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藤原 隆司
| 研究機構 科学分析支援センター | 准教授 |
業績情報
■ 論文- Low-dimensional magnetic properties of the ladder-like polynuclear complex Cu2(naphac)2(OH)2 (naphac = 3-(1-naphthyl)acrylate)
Zentaro Honda; Takashi Fujihara; Takanori Kida; Masayuki Hagiwara
Physica B: Condensed Matter, 開始ページ：416254, 終了ページ：416254, 2024年06月
Elsevier BV, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.physb.2024.416254
DOI ID：10.1016/j.physb.2024.416254, ISSN：0921-4526 - Cyclometalated Platinum(II) Complexes in a Cis-N,N Configuration: Photophysical Properties and Isomerization to Trans Isomers
Keiji Ohno; Kazuki Shiraishi; Tomoaki Sugaya; Akira Nagasawa; Takashi Fujihara
Inorganic Chemistry, 巻：61, 号：8, 開始ページ：3420, 終了ページ：3433, 2022年02月
American Chemical Society (ACS), 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/acs.inorgchem.1c03295
DOI ID：10.1021/acs.inorgchem.1c03295, ISSN：0020-1669, eISSN：1520-510X - Substituent effect on emission of flavonolate-boron difluoride complexes: The role of π-system for dual-state (solution and solid) emission
Keiji Ohno; Fuka Narita; Hidehisa Yokobori; Nanami Iiduka; Tomoaki Sugaya; Akira Nagasawa; Takashi Fujihara
Dyes and Pigments, 巻：187, 開始ページ：109081, 終了ページ：109081, 2021年03月, ［査読有り］
Elsevier {BV}, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.dyepig.2020.109081
DOI ID：10.1016/j.dyepig.2020.109081, ISSN：0143-7208, ORCID：96736411 - Large magnetic anisotropy in a quasi-1D ferromagnetic complex Co(sba)(H2O)2·H2O (sba = 4-sulfobenzoate)
Naoyuki Nomoto; Takashi Fujihara; Norihiko Kamata; Yuya Sawada; Takanori Kida; Masayuki Hagiwara; Zentaro Honda
Journal of Solid State Chemistry, 巻：290, 開始ページ：121527, 終了ページ：121527, 2020年10月
Elsevier BV, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jssc.2020.121527
DOI ID：10.1016/j.jssc.2020.121527, ISSN：0022-4596 - o-Azophenylboronic Acid-Based Colorimetric Sensors for d-Fructose: o-Azophenylboronic Acids with Inserted Protic Solvent Are the Key Species for a Large Color Change
Yota Suzuki; Ayumi Ikeda; Keiji Ohno; Takashi Fujihara; Tomoaki Sugaya; Koji Ishihara
The Journal of Organic Chemistry, 2020年08月, ［査読有り］
American Chemical Society ({ACS}), 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/acs.joc.0c01011
DOI ID：10.1021/acs.joc.0c01011, ORCID：77728778 - Spin-inversion mechanisms in O2 binding to a model heme complex revisited by density function theory calculations
Kohei Saito; Yuya Watabe; Takashi Fujihara; Toshiyuki Takayanagi; Jun-ya Hasegawa
Journal of Computational Chemistry, 巻：41, 号：11, 開始ページ：1130, 終了ページ：1138, 2020年04月
Spin-inversion mechanisms in O2 binding to a model heme complex, consisting of Fe(II)-porphyrin and imidazole, were investigated using density-functional theory calculations. First, we applied the recently proposed mixed-spin Hamiltonian method to locate spin-inversion structures between different total spin multiplicities. Nine spin-inversion structures were successfully optimized for the singlet–triplet, singlet–quintet, triplet–quintet, and quintet–septet spin-inversion processes. We found that the singlet–triplet spin-inversion points are located around the potential energy surface region at short Fe–O distances, whereas the singlet–quintet and quintet–septet spin-inversion points are located at longer Fe–O distances. This suggests that both narrow and broad crossing models play roles in O2 binding to the Fe-porphyrin complex. To further understand spin-inversion mechanisms, we performed on-the-fly Born-Oppenheimer molecular dynamics calculations. The reaction coordinates, which are correlated to the spin-inversion dynamics between different spin multiplicities, are also discussed.
John Wiley and Sons Inc., 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/jcc.26159
DOI ID：10.1002/jcc.26159, ISSN：1096-987X, PubMed ID：32020659, SCOPUS ID：85078919630 - Luminescence of mononuclear Pt(ii) complexes with glycolate: external stimuli-induced excimer emission changes to oligomer emissions
Keiji Ohno; Masaya Komuro; Tomoaki Sugaya; Akira Nagasawa; Takashi Fujihara
Dalton Transactions, 2020年, ［査読有り］
Royal Society of Chemistry ({RSC}), 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/C9DT03996A
DOI ID：10.1039/C9DT03996A, ORCID：67685829 - Computational Analysis of Two-State Reactivity in β-Hydride Elimination Mechanisms of Fe(II)– and Co(II)–Alkyl Complexes Supported by β-Diketiminate Ligand
Organometallics, 2019年10月, ［査読有り］
DOI：https://doi.org/10.1021/acs.organomet.9b00418
DOI ID：10.1021/acs.organomet.9b00418, ORCID：61488602 - The First Bis(μ-acetato)(μ-oxido)diruthenium(III) Complexes with Sulfur Donor Ligands
Yohei Ido; Takashi Fujihara; Tomoaki Sugaya; Akira Nagasawa
ChemistrySelect, 巻：4, 号：33, 開始ページ：9696, 終了ページ：9702, 2019年08月, ［査読有り］
WILEY-VCH Verlag GmbH & Co. KGaA, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/slct.201901821
DOI ID：10.1002/slct.201901821 - A water-soluble cyclometalated iridium(iii) complex for pH sensing based on aggregation-induced enhanced phosphorescence
Keiji Ohno; Tetuya Sakata; Machi Shiiba; Akira Nagasawa; Takashi Fujihara
Dalton Transactions, 2019年, ［査読有り］
Royal Society of Chemistry ({RSC})
DOI：https://doi.org/10.1039/C8DT04861D
DOI ID：10.1039/C8DT04861D, ORCID：55496070 - Cover Feature: Observation of the First Spin Crossover in an Iron(II) Complex with an S 6 Coordination Environment: Tris[bis( N , N ‐diethylamino)carbeniumdithiocarboxylato]iron(II) Hexafluorophosphate (Chem. Eur. J. 68/2018)
Tomoaki Sugaya; Takashi Fujihara; Takashi Naka; Takao Furubayashi; Akiyuki Matsushita; Hiroaki Isago; Akira Nagasawa
Chemistry – A European Journal, 2018年12月, ［査読有り］
Wiley
DOI：https://doi.org/10.1002/chem.201805312
DOI ID：10.1002/chem.201805312, ORCID：51622016 - Single-step preparation of topological gels using vinyl-modified β-cyclodextrin as a figure-of-six cross-linker
Yuki Kobayashi; Yu Kojima; Ryotaro Miki; Toshinobu Seki; Takashi Fujihara; Yoshihiro Ishimaru; Yuya Egawa
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 巻：92, 号：3-4, 開始ページ：311, 終了ページ：317, 2018年12月, ［査読有り］
Herein, we have proposed a single-step preparation of topological gels using vinyl-modified -cyclodextrin (V--CyD) and isoprene. Copolymerization of V--CyD and isoprene in an aqueous solution resulted in gelation due to V--CyD acting as a novel type of copolymer chain cross-linker. The vinyl moiety of V--CyD becomes a part of the copolymer, while the -CyD moiety of V--CyD simultaneously incorporates the isoprene component of the copolymer. V--CyD is capable of two different modes of cross-linking at each end, i.e., chemically bonding and mechanically interlocking. Due to the shape of the cross-linking point, we refer to it as figure-of-six cross-linking. Nuclear magnetic resonance analysis showed that the gel contained V--CyD and isoprene in an approximately 1:0.3 stoichiometry. The relatively high content of -CyD was reflected in the character of the gel; the gel swelled in dimethylformamide which is a good solvent of -CyD. A fluorometric analysis using 6-(p-toluidino)-2-naphthalenesulfonic acid showed that the appended -CyD was able to accommodate guest molecules. Introduction of an additional vinyl monomer into the gel was also successful. Addition of 4-vinylphenylboronic acid to the preparation procedure yielded a sugar-responsive gel that swelled in the presence of d-fructose.
