Researcher Database

Yuh Hijikata
Creative Research Institution Institute for Chemical Reaction Design and Discovery
Specially Appointed Associate Professor

Researcher Profile and Settings


  • Creative Research Institution Institute for Chemical Reaction Design and Discovery

Job Title

  • Specially Appointed Associate Professor


  • PhD.(Kyoto University)

Research funding number

  • 70622562

J-Global ID

Research Interests

  • 配位高分子   錯体化学   理論・計算化学   

Academic & Professional Experience

  • 2019/03 - Today Hokkaido University Institute for Chemical Reaction Design and Discovery Specially Appointed Associate Professor
  • 2014/09 - 2019/02 Nagoya University Institute of Transformative Bio-Molecules Designated assistant professor
  • 2011/10 - 2014/08 FIFC Fellow
  • 2011/04 - 2011/09 SPR Fellow


  • 2006/04 - 2011/03  Kyoto University  Graduate School, Division of Engineering  Department of Syntheic Chemistry and Biologival Chemistry
  • 2002/04 - 2006/03  Kyoto University  Faculty of Engineering

Association Memberships

  • 分子科学会   錯体化学会   日本化学会   

Research Activities

Published Papers

  • Shun Suginome, Hiroshi Sato, Akihiro Hori, Akio Mishima, Yuki Harada, Shinpei Kusaka, Ryotaro Matsuda, Jenny Pirillo, Yuh Hijikata, Takuzo Aida
    Journal of the American Chemical Society American Chemical Society ({ACS}) 2019/10 [Refereed][Not invited]
  • Shinpei Kusaka, Atsushi Kiyose, Hiroshi Sato, Yuh Hijikata, Akihiro Hori, Yunsheng Ma, Ryotaro Matsuda
    Journal of the American Chemical Society American Chemical Society ({ACS}) 2019/09 [Refereed][Not invited]
  • Yasutomo Segawa, Motonobu Kuwayama, Yuh Hijikata, Masako Fushimi, Taishi Nishihara, Jenny Pirillo, Junya Shirasaki, Natsumi Kubota, Kenichiro Itami
    Science American Association for the Advancement of Science ({AAAS}) 365 (6450) 272  2019/07 [Refereed][Not invited]
  • Taku Hayashi, Ka Hung Lee, Hiroki Iida, Eiji Yashima, Stephan Irle, Yuh Hijikata
    Journal of Computational Chemistry Wiley 2019/05 [Refereed][Not invited]
  • Soichiro Ogi, Natsumi Fukaya, Arifin, Bastian Bjerkem Skjelstad, Yuh Hijikata, Shigehiro Yamaguchi
    Chemistry – A European Journal Wiley 25 (30) 7303  2019/05 [Refereed][Not invited]
  • Yuki Harada, Yuh Hijikata, Shinpei Kusaka, Akihiro Hori, Yunsheng Ma, Ryotaro Matsuda
    Dalton Transactions Royal Society of Chemistry ({RSC}) 2019 [Refereed][Not invited]
  • Journal of Computational Chemistry 2019/01 [Refereed][Not invited]
  • Seokjin Moon, Yuh Hijikata, Stephan Irle
    Physical Chemistry Chemical Physics Royal Society of Chemistry ({RSC}) 21 (23) 12112  2019 [Refereed][Not invited]
  • Ryo Ohtani, Riho Yamamoto, Hiroyoshi Ohtsu, Masaki Kawano, Jenny Pirillo, Yuh Hijikata, Masaaki Sadakiyo, Leonard F. Lindoy, Shinya Hayami
    Dalton Transactions 48 (21) 7198 - 7202 1477-9226 2019 [Refereed][Not invited]

    Consecutive oxidative additions of iodine on the undulating 2D coordination polymer produced unprecedented anisotropic structures.

