Tokushima University / Educator and Researcher Directory --- Inukai, Munehiro

Personal Web Page

https://researchmap.jp/7000009650 (researchmap)

https://orcid.org/0000-0003-4830-6888 (ORCID)

Field of Study

○	chemical physics

Subject of Study

○	New application and hardware development in solid-state NMR

Book / Paper

Academic Paper (Judged Full Paper):

1.	Haruki Sato, Koichiro Miyanishi, Makoto Negoro, Akinori Kagawa, Yusuke Nishiyama, Satoshi Horike, Koichi Nakamura and Munehiro Inukai : Hyperpolarization of Biomolecules in Eutectic Crystals at Room Temperature Using Photoexcited Electrons, The Journal of Physical Chemistry Letters, Vol.14, No.19, 4560-4564, 2023. (Summary) The hyperpolarization of biomolecules at room temperature could facilitate highly sensitive magnetic resonance imaging for metabolic studies and nuclear magnetic resonance (NMR)-based screenings for drug discovery. In this study, we demonstrate the hyperpolarization of biomolecules in eutectic crystals using photoexcited triplet electrons at room temperature. Eutectic crystals composed of the domains of benzoic acid doped with the polarization source and analyte domains were prepared using a melting-quenching process. Spin diffusion between the benzoic acid and analyte domain was elucidated using solid-state NMR analysis, indicating that hyperpolarization was transferred from the domain of benzoic acid to the domain of the analyte. (Link to Publication Site) ● Publication site (DOI): 10.1021/acs.jpclett.3c00622 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 37159560 ● Summary page in Scopus @ Elsevier: 2-s2.0-85159772091 (DOI: 10.1021/acs.jpclett.3c00622, PubMed: 37159560, Elsevier: Scopus)
2.	Takuya Kurihara, Munehiro Inukai and Motohiro Mizuno : Slow CO₂ Diffusion Governed by Steric Hindrance of Rotatory Ligands in Small Pores of a Metal-Organic Framework., The Journal of Physical Chemistry Letters, Vol.13, No.30, 7023-7028, 2022. (Summary) Understanding the adsorption and diffusional dynamics of CO in metal-organic frameworks (MOFs) is essential in the application of these materials to CO capture and separation. We show that the dynamics of adsorbed CO is related to the rotational motion of ligands located in the narrow pore windows of a MOF using solid-state nuclear magnetic resonance (NMR) spectroscopy. NMR analyses of local dynamics reveal that CO adsorbed in the pore hinders the rotation of the ligands. The rate of diffusion of adsorbed CO monitored by C NMR is much less than that in the larger pores of MOFs and decreases cooperatively with ligand mobility, which indicates that the rate of diffusion is influenced by the steric hindrance of the rotatory ligands. Adsorbed CH also showed slow diffusion in the MOF, suggesting molecular size-selective effect of the mobile steric hindrance on the rate of adsorbate diffusion. (Link to Publication Site) ● Publication site (DOI): 10.1021/acs.jpclett.2c01664 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 35900108 ● Search Scopus @ Elsevier (PMID): 35900108 ● Search Scopus @ Elsevier (DOI): 10.1021/acs.jpclett.2c01664 (DOI: 10.1021/acs.jpclett.2c01664, PubMed: 35900108)
3.	Munehiro Inukai, T. Kurihara, Y. Noda, W. Jiang, K. Takegoshi, N. Ogiwara, H. Kitagawa and Koichi Nakamura : Probing dynamics of carbon dioxide in a metal-organic framework under high pressure by high-resolution solid-state NMR, Physical Chemistry Chemical Physics, Vol.22, No.26, 14465-14470, 2020. (Summary) The application of high-resolution NMR analysis for CO2 adsorbed in a MOF under high pressure is reported for the first time. The results showed that CO2 adsorbed in MOF-74 had an unusually slow mobility (τ ∼ 10-8 s). CO2-CO2 interactions suppressed the mobility of CO2 under high pressure, which, in turn, would have contributed to the stability of CO2 at the adsorption sites. (Tokushima University Institutional Repository) ● Metadata: 114711 (Link to Publication Site) ● Publication site (DOI): 10.1039/d0cp01216e (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 32400799 ● Search Scopus @ Elsevier (PMID): 32400799 ● Search Scopus @ Elsevier (DOI): 10.1039/d0cp01216e (Tokushima University Institutional Repository: 114711, DOI: 10.1039/d0cp01216e, PubMed: 32400799)
4.	Kazuaki Kisu, Sangryun Kim, Munehiro Inukai, Hiroyuki Oguchi, Shigeyuki Takagi and Shin-ichi Orimo : Magnesium Borohydride Ammonia Borane as a Magnesium Ionic Conductor, ACS Applied Energy Materials, Vol.3, No.4, 3174-3179, 2020. (Link to Publication Site) ● Publication site (DOI): 10.1021/acsaem.0c00113 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1021/acsaem.0c00113 (DOI: 10.1021/acsaem.0c00113)
5.	Naoki Ogiwara, Hirokazu Kobayashi, Munehiro Inukai, Yusuke Nishiyama, Patricia Concepción, Fernando Rey and Hiroshi Kitagawa : Ligand-Functionalization-Controlled Activity of MetalOrganic Framework-Encapsulated Pt Nanocatalyst toward Activation of Water, Nano Letters, Vol.20, No.1, 426-432, 2020. (Summary) We first report the systematic control of the reactivity of HO vapor in metal-organic frameworks (MOFs) with Pt nanocrystals (NCs) through ligand functionalization. We successfully synthesized Pt NCs covered with a water-stable MOF, UiO-66 (Pt@UiO-66), having different metal ions or functionalized ligands. The ligand functionalization of UiO-66 significantly affected the catalytic performance of the water-gas shift reaction, and the replacement of Zr ions with Hf ions in UiO-66 had no impact on the catalytic activity. The introduction of a -Br group lowered the reactivity of Pt@UiO-66 by nearly half, whereas the substitution of -Br with a -Me group triply enhanced the activity. The origin of the enhanced catalytic activity was found to be the change in HO activity in the UiO-66 pores by the ligand functionalization, which was investigated using HO sorption, solid-state NMR, X-ray photoelectron spectroscopy, and in situ IR measurements. This work opens a new prospect to develop MOFs as a platform to activate HO. (Link to Publication Site) ● Publication site (DOI): 10.1021/acs.nanolett.9b04124 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 31833371 ● Search Scopus @ Elsevier (PMID): 31833371 ● Search Scopus @ Elsevier (DOI): 10.1021/acs.nanolett.9b04124 (DOI: 10.1021/acs.nanolett.9b04124, PubMed: 31833371)
6.	Munehiro Inukai, Yusuke Nishiyama, Kayako Honjo, Chinmoy Das, Susumu Kitagawa and Satoshi Horike : Glass-phase coordination polymer displaying proton conductivity and guest-accessible porosity, Chemical Communications, Vol.55, No.59, 8528-8531, 2019. (Tokushima University Institutional Repository) ● Metadata: 113446 (Link to Publication Site) ● Publication site (DOI): 10.1039/c9cc02744k (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 31259321 ● Summary page in Scopus @ Elsevier: 2-s2.0-85069467935 (Tokushima University Institutional Repository: 113446, DOI: 10.1039/c9cc02744k, PubMed: 31259321, Elsevier: Scopus)
7.	Munehiro Inukai, Masanori Tamura, Satoshi Horike, Masakazu Higuchi, Susumu Kitagawa and Koichi Nakamura : Storage of CO₂ into Porous Coordination Polymer Controlled by Molecular Rotor Dynamics, Angewandte Chemie International Edition, Vol.57, No.28, 8687-8690, 2018. (Summary) Design to store gas molecules, such as CO , H , and CH , under low pressure is one of the most important challenges in chemistry and materials science. Herein, we describe the storage of CO in the cavities of a porous coordination polymer (PCP) using molecular rotor dynamics. Owing to the narrow pore windows of PCP, CO was not adsorbed at 195 K. As the temperature increased, the rotors exhibited rotational modes; such rotations dynamically expanded the size of the windows, leading to CO adsorption. The rotational frequencies of the rotors (k≈10 s) and correlation times of adsorbed CO (τ≈10 s) were elucidated via solid-state NMR studies, which suggest that the slow rotation of the rotors sterically restricts CO diffusion in the pores. This restriction results in an unusually slow CO mobility close to solid state (τ≥10 s). Once adsorbed at room temperature, CO is robustly stored in the PCP under vacuum at 195-233 K because of the steric hindrance of the rotors. We also demonstrate that this mechanism can be applied to the storage of CH . (Link to Publication Site) ● Publication site (DOI): 10.1002/anie.201805111 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 29774644 ● Search Scopus @ Elsevier (PMID): 29774644 ● Search Scopus @ Elsevier (DOI): 10.1002/anie.201805111 (DOI: 10.1002/anie.201805111, PubMed: 29774644)
8.	Munehiro Inukai, Satoshi Horike, Tomoya Itakura, Ryota Shinozaki, Naoki Ogiwara, Daiki Umeyama, Sanjog Nagarkar, Yusuke Nishiyama, Michal Malon, Akari Hayashi, Takashi Ohhara, Ryoji Kiyanagi and Susumu Kitagawa : Encapsulating Mobile Proton Carriers into Structural Defects in Coordination Polymer Crystals: High Anhydrous Proton Conduction and Fuel Cell Application, Journal of the American Chemical Society, Vol.138, No.27, 8505-8511, 2016. (Summary) We describe the encapsulation of mobile proton carriers into defect sites in nonporous coordination polymers (CPs). The proton carriers were encapsulated with high mobility and provided high proton conductivity at 150 °C under anhydrous conditions. The high proton conductivity and nonporous nature of the CP allowed its application as an electrolyte in a fuel cell. The defects and mobile proton carriers were investigated using solid-state NMR, XAFS, XRD, and ICP-AES/EA. On the basis of these analyses, we concluded that the defect sites provide space for mobile uncoordinated H3PO4, H2PO4(-), and H2O. These mobile carriers play a key role in expanding the proton-hopping path and promoting the mobility of protons in the coordination framework, leading to high proton conductivity and fuel cell power generation. (Link to Publication Site) ● Publication site (DOI): 10.1021/jacs.6b03625 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 27324658 ● Search Scopus @ Elsevier (PMID): 27324658 ● Search Scopus @ Elsevier (DOI): 10.1021/jacs.6b03625 (DOI: 10.1021/jacs.6b03625, PubMed: 27324658)
9.	Naoki Ogiwara, Munehiro Inukai, Tomoya Itakura, Satoshi Horike and Susumu Kitagawa : Fast Conduction of Organic Cations in Metal Sulfate Frameworks, Chemistry of Materials, Vol.28, No.11, 3968-3975, 2016. (Link to Publication Site) ● Publication site (DOI): 10.1021/acs.chemmater.6b01284 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1021/acs.chemmater.6b01284 (DOI: 10.1021/acs.chemmater.6b01284)
10.	Ritesh Haldar, Munehiro Inukai, Satoshi Horike, Kazuhiro Uemura, Susumu Kitagawa and Kumar Tapas Maji : ¹¹³Cd Nuclear Magnetic Resonance as a Probe of Structural Dynamics in a Flexible Porous Framework Showing Selective O₂/N₂ and CO₂/N₂ Adsorption, Inorganic Chemistry, Vol.55, No.9, 4166-4172, 2016. (Link to Publication Site) ● Publication site (DOI): 10.1021/acs.inorgchem.5b02873 (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1021/acs.inorgchem.5b02873 (DOI: 10.1021/acs.inorgchem.5b02873)
11.	T. Itakura, S. Horike, Munehiro Inukai and S. Kitagawa : Freeze-drying synthesis of an amorphous Zn2+ complex and its transformation to a 2-D coordination framework in the solid state, Dalton Transactions, Vol.45, No.10, 4127-4131, 2016. (Summary) An amorphous and metastable precursor for a Zn two-dimensional coordination framework was synthesised via freeze drying. The precursor comprises randomly packed discrete clusters of a Zn complex. The amorphous-to-crystalline framework transformation, which was triggered by the gentle application of heat or pressure, was accompanied by a change in the coordination geometry of the Zn2+ ions from tetrahedral to octahedral symmetry. (Link to Publication Site) ● Publication site (DOI): 10.1039/c5dt03286e (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 26523996 ● Summary page in Scopus @ Elsevier: 2-s2.0-84959466587 (DOI: 10.1039/c5dt03286e, PubMed: 26523996, Elsevier: Scopus)