SPRINGER, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1007/s10847-018-0852-7
DOI ID：10.1007/s10847-018-0852-7, ISSN：1388-3127, eISSN：1573-1111, ORCID：51094813, Web of Science ID：WOS:000451049300007 - Observation of the First Spin Crossover in an Iron(II) Complex with an S 6 Coordination Environment: Tris[bis( N , N ‐diethylamino)carbeniumdithiocarboxylato]iron(II) Hexafluorophosphate
Tomoaki Sugaya; Takashi Fujihara; Takashi Naka; Takao Furubayashi; Akiyuki Matsushita; Hiroaki Isago; Akira Nagasawa
Chemistry – A European Journal, 2018年12月, ［査読有り］
Wiley
DOI：https://doi.org/10.1002/chem.201803330
DOI ID：10.1002/chem.201803330, ORCID：51048314 - Chromism of Tartrate-Bridged Clamshell-like Platinum(II) Complex: Intramolecular Pt–Pt Interaction-Induced Luminescence Vapochromism and Intermolecular Interactions-Triggered Thermochromism
Keiji Ohno; Yukiko Kusano; Sumio Kaizaki; Akira Nagasawa; Takashi Fujihara
Inorganic Chemistry, 2018年11月, ［査読有り］
American Chemical Society ({ACS})
DOI：https://doi.org/10.1021/acs.inorgchem.8b02074
DOI ID：10.1021/acs.inorgchem.8b02074, ORCID：49948458 - Electron transfer kinetics of methylviologen included in 4-sulfonatocalix[n]arenes at glassy carbon electrode; adiabaticity and activation energy
Takahashi Yuki; Fujihara Takashi; Kobayashi Naritaka; Nakabayashi Seiichiro; Miskolczy Zsombor; Biczok Laszlo
Chemical Physics Letters, 巻：708, 開始ページ：222, 終了ページ：227, 2018年, ［査読有り］
DOI：https://doi.org/10.1016/j.cplett.2018.08.005
DOI ID：10.1016/j.cplett.2018.08.005, ORCID：49468474, Web of Science ID：WOS:000443278800037 - One-dimensional ferromagnetic array compound [Co3(SBA)2(OH)2(H2O)2]n, (SBA = 4-sulfobenzoate)
Zentaro Honda; Naoyuki Nomoto; Takashi Fujihara; Masayuki Hagiwara; Takanori Kida; Yuya Sawada; Takeshi Fukuda; Norihiko Kamata
Solid State Sciences, 巻：80, 開始ページ：155, 終了ページ：160, 2018年, ［査読有り］
DOI：https://doi.org/10.1016/j.solidstatesciences.2018.04.003
DOI ID：10.1016/j.solidstatesciences.2018.04.003, ORCID：49055449 - Safe and rapid development of capillary electrophoresis for ultratrace uranyl ions in radioactive samples by way of fluorescent probe selection for actinide ions from a chemical library
Tomoko Haraga; Kazuki Ouchi; Yoshiyuki Sato; Hitoshi Hoshino; Rei Tanaka; Takashi Fujihara; Hideki Kurokawa; Masami Shibukawa; Ken-ichiro Ishimori; Yutaka Kameo; Shingo Saito
Analytica Chimica Acta, 巻：1032, 開始ページ：188, 終了ページ：196, 2018年, ［査読有り］
After the serious nuclear accident at the Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Earthquake in 2011, the development of feasible, safe, and highly sensitive analytical methods (in terms of low levels of radiation exposure and radioactive waste generation) for radioactive samples, especially actinide (An) ions, represents an important challenge. Here we propose a methodology for selecting appropriate emissive probes for An ions with very low consumption and emission of radioactivity by capillary electrophoresis–laser-induced fluorescence detection (CE-LIF), using a small chemical library of probes with eight different chelating moieties. It was found that the emissive probe L1, which possesses the tetradentate chelating moiety 1,10-phenanthroline-2,9-dicarboxylic acid (PDA), was suitable for detecting uranyl ions. The detection limit for the uranyl–L1 complex using CE-LIF combined with dynamic ternary complexation and on-capillary concentration techniques was determined to be 2.9 × 10−12 M (0.7 ppt). No interference from the large excess of matrix metal ions was observed. This method was successfully applied to real radioactive liquid samples collected from nuclear facilities, including the Fukushima Daiichi Nuclear Power Plant. This strategy not only permitted the development of a safe and rapid analytical method but also provided insight into the coordination chemistry of An ion complexes. Specifically, the PDA structure provided substantial kinetic inertness to its uranyl complex
the formation of a ternary complex between uranyl–L1 and carbonate was revealed
and unusual interactions were observed between the π-electron systems of uranyl and the phenanthroline ring, which stabilized the uranyl–PDA interaction.
Elsevier B.V., 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.aca.2018.05.077
DOI ID：10.1016/j.aca.2018.05.077, ISSN：1873-4324, ORCID：49055441, SCOPUS ID：85048477881 - Syn and anti conformers of diammonium aquabis(malonato)oxidovanadate(IV) in an anhydrate crystal
Keiji Ohno; Takumi Yoshida; Akira Nagasawa; Takashi Fujihara
Acta Crystallographica Section E: Crystallographic Communications, 巻：74, 号：5, 開始ページ：664, 終了ページ：667, 2018年, ［査読有り］
The asymmetric unit of the title anhydrate compound, (NH4)2 [VO(C3 H2 O4)2 (H2 O)], consists of two independent complex anions and four ammonium cations. In the complex anions, the V IV atoms are each coordinated by two malonate ligands, one water molecule and one oxide O atom in a distorted octahedral geometry. The equatorial plane is formed by the malonate O atoms, while the axial positions are occupied by water and oxide O atoms. The difference between the two independent complexes is the relative conformation of the malonate ligands. The two ligands in one complex anion are in a syn conformation, while in the other they adopt an anti conformation. In the crystal, the complex anions interact with the counter-cations and adjacent anions through O - H...O, N - H...O and C - H...O hydrogen bonds. Stacks of alternating layers consisting of either anti or syn isomers, formed with the aid of the hydrogen bonding, are observed. DFT calculations for the anti and syn isomers show a similar thermodynamic stability to each other. The crystal used for this analysis was an inversion twin with the ratio of the twin components being 0.270 (13):0.730 (13).
International Union of Crystallography, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S2056989018005686
DOI ID：10.1107/S2056989018005686, ISSN：2056-9890, ORCID：43712858, SCOPUS ID：85046789915 - A polyrotaxane gel using boronic acid-appended γ-cyclodextrin as a hybrid cross-linker
Wataru Uchida; Maiki Yoshikawa; Tomohiro Seki; Ryotaro Miki; Toshinobu Seki; Takashi Fujihara; Yoshihiro Ishimaru; Yuya Egawa
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 巻：89, 号：3-4, 開始ページ：281, 終了ページ：288, 2017年12月, ［査読有り］
© 2017, Springer Science+Business Media B.V. A boronic acid-appended γ-cyclodextrin (BA-CyD) was synthesized as a hybrid cross-linker of polyvinyl alcohol (PVA) to form a new type of hydrogel. The CyD moiety of BA-CyD forms an inclusion complex with the PVA chain to produce a mechanically interlocking structure. At the same time, the BA moiety of BA-CyD forms covalent bonds with the 1,3-diol moieties of PVA. On the basis of these two modes of interaction, the hybrid cross-linker connects two PVA chains, thus resulting in the formation of a hydrogel. To investigate the possibility of this hydrogel becoming the basis for an intelligent material for drug delivery, sugar-responsive drug release from the hydrogel was demonstrated.