  • Daisuke Uraguchi, Keiko Kuwata, Yuh Hijikata, Rie Yamaguchi, Hanae Imaizumi, Sathiyanarayanan Am, Christin Rakers, Narumi Mori, Kohki Akiyama, Stephan Irle, Peter McCourt, Toshinori Kinoshita, Takashi Ooi, Yuichiro Tsuchiya
    Science (New York, N.Y.) 362 (6420) 1301 - 1305 2018/12/14 [Refereed][Not invited]
    The parasitic plant Striga hermonthica has been causing devastating damage to the crop production in Africa. Because Striga requires host-generated strigolactones to germinate, the identification of selective and potent strigolactone agonists could help control these noxious weeds. We developed a selective agonist, sphynolactone-7, a hybrid molecule originated from chemical screening, that contains two functional modules derived from a synthetic scaffold and a core component of strigolactones. Cooperative action of these modules in the activation of a high-affinity strigolactone receptor ShHTL7 allows sphynolactone-7 to provoke Striga germination with potency in the femtomolar range. We demonstrate that sphynolactone-7 is effective for reducing Striga parasitism without impinging on host strigolactone-related processes.
  • Liu Hong, Taishi Nishihara, Yuh Hijikata, Yuhei Miyauchi, Kenichiro Itami
    Scientific Reports 8 (1) 2045-2322 2018/12/01 [Refereed][Not invited]
    Precise fabrication of molecular assemblies on a solid surface has long been of central interest in surface science. Their perfectly oriented growth only along a desired in-plane direction, however, remains a challenge, because of the thermodynamical equivalence of multiple axis directions on a solid-surface lattice. Here we demonstrate the successful fabrication of an in-plane, unidirectional molecular assembly on graphene. Our methodology relies on nanomechanical symmetry breaking effects under atomic force microscopy tip scanning, which has never been used in molecular alignment. Individual one-dimensional (1D) molecular assemblies were aligned along a selected symmetry axis of the graphene lattice under finely-tuned scanning conditions after removing initially-adsorbed molecules. Experimental statistics and computational simulations suggest that the anisotropic tip scanning locally breaks the directional equivalence of the graphene surface, which enables nucleation of the unidirectional 1D assemblies. Our findings will open new opportunities in the molecular alignment control on various atomically flat surfaces.
  • Chonnikan Hanpaibool, Tipsuda Chakcharoensap, Arifin, Yuh Hijikata, Stephan Irle, Peter Wolschann, Nawee Kungwan, Piamsook Pongsawasdi, Puey Ounjai, Thanyada Rungrotmongkol
    Journal of Molecular Liquids 265 16 - 23 0167-7322 2018/09/01 [Refereed][Not invited]
    Genistein is an isoflavone with promising pharmaceutical applications. However, its low water solubility interferes with its potency, and therefore cyclodextrins (CDs) have been considered as possible drug delivery system (DDS). To investigate the complexation mechanism of genistein in cyclodextrin, we employed molecular dynamics (MD) simulations based on classical potentials and the density-functional tight-binding (DFTB) quantum chemical potential. Both classical and quantum chemical MD simulations predict that the phenol ring of genistein is preferentially complexed in the cavity of CD. The complexation process reduces the water-accessible solvation shell, and it is found that a hydrogen bond is formed between genistein and CD. The DFTB-based MD simulations reveal that spontaneous keto-enol tautomerization occurs even within a hundred picoseconds, which suggests that the encapsulated genistein is complexed in the ordinary enol form of the drug molecule. Analyses of the molecular charge distributions suggest that electrostatic interactions partially induce the complex formation, rather than extensive formation of hydrogen bonds.
  • Sujan Mondal, Ramana Singuru, Subhash Chandra Shit, Taku Hayashi, Stephan Irle, Yuh Hijikata, John Mondal, Asim Bhaumik
    ACS Sustainable Chemistry and Engineering 6 (2) 1610 - 1619 2168-0485 2018/02/05 [Refereed][Not invited]
    With the rapidly diminishing fossil fuel resources, development of a new strategy for synthesis of biofuels from renewable resources can provide a sustainable alternative to our energy demand. We present the design, synthesis, and characterization of a new porous organic network (TpPON) through acid-catalyzed condensation of 1,3,5-triformylphloroglucinol (Tp) and triphenylamine (TPA). Ru0 nanoparticles are successfully fabricated at the porous surface of TpPON to obtain a novel catalytic system Ru@TpPON, which exhibits excellent catalytic performance together with outstanding stability for the hydrodeoxygenation of various vegetable oils to long-chain alkanes in water, and thus TpPON has wide potential for large-scale biodiesel production from renewable resources.
  • Piyali Bhanja, Sabuj K. Das, Kousik Bhunia, Debabrata Pradhan, Taku Hayashi, Yuh Hijikata, Stephan Irle, Asim Bhaumik
    ACS Sustainable Chemistry and Engineering 6 (1) 202 - 209 2168-0485 2018/01/02 [Refereed][Not invited]
    The new porous polymer TPDA-1 has been synthesized via solvothermal Schiff base condensation reaction between two organic monomers, i.e., 2,4,6-trihydroxyisophthalaldehyde and 1,3,5-tris(4-aminophenyl)triazine. The TPDA-1 material showed a very high specific capacitance of 469.4 F g-1, at 2 mV s-1 scan rate, together with a high specific surface area of 545 m2 g-1. It also exhibited excellent cyclic stability with 95% retention of its initial specific capacitance after 1000 cycles at 5 A g-1, suggesting its potential as a high performance supercapacitor. Extended π-conjugation and ion conduction inside the micropores throughout the whole polymeric matrix and high BET surface area could be responsible for this high supercapacitor performance in energy storage device. TPDA-1 has been characterized thoroughly by various electrochemical techniques such as cyclic voltammetry, galvanic charge-discharge, and electrochemical impedance spectroscopy. Our experimental results suggested a high potential of this porous polymer in energy storage devices for future generation.
  • Kiriya Daisuke, Hijikata Yuh, Pirillo Jenny, Kitaura Ryo, Murai Akihiko, Ashida Atsushi, Yoshimura Takeshi, Fujimura Norifumi
    Langmuir 34 (35) 10243 - 10249 2018 [Refereed][Not invited]
  • S. Yamamoto, J. Pirillo, Y. Hijikata, Z. Zhang, K. Awaga
    Chemical Science 9 (13) 3282 - 3289 2041-6539 2018 [Refereed][Not invited]
    A spontaneous entrapment of electron-donating small guest molecules, including tetrathiafulvalene (TTF) and N,N,N′,N′-tetramethyl-1,3-propanediamine (TMPDA), was realized in a structurally flexible metal-organic framework, {Mn7(2,7-AQDC)6(2,6-AQDC)(DMA)6}∞ (AQDC = anthraquinone dicarboxylates, DMA = N,N-dimethylacetamide), with electron-accepting anthraquinone groups, generating two MOF guest charge transfer complexes: {Mn7(2,7-AQDC)6(2,6-AQDC)(DMA)6(TTF)5} and {Mn7(2,7-AQDC)6(2,6-AQDC)(DMA)4(H2O)2(TMPDA)7}. Using a mild impregnation procedure, single crystals of the target complexes were obtained via a crystal-to-crystal conversion, and the crystals were suitable for structural analysis. Single crystal X-ray analysis demonstrated the different arrangements of these intercalated donor molecules: some donor molecules interacted with the anthraquinone groups and formed infinite D-A-A-D stacks, some appeared beside the anthraquinone groups but only formed donor-acceptor pairs, and the remainder of the molecules simply filled the space. The charge transfer between the guests and the framework was spectroscopically confirmed, and the radical densities on the organic species were estimated using magnetic susceptibility measurements. Compared with a solid-state mixture of anthraquinone and donor molecules, the evenly distributed donor molecules in the micropores of the MOF resulted in a "solid solution" state and significantly promoted the degree of charge transfer between donors and acceptors. Such an encapsulation process may be adopted as a new strategy for post-modification of the electronic and magnetic properties of MOFs, as well as for generating new semiconducting charge-transfer complexes.
  • Aiko Fukazawa, Yusuke Toda, Masahiro Hayakawa, Anna Sekioka, Hiroyuki Ishii, Toshihiro Okamoto, Jun Takeya, Yuh Hijikata, Shigehiro Yamaguchi
    Chemistry - A European Journal 24 (44) 11503 - 11510 0947-6539 2018 [Refereed][Not invited]
    © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. The sulfur-containing nine-membered heterocycle thiacyclononene (TN) was evaluated as a new type of endcapping group for π-conjugated systems. A systematic study on TN-capped α-oligothiophenes (TNnTs; n=4–7) revealed that the capping with TN, which adopts a bent conformation, imparts the resulting oligothiophenes with drastically increased solubility at approximately 140oC and high electrochemical stability, whereas the electronic structure remains virtually unperturbed. The even-numbered oligothiophenes TN4T and TN6T form characteristic offset herringbone-type packing structures on account of the steric repulsion between the TN rings and the presence of intermolecular nonbonding S···S interactions. This packing mode in combination with the high solubility enabled the solutionprocess fabrication of field-effect transistors based on TN6T, which exhibited a high performance without degradation even upon exposure to air.