12.	Munehiro Inukai, Tomohiro Fukushima, Yuh Hijikata, Naoki Ogiwara, Satoshi Horike and Susumu Kitagawa : Control of Molecular Rotor Rotational Frequencies in Porous Coordination Polymers Using a Solid-Solution Approach, Journal of the American Chemical Society, Vol.137, No.38, 12183-12186, 2015. (Summary) Rational design to control the dynamics of molecular rotors in crystalline solids is of interest because it offers advanced materials with precisely tuned functionality. Herein, we describe the control of the rotational frequency of rotors in flexible porous coordination polymers (PCPs) using a solid-solution approach. Solid-solutions of the flexible PCPs [{Zn(5-nitroisophthalate)x(5-methoxyisophthalate)1-x(deuterated 4,4'-bipyridyl)}(DMF·MeOH)]n allow continuous modulation of cell volume by changing the solid-solution ratio x. Variation of the isostructures provides continuous changes in the local environment around the molecular rotors (pyridyl rings of the 4,4'-bipyridyl group), leading to the control of the rotational frequency without the need to vary the temperature. (Link to Publication Site) ● Publication site (DOI): 10.1021/jacs.5b05413 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 26368067 ● Summary page in Scopus @ Elsevier: 2-s2.0-84942881728 (DOI: 10.1021/jacs.5b05413, PubMed: 26368067, Elsevier: Scopus)
13.	Takashi Uemura, Tetsuya Kaseda, Yotaro Sasaki, Munehiro Inukai, Takaaki Toriyama, Atsushi Takahara, Hiroshi Jinnai and Susumu Kitagawa : Mixing of immiscible polymers using nanoporous coordination templates, Nature Communications, Vol.6, 7473, 2015. (Summary) The establishment of methodologies for the mixing of immiscible substances is highly desirable to facilitate the development of fundamental science and materials technology. Herein we describe a new protocol for the compatibilization of immiscible polymers at the molecular level using porous coordination polymers (PCPs) as removable templates. In this process, the typical immiscible polymer pair of polystyrene (PSt) and poly(methyl methacrylate) (PMMA) was prepared via the successive homopolymerizations of their monomers in a PCP to distribute the polymers inside the PCP particles. Subsequent dissolution of the PCP frameworks in a chelator solution affords a PSt/PMMA blend that is homogeneous in the range of several nanometers. Due to the unusual compatibilization, the thermal properties of the polymer blend are remarkably improved compared with the conventional solvent-cast blend. This method is also applicable to the compatibilization of PSt and polyacrylonitrile, which have very different solubility parameters. (Link to Publication Site) ● Publication site (DOI): 10.1038/ncomms8473 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 26130294 ● Summary page in Scopus @ Elsevier: 2-s2.0-84935100590 (DOI: 10.1038/ncomms8473, PubMed: 26130294, Elsevier: Scopus)
14.	Wenqian Chen, Satoshi Horike, Munehiro Inukai and Susumu Kitagawa : Study on a 2D layer coordination framework showing order-to-disorder phase transition by ionothermal synthesis, Polymer Journal, Vol.47, No.2, 141-145, 2015. (Link to Publication Site) ● Publication site (DOI): 10.1038/pj.2014.100 (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1520291855751449216 ● Summary page in Scopus @ Elsevier: 2-s2.0-84922325926 (DOI: 10.1038/pj.2014.100, CiNii: 1520291855751449216, Elsevier: Scopus)
15.	Daiki Umeyama, Satoshi Horike, Munehiro Inukai, Tomoya Itakura and Susumu Kitagawa : Reversible Solid-to-Liquid Phase Transition of Coordination Polymer Crystals, Journal of the American Chemical Society, Vol.137, No.2, 864-870, 2015. (Summary) The solid-to-liquid phase transition, a fundamental process commonly observed for various types of substances with significant potential for application, has been given little attention in the field of coordination polymers (CPs) despite the rich functionality of these compounds. In this article, we report the reversible solid-to-liquid phase transition of crystalline CPs. These CPs are composed of zinc ions, phosphate, and azoles, and a well-balanced composition, ionicity, and bond strength afford "melting" CPs. We examined the structure of one such melting framework in the liquid and glass states and found that the coordination bonds are not fully preserved in the liquid state but are re-formed in the glass state. As a demonstration, we fabricated, via phase transition, a thin film with an aligned crystal orientation and a monolith crystal of the CP. (Link to Publication Site) ● Publication site (DOI): 10.1021/ja511019u (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 25530162 ● Summary page in Scopus @ Elsevier: 2-s2.0-84921533844 (DOI: 10.1021/ja511019u, PubMed: 25530162, Elsevier: Scopus)
16.	Ryo Ohtani, Munehiro Inukai, Yuh Hijikata, Tetsuya Ogawa, Mikihito Takenaka, Masaaki Ohba and Susumu Kitagawa : Sequential Synthesis of Coordination Polymersomes, Angewandte Chemie International Edition, Vol.54, No.4, 1139-1143, 2015. (Summary) Novel organic-inorganic hybrid liposomes, so-called coordination polymersomes (CPsomes), with artificial domains that exhibit strong lateral cohesion were prepared by a three-step procedure that formed a coordinative interaction leading to a lipid bilayer. First, the lipophilic complex (dabco-C18)[Mn(N)(CN)4(dabco-C18)] (1; dabco-C18(+)=1,4-diazabicyclo[2,2,2]octane-(CH2)17-CH3 cation), was synthesized. 1 has a lipophilic alkyl tail part and a tetracyanometallate head group, which can be used for an expansion to two-dimensional coordination networks. Second, 1 and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine were mixed to prepare the liposomes. Finally, CPsomes were obtained by the addition of transition-metal ions (M) to form unilamellar faceted liposomes with plain CP raft domains with Mn-CN-M linkages. The concentration of 1 influences the size of the CP raft domains and the shape of the CPsomes. The synthesis of coordination polymers in lipid bilayers is a novel approach for the construction of artificial architectures as raft domains, for example, in cell membranes. (Keyword) coordination polymers liposomes nanostructures supramolecular chemistry (Link to Publication Site) ● Publication site (DOI): 10.1002/anie.201408101 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 25476115 ● Search Scopus @ Elsevier (PMID): 25476115 ● Search Scopus @ Elsevier (DOI): 10.1002/anie.201408101 (DOI: 10.1002/anie.201408101, PubMed: 25476115)
17.	S. Horike, K. Kadota, T. Itakura, Munehiro Inukai and S. Kitagawa : Synthesis of magnesium ZIF-8 from Mg(BH4)2, Dalton Transactions, Vol.44, No.34, 15107-15110, 2015. (Summary) Porous Mg(2-methyl imidazolate)2 (Mg-ZIF-8) was synthesised from Mg(BH4)2 as a precursor under an Ar atmosphere. It possesses an uncommon tetrahedral Mg2+-N coordination geometry that is stabilised by the formation of a framework, and it exhibits a Brunauer-Emmett-Teller surface area greater than 1800 m2 g-1. (Link to Publication Site) ● Publication site (DOI): 10.1039/C5DT01183C (Link to Search Site for Scientific Articles) ● Summary page in Scopus @ Elsevier: 2-s2.0-84939616018 (DOI: 10.1039/C5DT01183C, Elsevier: Scopus)
18.	Satoshi Horike, Wenqian Chen, Tomoya Itakura, Munehiro Inukai, Daiki Umeyama, Hiroyuki Asakura and Susumu Kitagawa : Order-to-disorder structural transformation of a coordination polymer and its influence on proton conduction, Chemical Communications, Vol.50, No.71, 10241-10243, 2014. (Summary) We observed an ordered-to-disordered structural transformation in a Cu(2+) coordination polymer and investigated its influence on the proton conductivity. The transformation generated highly mobile proton carriers in the structure. The resulting material exhibited a conductivity greater than 10(-2) S cm(-1) at 130 °C. The structural transformation and the conduction mechanism were investigated by EXAFS, TPD-MS and NMR. (Link to Publication Site) ● Publication site (DOI): 10.1039/c4cc04370g (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 25053211 ● Search Scopus @ Elsevier (PMID): 25053211 ● Search Scopus @ Elsevier (DOI): 10.1039/c4cc04370g (DOI: 10.1039/c4cc04370g, PubMed: 25053211)
19.	Munehiro Inukai, Satoshi Horike, Wenqian Chen, Daiki Umeyama, Tomoya Itakura and Susumu Kitagawa : Template-directed proton conduction pathways in a coordination framework, Journal of Materials Chemistry. A, Materials for Energy and Sustainability, Vol.2, No.27, 10404-10409, 2014. (Link to Publication Site) ● Publication site (DOI): 10.1039/C4TA01261E (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1039/C4TA01261E (DOI: 10.1039/C4TA01261E)
20.	D. Umeyama, S. Horike, Munehiro Inukai and S. Kitagawa : Integration of intrinsic proton conduction and guest-accessible nanospace into a coordination polymer, Journal of the American Chemical Society, Vol.135, No.30, 11345-11350, 2013. (Summary) We report the synthesis and characterization of a coordination polymer that exhibits both intrinsic proton conductivity and gas adsorption. The coordination polymer, consisting of zinc ions, benzimidazole, and orthophosphate, exhibits a degree of flexibility in that it adopts different structures before and after dehydration. The dehydrated form shows higher intrinsic proton conductivity than the original form, reaching as high as 1.3 x 10(-3) S cm(-1) at 120 degrees C. We found that the rearranged conduction path and liquid-like behavior of benzimidazole molecules in the channel of the framework afforded the high proton conductivity. Of the two forms of the framework, only the dehydrated form is porous to methanol and demonstrates guest-accessible space in the structure. The proton conductivity of the dehydrated form increases by 24 times as a result of the in situ adsorption of methanol molecules, demonstrating the dual functionality of the framework. NMR studies revealed a hydrogen-bond interaction between the framework and methanol, which enables the modulation of proton conductivity within the framework. (Link to Publication Site) ● Publication site (DOI): 10.1021/ja4051668 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 23829398 ● Search Scopus @ Elsevier (PMID): 23829398 ● Search Scopus @ Elsevier (DOI): 10.1021/ja4051668 (DOI: 10.1021/ja4051668, PubMed: 23829398)
21.	Yasuko Mito-oka, Satoshi Horike, Yusuke Nishitani, Tadao Masumori, Munehiro Inukai, Yuh Hijikata and Susumu Kitagawa : Siloxane D4 capture by hydrophobic microporous materials, Journal of Materials Chemistry. A, Materials for Energy and Sustainability, Vol.1, No.27, 7885-7888, 2013. (Link to Publication Site) ● Publication site (DOI): 10.1039/C3TA11217A (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1039/C3TA11217A (DOI: 10.1039/C3TA11217A)
22.	Y. Hijikata, S. Horike, M. Sugimoto, Munehiro Inukai, T. Fukushima and S. Kitagawa : Pore design of two-dimensional coordination polymers toward selective adsorption, Inorganic Chemistry, Vol.52, No.7, 3634-3642, 2013. (Summary) We have synthesized four porous coordination polymers (PCPs) using Zn(2+), 4,4'-sulfonyldibenzoate (sdb), and four types of dinitrogen linker ligands, 1,4-diazabicyclo[2,2,2]octane (dabco), 1,4-bis(4-pyridyl)benzene (bpb), 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine (bpt), and 4,4'-bipyridyl (bpy). The bent sdb ligands form a rhombic space connected by zinc paddle-wheel units to form a one-dimensional double chain, and each dinitrogen ligand linked the one-dimensional double chains. There are different assembled structures of two-dimensional sheets with the same connectivities between Zn(2+) and the organic ligands. [Zn2(sdb)2(dabco)]n (1) has a noninterpenetrated and noninterdigitated structure, [Zn2(sdb)2(bpb)]n (2) and [Zn2(sdb)2(bpt)]n (3) have interdigitated structures, and [Zn2(sdb)2(bpy)]n (4) has an interpenetrated structure. The length of the dinitrogen ligands dominated their assembled structures and flexibility, which influence the adsorption properties. The flexible frameworks of 2 and 3 provide different stepwise adsorption behaviors for CO2, CH4, C2H6, and C2H4 affected by their pore diameters and the properties of the gases. Their different adsorption properties were revealed by IR spectroscopy and X-ray analysis under a gas atmosphere. The framework of 4 possesses less flexibility and a smaller void space than the others and a negligible amount of CH4 was adsorbed; however, 4 can adsorb either C2H6 or C2H4 through the gate-opening phenomenon. Measurement of the solid-state (2)H NMR was also carried out to investigate the relationship between the framework structure and the dynamics of bpy with regard to the lower flexibility of 4. We have demonstrated a strategy to control the pore size and assembled structures toward selective adsorption properties of PCPs. (Link to Publication Site) ● Publication site (DOI): 10.1021/ic302006x (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 23496290 ● Search Scopus @ Elsevier (PMID): 23496290 ● Search Scopus @ Elsevier (DOI): 10.1021/ic302006x (DOI: 10.1021/ic302006x, PubMed: 23496290)