研究論文（学術雑誌）
DOI：https://doi.org/10.1007/s10847-017-0755-z
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85033486758&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85033486758&origin=inward
DOI ID：10.1007/s10847-017-0755-z, ISSN：0923-0750, eISSN：1573-1111, SCOPUS ID：85033486758 - Change in Luminescence Induced by Solution-Mediated Phase-Transition of Cyclometalated Platinum(II) Complex with Isoquinoline Carboxylate
Keiji Ohno; Mami Hasebe; Akira Nagasawa; Takashi Fujihara
INORGANIC CHEMISTRY, 巻：56, 号：20, 開始ページ：12158, 終了ページ：12168, 2017年10月, ［査読有り］
Changes in luminescence due to solution-mediated phase transition (SMPT) and crystal-to-crystal phase transitions of a novel cyclometalated platinum(II) complex with isoquinoline-1-carboxylate (Iq-1-COO-) [Pt(bzq)(Iq-1-COO)] (bzq(-) : benzoquinolinate) were studied experimentally and theoretically. Recrystallization of the complex allowed three crystal forms depending on the solvent: red polymorph R-DMF (lambda(emi) = 689 nm), yellow polymorph Y-DMSO (lambda(emi) = 641 nm), and red pseudopolymorph RBCHCl3 (lambda(emi) = 721 nm). Crystals of R-DMF in the DMF solution at room temperature showed SMPT to yellow crystals Y-DMF (lambda(emi) = 627 nm), in which R-DMF first dissolved partly into the solution, and then the dissolved complex crystallized as Y-DMF. RBCHCl3 exhibited crystal-to-crystal phase transitions to R-DMF and Y-DMF by being heated to 150 degrees C and stored in atmospheric conditions, respectively. Molecular structures of each of the four crystal forms, analyzed by X-ray crystallography, showed different planarities because of the dihedral angles between the bzq(-) and Iq planes being 3.15, 4.80, 8.35, and 17.7 degrees for RBCHCl3, R-DMF, Y-DMSO, and Y-DMF, respectively. The planar complexes in R-DMF and RBCHCl3 constructed dieters through intermolecular Pt-Pt and pi-pi interactions, whereas the distorted complexes in Y-DMF and Y-DMSO remained as monomers. Density functional theory (DFT) calculations, which reveal the relation between the molecular structure and thermodynamic stability, suggest that the SMPT is triggered by thermodynamic transformation from the metastable planar structure to the stable distorted structure. The intradimer interactions in R-DMF and RBCHCl3 induced red-shifts in the absorption and emission colors from those of Y-DMF and Y-DMSO; thus, the photophysical properties of RBCHCl3 and R-DMF originate from the MMLIqCT state in contrast with the MLIqCT/LbzqLIqCT character for Y-DMF and Y-DMSO. DFT and time-dependent DFT (TD-DFT) calculations in the ground and excited states provide insight into the structural, electronic, and optical properties.
AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/acs.inorgchem.7b01466
DOI ID：10.1021/acs.inorgchem.7b01466, ISSN：0020-1669, eISSN：1520-510X, ORCID：37343408, Web of Science ID：WOS:000413279300011 - Luminescence of tartrate bridged dinuclear 2,2 '-bipyridine platinum(II) complexes: emission color controlled by intra- and inter-molecular interactions in the solid state
Keiji Ohno; Honami Tanuma; Yukiko Kusano; Sumio Kaizaki; Akira Nagasawa; Takashi Fujihara
DALTON TRANSACTIONS, 巻：46, 号：23, 開始ページ：7612, 終了ページ：7618, 2017年06月, ［査読有り］
Novel dinuclear Pt-II complexes with a chiral (L-) and an achiral (meso-) tartrate [{Pt-II(bpy)}(2)(mu-x-tart)] (bpy: 2,2'-bipyridine; tartH(2)(2-): tartrate; x = L (1), meso (2)) and with a racemic (DL-) tartrate [{Pt-II(bpy)}(2)(mu-D-tart)][{Pt-II(bpy)}(2)(mu-L-tart)] (3) were synthesized, and the influence of their stereochemistry on their molecular and crystal structures affecting their luminescence was discussed. Effects of the dinuclearity on the structures and luminescence were revealed by comparison with those of a novel racemic mononuclear complex [PtII(bpy)(D-tartH(2))][Pt-II(bpy)(L-tartH(2))] (4). The X-ray crystallography showed the crystallization of 1 in two polymorphs, namely monoclinic 3[1.6H(2)O] (1 alpha) and triclinic 2[1.6H(2)O] (1 beta), and those of other complexes in monoclinic hydrate crystals 2.12.5H(2)O, 3.4H(2)O, and 4.H2O. The chiral complexes in 1 alpha, 1 beta, and 3.4H(2)O showed clamshell-like structures with Pt-Pt and pi-pi interactions, while the achiral complex in 2.12.5H(2)O displayed a twisted form without intramolecular interactions. The complexes in 1 alpha were assembled in a right-handed helical arrangement through significant Pt-Pt interactions, and those in 1 beta and 3.4H(2)O were stacked in one-dimensional columns through significant and slight pi-pi interactions, respectively. The complex in 2.12.5H(2)O constructed an intermolecular dimer through Pt-Pt interactions with its adjacent complex. The crystal structure of 4.H2O displayed a three-dimensional network architecture through pi-pi interactions and hydrogen bonding. These crystals exhibited luminescence depending on their molecular and crystal structures (lambda(max) nm = 535 (4.H2O), 569 (3.4H(2)O), 621 (2.12.5H(2)O), 649 (1 beta), and 656 (1 alpha)). The formations of intermolecular dimers and clamshell-like structures through Pt-Pt interactions in 2.12.5H(2)O and in 3.4H(2)O, respectively, lead to red-shifts in emissions compared to 4.H2O, and further low-energy emissions of 1 alpha and 1 beta were derived from the intermolecular Pt-Pt and pi-pi interactions, respectively.
ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/c7dt00745k
DOI ID：10.1039/c7dt00745k, ISSN：1477-9226, eISSN：1477-9234, Web of Science ID：WOS:000403436200028 - A red fluorophore comprising a borinate-containing xanthene analogue as a polyol sensor
下村 有輝; 江川 祐哉; 三木 涼太郎; 藤原 隆司; 石丸 雄大; 関 俊暢
Organic & biomolecular chemistry, 巻：2016, 号：14, 開始ページ：10031, 終了ページ：10036, 2016年
A xanthene derivative containing a borinate moiety emitted red fluorescence with a high quantum yield. The interaction between the borinate and a sugar molecule induced a fluorescence change based on the change in the HOMO–LUMO gap. The response was pH-resistant in a wide range. In addition, catechol quenched through photoinduced electron transfer. The red fluorescence and polyol binding ability of dyes will pave the way for new biological applications of chemical sensors.Open Access Article
Royal Society of Chemistry, 英語
DOI：https://doi.org/10.1039/c6ob01695b
DOI ID：10.1039/c6ob01695b, ISSN：1477-0520, CiNii Articles ID：120005960911, CiNii Books ID：AA1168650X - Mechanochromism in the luminescence of novel cyclometalated platinum(II) complexes with alpha-aminocarboxylates
Keiji Ohno; Shohei Yamaguchi; Akira Nagasawa; Takashi Fujihara
DALTON TRANSACTIONS, 巻：45, 号：13, 開始ページ：5492, 終了ページ：5503, 2016年, ［査読有り］
Six novel phosphorescent cyclometalated platinum(II) complexes with alpha-aminocarboxylato ligands, [Pt-II(ppy) L] (ppy = 2-phenylpyridinato, L-= Gly, Ala, Leu, Ile, Phe, Sar), were synthesized, and the structures were determined by X-ray crystallography. [Pt-II(ppy) L] (L-= Gly, Ala) in crystals are in monomeric structures and stack through pi-pi interactions to form columns, and the features of the luminescence are similar to each other and those in solution, suggesting little influence of the pi-pi interactions on the luminescence. [Pt-II(ppy) Leu] has a dimeric structure through the Pt-Pt interaction. [Pt-II(ppy) Sar] showed two pseudo-polymorphs, one of which contains both monomeric and dimeric forms, while the other consists of only dimeric units. Intra-dimer pi-pi interactions were observed in both the dimeric units. [Pt-II(ppy) L] (L-= Leu, Ile, Phe) in the solid state displayed different spectral patterns of luminescence from those in solution, suggesting that the dimeric structures through the Pt-Pt interaction in the solid state are dissociated into the corresponding monomeric ones in solution. The complexes except [Pt-II(ppy) Phe] in the solid state exhibited reversible luminescent mechanochromism in response to the mechanical grinding and treatment with a few drops of solvent. These phenomena are induced by the change in the energy level of the triplet state due to the change in the extent of intermolecular interactions, which appeared due to the crystalline-amorphous phase conversion.
ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/c5dt04516a
DOI ID：10.1039/c5dt04516a, ISSN：1477-9226, eISSN：1477-9234, Web of Science ID：WOS:000372608300012 - Synthesis and Antiaromatic Properties of Highly Planar Dithiaamethyrin
Yoshihiro Ishimaru; Naoyuki Shimoyama; Takashi Fujihara; Keigo Watanabe; Jun-ichiro Setsune
CHEMISTRY-AN ASIAN JOURNAL, 巻：10, 号：2, 開始ページ：329, 終了ページ：333, 2015年02月, ［査読有り］
2,5-Bis(4-propyl-2-pyrrolyl) thiophene was reacted with aryl aldehydes to afford large porphyrinoids; [24]dithiaamethyrin(1.0.0.1.0.0) and [36]trithianonaphyrin(1.0.0.1.0.0.1.0.0). X-ray crystallography of the dithiaamethyrin revealed a highly planar ring structure with mean plane deviation (MPD) value of 0.053 angstrom. A large positive NICS(0) value (+13.9 ppm) calculated for this planar 24 pi system unambiguously indicates an antiaromatic character that is consistent with a remarkably low field H-1 chemical shift of the inner NH proton at 24.0 ppm. The magnitude of the paratropic ring current effect in the 24 pi amethyrin framework in the free base form and the diprotonated form was discussed on the basis of the MPD value and the NICS value. The present dithiaamethyrin is much more strongly antiaromatic than the dodecaalkylamethyrin in their free base forms, but the order inversed in their di-protonated forms.
WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/asia.201403126
DOI ID：10.1002/asia.201403126, ISSN：1861-4728, eISSN：1861-471X, Web of Science ID：WOS:000348719500006 - Crystal Structure of the Spin 1=2 Honeycomb-Lattice Antiferromagnet Cu2(pymca)3(ClO4)
Zentaro Honda; Takafumi Kodama; Reo Kikukawa; Masayuki Hagiwara; Takanori Kida; Masamichi Sakai; Takeshi Fukuda; Takashi Fujihara; Norihiko Kamata
Journal of the Physical Society of Japan, 2015年02月, ［査読有り］, ［招待有り］
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.7566/JPSJ.84.034601
DOI ID：10.7566/JPSJ.84.034601 - Crystal structure of 4,4'-dimethoxy-2,2'-bipyridine
Yukiko Kusano; Keiji Ohno; Takashi Fujihara
Acta Crystallographica Section E: Crystallographic Communications, 巻：71, 開始ページ：o623, 終了ページ：o624, 2015年, ［査読有り］
In the title compound, C12H12N2O2, the dihedral angle between the planes of the two pyridine rings is 5.8 (1)°. Neighbouring molecules are linked via C(Me)-H···N interactions, generating a two-dimensional sheet structure
C-H···π interactions further link the molecules into a three-dimensional network. An overlapped arrangement of parallel pyridine rings in neighbouring molecules [centroid-to-centroid distance = 3.6655 (15) Å] is observed in the crystal structure.
International Union of Crystallography, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S2056989015013985
DOI ID：10.1107/S2056989015013985, ISSN：2056-9890, SCOPUS ID：84976476538 - Crystal structure of fac-trichlorido[tris(pyridin-2-yl-N)amine]chromium(III)
Yukiko Yamaguchi-Terasaki; Takashi Fujihara; Akira Nagasawa; Sumio Kaizaki; M. Weil
Acta Crystallographica Section E: Structure Reports Online, 巻：71, 号：1, 開始ページ：73, 終了ページ：75, 2015年01月, ［査読有り］
In the neutral complex molecule of the title compound, fac-[CrCl<
inf>
3<
/inf>
(tpa)] [tpa is tris(pyridin-2-yl)amine
C<
inf>
15<
/inf>
H<
inf>
12<
/inf>
N<
inf>
4<
/inf>
], the Cr<
sup>
III<
/sup>
ion is bonded to three N atoms that are constrained to a facial arrangement by the tpa ligand and by three chloride ligands, leading to a distorted octahedral coordination sphere. The average Cr - N and Cr - Cl bond lengths are 2.086 (5) and 2.296 (4) Å, respectively. The complex molecule is located on a mirror plane. In the crystal, a combination of C - H⋯N and C - H⋯Cl hydrogen-bonding interactions connect the molecules into a three-dimensional network.
International Union of Crystallography, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S2056989014027066
DOI ID：10.1107/S2056989014027066, ISSN：1600-5368, SCOPUS ID：84928156017 - Dinuclear nickel(II) complexes with 2,5-diamino-1,4-benzoquinonediimine ligands as precatalysts for the polymerization of styrene: electronic and steric substituent effects
Keiji Ohno; Akira Nagasawa; Takashi Fujihara
DALTON TRANSACTIONS, 巻：44, 号：1, 開始ページ：368, 終了ページ：376, 2015年, ［査読有り］
Catalytic polymerization of styrene with a series of dinuclear nickel(II) complexes [{Ni(acac)}(2){mu-C6H2-(N-Ph-R)(4)}] (R = 4-Et (1a), 4-OEt (1b), 2-OEt (1c), 2-Et (1d), and 2,6-Et-2 (1e)) in the presence of methyl-aluminoxane was studied under various conditions to evaluate the substituent effect. The activity of 1a-1e, except 1c, increased with an increase in the reaction temperature, and the highest activity (7.46 x 10(5) g PS mol(-1) Ni h(-1)) was obtained using 1e at 70 degrees C. The electronic and steric properties of the ligand influenced the activity at room temperature, 50 degrees C, and 60 degrees C, steric factors barely, whereas electronic factors slightly dominated the activity at 70 degrees C. The activity with 1c remained constant at all temperatures, probably due to the masking of the active center by the formation of inactive N,N',O-chelate species. The obtained polymers were atactic polystyrenes with molecular weights and molecular weight distributions in the range of 15 000-43 400 and 1.71-2.14, respectively. While a clear dependence of the molecular weight and molecular weight distribution on the temperature was observed, no significant dependence on the substituent was noted.
ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/c4dt02858a
DOI ID：10.1039/c4dt02858a, ISSN：1477-9226, eISSN：1477-9234, Web of Science ID：WOS:000346408900045 - Preparation of polypseudorotaxanes composed of cyclodextrin and polymers in microspheres
Katsunori Shinohara; Miki Yamashita; Wataru Uchida; Chie Okabe; Shinji Oshima; Masahiro Sugino; Yuya Egawa; Ryotaro Miki; Osamu Hosoya; Takashi Fujihara; Yoshihiro Ishimaru; Tohru Kishino; Toshinobu Seki; Kazuhiko Juni
Chemical and Pharmaceutical Bulletin, 巻：62, 号：10, 開始ページ：962, 終了ページ：966, 2014年10月, ［査読有り］
© 2014 The Pharmaceutical Society of Japan. We prepared polypseudorotaxanes (PPRXs) composed of cyclodextrin (CyD) and polyethylene glycol (PEG) inside microspheres (MSs) by an emulsifying process using polypropylene glycol (PPG) that shows temperature-dependent hydrophilicity changes; PPG is hydrophobic at high temperatures but hydrophilic at low temperatures. An aqueous solution of CyD and PEG was dispersed as droplets in PPG at 60°C then cooled to 0°C to allow water of droplets to transfer into PPG. On removal of water in the droplets, CyD and PEG were left behind as a CyD/PEG PPRX inside the solid-state MSs. Examination of α-, β-, and γ-CyD revealed that α-CyD was suitable for the formation of PPRX containing PEG in this MS preparation procedure. Interestingly, a new PPRX composed of α-CyD and PPG was formed in the α-CyD MSs when they were prepared in the absence of PEG from the aqueous solution of α-CyD. This MS fabrication procedure can control the size and shape of PPRX particles, and will contribute to the production of new types of CyD inclusion complexes.