  • Yunsheng Ma, Yuki Harada, Akihiro Hori, Yuh Hijikata, Liangchun Li, Ryotaro Matsuda
    DALTON TRANSACTIONS 46 (44) 15200 - 15203 1477-9226 2017/11 [Refereed][Not invited]
    [Zn-2(FDC)(2)(bpy)] (LMOF-202) and [Zn-2(OFDC)(2)(bpy)] (LMOF-201) (FDC: fluorene-2,7-dicarboxylate, OFDC: 9-fluorenone-2,7-dicarboxylate, bpy: 4,4'-bipyridine) have interpenetrated isostructures. However, their gas sorption behaviors indicate that LMOF-202 is rigid, whereas LMOF-201 is flexible. We found that the structural flexibility of LMOF-201 was due to the addition of only one oxygen atom into the ligand.
  • Rika Ochi, Shin-ichiro Noro, Yuh Hijikata, Kazuya Kubo, Takayoshi Nakamura
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 34 (34) 4013 - 4019 1434-1948 2017/09 [Refereed][Not invited]
    We attempted the synthesis and crystallographic characterization of light-metal coordination polymers (CPs) using a 4-(methylsulfonyl)benzoate (msbza(-)) ligand with a charge-polarized neutral methylsulfonyl coordination moiety, in order to diversify the limited structures of light-metal CPs, as compared with heavy-metal CPs. As expected from the results of DFT calculations, all of the obtained CPs {three-dimensional (3D) [Mg2Na2(msbza)(6)(H2O)(3)](n) (1), two-dimensional (2D) [KH(msbza)(2)](n) (2) and 2D [Na(msbza)](n) (3)} exhibited coordination of the methylsulfonyl moiety to light-metal cations, in addition to coordination of the carboxylate. These structural features suggest that the use of a neutral methylsulfonyl coordination site is a powerful tool for the structural diversification of light-metal CPs. In addition, the 3D CP 1, with the rare and unique tetranuclear Mg2Na2 secondary building unit, showed an unprecedented single-crystal-to-single-crystal transformation via the low-crystalline state.
  • Noriaki Ozaki, Hirotoshi Sakamoto, Taishi Nishihara, Toshihiko Fujimori, Yuh Hijikata, Ryuto Kimura, Stephan Irle, Kenichiro Itami
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 56 (37) 11196 - 11202 1433-7851 2017/09 [Refereed][Not invited]
    Numerous otherwise difficult applications have been realized with materials, the chemical/physical properties of which can be controlled by external stimuli such as heat, pressure, photo-irradiation, and voltage bias. However, the complexity of design and the lack of easy-to-conduct synthetic methods make the creation of on-demand stimuli responsive materials a formidable task. Here we report an electric-stimuli-responsive multifunctional material, [10]CPP-I: crystalline assembly of a hydrocarbon nanoring ([10]cycloparaphenylene: [10]CPP) as an "electro-responsive porous host" and iodine as a "potentially functional molecule". Through applying electric stimulus, [10]CPP-I turned to exhibit two attractive properties: electronic conductivity and white light emission. We revealed that electric stimuli trigger the cascade formation of polyiodide chains inside the [10]CPP assembly through charge transfer, leading to the emergence of these properties. This "responsive porous host" approach is expected to be applicable for different stimuli, and opens the path for devising a generic strategy to the development of stimuli-responsive materials.
  • Aulia Sukma Hutama, Yuh Hijikata, Stephan Irle
    Journal of Physical Chemistry C 121 14888-14898  2017/06/12 [Refereed][Not invited]
  • Tomohiro Fukushima, Hirotoshi Sakamoto, Kohei Tanaka, Yuh Hijikata, Stephan Irle, Kenichiro Itami
    CHEMISTRY LETTERS 46 (6) 855 - 857 0366-7022 2017/06 [Refereed][Not invited]
    Molecular carbon nanorings, [n]cycloparaphenylenes ([n]CPP), are a unique class of porous molecules with allbenzene surface. Herein, we report the preparation of polymorphs of [6] CPP crystals for the first time, and the discovery of their packing structure-dependent properties. We found that the herringbone-packed structure is thermodynamically more stable than the tubular-packed structure. We revealed that their host-guest interaction depends on the packing structures of [6] CPP: the tubular-packing affords one-dimensional open channels for weak guest sorption, while the herringbone-packing gives closed cavities for strong guest entrapment. This study exemplifies that the solid-state host-guest chemistry of CPP crystals can be directed by controlling their packing structures.
  • Sudipta K. Kundu, Ramana Singuru, Taku Hayashi, Yuh Hijikata, Stephan Irle, John Mondal
    CHEMISTRYSELECT 2 (17) 4705 - 4716 2365-6549 2017/06 [Refereed][Not invited]
    Sulfonic acid (-SO3H) functionalized anthracene derived conjugated porous organic polymer (AnPOP-SO3H) have been constructed through Friedel-Crafts alkylation of anthracene by using formaldehyde dimethyl acetal as a cross-linker and anhydrous FeCl3 as a promoter followed by sulfonation of aromatic rings using chlorosulfonic acid under controlled reaction conditions. Morphological evolution, porous structure, nature and strength of the acid sites and structural integrity with different chemical environments have been comprehensively examined by employing HR-TEM (High Resolution Transmission Electron Microscopy), FE-SEM (Field Emission-Scanning Electron Microscopy), Powder X-ray diffraction, N-2 sorption, NH3-TPD (Temperature Programmed Desorption), solid state C-13 CP MAS-NMR (Cross Polarization Magic Angle Spinning-Nuclear Magnetic Resonance), HAADF-STEM (High Angle Annular Dark Field-Scanning Transmission Electron Microscopy) with the corresponding elemental mapping and FT-IR (Fourier Transform Infrared) spectroscopic tools. This newly designed AnPOP-SO3H metal-free organocatalyst exhibited an excellent catalytic activity in the acetalization of Bio-Glycerol with acetone, furfural, and benzaldehyde under solvent free and ambient temperature conditions to furnish 2,2-dimethyl-1,3-dioxalane-4-methanol (solketal) derivatives, with quantitative conversion and good selectivities. An enhancement in the catalytic performance of the nanohybrid metal-free solid acid catalyst is observed compared with the conventional reported catalysts which could be attributed to the presence of high acidic sites, huge surface area accompanied with the highly rigid cross linked framework thereby facilitating easy diffusion of organic substrates to interact with the catalytic active sites and prohibiting water diffusion inside the pore owing to the hydrophobic nature of the catalyst. The investigated AnPOP-SO3H represents a novel class of promising heterogeneous metal-free organocatalyst with ten recycles in succession and no sign of catalyst deactivation, useful for the transformation of Bio-Glycerol to value-added chemicals in an eco-friendly manner for future industry.
  • Fei Wang, Shinpei Kusaka, Yuh Hijikata, Nobuhiko Hosono, Susumu Kitagawa
    ACS Applied Materials & Interface 9 33455-33460  2017/04/20 [Refereed][Not invited]
  • Hiroki Iida, Kenji Ohmura, Ryuta Noda, Soichiro Iwahana, Hiroshi Katagiri, Naoki Ousaka, Taku Hayashi, Yuh Hijikata, Stephan Irle, Eiji Yashima
    CHEMISTRY-AN ASIAN JOURNAL 12 (8) 927 - 935 1861-4728 2017/04 [Refereed][Not invited]
    Novel double helices covalently bridged by cyclic boronate esters were synthesized from complementary dimers with an m-terphenyl backbone joined by a chiral or achiral phenylene linker bearing diethyl boronates and diols, respectively. The X-ray crystallographic analysis and variable-temperature NMR and circular dichroism measurements, along with theoretical calculations, revealed that the double helices function as a molecular rotor in which the cyclic boronate ester units rotate, yielding two stable rotamers at low temperatures. Moreover, our data indicates that the covalently bonded double helices can undergo a unique helix-inversion simultaneously with a rotational motion of the boronate esters.
  • Structural influence of transition metal (Sc, Y, and Lu) atoms inside gold nanoparticles
    Li-Xia Zhao, Yuh Hijikata, Stephan Irle
    International Journal of of Quantum Chemistry 2017/03/21 [Refereed][Not invited]
  • Piyali Bhanja, Kousik Bhunia, Sabuj K. Das, Debabrata Pradhan, Ryuto Kimura, Yuh Hijikata, Stephan Irle, Asim Bhaumik
    CHEMSUSCHEM 10 (5) 921 - 929 1864-5631 2017/03 [Refereed][Not invited]