23.	S. Horike, Y. Kamitsubo, Munehiro Inukai, T. Fukushima, D. Umeyama, T. Itakura and S. Kitagawa : Postsynthesis modification of a porous coordination polymer by LiCl To enhance H+ transport, Journal of the American Chemical Society, Vol.135, No.12, 4612-4615, 2013. (Summary) A Ca(2+) porous coordination polymer with 1D channels was functionalized by the postsynthesis addition of LiCl to enhance the H(+) conductivity. The compound showed over 10(-2) S cm(-1) at 25 degrees C and 20 (Link to Publication Site) ● Publication site (DOI): 10.1021/ja3122872 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 23485151 ● Search Scopus @ Elsevier (PMID): 23485151 ● Search Scopus @ Elsevier (DOI): 10.1021/ja3122872 (DOI: 10.1021/ja3122872, PubMed: 23485151)
24.	Satoshi Horike, Masayuki Sugimoto, Kanokwan Kongpatpanich, Yuh Hijikata, Munehiro Inukai, Daiki Umeyama, Shinji Kitao, Makoto Seto and Susumu Kitagawa : Fe²⁺-based layered porous coordination polymers and soft encapsulation of guests via redox activity, Journal of Materials Chemistry. A, Materials for Energy and Sustainability, Vol.1, No.11, 3675-3679, 2013. (Link to Publication Site) ● Publication site (DOI): 10.1039/C3TA01414B (Link to Search Site for Scientific Articles) ● Search Scopus @ Elsevier (DOI): 10.1039/C3TA01414B (DOI: 10.1039/C3TA01414B)
25.	S. Noro, Y. Hijikata, Munehiro Inukai, T. Fukushima, S. Horike, M. Higuchi, S. Kitagawa, T. Akutagawa and T. Nakamura : Highly selective CO2 adsorption accompanied with low-energy regeneration in a two-dimensional Cu(II) porous coordination polymer with inorganic fluorinated PF6(-) anions, Inorganic Chemistry, Vol.52, No.1, 280-285, 2013. (Summary) High selectivity and low-energy regeneration for adsorption of CO(2) gas were achieved concurrently in a two-dimensional Cu(II) porous coordination polymer, [Cu(PF(6))(2)(4,4'-bpy)(2)](n) (4,4'-bpy = 4,4'-bipyridine), containing inorganic fluorinated PF(6)(-) anions that can act as moderate interaction sites for CO(2) molecules. (Keyword) Adsorption / Anions / Carbon Dioxide / Copper / Crystallography, X-Ray / Hydrocarbons, Fluorinated / Models, Molecular / Organometallic Compounds / Polymers / Porosity / Surface Properties (Link to Publication Site) ● Publication site (DOI): 10.1021/ic301823j (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 23249245 ● Search Scopus @ Elsevier (PMID): 23249245 ● Search Scopus @ Elsevier (DOI): 10.1021/ic301823j (DOI: 10.1021/ic301823j, PubMed: 23249245)
26.	Munehiro Inukai, S. Horike, D. Umeyama, Y. Hijikata and S. Kitagawa : Investigation of post-grafted groups of a porous coordination polymer and its proton conduction behavior, Dalton Transactions, Vol.41, No.43, 13261-13263, 2012. (Summary) We investigated the configuration of substituent groups that are post-synthetically bound to the pore surface in a porous coordination polymer. This study demonstrates the observations of orientation and coordination fashions of the grafted groups, which contribute towards improved proton conductivity in porous frameworks. (Keyword) Coordination Complexes/chemical synthesis/chemistry Histamine/chemistry Magnetic Resonance Spectroscopy Organic Chemicals/chemistry Polymers/*chemistry Porosity Protons Surface Properties (Link to Publication Site) ● Publication site (DOI): 10.1039/c2dt31836a (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 23007863 ● Search Scopus @ Elsevier (PMID): 23007863 ● Search Scopus @ Elsevier (DOI): 10.1039/c2dt31836a (DOI: 10.1039/c2dt31836a, PubMed: 23007863)
27.	D. Umeyama, S. Horike, Munehiro Inukai, T. Itakura and S. Kitagawa : Inherent proton conduction in a 2D coordination framework, Journal of the American Chemical Society, Vol.134, No.30, 12780-12785, 2012. (Summary) We synthesized a coordination polymer consisting of Zn(2+), 1,2,4-triazole, and orthophosphates, and demonstrated for the first time intrinsic proton conduction by a coordination network. The compound has a two-dimensional layered structure with extended hydrogen bonds between the layers. It shows intrinsic proton conductivity along the direction parallel to the layers, as elucidated by impedance studies of powder and single crystals. From the low activation energy for proton hopping, the conduction mechanism was found to be of the Grotthuss fashion. The hopping is promoted by rotation of phosphate ligands, which are aligned on the layers at appropriate intervals. (Link to Publication Site) ● Publication site (DOI): 10.1021/ja304693r (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 22783808 ● Search Scopus @ Elsevier (PMID): 22783808 ● Search Scopus @ Elsevier (DOI): 10.1021/ja304693r (DOI: 10.1021/ja304693r, PubMed: 22783808)
28.	S. Horike, K. Kishida, Y. Watanabe, Y. Inubushi, D. Umeyama, M. Sugimoto, T. Fukushima, Munehiro Inukai and S. Kitagawa : Dense coordination network capable of selective CO2 capture from C1 and C2 hydrocarbons, Journal of the American Chemical Society, Vol.134, No.24, 9852-9855, 2012. (Summary) We elucidated the specific adsorption property of CO(2) for a densely interpenetrated coordination polymer which was a nonporous structure and observed gas separation properties of CO(2) over CH(4), C(2)H(4), and C(2)H(6), studied under both equilibrium and kinetic conditions of gases at ambient temperature and pressure. (Link to Publication Site) ● Publication site (DOI): 10.1021/ja302043u (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 22667323 ● Search Scopus @ Elsevier (PMID): 22667323 ● Search Scopus @ Elsevier (DOI): 10.1021/ja302043u (DOI: 10.1021/ja302043u, PubMed: 22667323)
29.	S. Horike, D. Umeyama, Munehiro Inukai, T. Itakura and S. Kitagawa : Coordination-network-based ionic plastic crystal for anhydrous proton conductivity, Journal of the American Chemical Society, Vol.134, No.18, 7612-7615, 2012. (Summary) An ionic coordination network consisting of protonated imidazole and anionic one-dimensional chains of Zn(2+) phosphate was synthesized. The compound possesses highly mobile ions in the crystal lattice and behaves as an ionic plastic crystal. The dynamic behavior provides a proton conductivity of 2.6 x 10(-4) S cm(-1) at 130 degrees C without humidity. (Link to Publication Site) ● Publication site (DOI): 10.1021/ja301875x (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 22512400 ● Search Scopus @ Elsevier (PMID): 22512400 ● Search Scopus @ Elsevier (DOI): 10.1021/ja301875x (DOI: 10.1021/ja301875x, PubMed: 22512400)
30.	D. Umeyama, S. Horike, Munehiro Inukai, Y. Hijikata and S. Kitagawa : Confinement of mobile histamine in coordination nanochannels for fast proton transfer, Angewandte Chemie International Edition, Vol.50, No.49, 11706-11709, 2011. (Keyword) Anisotropy Histamine/chemistry Magnetic Resonance Spectroscopy Nanostructures/chemistry/ultrastructure Polymers/chemistry Porosity Protons (Link to Publication Site) ● Publication site (DOI): 10.1002/anie.201102997 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 21989965 ● Summary page in Scopus @ Elsevier: 2-s2.0-82455192767 (DOI: 10.1002/anie.201102997, PubMed: 21989965, Elsevier: Scopus)
31.	Munehiro Inukai, Y. Noda and K. Takeda : Nondestructive high-resolution solid-state NMR of rotating thin films at the magic-angle, Journal of Magnetic Resonance, Vol.213, No.1, 192-195, 2011. (Summary) We present a new approach to nondestructive magic-angle spinning (MAS) nuclear magnetic resonance (NMR) for thin films. In this scheme, the sample put on the top of a rotor is spun using the conventional MAS system, and the NMR signals are detected with an additional coil. Stable spinning of disk-shaped samples with diameters of 7 mm and 12 mm at 14.2 and 7 kHz are feasible. We present 7Li MAS NMR experiments of a thin-film sample of LiCoO2 with a thickness of 200 nm. Taking advantage of the nondestructive feature of the experiment, we also demonstrate ex situ experiments, by tracing conformation change upon annealing for various durations. This approach opens the door for in situ MAS NMR of thin-film devices as well. (Keyword) Electrodes Lithium/chemistry Lithium Carbonate/chemistry Magnetic Resonance Spectroscopy/instrumentation/*methods (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jmr.2011.09.013 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 21958755 ● Search Scopus @ Elsevier (PMID): 21958755 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jmr.2011.09.013 (DOI: 10.1016/j.jmr.2011.09.013, PubMed: 21958755)
32.	Munehiro Inukai and K. Takeda : Double-resonance magic angle coil spinning, Journal of Magnetic Resonance, Vol.202, No.2, 274-278, 2010. (Summary) We present an extension of magic angle coil spinning (MACS) solid-state NMR spectroscopy to double-resonance experiments, enabling implementation of powerful double-resonance solid-state NMR methodologies including cross polarization, proton decoupling, and two-dimensional correlation spectroscopy etc., while still enjoying the merits that are intrinsic to MACS, such as high concentration sensitivity, eliminated magnetic susceptibility-induced field distortion, and an easy-to-use approach with the conventional and widespread hardware. (Keyword) Carbon Isotopes Magnetic Resonance Spectroscopy/*methods Nitrogen Isotopes Protons Signal Processing, Computer-Assisted Silicon Sodium Isotopes (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jmr.2009.10.011 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 19926320 ● Search Scopus @ Elsevier (PMID): 19926320 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jmr.2009.10.011 (DOI: 10.1016/j.jmr.2009.10.011, PubMed: 19926320)
33.	M. Fukuchi, Munehiro Inukai, K. Takeda and K. Takegoshi : Double-acquisition: utilization of discarded coherences in a 2D separation experiment using the States method, Journal of Magnetic Resonance, Vol.194, No.2, 300-302, 2008. (Summary) We propose a new data-acquisition scheme for 2D separation experiments to save the spectrometer time by 1/2. This scheme, referred to as a double-acquisition scheme, is applicable to most of separation experiments with the hypercomplex time-domain data-acquisition scheme (the States method) for data collection. (Keyword) Algorithms Information Storage and Retrieval/methods Magnetic Resonance Spectroscopy/methods Sample Size Signal Processing, Computer-Assisted (Link to Publication Site) ● Publication site (DOI): 10.1016/j.jmr.2008.07.004 (Link to Search Site for Scientific Articles) ● PubMed @ National Institutes of Health, US National Library of Medicine (PMID): 18667347 ● Search Scopus @ Elsevier (PMID): 18667347 ● Search Scopus @ Elsevier (DOI): 10.1016/j.jmr.2008.07.004 (DOI: 10.1016/j.jmr.2008.07.004, PubMed: 18667347)
34.	Munehiro Inukai and Kazuyuki Takeda : Studies on multiple-quantum magic-angle-spinning NMR of half-integer quadrupolar nuclei under strong rf pulses with a microcoil, Concepts in Magnetic Resonance. Part B, Magnetic Resonance Engineering, Vol.33B, No.2, 115-123, 2008. (Link to Publication Site) ● Publication site (DOI): 10.1002/cmr.b.20110 (Link to Search Site for Scientific Articles) ● Summary page in Scopus @ Elsevier: 2-s2.0-54949132920 (DOI: 10.1002/cmr.b.20110, Elsevier: Scopus)