研究論文（学術雑誌）
DOI：https://doi.org/10.1248/cpb.c14-00313
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84908179531&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=84908179531&origin=inward
DOI ID：10.1248/cpb.c14-00313, ISSN：0009-2363, eISSN：1347-5223, PubMed ID：25273055, SCOPUS ID：84908179531 - Formation of boron, nickel(II) and iridium(III) complexes with an azophenine derivative: Isomerization, delocalization and extension of the pi-conjugated system on coordination
Keiji Ohno; Takashi Fujihara; Akira Nagasawa
POLYHEDRON, 巻：81, 開始ページ：715, 終了ページ：722, 2014年10月, ［査読有り］
The azophenine N,N',N '',N'''-tetra-4-ethylpheny1-2,5-diamino-1,4-benzoquinonediimine (4-EtApH(2)), its diprotonated species [4-EtApH(4)](ClO4)(2) (1) and complexes, the bis(boron difluoride) complex (2), the mono- and dinuclear nickel(II) complexes (Ni(4-EtApH(2))(3)](ClO4)(2) (3) and [{Ni(acac)}2(R-4-EtAp)] (4), respectively, and the dinuclear iridium(III) complex [{Ir(cp*)Cl)(2)(mu-4-EtAp)] (5), have been prepared. The molecular structures of these compounds were determined by X-ray analysis. The coordination environments around the boron center of 2 and the Ni centers of 3 and 4 were tetrahedral, octahedral and square-planar, respectively. Furthermore, each Ir center of 5 was coordinated by two nitrogen atoms from 4-EtAp(2-), Cl- and eta(5)-cp*. Coordination of the ligand to Ni to form 3 caused an isomerization from the para-benzoquinonediimine of 4-EtApH(2) to the ortho form, with a bond alternation at each of the two N-C-C-C-N 7c-systems. Diprotonation and dinuclear complex formation to construct 1, 2, 4 and 5 led to a delocalization of six pi-electrons over each of the two N-C-C-C-N moieties connected by single bonds. The pi-pi* transition absorption gradually shifted to longer wavelengths (4-EtApH(2)approximate to 3 -> 2 -> 1 -> 4 approximate to 5), suggesting an extension of the pi-conjugation range. Cyclic voltammograms of 3 and 4 showed one and two redox potential(s), respectively. (C) 2014 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.poly.2014.07.030
DOI ID：10.1016/j.poly.2014.07.030, ISSN：0277-5387, Web of Science ID：WOS:000343339600090 - Lattice Water-Induced Helical Stacking of Tartrate-Bridged Dinuclear Palladium(II) Complexes: The Role of Hydrogen Bonding
Keiji Ohno; Tomoaki Sugaya; Masaru Kato; Noriko Matsumoto; Ryoko Fukano; Yasuyo Ogino; Sumio Kaizaki; Takashi Fujihara; Akira Nagasawa
CRYSTAL GROWTH & DESIGN, 巻：14, 号：8, 開始ページ：3675, 終了ページ：3679, 2014年08月, ［査読有り］
Hydrous crystals of [{Pd-II(bpy)}(2)(mu-x-tart)]. nH(2)O (bpy: 2,2'-bipyridine; tartH(2)(2-): tartrate; 1a: x = L, n = 6; 2a: x = D, n = 6; 3a: x = DL, n = 4; 4a: x = meso, n = 4) and anhydrous crystals of [{Pd-II(bpy)}(2)(mu-L-tart)] (1b) were isolated from aqueous and MeOH solutions, respectively. X-ray crystallography revealed the stacked structures of clamshell-like dinuclear units in 1a-3a and 1b, where intramolecular metal metal and pi-pi stacking interactions were observed. Right- and left-handed helically stacked columns were formed in the 1a and 2a crystals, respectively. The significant role of hydrogen bonding among lattice water molecules and tartrate is suggested because 1b exhibited a zigzag arrangement only through intermolecular metal-metal interactions. In 3a, L- and D-tart units stacked alternately in a zigzag arrangement with intermolecular pi-pi interactions. In 4a, dimeric aggregates of the twisted dinuclear units further formed a 2D sheet architecture.
AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/cg500143w
DOI ID：10.1021/cg500143w, ISSN：1528-7483, eISSN：1528-7505, ORCID：16525295, Web of Science ID：WOS:000340080400001 - An orthorhombic polymorph ofN1,N4-diphenyl-3,6-bis(phenylimino)cyclohexa-1,4-diene-1,4-diamine
Keiji Ohno; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E Structure Reports Online, 巻：70, 号：4, 開始ページ：o495, 終了ページ：o496, 2014年03月
A new orthorhombic polymorph of the title compound, C30H24N4, with a density of 1.315 Mg m−3, has been obtained. The molecule is centrosymmetric with the centroid of the cyclohexa-1,4-diene ring located on an inversion center. The two unique benzene rings are almost perpendicular to each other [dihedral angle = 86.70 (6)°] and are oriented at dihedral angles of 30.79 (5) and 68.07 (5)° with respect to the central cyclohexadiene ring. In the crystal, π–π stacking is observed between the central cyclohexa-1,4-diene-1,4-diamine unit and a phenyl ring of a neighboring molecule [centroid–centroid distance = 3.7043 (7) Å]. The crystal structure of the triclinic polymorph [Ohnoet al.(2014).Acta Cryst.E70, o303–o304] showed chains running along theb-axis direction through weak C—H...π interactions.
International Union of Crystallography (IUCr), 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/s1600536814006254
DOI ID：10.1107/s1600536814006254, eISSN：1600-5368 - N 1,N 4-Diphenyl-3,6-bis(phenylimino)cyclohexa-1,4- diene-1,4-diamine
Keiji Ohno; Haruki Maruyama; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：70, 号：3, 開始ページ：o303, 終了ページ：o304, 2014年03月, ［査読有り］
In the title compound, C30H24N4, the central benzoquinonediimine moiety is approximately planar, with a maximum deviation of 0.044 (14) Å. The four terminal phenyl rings are twisted by 44.95 (11), 54.90 (10), 44.98 (10) and 50.68 (11)° with respect to the mean plane the benzoquinonediimine unit. In the crystal, molecules are linked by weak C - H⋯π interactions into supramolecular chains running along the b-axis direction.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536814002906
DOI ID：10.1107/S1600536814002906, ISSN：1600-5368, SCOPUS ID：84897744694 - Preferential Behavior on Donating Atoms of an Ambidentate Ligand 2-Methylisothiazol-3(2H)-one in Its Metal Complexes
Masaru Kato; Kei Unoura; Toshiyuki Takayanagi; Yasuhisa Ikeda; Takashi Fujihara; Akira Nagasawa
INORGANIC CHEMISTRY, 巻：52, 号：23, 開始ページ：13375, 終了ページ：13383, 2013年12月, ［査読有り］
Five metal complexes of 2-methylisothiazol-3(2H)-one (MIO), [Co-III(NH3)(5)(MIO)](3+), [Ru-II(NH3)(5)(MIO)](2+), [Ru-III(NH3)(5)(MIO)](3+), (-), and trans-, were synthesized, and their structures were determined by single-crystal X-ray crystallography. MIO is an ambidentate ligand and coordinates to metal centers through its oxygen atom in the cobalt(III), ruthenium(III), and uranium(VI) complexes and through its sulfur atom in the ruthenium(II) and platinum(III) complexes. This result suggests that MIO shows preferential behavior on its donating atoms. We also studied the electron-donor abilities of the oxygen and sulfur atoms of MIO. Various physical measurements on the conjugate acid of MIO and the MIO complexes allowed us to determine an acid dissociation constant (pK(a)) and donor number (DN) for the oxygen atom of MIO and Lever's electrochemical parameter (E-L) and a relative covalency parameter (k(L)) for the sulfur atom.
AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/ic401673z
DOI ID：10.1021/ic401673z, ISSN：0020-1669, eISSN：1520-510X, ORCID：12234327, Web of Science ID：WOS:000327831600015 - Dinuclear niobium(III) and tantalum(III) complexes with thioether and selenoether ligands [{(MX2)-X-III(L)}(2)(mu-X)(2)(mu-L)] (M = Nb, Ta; X = Cl, Br; L = R2S, R2Se): Syntheses, structures, and the optimal conditions and the mechanism of the catalysis for regioselective cyclotrimerization of alkynes
Masatoshi Matsuura; Takashi Fujihara; Masaki Kakeya; Tomoaki Sugaya; Akira Nagasawa
JOURNAL OF ORGANOMETALLIC CHEMISTRY, 巻：745, 開始ページ：288, 終了ページ：298, 2013年11月, ［査読有り］
A series of dinuclear niobium(III) and tantalum(III) halide complexes with chalcogen donors [{(MX2)-X-III(L)}(2)(mu-X)(2)(mu-L)] (M = Nb; X = Cl, Br; L = R2S, R2Se) (M = Ta; X = Cl, Br; L = R2S) have been prepared by the reaction of dimetal(V) decahalide (M2X10) with magnesium and L. The structures of five of those new complexes were determined by X-ray crystallography to have a M-M double bond. It is evidenced that the solvent and the temperature play important roles in achieving high yield and regioselectivity for cyclotrimerization of alkynes. The reaction of the niobium(III) chloride complexes (L = dimethyl sulfide (Me2S), tetrahydrothiophene (C4H8S, THT, thiolane)) with phenylacetylene at room temperature in toluene gave both head-to-tail cycloadded trimers of alkyne, 1,3,5-(Ph)(3)-2,4,6-(H)(3)-benzene and head-to-head cycloadded 1,2,4-(Ph)(3)-3,5,6-(H)(3)-benzene, in high yields. The smaller the thioether ligands, the higher the catalytic activity. The niobium(III) chloride complexes with selenoether (L dimethyl selenide (Me2Se), tetrahydroselenophene (C4H8Se, THSe, selenolane) have higher rates for the reaction with alkynes, but low activity for the cyclotrimerization. Tantalum(III) chloride complexes (L = Me2S, THT, tetrahydrothiopyran (C5H10S, THTP, thiane)) have lower catalytic activities than the niobium(III) ones, because the Ta-S(mu-L) bond lengths are shorter than those of niobium analogs. The stability of the precursor complexes toward the first oxidative addition depends on the M-S(mu-L) bond strength, and controls the concentration of catalytic active species. The niobium(III) bromide complexes (L = Me2S, THT) and the tantalum(III) bromide one (L = Me2S) react with alkynes to give head-to-tail compounds regioselectively, but are less catalytically active than those of chloride complexes. (C) 2013 Elsevier B. V. All rights reserved.