    The new covalent organic framework material TDFP-1 was prepared through a solvothermal Schiff base condensation reaction of the monomers 1,3,5-tris-(4-aminophenyl) triazine and 2,6-diformyl-4-methylphenol. Owing to its high specific surface area of 651 m(2)g(-1), extended pi conjugation, and inherent microporosity, TDFP-1 exhibited an excellent energy-storage capacity with a maximum specific capacitance of 354 Fg(-1) at a scan rate of 2 mVs(-1) and good cyclic stability with 95% retention of its initial specific capacitance after 1000 cycles at 10 Ag-1. The pi-conjugated polymeric framework as well as ionic conductivity owing to the possibility of ion conduction inside the micropores of approximately 1.5 nm make polymeric TDFP-1 a favorable candidate as a supercapacitor electrode material. The electrochemical properties of this electrode material were measured through cyclic voltammetry, galvanic charge-discharge, and electrochemical impedance spectroscopy, and the results indicate its potential for application in energy-storage devices.
  • Ryo Ohtani, Yuu Kitamura, Yuh Hijikata, Masaaki Nakamura, Leonard F. Lindoy, Shinya Hayami
    DALTON TRANSACTIONS 46 (11) 3749 - 3754 1477-9226 2017/03 [Refereed][Not invited]
    Slight changes in the coordination structure of the manganese(V)-nitrido anionic complex, [Mn-V(N) (CN)(4)](2-), induced by using a "lipid package" approach markedly made an impact on the corresponding redox potentials. The single crystals of four lipid assemblies, [dabco-(CH2)(n-1)-CH3](2)[Mn(N)(CN)(4)(H2O)]center dot xH(2)O (n = 15, 16, 17 and 18; dabco = 1,4-diazabicyclo[2,2,2] octane), were synthesized and solid-state cyclic voltammetric studies demonstrated that the [Mn-V(N)(CN)(4)](2)-anions with smaller "cross" NC-Mn-CN bond angles exhibit higher redox potentials. The observed trend reflects the energy change associated with the structural transformation from [Mn-V(N)(CN)(4)](2-)to [ Mn-VI(N)(CN)(4)](2-) and is supported by the results of DFT calculations. The NC-Mn-CN bond angles in the flexible [Mn(N)(CN)(4)](2-) structure exhibit excellent correlation with the redox potentials of the complexes in the solid state.
  • Kawano R, Horike N, Hijikata Y, Kondo M, Carne-Sanchez A, Larpent P, Ikemura S, Osaki T, Kamiya K, Kitagawa S, Takeuchi S, Furukawa S
    Chem 2 (3) 393 - 403 2017 [Refereed][Not invited]
  • Taku Hayashi, Yuh Hijikata, Alister Page, Donglin Jiang, Stephan Irle
    CHEMICAL PHYSICS LETTERS 664 101 - 107 0009-2614 2016/11 [Refereed][Not invited]
    Covalent organic frameworks (COFs) have attracted much interest due to their utility as functional materials. Unfortunately, experimental synthesis struggles with low single crystallinity of COFs. We have theoretically investigated isomer structures of a representative two-dimensional COF for both monolayer and three-dimensional stacking orders. We show that rotations of p-phenylene rings are common in monolayers, however, affect the global stacking order substantially. We also discuss the discrepancy between powder X-ray diffraction patterns corresponding to the structures predicted by our calculations and those experimentally observed. The discrepancy demonstrates the importance of dynamics in the self-assembly process of COF organic components. (C) 2016 Elsevier B.V. All rights reserved.
  • Shuhei Furukawa, Nao Horike, Mio Kondo, Yuh Hijikata, Arnau Carne-Sanchez, Patrick Larpent, Nicolas Louvain, Stephane Diring, Hiroshi Sato, Ryotaro Matsuda, Ryuji Kawano, Susumu Kitagawe
    INORGANIC CHEMISTRY 55 (21) 10843 - 10846 0020-1669 2016/11 [Refereed][Not invited]
    The upbuilding of dirhodium tetracarboxylate paddlewheels into porous architectures is still challenging because of the inertness of equatorial carboxylates for ligand-exchange reaction. Here we demonstrate the synthesis of a new family of metal organic cuboctahedra by connecting dirhodium units through 1,3-benzenedicarboxylate and assembling cuboctahedra as porous solids. Carbon monoxide and nitric oxide were strongly trapped in the internal cavity thanks to the strong affinity of unsaturated axial coordination sites of dirhodium centers.
  • Clothilde A. Eveleens, Yuh Hijikata, Stephan Irle, Alister J. Page
    JOURNAL OF PHYSICAL CHEMISTRY C 120 (35) 19862 - 19870 1932-7447 2016/09 [Refereed][Not invited]
    Density functional theory is employed to demonstrate how ammonia derived etchant radicals (H, NH, and NH2) can be used to promote particular (n,m) chirality single-walled carbon nanotube (SWCNT) caps during chemical vapor deposition (CVD) growth. We reveal that the chemical reactivity of these etchant radical species with SWCNTs depends on the SWCNT chirality. This reactivity is determined by the extent of disruption to the pi-conjugation of the cap structure caused by reaction with the etchant species. H and NH2 attack single carbon atoms and preferentially react with near-zigzag SWCNT caps, whereas NH prefers to attack across C-C bonds and selectively etches near-armchair SWCNT caps. We derive a model for predicting abundances of (n,m) SWCNTs in the presence of ammonia-derived radicals, which is consistent with (n,m) distributions observed in recent CVD experiments with ferrocene and ammonia. This model also demonstrates that chiral-selective etching of SWCNTs during CVD growth can be potentially exploited for achieving chirality control in standard CVD synthesis.
  • Maw Lin Foo, Ryotaro Matsuda, Yuh Hijikata, Rajamani Krishna, Hiroshi Sato, Satoshi Horike, Akihiro Hori, Jingui Duan, Yohei Sato, Yoshiki Kubota, Masaki Takata, Susumu Kitagawa
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 138 (9) 3022 - 3030 0002-7863 2016/03 [Refereed][Not invited]
    The adsorptive separation of C2H2 and CO2 via porous materials is nontrivial due to the close similarities of their boiling points and kinetic diameters. In this work, we describe a new flexible porous coordination polymer (PCP) [Mn(bdc)(dpe)] (H(2)bdc = 1,4-benzenedicarboxylic acid, dpe = 1,2-di(4-pyridyl)ethylene) having zero-dimensional pores, which shows an adsorbate discriminatory gate effect. The compound shows gate opening, type abrupt adsorption for C2H2 but not for CO2, leading to an appreciable selective adsorption of CO2 over C2H2 at near ambient temperature (273 K). The origin of this unique selectivity, as unveiled by in situ adsorption-X-ray diffraction experiments and density functional theory calculations, is due to vastly different orientations between the phenylene ring of bdc and each gas in the nanopores. The structural change by photochemical transformation of this PCP via [2 + 2] photodimerization leads to the removal of inverse CO2/C2H2 selectivity, verifying the mechanism of the guest discriminatory gate effect.
  • Hirotoshi Sakamoto, Toshihiko Fujimori, Xiaolin Li, Katsumi Kaneko, Kai Kan, Noriaki Ozaki, Yuh Hijikata, Stephan Irle, Kenichiro Itami
    CHEMICAL SCIENCE 7 (7) 4204 - 4210 2041-6520 2016 [Refereed][Not invited]
    The molecular carbon nanoring, cycEoparaphenyEene (CPP), is fascinating as a new class of carbonaceous porous solids with the uniform structure of an all-benzene surface. We explored the feasibility of [12]CPP as a carbon-based porous material and uncovered its unique adsorption properties due to its shape and highly non polar surface. Unlike other porous carbon solids, [12]CPP shows stepwise adsorption behaviors sensitive to the functionahties of the guest molecules. In situ powder X-ray diffraction and infrared spectra provided insights into how [12]CPP accommodates the guest molecules with structural deformation retaining its structural periodicity during the whole adsorption process, which exemplifies that this molecular nanoring represents an unprecedented carbon-based soft porous solid.
  • Yunsheng Ma, Ryotaro Matsuda, Hiroshi Sato, Yuh Hijikata, Liangchun Li, Shinpei Kusaka, Mawlin Foo, Fengfeng Xue, George Akiyama, Rongxin Yuan, Susumu Kitagawa
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137 (50) 15825 - 15832 0002-7863 2015/12 [Refereed][Not invited]
    Direct observation of gas molecules confined in the nanospace of porous materials by single-crystal X-ray diffraction (SXRD) technique is, significant because it leads to deep insight into the adsorption mechanism and the actual state of the adsorbents in molecular level. A recent study revealed that flexibility is one of the important factors to achieve periodic guest accommodation in the nanospace enabling direct observation of gas molecules. Here, we report a convenient strategy to tune the framework flexibility by just an atomic exchange in a ligand, which enables us to easily construct a soft nanospace as the best platform to study gas adsorption. Indeed, we succeeded to observe C2H2 and CO2 molecules confined in the pores of a flexible porous coordination polymer (PCP-N) in different configurations using SXRD measurement, whereas gas molecules in a rigid framework (PCP-C) isostructural to PCP-N were not seen crystallographically. The result of the coincident in situ powder X-ray diffraction and adsorption measurement for PCP-N unambiguously showed that the framework could flexibly transform to trap gas molecules with a commensurate fashion. In addition, for PCP-N, we found that the adsorbed gas molecules induced significant structural change involving dimensional change of the pore from one-dimensional to three-dimensional, and subsequently, additional gas molecules formed periodic molecular clusters in the nanospace.