Review, Commentary:

1.	Munehiro Inukai : 固体NMRによるCP/MOFの静的・動的構造解析, NMRによる有機材料分析とその試料前処理, 639-647, Sep. 2021.
2.	Munehiro Inukai : 錯体結晶の固体NMR, Bull. Nuc. Magn. Reson. Soc. Jpn., Vol.10, 108-112, Nov. 2019. (Link to Search Site for Scientific Articles) ● CiNii @ National Institute of Informatics (CRID): 1010568455823854848 (CiNii: 1010568455823854848)

Proceeding of International Conference:

1.	Haruki Sato, Koichiro Miyanishi, Makoto Negoro, Akinori Kagawa, Koichi Nakamura and Munehiro Inukai : Hyperpolarized NMR for cocrystals at room temperature using photoexcited triplet-states electron spins, The 8th International Forum on Advanced Technologies 2022, Mar. 2022.
2.	Munehiro Inukai, Yusuke Nishiyama, Susumu Kitagawa and Satoshi Horike : Glass-phase coordination polymer displaying proton conductivity and guest-accessible porosity, 1st International symposium Hydrogenomics, Jan. 2020.
3.	Munehiro Inukai, Takuya Kurihara, Yasuto Noda and Koichi Nakamura : Dynamics of carbon dioxides in a metal-organic framework under high pressure, EUROISMAR 2019, Aug. 2019.

Proceeding of Domestic Conference:

1.	Koichi Nakamura, 田中康照, Munehiro Inukai and Toshihiro Moriga : チタン酸リチウムの局所構造とリチウムイオン運動における酸素欠損およびミリングの効果, 2023年春季大会プログラム講演概要集, Mar. 2023. (Summary) Li₄Ti₅O₁₂(LTO)はリチウムイオン2次電池の負極材料として注目されている．本研究ではメカニカルミリング法および酸素欠損にともなう構造変化，電子状態，およびLi⁺イオンの運動状態の変化について，粉末XRD，XPS，輸送特性などの結果から議論した．
2.	田中康照, Koichi Nakamura, Munehiro Inukai and Toshihiro Moriga : チタン酸リチウムの電気伝導度における酸素欠損およびミリング効果, 第48回固体イオニクス討論会講演要旨集, 196-197, Dec. 2022. (Summary) Li₄Ti₅O₁₂ (LTO) has been attracting attention as an anode material for lithium ion batteries due to its structural stability and good cycle characteristics. However, the electrical conductivity of LTO is low because of its insulating ionic crystal structure. In this study, we aimed to improve the ionic conductivity of LTO by forming lattice defects in the LTO crystal, which would be advantageous for ionic diffusion, using the mechanical milling method. Fabricating oxygen deficient LTOs was also carried out for an enhancement of the electronic conduction. Their modifications to LTO resulted in different effects of the ionic and electronic conductivity of LTO. They were analyzed and discussed by powder X-ray diffraction (XRD) and electrical conductivity measurements.
3.	金子宗平, 栗原拓也, 水野元博, Koichi Nakamura and Munehiro Inukai : 多孔性配位高分子における二酸化炭素と水の動的挙動と競争吸着, 第61回NMR討論会, Nov. 2022.
4.	佐藤晴紀, 宮西孝一郎, 根来誠, 香川晃徳, 西山祐介, Koichi Nakamura and Munehiro Inukai : 共晶法による生体分子のTriplet DNP, 第61回NMR討論会, Nov. 2022.
5.	Koichi Nakamura, 田中康照, 富本健介, Munehiro Inukai and Toshihiro Moriga : M-Ti 酸化物(M=Na, Li)の局所構造変化と電気伝導挙動, 日本物理学会2022年秋季大会講演概要集, Sep. 2022. (Summary) Na2Ti3O7(NTO)やLi4Ti5O12(LTO)はナトリウムイオン二次電池やリチウムイオン2 次電池の電極材料として注目されている．本研究ではメカニカルミリング法によって生じる構造変化と伝導挙動の変化について，粉末XRD，電気伝導度やNMR を用いることで議論した．
6.	Munehiro Inukai : 共晶・混晶のトリプレットDNP, DNP研究会, Jul. 2022.
7.	安部聖竜, 佐藤晴紀, 宮西孝一郎, 根来誠, 香川晃徳, Koichi Nakamura and Munehiro Inukai : 室温核スピン超偏極を可能とする共晶の構造解析, 日本化学会第102回春季年会, Mar. 2022.
8.	佐藤晴紀, 宮西孝一郎, 根来誠, 香川晃徳, Koichi Nakamura and Munehiro Inukai : 光励起三重項状態の電子スピンを用いた混晶の室温核スピン超偏極, 日本化学会第102回春季年会, Mar. 2022.
9.	田中康照, Munehiro Inukai, Toshihiro Moriga, 河村純一 and Koichi Nakamura : チタン酸リチウムのミリングにともなう電気伝導挙動の変化, 第47回固体イオニクス討論会講演要旨集, 156-157, Dec. 2021. (Summary) 近年，リチウムイオン電池は，高エネルギー密度で軽量化が可能なため小型電池や電気自動車や電力貯蔵機器などの大型デバイス用の電池への利用も期待されている．リチウムイオン電池の負極材料として注目されているLi₄Ti₅O₁₂(LTO) は，構造安定性や良好なサイクル特性により注目されている．しかし， LTO は絶縁性のイオン結晶であるため電気伝導度が低い．本研究では，メカニカルミリング法を用いて LTO 結晶内にイオン拡散に有利になると考えられる格子欠陥を形成することなどにより，イオン伝導の向上を目指した．また，これらを粉末 X 線回折( XRD ，電気伝導度測定，輸率測定を行い，ミリング時間の変化における結晶構造と電気伝導挙動の変化を議論した．
10.	Koichi Nakamura, 富本健介, Munehiro Inukai and Toshihiro Moriga : チタン酸ナトリウムの局所構造とイオン運動におけるミリング効果, 日本物理学会2021年秋季大会講演概要集, Sep. 2021. (Summary) Na₂Ti₃O₇(NTO)はNa⁺イオン二次電池の負極材料として注目されている．本研究ではメカニカルミリング法によって生じる構造変化と伝導挙動の変化について，粉末XRD，電気伝導度やNMRを用いることで議論した．
11.	Koichi Nakamura, 富本健介, Munehiro Inukai and Toshihiro Moriga : チタン酸ナトリウムの局所構造と電気伝導におけるミリング効果, 日本物理学会第76回年次大会講演概要集, Mar. 2021. (Summary) ナトリウムイオン2次電池の負極材料としてのチタン酸ナトリウム(NTO)は電子伝導性の向上のための取り組みが進められている．NTOにおける電気伝導挙動を明らかにするために，メカニカルミリング法を用いて結晶構造中に構造擾乱を誘起することで局所的に格子ひずみを導入し，局所構造の変化に対する伝導挙動の変化を電気伝導度測定と⁷Li-NMR測定の結果を中心に議論した．
12.	富本健介, Munehiro Inukai, Toshihiro Moriga, 河村純一 and Koichi Nakamura : Na₂Ti₃O₇の局所構造と伝導挙動におけるミリング効果と置換効果, 第46回固体イオニクス討論会講演要旨集, 126-127, Dec. 2020. (Summary) 次世代ナトリウムイオン2次電池の負極材料として期待されるチタン酸ナトリウム(NTO)における電気伝導挙動を明らかにするために，メカニカルミリング法を用いて結晶構造中に構造擾乱を誘起することで局所的に格子ひずみを導入するとともにナトリウムをイオン半径の異なるリチウムに置換し，局所構造の変化に対する伝導挙動の変化を電気伝導度測定の結果を議論した．ミリング処理により結晶構造内にひずみなど擾乱が導入されたことが分かった．電気伝導度測定の結果からミリングにともない活性化エネルギーは0.9eVから0.5eV程度にまで低下し，電気伝導度が向上することが明らかになった．²³Na MAS-NMR測定の結果から，ミリングによりNa(2)サイトから新たな準安定なサイトの生成が示唆され，また活性化エネルギーも低下することが明らかになった．
13.	Munehiro Inukai : Rotation of pillar ligands of MOFs and solid-state NMR analyses, 錯体化学会第70回討論会, Sep. 2020.
14.	富本健介, Munehiro Inukai, Toshihiro Moriga, 桑田直明, 河村純一 and Koichi Nakamura : チタン酸ナトリウムの結晶構造と伝導挙動におけるリチウム置換とミリングの効果, 日本物理学会2020年秋季大会講演概要集, Sep. 2020. (Summary) 次世代ナトリウムイオン2次電池の負極材料として期待されるチタン酸ナトリウム(NTO)における電気伝導挙動を明らかにするために，メカニカルミリング法を用いて結晶構造中に構造擾乱を誘起することで局所的に格子ひずみを導入するとともにナトリウムをイオン半径の異なるリチウムに置換し，局所構造の変化に対する伝導挙動の変化を電気伝導度測定の結果を議論した．ミリング処理により結晶構造内にひずみなど擾乱が導入されたことが分かった．電気伝導度測定の結果からミリングにともない活性化エネルギーは0.9eVから0.5eV程度にまで低下し，電気伝導度が向上することが明らかになった．
15.	Koichi Nakamura, 田中康照, Munehiro Inukai, Toshihiro Moriga, 桑田直明 and 河村純一 : チタン酸リチウムの局所構造とLi⁺イオン運動におけるミリング効果, 日本物理学会第75回年次大会講演概要集, Mar. 2020. (Summary) リチウムイオン2次電池の負極材料としてのスピネル型チタン酸リチウム(LTO)はLiの挿入脱離反応において体積膨張率が小さいことからひずみの影響を受けにくくサイクル特性が良いとされるが，電子伝導性の向上のための取り組みが進められている．LTOにおける電気伝導挙動を明らかにするために，メカニカルミリング法を用いて結晶構造中に構造擾乱を誘起することで局所的に格子ひずみを導入し，局所構造の変化に対する伝導挙動の変化を電気伝導度測定と⁷Li-NMR測定の結果を中心に議論した．
16.	Munehiro Inukai : ガラス状プロトン伝導性配位高分子の合成と NMR 解析, 第66回固体NMR・材料フォーラム, Dec. 2019.
17.	Koichi Nakamura, Munehiro Inukai, Toshihiro Moriga, 桑田直明 and 河村純一 : Li-Ti系酸化物の局所構造変化とLi⁺イオンの運動状態, 第45回固体イオニクス討論会講演要旨集, 2-3, Nov. 2019. (Summary) Local structure and Li+ ion motion in spinel Li-Ti oxides (LTO) have been studied with complex impedance and broadband NMR techniques. XRD profiles of LTO milled showed weakening and broadening of reflection peaks because of local lattice distortions in LTO. LTO milled for 10 h showed lower activation energy in conductivity compared to non-milled sample. 7Li NMR spectra of LTO milled showed characteristic changes with temperature and milling, implying that distinct Li+ ion motions would develop in the LTO system.
18.	Munehiro Inukai, 栗原拓也, 野田泰斗 and Koichi Nakamura : 高圧環境下における配位高分子内部の二酸化炭素の運動, 第58回 NMR討論会, Nov. 2019.
19.	Munehiro Inukai : 錯体結晶の固体NMR, 第58回 NMR討論会, Nov. 2019.
20.	Koichi Nakamura, 富本健介, Munehiro Inukai, Toshihiro Moriga, 桑田直明 and 河村純一 : チタン酸リチウムにおける局所的な構造擾乱とリチウムイオンの運動状態, 日本物理学会2019年秋季大会講演概要集, Sep. 2019. (Summary) リチウムイオン2次電池の負極材料としてのスピネル型チタン酸リチウム(LTO)はLiの挿入脱離反応において体積膨張率が小さいことからひずみの影響を受けにくくサイクル特性が良いとされるが，電子伝導性は高くなく伝導性向上のための取り組みが進められている．LTOにおける電気伝導挙動を明らかにするために，メカニカルミリング法を用いて結晶構造中に構造擾乱を誘起することで局所的に格子ひずみを導入し，局所構造の変化に対する伝導挙動の変化を電気伝導度測定と7Li-NMR測定の結果を議論した．ミリング処理によりXRDパターンは拡がり，回折強度の大きく減少したことからミリングにより結晶構造内にひずみなど擾乱が導入されたことが分かった．ミリングされた試料のstatic NMRスペクトルにはLi+イオンの運動状態を反映した2つのスペクトルが重畳して見られる．運動状態にあるLi⁺イオンの割合がミリング時間の増加にしたがい大きく増大することが分かった．ニオブ酸リチウムでは最大で10%程度のLi⁺イオンが運動状態に移るが，LTOでは10hミリングで20%程度のLi+イオンが運動状態にあると考えられる．