ELSEVIER SCIENCE SA, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jorganchem.2013.07.035
DOI ID：10.1016/j.jorganchem.2013.07.035, ISSN：0022-328X, eISSN：1872-8561, Web of Science ID：WOS:000326112700041 - A Kinetic Study on the Substitution for Acetonitrile at the trans-to-Oxido Sites in a Bis(mu-acetato)(mu-oxido)diruthenium(III) Dipositive Complex: Dissociative-Associative Transition of the Activation Mode for the Substitution of Pyridine Derivatives
Yohei Ido; Kiyoshi Sakaguchi; Minako Tasei; Suguru Minami; Hiroki Sawamoto; Takashi Fujihara; Akira Nagasawa
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 巻：2013, 号：21, 開始ページ：3641, 終了ページ：3650, 2013年07月, ［査読有り］
<title content-type="main">Abstract
A new diruthenium(III) complex [Ru-2(III)(-O)(-CH3CO2)(2)(bpy)(2)(CH3CN)(2)](PF6)(2) [1(PF6)(2), bpy = 2,2-bipyridine] has been synthesized, and the dynamic behaviour of CH3CN at the trans-to--oxido sites were investigated by H-1 NMR and UV/Vis spectroscopy at 0-60 degrees C under 0.101-147 MPa in CH3CN. The solvent exchange in CD3CN at 5 degrees C gave the rate constant k = 2.43x10(-3) s(-1) and the activation parameters H-double dagger = 124 kJmol(-1) and S-double dagger = +150 JK(-1)mol(-1), which point to a dissociative mechanism (I-d or D). The ligand substitution of pyridine (py) in CD3CN at 30 degrees C, yielding [Ru-2(III)(-O)(-CH3CO2)(2)(bpy)(2)(py)(2)](PF6)(2) [2a(PF6)(2)], gave a rate constant per site of k = 1.56x10(-2) M(-1)s(-1), and the activation parameters H-double dagger = 81 kJmol(-1) and S-double dagger = -13 JK(-1)mol(-1). The substitution of various pyridine derivatives (Rpy) for CH3CN in 1(PF6)(2) exhibited varying activation parameters: H-double dagger ranged from 66 to 92 kJmol(-1), S-double dagger ranged from -51 to +22 JK(-1)mol(-1), and V-double dagger (for Rpy with R = H, 3-Ac, 4-NH2, 4-CN, 3-CN) ranged from +1.3 to +3.2 cm(3)mol(-1). These results suggest an interchange (I) mechanism for the substitution of Rpy, for which its strong electron-donating ability is responsible. A compensation effect is seen between H-double dagger and S-double dagger, and both have linear relationships with the Hammett parameters. The substituent R electronically influences the strength of the interaction of Rpy with Ru center in the transition state to shift the activation mode to a dissociative (I-d) or an associative (I-a) interchange.
WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/ejic.201300173
DOI ID：10.1002/ejic.201300173, ISSN：1434-1948, Web of Science ID：WOS:000321632100014 - Syntheses and Properties of Dinuclear Group 6 Metal Complexes with the Zwitterionic Sulfur Donor Ligand Bis(N,N-diethylamino)carbeniumdithiocarboxylate
Tomoaki Sugaya; Takeshi Ohba; Fumiya Sai; Shigeru Mashima; Takashi Fujihara; Kei Unoura; Akira Nagasawa
ORGANOMETALLICS, 巻：32, 号：12, 開始ページ：3441, 終了ページ：3450, 2013年06月, ［査読有り］
A class of dinuclear group 6 metal complexes [{M-0(CO)(5)}(2)(mu-S,S'-EtL)] (M = Cr, Mo, W) with the asymmetrically bridged zwitterionic sulfur donor bis(N,N-diethylamino)carbeniumdithiocarboxylate (EtL) was prepared by photoreaction of [M-0(CO)(6)] with EtL in hexane-CH2Cl2 for Cr and Mo or THF for W. The same structure in a syn-anti coordination mode was revealed by X-ray analyses for chromium(0) and tungsten(0) complexes, 1 and 3, respectively, and speculated from various analytical data for the molybdenum(0) complex 2. The pertinent criteria for the coordination mode are found to be the wavenumber of the asymmetric stretching vibration of the -CS2 moiety in the solid state and the ligand-based reduction potential in solution. Complexes 1 and 3 showed quasi-reversible reduction waves, which are assigned to a two-step, one-electron reduction process derived from the bridging EtL. In a series of [Cr(CO)(5)L] complexes (L = monodentate ligand), the C-13 NMR chemical shifts of the trans-to-L carbonyl group showed the order of increasing sigma-donor/pi-acceptor ratio of the ligands. The sulfur donor ligands, including EtL and thione, are positioned in the middle of this range. All complexes exhibited negative solvatochromism: the wavelength of the absorption maximum shifted to the blue side in the range 500-600 nm with an increase in the Reichardt solvent polarity parameters E-T(30), except for protic solvents. Quantum chemical calculations by time-dependent density functional theorypolarized continuum model were employed for understanding the excited states and solvatochromic properties of complex 3. The calculated vertical excitation energies in solution are consistent with the experimental data, suggesting that the transition is a metal-to-ligand charge-transfer transition. In addition, UV-vis, NMR, and cyclic voltammetry data showed that complex 3 dissociates into two mononuclear species in polar solvents: [W(CO)(5)(EtL)] and [W(CO)(5)(solvent)].
AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/om300831y
DOI ID：10.1021/om300831y, ISSN：0276-7333, Web of Science ID：WOS:000321074500003 - Cis-Dichloridobis(ethyl methyl sulfide-κS)oxidovanadium(IV)
Masatoshi Matsuura; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：69, 号：4, 開始ページ：m209, 2013年04月, ［査読有り］
The mononuclear title complex, [VCl2O(C3H 8S)2], features a VIV=O double bond [1.5845 (15) Å] in an overall trigonal-bipyramidal coordination environment defined by two Cl- and the S atoms of two (CH3CH 2)(CH3)S ligands. In the crystal, pairs of molecules form centrosymmetric dimers via C-H⋯O hydrogen bonds between the methyl C-H group and the oxidovanadium O atom of a neighbouring molecule.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536813006703
DOI ID：10.1107/S1600536813006703, ISSN：1600-5368, SCOPUS ID：84875979626 - Di-μ-acetato-κ4 O:O′-μ-oxido- κ2 O:O′-bis[cis-(2,2′-bipyridine- κ2 N,N′)-trans-(pyridine-κN)ruthenium(III)] bis(hexafluoridophosphate)
Yohei Ido; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：69, 号：3, 開始ページ：m145, 終了ページ：m146, 2013年03月, ［査読有り］
The hemerythrin-type dinuclear title complex, [Ru2(CH3COO)2O(C10H8N2) 2(C5H5N)2](PF6)2, consists of two RuIII ions with a six-coordinate octahedral geometry, bridged by an oxide and two acetate ligands, with a bidentate 2,2′-bipyridine ligand and a pyridine ligand bonding at terminal positions. The Ru - Ru distance and Ru - O - Ru angle are 3.2838 (3) Å and 121.79 (7)°, respectively, and the average Ru - N(pyridine) bond length is 2.164 (8) Å. Several C - H⋯F, C - H⋯O and C - H⋯N interactions generate a three-dimensional network in the crystal structure. π-π stacking interactions [centroid-centroid distance = 3.6389 (3) Å] between inversion-related 2,2′-bipyridine rings are also observed. © 2013 Ido et al.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536813003334
DOI ID：10.1107/S1600536813003334, ISSN：1600-5368, SCOPUS ID：84874861855 - 2-{[2,2-Bis(diethylamino)ethan-2-yliumthioyl]sulfanyl}-1, 1-bis-(diethylamino)-ethylium bis(perchlorate)
Keiji Ohno; Tomoaki Sugaya; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E, 巻：68, 号：9, 開始ページ：o2753, 終了ページ：o2754, 2012年08月, ［査読有り］
International Union of Crystallography, 英語, 研究論文（学術雑誌） - Electronic structure calculation study of metal complexes with a phytosiderophore mugineic acid
Masaru Kato; Shinjiro Izuka; Takashi Fujihara; Akira Nagasawa; Sigenao Kawai; Tomokazu Tanaka; Toshiyuki Takayanagi
INORGANICA CHIMICA ACTA, 巻：370, 号：1, 開始ページ：304, 終了ページ：310, 2011年05月, ［査読有り］
Structural and thermodynamic properties of biologically important metal-mugineic acid complexes have been studied from the theoretical side in order to understand the metal-chelating mechanism of phytosiderophore mugineic acid at an atomic level. Density-functional theory methods combined with the polarizable continuum model (PCM) have been employed to obtain free energies of complex formation and redox potentials for metal-mugineic acid complexes in solution. It has been found that the free energies of complex formation calculated at the B3LYP/PCM level of theory are in moderate agreement with available experimental results. The inclusion of explicit water molecules interacting with the carboxylic groups in deprotonated mugineic acid through strong hydrogen-bonds is found to further improve the calculated free energies of complex formation. (C) 2011 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.ica.2011.01.091
DOI ID：10.1016/j.ica.2011.01.091, ISSN：0020-1693, ORCID：12234332, Web of Science ID：WOS:000289556300045 - Ferromagnetic Spin Ladder System: Stack of Chlorido-Bridged Dinuclear Copper(II) Complexes with 2-Methylisothiazol-3(2H)-one
Masaru Kato; Kazuo Hida; Takashi Fujihara; Akira Nagasawa
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 号：4, 開始ページ：495, 終了ページ：502, 2011年02月, ［査読有り］
A dinuclear copper(II) complex, [{Cu(II)Cl(O-mi)}(2)(mu-Cl)(2)] [mi = 2-methylisothiazol-3(2H)-one], has been synthesized and its molecular structure in the solid state determined by single-crystal X-ray analysis. The crystal consists of centrosymmetric dinuclear copper(II) units in which each copper(II) ion is doubly bridged by two chloride ions and has a slightly distorted square-planar geometry with a terminal chlorido ligand and a terminal mi ligand coordinated through the oxygen atom. The dinuclear units stack one on top of another to form a one-dimensional two-leg ladder structure. The magnetic susceptibility of the powder was measured in the temperature range 3.0-302 K. It was found that there are ferromagnetic interactions along the rung (in the same direction of the intramolecule; J(rung) = +5.03 +/- 0.03 cm(-1)) and the leg (in the same direction of the intermolecule; J(leg) = +1.96 +/- 0.02 cm(-1)) and an antiferromagnetic interaction along the diagonal (J(x) = -1.36 +/- 0.02 cm(-1)), the experimental data being fitted by the numerical calculation for a twelve-site ladder Hamiltonian. In addition, DFT calculations with the UB3LYP functional on the model complex [{Cu(II)Cl(O-mi)}(2)(mu-Cl)(2)] gave an intramolecular magnetic coupling constant J = +28.6 cm(-1) and indicated that the spin-density distribution on O in mi is less than that on the terminal Cl. We conclude that the O-donor ligand at the terminal position plays an essential role in the emerging intramolecular ferromagnetic interaction.
WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/ejic.201000096
DOI ID：10.1002/ejic.201000096, ISSN：1434-1948, ORCID：12234333, Web of Science ID：WOS:000287160500006 - Resorcin[4]arene cavitand with 1,3,2-benzodiazaborolyl walls as a fluorescence receptor for ammonium cations
Yuji Kubo; Kazusa Tsuruzoe; Sachiko Okuyama; Ryuhei Nishiyabu; Takashi Fujihara
CHEMICAL COMMUNICATIONS, 巻：46, 号：20, 開始ページ：3604, 終了ページ：3606, 2010年
Resorcin[4]arene cavitand 1 with 1,3,2-benzodiazaborolyl walls was newly synthesized. It showed a large blue shift in the fluorescence spectra upon selective complexation with alkyltrimethylammonium salts in CH2Cl2-DMSO (9:1 v/v); this shift was detectable with the naked eye.
ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/c0cc00259c
DOI ID：10.1039/c0cc00259c, ISSN：1359-7345, eISSN：1364-548X, PubMed ID：20383396, SCOPUS ID：77952391505, Web of Science ID：WOS:000277487700053 - Group 12 metal complexes with inner-salt, bis(N,N-disubstituted amino)carbeniumdithiocarboxylate. Asymmetric stretching vibration of thiocarboxylate and reduction potential as probes for the coordination mode
Tomoaki Sugaya; Takashi Fujihara; Akira Nagasawa; Kei Unoura
Inorganica Chimica Acta, 巻：362, 号：13, 開始ページ：4813, 終了ページ：4822, 2009年07月, ［査読有り］
Elsevier B.V., 英語, 研究論文（学術雑誌） - Linkage isomerism of pentaammine(dimethylsulfoxide)ruthenium(II/III) complexes: A theoretical study
Kato Masaru; Takayanagi Toshiyuki; Fujihara Takashi; Nagasawa Akir
Inorganica Chimica Acta, 巻：362, 号：4, 開始ページ：1199, 終了ページ：1203, 2009年, ［査読有り］
DOI：https://doi.org/10.1016/j.ica.2008.06.012
DOI ID：10.1016/j.ica.2008.06.012, ORCID：12234336 - Rearrangement of the tert-butyl group of 5,6-di-tert-butyl-2,3,7-trithiabicylo-5-ene 7-endoxide
Sanae Yoshida; Yuta Morohashi; Takashi Fujihara; Yoshiaki Sugihara; Juzo Nakayama
JOURNAL OF SULFUR CHEMISTRY, 巻：29, 号：1, 開始ページ：1, 終了ページ：7, 2008年, ［査読有り］
Treatment of 5,6-di-tert-butyl-2,3,7-trithiabicylo-5-ene 7-endoxide with trimethylsilyl trifluoromethanesulfonate at room temperature resulted in the rearrangement of tert-butyl group to furnish 4,6-di-tert-butyl- 2,3,7-trithiabicylo-5-ene 7-endoxide quantitatively. Meanwhile, treatment of the compound by trimethyloxonium tetrafluoroborate afforded 4,5-di-tert-butyl-1,2-dithiin 1,1-dioxide in addition to the above rearrangement product.
TAYLOR & FRANCIS LTD, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1080/17415990701753373
DOI ID：10.1080/17415990701753373, ISSN：1741-5993, Web of Science ID：WOS:000269194500001 - 1,1,1-tris(phenylsulfonyloxymethyl)ethane
Takashi Fujihara; Eri Shioji; Akira Nagasawa
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 巻：63, 開始ページ：O3628, 終了ページ：U4627, 2007年08月, ［査読有り］
In the crystal structure of the title compound, C23H24O9S3, intermolecular C-H center dot center dot center dot O hydrogen bonds are found, which link the molecules into a three-dimensional network. Weak C-H center dot center dot center dot pi interactions are also present in the structure.