  • Shin-ichiro Noro, Ryotaro Matsuda, Yuh Hijikata, Yasutaka Inubushi, Sadamu Takeda, Susumu Kitagawa, Yukiko Takahashi, Masashi Yoshitake, Kazuya Kubo, Takayoshi Nakamura
    CHEMPLUSCHEM 80 (10) 1517 - 1524 2192-6506 2015/10 [Refereed][Not invited]
    The development of highly efficient CO2 separation materials is very important for environmental preservation and energy conservation. Crystalline porous coordination polymers (PCPs)/metal-organic frameworks are one of a number of promising types of porous materials for CO2 separation because of their controllable pore size, shape and surface function. Simultaneously, the unique structural flexibility of PCPs affords both high CO2 selectivity and inexpensive regeneration. However, this family of materials suffers from the coexistence of water that destroys the framework of PCPs and its adsorption in the pores is greater than that of CO2, which results in a deterioration in CO2-separation performance. Herein, a flexible and hydrophobic CuII PCP that is stable towards water has been designed and synthesised. This PCP has extremely high adsorption selectivity for CO2 over CH4, derived from its structural flexibility. Furthermore, the obtained water-tolerant flexible PCP, under CO2/CH4 mixed-gas conditions, exhibits highly selective CO2 adsorption over CH4, even in the presence of water.
  • Munehiro Inukai, Tomohiro Fukushima, Yuh Hijikata, Naoki Ogiwara, Satoshi Horike, Susumu Kitagawa
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 137 (38) 12183 - 12186 0002-7863 2015/09 [Refereed][Not invited]
    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.
  • Ryo Ohtani, Munehiro Inukai, Yuh Hijikata, Tetsuya Ogawa, Mikihito Takenaka, Masaaki Ohba, Susumu Kitagawa
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 54 (4) 1139 - 1143 1433-7851 2015/01 [Refereed][Not invited]
    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-C-18)[Mn(N)(CN)(4)(dabco-C-18)] (1; dabco-C-18(+)=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 MnCNM 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.
  • Shin-ichiro Noro, Junya Mizutani, Yuh Hijikata, Ryotaro Matsuda, Hiroshi Sato, Susumu Kitagawa, Kunihisa Sugimoto, Yasutaka Inubushi, Kazuya Kubo, Takayoshi Nakamura
    NATURE COMMUNICATIONS 6 2041-1723 2015/01 [Refereed][Not invited]
    The design of inexpensive and less toxic porous coordination polymers (PCPs) that show selective adsorption or high adsorption capacity is a critical issue in research on applicable porous materials. Although use of Group II magnesium(II) and calcium(II) ions as building blocks could provide cheaper materials and lead to enhanced biocompatibility, examples of magnesium(II) and calcium(II) PCPs are extremely limited compared with commonly used transition metal ones, because neutral bridging ligands have not been available for magnesium(II) and calcium(II) ions. Here we report a rationally designed neutral and charge-polarized bridging ligand as a new partner for magnesium(II) and calcium(II) ions. The three-dimensional magnesium(II) and calcium(II) PCPs synthesized using such a neutral ligand are stable and show selective adsorption and separation of carbon dioxide over methane at ambient temperature. This synthetic approach allows the structural diversification of Group II magnesium(II) and calcium(II) PCPs.
  • D. Umeyama, N. P. Funnell, M. J. Cliffe, J. A. Hill, A. L. Goodwin, Y. Hijikata, T. Itakura, T. Okubo, S. Horike, S. Kitagawa
    CHEMICAL COMMUNICATIONS 51 (64) 12728 - 12731 1359-7345 2015 [Refereed][Not invited]
    The structure of a glass obtained by the melt quenching of a two-dimensional (2D) coordination network was examined. X-ray analyses disclosed a 2D-to-0D structural transformation before and after glass formation. The mechanism is unique to coordination compounds, as it is characterized by labile and flexible coordination bonds.
  • Keisuke Kishida, Yumiko Watanabe, Satoshi Horike, Yoshihiro Watanabe, Yoshikuni Okumura, Yuh Hijikata, Shigeyoshi Sakaki, Susumu Kitagawa
    EUROPEAN JOURNAL OF INORGANIC CHEMISTRY 2014 (17) 2747 - 2752 1434-1948 2014/06 [Refereed][Not invited]
    The separation of olefins from paraffin is important for the production of industrial chemicals. Therefore, there is a need for a better separation system such as a pressure-swing adsorption (PSA) process. With regard to adsorbents that enable gas separation by PSA, CPL-1 {[Cu2(2,3-pyrazinedicarboxylate)2(pyrazine)]n} is an attractive porous material because of the flexibility and microporosity of the material, which provides it with a unique guest-responsive nature. Adsorption isotherm studies were conducted to elucidate the ethylene-selective adsorption properties of CPL-1, which was further examined by breakthrough experiments with ethylene-ethane binary gas mixtures at near room temperatures. Spectroscopic and computational approaches used to investigate the interaction between CPL-1 and the C2 gas molecules suggested that hydrogen bonds are important in the selective adsorption of ethylene over ethane.
  • Yuh Hijikata, Shigeyoshi Sakaki
    INORGANIC CHEMISTRY 53 (5) 2417 - 2426 0020-1669 2014/03 [Refereed][Not invited]
    We theoretically evaluated binding energies (E-b's) between various gas molecules and the Cu center open metal site (Cu-OMS) of Cu paddle-wheel units, [Cu-2(O2CR)(4)] (R = H, Me, or Ph) using density functional theory (DFT) and MP2-MP4. The optimized geometry of the model system [Cu-2(O2CPh)(4)] agrees with the experimental structure. The E-b of CO with [Cu-2(O2CH)(4)] is only slightly different between the open-shell singlet and triplet states. The calculated E-b decreases in the order MeNC > H2O > MeCN > C2H4 > C2H2 > CO > CO2 > N-2 > CH4 > H-2. The trend is discussed in terms of the electrostatic interaction energy (ES), exchange repulsion energy (EX), and charge-transfer (CT) + polarization (Pol) interaction energy at the Hartree-Fock level and the electron correlation effect. The ES increases linearly with an increase in E-b, while the EX decreases linearly with an increase in E-b. These relationships indicate that the ES compensates for the EX. In other words, the E-b does not depend on the sum of ES and EX, which corresponds to the static energy. The electron correlation effect contributes little to the above-mentioned decreasing order of E-b. The total E-b roughly increases with an increase in the CT+Pol term, suggesting that the CT+Pol term plays important roles in determining the trend of E-b. The shift of the stretching frequency of adsorbed gas molecules on the Cu-OMS is reproduced well by the DFT calculation with the model system [Cu-2(O2CH)(4)(L)(2)] (L = gas molecule). We found that the positive charge on the Cu significantly contributes to the shift in the end-on coordination gas molecules such as CO, MeNC, MeCN, and N-2. Although the shift has been generally discussed in terms of donation and back. donation, the present result indicates that the electrostatic potential field in the porous coordination polymer should be considered in the discussion of the frequency shift.
  • Hiroshi Sato, Wataru Kosaka, Ryotaro Matsuda, Akihiro Hori, Yuh Hijikata, Rodion V. Belosludov, Shigeyoshi Sakaki, Masaki Takata, Susumu Kitagawa
    SCIENCE 343 (6167) 167 - 170 0036-8075 2014/01 [Refereed][Not invited]
    Carbon monoxide (CO) produced in many large-scale industrial oxidation processes is difficult to separate from nitrogen (N-2), and afterward, CO is further oxidized to carbon dioxide. Here, we report a soft nanoporous crystalline material that selectively adsorbs CO with adaptable pores, and we present crystallographic evidence that CO molecules can coordinate with copper(II) ions. The unprecedented high selectivity was achieved by the synergetic effect of the local interaction between CO and accessible metal sites and a global transformation of the framework. This transformable crystalline material realized the separation of CO from mixtures with N-2, a gas that is the most competitive to CO. The dynamic and efficient molecular trapping and releasing system is reminiscent of sophisticated biological systems such as heme proteins.
  • Hiroyuki Nakashima, Yuh Hijikata, Hiroshi Nakatsuji
    ASTROPHYSICAL JOURNAL 770 (2) 0004-637X 2013/06 [Refereed][Not invited]
    Highly accurate wave functions of the ground and electronic (1s sigma(g) g and 3d sigma(g)), vibrational (v = 0-15 for 1s sigma(g) and v = 0-8 for 3d sigma(g)), and rotational (L = 0-6: S-1, P-3, D-1, F-3, (1)G, H-3, and I-1) excited states of the hydrogen molecular ion were obtained by solving the non-Born-Oppenheimer (non-BO) Schrodinger equation using the free complement (FC) method. The vibronic states belonging to the electronic excited state 3d sigma(g) are embedded in the continuum of the dissociation, H(1s) + H+. Nevertheless, they exist as physical bound states that have negligible coupling with the continuum. The complex scaled Hamiltonian was employed to analyze the bound and/or resonance natures of the obtained eigenstates, and a new resonance state appeared between the above two electronic states. We numerically proved that the FC method is a reliable theoretical tool for investigating non-BO quantum effects, and it should be available for various studies of hydrogen-related space chemistry and low-temperature physics.