21.	Koichi Nakamura, Kensuke Tomimoto, Munehiro Inukai, Toshihiro Moriga, 桑田直明 and 河村純一 : Local distorted structure and ion diffusion in transition metal oxides, 第22回超イオン導電体物性研究会講演要旨集, 97-102, May 2019. (Summary) 7Li NMR and electrical conductivity measurements have been performed to study milling effects on ionic motion and local structure in lithium transition-metal oxides, LiNbO₃, LiTaO₃, Li-doped AgNbO₃, and Li-Ti oxide. Mechanical milling technique successfully induced lattice distortion/defects into their crystal structure. The motional states of Li⁺ ion with relatively low activation energy is realized by exposing to a moderate milling process in these systems. Instability of Li sites would be strongly connected with local lattice distortion and defects, and it would be useful for controlling Li⁺ ionic motion in oxides.
22.	Munehiro Inukai, 栗原拓也, 野田泰斗, Akira Kikkawa and Koichi Nakamura : 高圧ガス雰囲気下のその場高分解能固体NMR, 日本化学会第99春季年会, Mar. 2019.
23.	Koichi Nakamura, Munehiro Inukai, Toshihiro Moriga, 桑田直明 and 河村純一 : ミリングによるLi₄Ti₅O₁₂の結晶構造と電気伝導挙動の変化, 日本物理学会第74回年次大会講演概要集, Mar. 2019. (Summary) リチウムイオン2次電池の負極材料としてのスピネル型Li₄Ti₅O₁₂(LTO)はLiの挿入脱離反応において体積膨張率が小さいことからひずみの影響を受けにくくサイクル特性が良いとされるが，電子伝導性は高くなく伝導性向上のための取り組みが進められている．LTOにおける電気伝導挙動を明らかにするために，メカニカルミリング法を用いて結晶構造中に構造擾乱を誘起することで局所的に格子ひずみを導入し，その際の局所構造の変化に対する伝導挙動の変化を調べた．LTOの複素抵抗率の虚部𝜌 の周波数依存性にはデバイ型緩和の振る舞いが見られ，その周波数依存性から，ミリングにより活性化エネルギーが低下することが分かった．
24.	Koichi Nakamura, Munehiro Inukai and Toshihiro Moriga : Li₄Ti₅O₁₂の局所構造の擾乱と伝導挙動の変化, 第44回固体イオニクス討論会講演要旨集, 100-101, Dec. 2018. (Summary) Local structure and electrical resistivity of spinel Li₄Ti₅O₁₂ (LTO) have been studied with a complex impedance technique. XRD profile of LTO exposed to milling indicated weakening and broadening of reflection peaks, implying that lattice disturbance is caused in the crystal structure. The temperature dependence of the imaginary resistivity of LTO exposed to 10 h milling yielded low activation energy of 0.31 eV. This means that lattice disturbance induced in 10 h milling LTO would effectively cause lowering of the activation energy.
25.	Munehiro Inukai, 堀毛悟史 and 西山裕介 : プロトン伝導経路とゲスト分子吸着サイトを両立する配位高分子, 第44回固体イオニクス討論会, Dec. 2018.
26.	Munehiro Inukai, 堀毛悟史 and 西山裕介 : プロトン伝導経路とゲスト分子吸着サイトを両立する配位高分子の合成と構造解析, 第57回NMR討論会, Sep. 2018.
27.	Koichi Nakamura, 竹内智史, Munehiro Inukai, Yu Kawasaki, Toshihiro Moriga, 桑田直明 and 河村純一 : Na系遷移金属酸化物における電気伝導のNa組成依存性, 日本物理学会第73回年次大会講演概要集, Mar. 2018. (Summary) Na_xCoO₂をはじめとする層状Na遷移金属酸化物は，リチウムイオン二次電池に代わる次世代二次電池の正極材料として注目されている．Na_xMO₂ (M=Co, Cr)に着目し，電気伝導度と²3Na 核のスピン-格子緩和時間T₁の温度依存性から，Na⁺イオンの運動状態や局所構造について議論した．電気伝導度の温度依存性からNa_xCoO₂においてx=1, 0.9, 0.8に対して，それぞれ1.15eV，0.98eV，0.76eVとなり，Na_xCo_{2}O₂での活性化エネルギー(x=0.8で0.39eV，x=0.5で0.37eV)に比べて大きな値を示した．Na_xCrO₂のNa層内でのキャリアホッピング障壁が大きく，伝導度がNa_xCoO₂に比べ小さい一因と考えられる．
28.	Munehiro Inukai, 田村優実, 堀毛悟史, 樋口雅一, 北川進 and Koichi Nakamura : Storage and dynamics of CO2 into porous coordination polymer controlled by ligand dynamics, 日本化学会第98春季年会, Mar. 2018.
29.	Munehiro Inukai, 高木翼 and Koichi Nakamura : 構造欠陥を利用したプロトン伝導性配位高分子, 第43回固体イオニクス討論会, Dec. 2017.
30.	竹内智史, Koichi Nakamura, Munehiro Inukai, Yu Kawasaki, Toshihiro Moriga, 桑田直明 and 河村純一 : Na_xMO₂(M=Co,Cr)の電気伝導と局所構造変化, 第43回固体イオニクス討論会, 4-5, Dec. 2017. (Summary) Layered oxides such as NaxMO2 (M = Co, Cr) have been studied as electrodes for replacing the lithium ion batteries. The relaxation time T1 of 23Na nucleus in Na0.8CoO2 decreased in the range from 180 K to 300 K and increased above 300 K. Temperature dependence of Electrical conductivity NaxCoO2 and NaxCrO2 shows that electric conduction of NaxCoO2 becomes larger than that of NaxCrO2.These results suggest that the crystal structure of NaxCoO2 becomes locally disordered. It is considered that the crystal structure of NaxCoO2 is unstable, and related to the improvement Na+ ion diffusion.
31.	Munehiro Inukai : 配位高分子の固体NMR, 第62回固体NMR・材料フォーラム, Oct. 2017.
32.	Koichi Nakamura, Satoshi Takeuchi, Munehiro Inukai, Yu Kawasaki and Toshihiro Moriga : Na系遷移金属酸化物における局所構造とNa⁺イオンの運動状態, 日本物理学会2017年秋季大会講演概要集, Sep. 2017. (Summary) Na_xCoO₂をはじめとする層状酸化物は，リチウムイオン二次電池に代わる次世代型二次電池の正極材料として注目され，近年活発に研究されている．Na_xCoO₂におけるイオンの運動状態に着目し，電気伝導度測定やNMR(核磁気共鳴)法を用いた²³Naにおけるスピン-格子緩和時間T₁の結果から，Na⁺イオンの運動状態や局所構造について議論した．250K以下での23Na-NMR スペクトルは1本の中心線を示すが，室温以上ではCo副格子の局所的な変化にともなう電場勾配の変化の影響で四重極相互作用の2次の粉末図形スペクトルを示したが，700Kまでの高温度域でもスペクトルの先鋭化は見られなかった．Na_xCrO₂の電気伝導度における活性化エネルギーはNa組成に依存し0.7∼1eVと見積もられ，Na_xCoO₂(∼0.4eV)に比べ大きい．NaxCrO2の四重極相互作用はNa_xCoO₂より小さく，四重極相互作用の1次の粉末図形が観測された．
33.	Koichi Nakamura, Hiroaki Ito, Munehiro Inukai, Toshihiro Moriga, 岩井良樹, 桑田直明 and 河村純一 : Changes of local structure and Li⁺ ion motion in LiMPO₄ (M=Fe, Mn), 第20回超イオン導電体物性研究会講演要旨集, 71-74, Jul. 2017. (Summary) Olivine-type LiMPO₄ (M=Fe and Mn) has been studied as a cathode material for lithium ion secondary batteries. The XRD peak broadening and peak shift of LiFePO₄ at high temperatures suggest that the crystal structure around Li sites becomes locally disordered. The NMR line width and the spin-lattice relaxation time, T₁, for ⁷Li nucleus of LiFePO₄ depended on temperature from 550K to 700K, while those of LiMnPO₄ did not show a remarkable temperature dependence up to 700K. The results imply that a local structural change of LiFePO₄ at high temperatures is related to the motion of a part of Li⁺ ions.
34.	Munehiro Inukai : 配位高分子のダイナミクスとプロトン伝導能, 第1 回有機・バイオイオニクス研究会・第67 回固体イオニクス研究会, Mar. 2017.
35.	竹内智史, Munehiro Inukai, Yu Kawasaki, Toshihiro Moriga and Koichi Nakamura : Na_xCoO₂の電気伝導と局所構造変化, 日本物理学会第72回年次大会講演概要集, Mar. 2017.
36.	Munehiro Inukai : 固体NMRによる多孔性配位高分子のダイナミクス解析と機能発現, 1. 環境調和セラミック材料研究会名工大-FS調査共同研究支援事業共同研究講演会, Jan. 2017.
