, the heterometallic Tb-Pt bond has a significant effect on the luminescence and magnetic properties of the complex.

DOI

Field-Induced Slow Magnetic Relaxation of Gd-III Complex with a Pt-Gd Heterometallic Bond

Takefumi Yoshida, Goulven Cosquer, David Chukwuma Izuogu, Hiroyoshi Ohtsu, Masaki Kawano, Yanhua Lan, Wolfgang Wernsdorfer, Hiroyuki Nojiri, Brian K. Breedlove, Masahiro Yamashita (担当区分：筆頭著者,　責任著者 )

CHEMISTRY-A EUROPEAN JOURNAL ( WILEY-V C H VERLAG GMBH ) 23 ( 19 ) 4551 - 4556 2017年04月 [査読有り]

Heterometallic Gd-Pt complexes ([Gd2Pt3(H2O)(2)(SAc)(12)] (SAc=thioacetate), [Y1.4Gd0.6Pt3(H2O)(2)(SAc)(12)], and [Gd2Pt3(H2O)(6)(SAc)(12)]7H(2)O have been synthesized. The crystal structures and DFT calculations indicated a Gd-Pt heretometallic bond. Single-crystal ESR spectra determined the direction of magnetic anisotropy as direction of the Gd-Pt bond. In other words, the Gd-Pt bond dictates the direction of magnetic anisotropy. The heterometallic Gd-Pt bond lowers the symmetry of the Gd ion, splitting the Kramers doublet in a dc field. Thus, we observed clear field-induced slow magnetic relaxation of [Y1.4Gd0.6Pt3(H2O)(2)(SAc)(12)] up to 36K. The relaxation process was determined to be a direct process.

DOI

Temperature dependence of Peierls-Hubbard phase transition in [Pd(cptn)(2)Br]Br-2 studied by scanning tunneling microscopy

Yuka Hosomi, Shoji Yoshida, Atsushi Taninaka, Takefumi Yoshida, Shinya Takaishi, Osamu Takeuchi, Masahiro Yamashita, Hidemi Shigekawa

JAPANESE JOURNAL OF APPLIED PHYSICS ( IOP PUBLISHING LTD ) 55 ( 8 ) 08NB16 2016年08月 [査読有り]

The temperature dependence of the Peierls-Hubbard phase transition in [Pd(cptn)(2)Br]Br-2 (cptn: 1R,2R diaminocyclopentane) was directly observed using a low-temperature scanning tunneling microscope. A short ligand without alkyl chains was used to form a rigid crystal lattice to reduce the effect of structural changes in the crystal with temperature. The hysteresis in the temperature dependence of the ratio between the areas of the charge density wave (CDW) state produced by the Pd-II-Pd-IV mixed-valence state and the Mott-Hubbard (MH) state with a Pd-III-averaged valence state which is a characteristic of the first-order phase transition, was directly observed at the atomic scale. Pinning of the CDW phase by defects was observed below the critical temperature, suggesting the growth of the CDW phase with defects as nuclei. (C) 2016 The Japan Society of Applied Physics

DOI

Direct Observation of Ordered High-Spin–Low-Spin Intermediate States of an Iron(III) Three-Step Spin-Crossover Complex

Zhao-Yang Li, Hiroyoshi Ohtsu, Tatsuhiro Kojima, Jing-Wei Dai, Takefumi Yoshida, Brian K. Breedlove, Wei-Xiong Zhang, Hiroaki Iguchi, Osamu Sato, Masaki Kawano, Masahiro Yamashita

Angew. Chem. Int. Ed. ( WILEY-V C H VERLAG GMBH ) 55 ( 17 ) 5184 - 5189 2016年04月 [査読有り]

A neutral mononuclear Fe-III complex [Fe-III(H-5-Br-thsa-Me)(5-Br-thsa-Me)]H2O (1; H-2-5-Br-thsa-Me=5-bromosalicylaldehyde methylthiosemicarbazone) was prepared that exhibited a three-step spin-crossover (SCO) with symmetry breaking and a 14K hysteresis loop owing to strong cooperativity. Two ordered intermediate states of 1 were observed, 4HS-2LS and 2HS-4LS, which exhibited reentrant phase-transition behavior. This study provides a new platform for examining multistability in SCO complexes.

DOI

Optically Visible Phase Separation between Mott-Hubbard and Charge-Density-Wave Domains in a Pd-Br Chain Complex

Takefumi Yoshida, Shinya Takaishi, Hiroaki Iguchi, Hiroshi Okamoto, Hisaaki Tanaka, Shin-ichi Kuroda, Yuka Hosomi, Shoji Yoshida, Hidemi Shigekawa, Tatsuhiro Kojima, Hiroyoshi Ohtsu, Masaki Kawano, Brian K. Breedlove, Laurent Guerin, Masahiro Yamashita (担当区分：筆頭著者 )

CHEMISTRYSELECT ( WILEY-V C H VERLAG GMBH ) 1 ( 2 ) 259 - 263 2016年02月 [査読有り]

We synthesized a bromo-bridged Pd complex, which underwent as lowering the temperature a charge-density-wave (CDW) to Mott-Hubbard (MH) phase transition, as confirmed by using X-ray diffraction analysis, ESR, FT-IR and Raman spectroscopies. The complex showed a phase-separation phenomenon with a striped pattern over a wide temperature range, and domain propagation was observed using an optical microscope. Moreover, we observed changes in the local electronic state accompanying the phase transition by using scanning tunneling microscopy (STM).

DOI

CDW-MH相転移を示す新規Br架橋Pd錯体[Pd(cptn)_2Br]Br_2の電子状態

高石, 慎也, 吉田, 健文, 山下, 正廣, 岡本, 博, 田中, 久暁, 黒田, 新一, 細見, 由香, 吉田, 昭二, 重川, 秀実

日本物理学会講演概要集 ( 一般社団法人日本物理学会 ) 70 ( 2 ) 1577 - 1577 2015年09月

DOI

低次元有機伝導体におけるパイエルス－モット転移過程のSTM観察

細見友香, 吉田昭二, 高石慎也, 山下正廣, 吉田健文, 武内修, 重川秀実

表面科学学術講演会要旨集 ( 公益社団法人日本表面科学会 ) 35 329 - 329 2015年

DOI

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