  • Shin-ichiro Noro, Katsuo Fukuhara, Yuh Hijikata, Kazuya Kubo, Takayoshi Nakamura
    INORGANIC CHEMISTRY 52 (10) 5630 - 5632 0020-1669 2013/05 [Refereed][Not invited]
    The use of divalent Cu-II ions and an anion-mixing method led to the rational construction of a porous coordination polymer bridged by weak Lewis base inorganic CF3SO3- monoanions.
  • Yuh Hijikata, Satoshi Horike, Masayuki Sugimoto, Munehiro Inukai, Tomohiro Fukushima, Susumu Kitagawa
    Inorganic Chemistry 52 (7) 3634 - 3642 0020-1669 2013/04 [Refereed][Not invited]
    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 Zn2+ 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, C 2H6, 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 C2H 4 through the gate-opening phenomenon. Measurement of the solid-state 2H 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. © 2013 American Chemical Society.
  • Yasuko Mito-Oka, Satoshi Horike, Yusuke Nishitani, Tadao Masumori, Munehiro Inukai, Yuh Hijikata, Susumu Kitagawa
    JOURNAL OF MATERIALS CHEMISTRY A 1 (27) 7885 - 7888 2050-7488 2013 [Refereed][Not invited]
    Porous substances, including crystalline coordination materials and an amorphous organic polymer, were studied for their selective adsorption of siloxane D4. The investigated materials demonstrated a level of uptake comparable to that of conventional activated carbon.
  • Shin-ichiro Noro, Yuh Hijikata, Munehiro Inukai, Tomohiro Fukushima, Satoshi Horike, Masakazu Higuchi, Susumu Kitagawa, Tomoyuki Akutagawa, Takayoshi Nakamura
    INORGANIC CHEMISTRY 52 (1) 280 - 285 0020-1669 2013/01 [Refereed][Not invited]
    High selectivity and low-energy regeneration for adsorption of CO2 gas were achieved concurrently in a two-dimensional Cu(II) porous coordination polymer, [Cu-(PF6)(2)(4,4'-bpy)(2)] (4,4'-bpy = 4,4'-bipyridine), containing inorganic fluorinated PF6- anions that can act as moderate interaction sites for CO2 molecules.
  • Satoshi Horike, Masayuki Sugimoto, Kanokwan Kongpatpanich, Yuh Hijikata, Munehiro Inukai, Daiki Umeyama, Shinji Kitao, Makoto Seto, Susumu Kitagawa
    JOURNAL OF MATERIALS CHEMISTRY A 1 (11) 3675 - 3679 2050-7488 2013 [Refereed][Not invited]
    2-D layer type porous coordination polymers containing redox active Fe2+ centers were synthesized. One of the compounds [Fe(isophthalate)(4,4'-bipyridyl)] showed structural flexibility via guest adsorption, and we observed reversible Fe2+ and Fe3+ switching by iodine insertion. The composite showed electric conductivity.
  • Shin-ichiro Noro, Katsuo Fukuhara, Kunihisa Sugimoto, Yuh Hijikata, Kazuya Kubo, Takayoshi Nakamura
    DALTON TRANSACTIONS 42 (31) 11100 - 11110 1477-9226 2013 [Refereed][Not invited]
    We report the syntheses and crystal structures of novel porous assemblies of coordination complexes (PACs) with/without guest molecules, alpha-[Cu(A)(2)(py)(4)] (alpha-PAC-2-A (A = PF6, BF4, CF3SO3, and CH3SO3); py = pyridine), gamma-{[Cu(PF6)(2)(py)(4)]center dot 2guest} (gamma-PAC-2-PF6 superset of 2guest (guest = acetone and py)), gamma-{[Cu(BF4)(2)-(py)(4)]center dot 2acetone} (gamma-PAC-2-BF4 superset of 2acetone), and beta-{[Cu(CH3SO3)(2)(py)(4)]center dot 2.67H(2)O} (beta-PAC-2-CH3SO3 superset of 2.67H(2)O). The single-crystal X-ray diffraction analyses of alpha-PAC-2-A show that alpha-PAC-2-A have dense packing structures, in which anions of the discrete coordination complexes form weak hydrogen-bonding and anion-pi interactions. In contrast, gamma-PAC-2-PF6 superset of 2guest, gamma-PAC-2-BF4 superset of 2acetone, and beta-PAC-2-CH3SO3 superset of 2.67H(2)O form guest-including structures with coordination environments around the Cu-II atoms similar to the a-forms. The vapour adsorption measurements for MeCN and acetone in alpha-PAC-2-A suggest that the adsorption associated with structural transformations is induced by weak Lewis-base PF6- and BF4- anions covered only with fluorine atoms, which weaken the host-host interactions.
  • J. Alberto Rodriguez-Velamazan, Miguel A. Gonzalez, Jose A. Real, Miguel Castro, M. Carmen Munoz, Ana B. Gaspar, Ryo Ohtani, Masaaki Ohba, Ko Yoneda, Yuh Hijikata, Nobuhiro Yanai, Motohiro Mizuno, Hideo Ando, Susumu Kitagawa
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 134 (11) 5083 - 5089 0002-7863 2012/03 [Refereed][Not invited]
    A quasielastic neutron scattering and solid-state H-2 NMR spectroscopy study of the polymeric spin-crossover compound {Fe(pyrazine)[Pt(CN)(4)]} shows that the switching of the rotation of a molecular fragment- the pyrazine ligand-occurs in association with the change of spin state. The rotation switching was examined on a wide time scale (10(-13)-10(-3) s) by both techniques, which clearly demonstrated the combination between molecular rotation and spin-crossover transition under external stimuli (temperature and chemical). The pyrazine rings are seen to perform a 4-fold jump motion about the coordinating nitrogen axis in the high-spin state. In the low-spin state, however, the motion is suppressed, while when the system incorporates benzene guest molecules, the movements of the system are even more restricted.
  • Maw Lin Foo, Satoshi Horike, Tomohiro Fukushima, Yuh Hijikata, Yoshiki Kubota, Masaki Takata, Susumu Kitagawa
    DALTON TRANSACTIONS 41 (45) 13791 - 13794 1477-9226 2012 [Refereed][Not invited]
    By adopting a ligand-based solid solution approach, the sulphonic acid functional group can be successfully incorporated into a porous coordination polymer with UiO-66 structure type. Zr6O4(OH)(4)(BDC-SO3H)(1.1)(BDC)(4.9) possesses enhanced heat of adsorption for carbon dioxide and acetone compared to Zr6O4(OH)(4)(BDC)(6).
  • Munehiro Inukai, Satoshi Horike, Daiki Umeyama, Yuh Hijikata, Susumu Kitagawa
    DALTON TRANSACTIONS 41 (43) 13261 - 13263 1477-9226 2012 [Refereed][Not invited]
    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.
  • Masakazu Higuchi, Kohei Nakamura, Satoshi Horike, Yuh Hijikata, Nobuhiro Yanai, Tomohiro Fukushima, Jungeun Kim, Kenichi Kato, Masaki Takata, Daisuke Watanabe, Shinji Oshima, Susumu Kitagawa
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 51 (33) 8369 - 8372 1433-7851 2012 [Refereed][Not invited]
  • Nobuhiro Yanai, Koji Kitayama, Yuh Hijikata, Hiroshi Sato, Ryotaro Matsuda, Yoshiki Kubota, Masaki Takata, Motohiro Mizuno, Takashi Uemura, Susumu Kitagawa
    NATURE MATERIALS 10 (10) 787 - 793 1476-1122 2011/10 [Refereed][Not invited]
    The development of a new methodology for visualizing and detecting gases is imperative for various applications. Here, we report a novel strategy in which gas molecules are detected by signals from a reporter guest that can read out a host structural transformation. A composite between a flexible porous coordination polymer and fluorescent reporter distyrylbenzene ( DSB) selectively adsorbed CO(2) over other atmospheric gases. This adsorption induced a host transformation, which was accompanied by conformational variations of the included DSB. This read-out process resulted in a critical change in DSB fluorescence at a specific threshold pressure. The composite shows different fluorescence responses to CO(2) and acetylene, compounds that have similar physicochemical properties. Our system showed, for the first time, that fluorescent molecules can detect gases without any chemical interaction or energy transfer. The host-guest coupled transformations play a pivotal role in converting the gas adsorption events into detectable output signals.
  • Yuh Hijikata, Satoshi Horike, Masayuki Sugimoto, Hiroshi Sato, Ryotaro Matsuda, Susumu Kitagawa
    CHEMISTRY-A EUROPEAN JOURNAL 17 (18) 5138 - 5144 0947-6539 2011/04 [Refereed][Not invited]