37.	Hiroaki Ito, Munehiro Inukai, Toshihiro Moriga, 岩井良樹, 桑田直明, 河村純一 and Koichi Nakamura : LiMPO₄(M=Fe, Mn, Co)における高温でのイオン運動と局所構造の変化, 第42回固体イオニクス討論会, 100-101, Dec. 2016. (Summary) Olivine type lithium iron phosphates have been studied as a cathode material for lithium ion secondary batteries. The NMR line widths and spin-lattice relaxation time T1 of 7Li nucleus in LiFePO₄ changed from 550K to 700K, while those of LiMnPO₄ and LiCoPO₄ did not show the remarkable temperature dependence. The peak broadening of XRD pattern of LiFePO₄ at high temperatures suggests that the crystal structure around Li sites becomes locally disordered. It is considered that these situations would stimulate Li⁺ ion dynamics related to changes of the NMR line width and T₁ at high temperatures.
38.	Munehiro Inukai : 多孔性配位高分子の多核NMR, 16-2 NMR 研究会最新の多核NMR, Dec. 2016.
39.	田村優実, Munehiro Inukai and Koichi Nakamura : 多孔性配位高分子の空隙に物理吸着させた気体分子のダイナミクス, 第55回 NMR討論会, Nov. 2016.
40.	Munehiro Inukai, 田村優実 and Koichi Nakamura : 多孔性配位高分子内部の架橋配位子と二酸化炭素のダイナミクス, 第60回固体NMR・材料フォーラム, Oct. 2016.
41.	Koichi Nakamura, Satoshi Takeuchi, Munehiro Inukai and Toshihiro Moriga : NaCoO₂のNa組成とNaサイト周辺の局所構造, 日本物理学会2016年秋季大会講演概要集, Sep. 2016. (Summary) Na_xCoO₂をはじめとする層状酸化物は，リチウムイオン二次電池に代わる次世代型二次電池の正極材料として注目され，近年活発に研究されている．Na_xCoO₂におけるイオンの運動状態に着目し，電気伝導度測定やNMR(核磁気共鳴)法を用いた²³Naにおけるスピン-格子緩和時間T₁の結果から，Na⁺イオンの運動状態や局所構造について議論した．250K以下での23Na-NMR スペクトルは1本の中心線を示すが，室温以上ではCo副格子の局所的な変化にともなう電場勾配の変化の影響で四重極相互作用の2次の粉末図形スペクトルを示した．室温以上700Kまでの高温度域でもスペクトルの先鋭化は見られず，四重極周波数は温度の上昇にともなって徐々に増大した．
42.	Koichi Nakamura, Munehiro Inukai, Toshihiro Moriga, 岩井良樹, 桑田直明 and 河村純一 : 局所構造の擾乱にともなうニオブ酸ナトリウムのイオン伝導挙動の変化, 第19回超イオン導電体物性研究会講演要旨集, 79-82, Jun. 2016. (Summary) ²³Na NMR and electrical conductivity measurements have been performed to study milling effects on ion conducting behavior and local structure of NaNbO3 exposed to milling. A complex MAS NMR spectrum attributed to Na(1) and Na(2) sites was dependent on milling time as well as XRD patterns. It was found that inequivalent local structures around Na sites of NaNbO3 are disturbed severely by milling. This structural change is considered to be connected with the Na+ ion conductivity with the activation energy of 0.3~0.4 eV because narrowing in the NMR line widths and changes in electrical conductivity were observed at high temperatures.
43.	Munehiro Inukai, 田村優実 and Koichi Nakamura : 規則性ナノ空間に閉じ込められた二酸化炭素の特異的なダイナミクス, 第59回固体NMR・材料フォーラム, May 2016.
44.	Koichi Nakamura, Hiroaki Ito, Munehiro Inukai, Yu Kawasaki, Toshihiro Moriga, 桑田直明, 岩井良樹 and 河村純一 : オリビン型LiMPO₄(M=Fe, Mn)におけるLi⁺イオンの運動状態の変化, 日本物理学会第71回年次大会講演概要集, Mar. 2016. (Summary) オリビン系LiMnPO₄(LMO)とLiFePO₄(LFO)，特にLFO はこれまでの正極材料と同等な電極性能を有することから注目されている．LMO とLFO のLi⁺イオン拡散挙動と結晶構造の変化について，NMR測定の結果から議論した．LFOの線幅は550K以上で先鋭化を示し，Li⁺イオンの運動の存在を示唆しているが，600K以上では緩やかな温度依存性を示した．一方，LFOの600K以上でのXRDパターンはLi欠損したものと同様に，回折線の強度と半値幅などに変化が見られた．Li⁺イオンのdisorderやFeの酸化にともなう結晶構造の変化がLi⁺イオン運動の発現に関係していると考えられる．
45.	Koichi Nakamura, Hiroaki Ito, Masanori Tamura, Munehiro Inukai, Yu Kawasaki, Toshihiro Moriga, 岩井良樹, 桑田直明 and 河村純一 : LiMPO₄(M=Fe, Mn)における局所構造とLi⁺イオンの運動状態, 第41回固体イオニクス討論会, 16-17, Nov. 2015. (Summary) NMR spectra and spin-lattice relaxation time, T^-1, for ⁷Li nucleus have been probed to study the local structure and Li⁺ ion dynamics in olivine-type LiMPO₄ (M=Fe, Mn). Antimagnetic spin correlation was dominant at low temperatures in the NMR spectrum and relaxation time of both samples, while changes in the line width and relaxation time were observed in LiFePO₄ above 550K. This would be related with the Li⁺ ion motion in LiFePO₄ at high temperatures.
46.	Munehiro Inukai, 板倉智也, 堀毛悟史 and 北川進 : Encapsulating mobile proton carriers into structural defects in dense metal-organic framework: high anhydrous proton conduction and fuel cell appplication, 第41回固体イオニクス討論会講演要旨集, Nov. 2015.
47.	Koichi Nakamura, Hiroaki Ito, Masanori Tamura, Munehiro Inukai, Yu Kawasaki, Toshihiro Moriga, 桑田直明, 岩井良樹 and 河村純一 : オリビン系リチウム遷移金属酸化物における高温でのリチウムイオンの運動状態, 日本物理学会2015年秋季大会講演概要集, Sep. 2015. (Summary) オリビン系LiMnPO₄(LMO)とLiFePO₄(LFO)，特にLFO はこれまでの正極材料と同等な電極性能を有することから注目されている．LMO とLFO のLi⁺イオン拡散挙動と結晶構造の変化について，NMR測定の結果から議論した．LMOでは⁷Li核のNMRスペクトルの室温以上の温度依存性に変化は見られなかったが，LFOの[7}Li核のNMRスペクトルの線幅は帯磁率にスケールするとともに，550K以上でLi⁺イオンの運動によると考えられる先鋭化を観測した．この温度域でLiFePO₄のLi核の磁化の回復曲線は単一指数関数に従うが，LiMnPO₄では従わなかった．
48.	Koichi Nakamura, 村上明 and Munehiro Inukai : 非線形超音波共鳴を用いた緩和現象の間接的観測, 第18回超イオン導電体物性研究会講演要旨集, 45-48, Jul. 2015. (Summary) Non-linear ultrasonic resonance measurement with acoustic echo (phonon echo) has been applied to detect indirectly ion motion in solids. The relaxation time, T₂, of SiO₂ particles with a small amount of LiNbO₃ particles was different from that of SiO₂ particles above 600K. The T₂ values were significantly dependent on temperature. A simple Debye model was applied to interpret its temperature dependence, and derived thermal activation energy would be related to an activation energy for the Li⁺ ion motion These results suggest that the indirect measurement is available to detect the Li⁺ ion motion in solids.
49.	Munehiro Inukai, Tomoya Itakura, Satoshi Horike and Susumu Kitagawa : EnEnhanced proton conduction in coordination polymers via encapsulating mobile phosphoric acid into structural defects, 第18回超イオン導電体物性研究会講演要旨集, 9-12, Jul. 2015.
50.	Koichi Nakamura, Kazuma Fujitsugu, Masanori Tamura, Akira Murakami, Munehiro Inukai, Toshihiro Moriga, Yu Kawasaki, 岩井良樹, 桑田直明 and 河村純一 : オリビン系リチウム遷移金属酸化物の局所構造とリチウムイオンの運動状態, 日本物理学会第70回年次大会(2015 年)概要集, 1541, Mar. 2015. (Summary) オリビン系LiMnPO₄(LMO)とLiFePO₄(LFO)，特にLFO はこれまでの正極材料と同等な電極性能を有することから注目されている．LMO とLFO のLi⁺イオン拡散挙動と結晶構造の変化について，NMR測定の結果から議論した．LMOでは⁷Li核のNMRスペクトルの室温以上の温度依存性に変化は見られなかったが，LFOの[7}Li核のNMRスペクトルの線幅は帯磁率にスケールするとともに，550K以上でLi⁺イオンの運動によると考えられる先鋭化を観測した．デバイ型の緩和モデルによるLi⁺イオンの拡散の活性化エネルギーは室温以下のμSR測定から得られたものより大きなものであった．

Et cetera, Workshop:

1.	Munehiro Inukai : 共晶を利用した生体分子の室温DNP, 金沢固体NMRセミナー2022, Jan. 2023.
2.	Munehiro Inukai : ゲスト分子吸着能を示すガラス状プロトン伝導性配位高分子, 金沢固体NMRセミナー2019, Jan. 2020.
3.	Munehiro Inukai : Storage and dynamics of gas molecules into porous coordination polymer, 1. 1st India-Japan NMR workshop, Jun. 2018.
4.	Munehiro Inukai : 多孔性配位高分子に吸着させた気体分子の固体NMR解析, NIMS微細構造解析プラットフォーム 2017年度地域セミナー, Feb. 2018.

Report:

1.	Koichi Nakamura, Munehiro Inukai and 河村純一 : 多核NMR による酸化物の局所構造変化とイオン拡散挙動に関する研究, 物質・デバイス領域共同研究拠点研究成果報告書(平成27年度), Osaka, Mar. 2016. (Summary) LiFePO₄に代表されるオリビン系LiMPO₄系酸化物はPを中心とする酸素四面体ブロックと遷移金属M(Fe)を中心とする酸素八面体ブロックの作るb軸方向のトンネル構造中をLi⁺イオンが拡散することが知られている．PO₄四面体はP-O間の強い共有結合により安定した骨格構造を形成するため，コバルト酸リチウムなどで問題となる充電時の安定性に優れている．一方，LiMnPO₄では顕著なLi⁺イオン拡散を示さないなど母構造を形成する遷移金属によりLi⁺イオンの拡散挙動が大きく変化する．本研究ではオリビン型LiMPO₄における局所構造とLi⁺イオン拡散挙動について，広帯域NMRによるスペクトル，スピン-格子緩和率及び高温XRD測定の結果について報告した．

Patent:

1.	Munehiro Inukai, Haruki Satoh, 根来誠, 宮西孝一郎 and 香川晃徳 : 高偏極化対象物，並びに，その製造方法，高偏極化方法及び高偏極化装置, 2023-034250 (Mar. 2023), 2023-034250 (Mar. 2023).

Grants-in-Aid for Scientific Research (KAKEN Grants Database @ NII.ac.jp)

機能性材料を対象とした室温超高感度NMR (Project/Area Number: 21H01965 )
Control of dynamics and storage of CO2 in soft porous solids (Project/Area Number: 19K22233 )
高温・高圧環境下における活性水素の高分解能NMR計測 (Project/Area Number: 19H05060 )
Study of locally disturbed crystal structure and multi carrier dynamics (Project/Area Number: 19K05003 )
Control of dynamics of gas molecules and functions in porous solids (Project/Area Number: 17H03043 )
Hyperpolarization NMR of gas molecules in porous coordination polymers (Project/Area Number: 15K17902 )
Proton conducting coordination polymer operating over 200 degC (Project/Area Number: 25810047 )
Construction of crystalline coordination frameworks showing uni-directional ion transport (Project/Area Number: 25620043 )
Search by Researcher Number (60537124)

Associate Professor : Inukai, Munehiro

Research

Personal Web Page

Field of Study

Subject of Study

Book / Paper

Academic Paper (Judged Full Paper):

Review, Commentary:

Proceeding of International Conference:

Proceeding of Domestic Conference:

Et cetera, Workshop:

Report:

Patent:

Grants-in-Aid for Scientific Research (KAKEN Grants Database @ NII.ac.jp)