    Porous coordination polymers constructed from Zn2+ and isophthalate with linear bipyridyl-type ligands were synthesized. [Zn(ip)(bpb)](n) (CID-21; ip = isophthalate, bpb = 1,4-bis(4-pyridyl)benzene), [Zn(ip)(bpt)](n) (CID-22; bpt= 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine), and [Zn(ip)(bpa)](n) (CID-23; bpa= 1,4-bis(4-pyridyl)acetylene) all have interdigitated structures of layers and similar void volumes (approximate to 27%). In these compounds, 1D bottleneck-type channels run along the perpendicular direction of the layer stacking and their properties are strongly dominated by the dipyridyl linker ligands. Because of the difference in packing of 2D layers, CID-21 and CID-22 have relatively rigid porous structures, whereas CID-23 has greater flexibility, as indicated by the results of powder X-ray diffraction studies. The micropores of CID-22 surrounded by tetrazine moieties adsorb polar molecules, such as methanol and water. The higher affinity of CID-22 for water than CID-21 is supported by a theoretical study. The 1D channel of CID-23 is wider than that of the other two compounds, which enables the incorporation of aromatic molecules. This is because the shape of the bpa linker ligand generates a wider pore diameter (8.6 angstrom). Only CID-23 can adsorb a benzene molecule and the isotherm of benzene has a gate-openingtype profile. This offers proof of the guest accommodation process through large structural transformation from a nonporous to a porous structure. The flexibility and restricted pore space of CID-23, at 298 K, allows only benzene, but not cyclohexane, to enter the channels. The porous structure exhibits clear selectivity for these similar guests. The incorporation of an elongated dipyridyl linker ligand in the 2D coordination layers provides a strategy for the design of microporous compounds with different flexibilities, microporous environments, and separation abilities.
  • Yuh Hijikata, Satoshi Horike, Daisuke Tanaka, Juergen Groll, Motohiro Mizuno, Jungeun Kim, Masaki Takata, Susumu Kitagawa
    CHEMICAL COMMUNICATIONS 47 (27) 7632 - 7634 1359-7345 2011 [Refereed][Not invited]
    We have demonstrated downsizing effects of the soft porous crystal, [Zn(isophthalate)(4,40-bipyridyl)](n) (CID-1), on the adsorption behavior between CID-1 and CID-1 nanocrystal (NCID-1). The difference results from the packing crystal structures and the dynamics of the frameworks.
  • Daiki Umeyama, Satoshi Horike, Munehiro Inukai, Yuh Hijikata, Susumu Kitagawa
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 50 (49) 11706 - 11709 1433-7851 2011 [Refereed][Not invited]
  • Satoru Shimomura, Masakazu Higuchi, Ryotaro Matsuda, Ko Yoneda, Yuh Hijikata, Yoshiki Kubota, Yoshimi Mita, Jungeun Kim, Masaki Takata, Susumu Kitagawa
    NATURE CHEMISTRY 2 (8) 633 - 637 1755-4330 2010/08 [Refereed][Not invited]
    Porous coordination polymers are materials formed from metal ions that are bridged together by organic linkers and that can combine two seemingly contradictory properties-crystallinity and flexibility. Porous coordination polymers can therefore create highly regular yet dynamic nanoporous domains that are particularly promising for sorption applications. Here, we describe the effective selective sorption of dioxygen and nitric oxide by a structurally and electronically dynamic porous coordination polymer built from zinc centres and tetracyanoquinodimethane (TCNQ) as a linker. In contrast to a variety of other gas molecules (C(2)H(2), Ar, CO(2), N(2) and CO), O(2) and NO are accommodated in its pores. This unprecedented preference arises from the concerted effect of the charge-transfer interaction between TCNQ and these guests, and the switchable gate opening and closing of the pores of the framework. This system provides further insight into the efficient recognition of small gas molecules.
  • Takashi Uemura, Yukari Ono, Yuh Hijikata, Susumu Kitagawa
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 132 (13) 4917 - 4924 0002-7863 2010/04 [Refereed][Not invited]
    Systematic functionalization of porous coordination polymers (PCPs), [Cu(2)(L)(2)(ted)](n) (where L = dicarboxylates and ted = triethylenediamine), by introducing various substituents onto the component organic ligand, L, was performed to regulate the radical polymerization of methyl methacrylate (MMA) in the nanochannels. The effect of the substituent groups on stereoregularity of the resulting poly(methyl methacrylate) (PMMA) was observed, where the tacticity of the PMMA strongly depended on the number and position of the substituent. In particular, polymerization of MMA in [Cu(2)(2,5-dimethoxyterephthalate)(2)(ted)](n) gave PMMA with high isotactic and heterotactic triad fractions, which is one of the most effective systems for changing the tacticity of PMMA in radical polymerization. To understand the mechanism of this drastic stereoregularity change, a variety of experimental and theoretical analyses, such as IR, N(2) adsorption, a statics study, and molecular dynamics (MD) calculations, were performed. Accurate MD calculations were helpful to determine the most plausible structures of [Cu(2)(L)(2)(ted)](n) and revealed that the specific channel shape of [Cu(2)(2,5-dimethoxyterephthalate)(2)(ted)](n) induces the large tacticity change of the resulting PMMA.
  • Masakazu Higuchi, Daisuke Tanaka, Satoshi Horike, Hirotoshi Sakamoto, Kohei Nakamura, Yohei Takashima, Yuh Hijikata, Nobuhiro Yanai, Jungeun Kim, Kenichi Kato, Yoshiki Kubota, Masaki Takata, Susumu Kitagawa
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 131 (30) 10336 - + 0002-7863 2009/08 [Refereed][Not invited]
    We have synthesized a porous coordination polymer containing a pyridinium cation as an organic linker and have investigated the methanol absorptive ability of the pyridinium cationic surface. The result implies that the pyridinium cationic surface participates in the strong adsorption of methanol.
  • Jun-ya Hasegawa, Masakazu Higuchi, Yuh Hijikata, Susumu Kitagawa
    CHEMISTRY OF MATERIALS 21 (9) 1829 - 1833 0897-4756 2009/05 [Refereed][Not invited]
    We investigated the concept "charge-polarized coordination spaces" in porous coordination polymers to increase the adsorption of H-2. Ab initio calculations were performed to investigate the H-2-adsorption capabilities of organic ligands. The adsorption energy of a pyrazine-carboxylate ligand (2.4 kcal/mol), relevant to a coordination polymer with a pillared layer structure, was found to be larger than that obtained by van der Waals interactions alone. An ab initio energy decomposition analysis showed that the stabilization arose mainly from the electronic polarization of H2. We therefore propose a concept of "charge-polarized spaces" to promote polarization. Under the dipolar electric field created by ideal charge-polarized spaces, the adsorption energy markedly increased to 5-8 kcal/cool, which is in the ideal energy range for H-2 adsorption in storage materials. Charge-neutral ligands can also provide electrostatically polarized spaces. Although the binding energy decreases to around 2 kcal/mol, the H-2 polarization effect still increases the adsorption energy. The charge-polarized and electrostatically polarized spaces are therefore an important direction for molecular design of H-2 storage materials.
  • Yuh Hijikata, Hiroyuki Nakashima, Hiroshi Nakatsuji
    JOURNAL OF CHEMICAL PHYSICS 130 (2) 0021-9606 2009/01 [Refereed][Not invited]
    The Schrodinger equations for the hydrogen molecular ion (H-2(+)) and its isotopomers (D-2(+), T-2(+), HD+, HT+, and DT+) were solved very accurately using the free iterative complement interaction method, whih is referred to in short as the free complement (FC) method, in the non-Born-Oppenheimer (non-BO) level, i.e., in the nonrelativistic limit. Appropriate complement functions for both electron and nuclei were generated automatically by the FC procedure with the use of the non-BO Hamiltonian, which contains both electron and nuclear operators on an equal footing. Quite accurate results were obtained not only for the ground state but also for the vibronic excited states. For example, we obtained the ground-state energy of H-2(+) as -0.597 139 063 123 405 074 834 134 096 025 974 142 a.u., which is variationally the best in literature. The difference in the nuclear spin states of S-1 (para) and P-3 (ortho) of H-2(+) and some physical expectation values for several of the isotopomers shown above were also examined. The present study is the first application of the FC method to molecular systems with the non-BO Hamiltonian. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3048986]
  • Hiroyuki Nakashima, Yuh Hijikata, Hiroshi Nakatsuji
    JOURNAL OF CHEMICAL PHYSICS 128 (15) 0021-9606 2008/04 [Refereed][Not invited]
    Very accurate variational calculations with the free iterative-complement- interaction (ICI) method for solving the Schrodinger equation were performed for the 1sNs singlet and triplet excited states of helium atom up to N=24. This is the first extensive applications of the free ICI method to the calculations of excited states to very high levels. We performed the calculations with the fixed-nucleus Hamiltonian and moving-nucleus Hamiltonian. The latter case is the Schrodinger equation for the electron-nuclear Hamiltonian and includes the quantum effect of nuclear motion. This solution corresponds to the nonrelativistic limit and reproduced the experimental values up to five decimal figures. The small differences from the experimental values are not at all the theoretical errors but represent the physical effects that are not included in the present calculations, such as relativistic effect, quantum electrodynamic effect, and even the experimental errors. The present calculations constitute a small step toward the accurately predictive quantum chemistry. (C) 2008 American Institute of Physics.

Books etc

  • 錯体化学選書10 金属錯体の量子・計算化学 4.4章
    土方優, 高柳昌芳, 長岡正隆 (Joint work)
    三共出版 2014/10 (ISBN: 4782707096) 383-402
  • セラミック機能化ハンドブック 多孔性配位高分子の分離・吸着能
    土方 優, 北川 進 (Single work)
    エヌ・ティー・エス出版 2011/01 (ISBN: 4860433505) 347-352

Research Grants & Projects

  • Chemistry of Adaptable Space
    科学研究費補助金 基盤研究(S)
    Date (from‐to) : 2018/06 -2023/03 
    Author : KITAGAWA Susumu
  • 記憶力を有するラセン高分子の創成と究極機能の開拓
    科学研究費補助金 特別推進研究
    Date (from‐to) : 2018/04 -2023/03 
    Author : 八島 栄次
  • 多孔性配位高分子の細孔壁修飾と細孔壁運動による細孔内静電場への摂動的影響の評価
    新学術領域研究(研究領域提案型) 公募研究
    Date (from‐to) : 2017/04 -2019/03 
    Author : 土方 優
  • 吸着が誘起する局所構造変化の配位高分子骨格全体への伝搬過程の解明
    科学研究費補助金 若手研究(B)
    Date (from‐to) : 2017/04 -2019/03 
    Author : 土方 優

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