BLACKWELL PUBLISHING, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536807035507
DOI ID：10.1107/S1600536807035507, ISSN：1600-5368, Web of Science ID：WOS:000249692200421 - Mutual influences of ligands as revealed by H-2 NMR shifts and the angular overlap model parameters: trans- and cis-[CrX2(N)(4)]-type complexes with aliphatic amine ligands
Yukiko Yamaguchi-Terasaki; Takashi Fujihara; Sumio Kaizaki
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 号：21, 開始ページ：3394, 終了ページ：3399, 2007年07月, ［査読有り］
We have previously reported the relationship between H-2 NMR chemical shift differences (Delta delta) and the angular overlap model (AOM) parameter e(sigma)(F), which represents the sigma antibonding interaction energy obtained from the solvatochromism, for trans-[CrF2([D-4]-3,2,3-tet)](n+) {[D-4]3,2,3-tet = 1,10-diamino-4,7-diazadecane [NH2(CH2)(3)NH(CD2)(2)NH(CH2)(3)NH2]} and cis-alpha-[CrF2([D-4]trien)](n+) {[D-4]trien = triethylene-tetraamine [NH2(CH2)(2)NH(CD2)(2)NH(CH2)(2)NH2]}. In analogy to these relations, the co-ligand effect on the Delta delta values for cis-alpha-[CrX2([D-4]trien)](n+) and trans-[CrX2([D-4]3,2,3-tet)](n+) is found to be well correlated with the reported e(sigma)(X) values for the co-ligands X. This is the first example of the co-ligand effect, or a mutual influence of ligands, associated with variation of the Cr-N and Cr-X bonds in cis- and trans-[CrX2N4]-type complexes. This Delta delta vs. e,(X) correlation offers an indirect method for estimating the e(sigma)(X) values for didentate X-2 as well as monodentate X ligands from the H-2 NMR chemical shifts and ranking them in the two-dimensional spectrochemical series. Plots of Delta delta vs. e(sigma)(FX) for trans-[CrF(X)([D-4]3,2,3-tet)](n+) do not necessarily lie on the Delta delta vs. e(sigma)(X) correlation line for the F(X) complexes with averaged e(sigma)(FX) = 1/2[e(sigma)(X) + e(sigma)(F)] values - e(sigma)[F(CN)] is close to e(sigma)(F), for example - thereby demonstrating a mutual influence between the CN- and F- ligands in the trans positions through a pushpull action or pi donor-acceptor interaction. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).
WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/ejic.200601092
DOI ID：10.1002/ejic.200601092, ISSN：1434-1948, Web of Science ID：WOS:000248558600013 - Mutual influences of ligands as revealed by the H-2 NMR chemical shifts and the angular overlap model parameters: cis-[CrX2(N)(4)] and fac-[CrX3(N)(3)]-type complexes with aromatic amines
Yukiko Terasaki; Takashi Fujihara; Sumio Kaizaki
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 号：21, 開始ページ：3400, 終了ページ：3404, 2007年07月, ［査読有り］
A mutual influence of ligands through a pi donor-acceptor interaction is found by examining how the X co-ligands of the aromatic amine complexes cis-[CrX2([D-4]bpy)(2)](n+) (bpy = 2,2'-bipyridine) and fac-[CrX3([D-12]tpa)](n+) [tpa = tris(2-pyridyl)amine] affect the H-2 NMR chemical shifts in connection with the Angular Overlap Model (AOM) parameterization in an analogous manner to our previous study on the solvato-chromism and solvent-dependent H-2 NMR spectra of cis-[CrF2([D-4]bPy)(2)](+) and fac-[CrF3([D-12]tpa)]. The ranking of the AOM parameter for monodentate and/or didentate ligands can be obtained from this co-ligand effect only from the H-2 NMR shifts. The postulated relative order in the two-dimensional spectrochemical series is Cl- > Br- > O or N donors (mal(2-) > acac(-) or H2O > dmf > NCS-) for the aromatic amine complexes, which contrasts with the order O or N donors > Cl- > Br- for the aliphatic amine complexes(see the preceding paper in this issue). This fact suggests that the Cr-Cl and Cr-Br sigma bonds are stronger in the soft acidic aromatic amine complexes than those in the hard acidic aliphatic amine complexes. This means they have a higher affinity for soft basic Cl- and Br- ligands and can be explained in terms of the hard/soft acid/base (HSAB) concept. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).
WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/ejic.200601093
DOI ID：10.1002/ejic.200601093, ISSN：1434-1948, Web of Science ID：WOS:000248558600014 - 3-hydroxy-2-methylisothiazolium chloride monohydrate: an intermolecular three-dimensional network via O-H center dot center dot center dot O and O-H center dot center dot center dot Cl hydrogen bonds
Masaru Kato; Takashi Fujihara; Daisaku Yano; Akira Nagasawa
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 巻：63, 開始ページ：O1839, 終了ページ：O1841, 2007年04月, ［査読有り］
The title compound, C4H6ClNOS center dot H2O, has a planar five-membered ring, with a delocalized positive charge. A three-dimensional network is formed through intermolecular O-H center dot center dot center dot O and O-H center dot center dot center dot Cl hydrogen bonds between 3-hydroxy-2-methylisothiazolium cations and water molecules, and between water molecules and chloride anions.
BLACKWELL PUBLISHING, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536807011129
DOI ID：10.1107/S1600536807011129, ISSN：1600-5368, ORCID：12234339, Web of Science ID：WOS:000245436300244 - On the accuracy of density-functional methods for determining structures of dicationic binuclear ruthenocene derivatives bridged by an unsaturated molecule
Toshiyuki Takayanagi; Kenta Takahashi; Takashi Fujihara; Masaru Sato
JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM, 巻：806, 号：1-3, 開始ページ：85, 終了ページ：92, 2007年03月, ［査読有り］
Various exchange and correlation functionals have been examined in density-functional calculations for obtaining reliable optimized structures for dicationic binuclear ruthenocenes bridged by an unsaturated compound, which has a characteristic fulvene-type structure. First, we have performed extensive calculations for ruthenocene (RuCp2) in D-5h symmetry. It has been found that the Ru-Cp optimized distance is linearly correlated with the energy difference between highest occupied a(1)' and e(2)' orbitals. We have then found that the optimized structure of dicationic binuclear ruthenocenes is strongly dependent of the a(1)'-e(2)' orbital sequence observed in RuCp2. In particular, when exchange-correlation functionals giving the a(1)' < e(2)' orbital sequence are employed, the contribution of the fulvene-type structure is found to be significantly underestimated in the optimized structure of dicationic binuclear ruthenocenes. We finally demonstrate that the SVWN exchange-correlation functionals give reasonable optimized structures comparable to experimental structures determined by X-ray crystallography analysis. (c) 2006 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.theochem.2006.11.011
DOI ID：10.1016/j.theochem.2006.11.011, ISSN：0166-1280, Web of Science ID：WOS:000244829700009 - cis-Bis(2,2 '-bipyridine)difluorochromium(III) perchlorate
Yukiko Yamaguchi-Terasaki; Takashi Fujihara; Akira Nagasawa; Sumio Kaizaki
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 巻：63, 開始ページ：M593, 終了ページ：M595, 2007年02月, ［査読有り］
In the title compound, cis-[CrF2(C10H8N2)(2)]ClO4, the Cr-III ion is coordinated by the four N atoms [Cr-N = 2.0480 ( 14)2.0842 ( 14) angstrom] from two 2,2'-bipyridine ligands and two F- ions [Cr-F = 1.8409 ( 10) and 1.8541 ( 10) A] in a distorted octahedral arrangement. The crystal packing is stabilized by pi-pi interactions and weak intermolecular C - H center dot center dot center dot F and C-H H center dot center dot center dot O hydrogen bonds.
BLACKWELL PUBLISHING, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536807003157
DOI ID：10.1107/S1600536807003157, ISSN：1600-5368, Web of Science ID：WOS:000245187300135 - 5-Chloro-2-methylisothiazolin-3-one: intermolecular two-dimensional networks via unusual C-Cl...O=C interactions
Kato Masaru; Fujihara Takashi; Yano Daisaku; Nagasawa Akir
Acta Crystallographica Section E-Structure Reports Online, 巻：63, 開始ページ：O3097, 終了ページ：U2523, 2007年, ［査読有り］
DOI：https://doi.org/10.1107/S1600536807026025
DOI ID：10.1107/S1600536807026025, ORCID：12234340 - Synthesis and some properties of bis(ruthenocenyl)thiophene derivatives - Possible spin-coupling in the two-electron oxidized species of dinuclear ruthenocenes bridged by thiophene derivatives
Masaru Sato; Yusuke Kubota; Atsushi Tanemura; Genta Maruyama; Takashi Fujihara; Juzo Nakayama; Toshiyuki Takayanagi; Kenta Takahashi; Kei Unoura
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, 号：22, 開始ページ：4577, 終了ページ：4588, 2006年11月, ［査読有り］
WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/ejic.200600370
DOI ID：10.1002/ejic.200600370, ISSN：1434-1948, Web of Science ID：WOS:000242551900015 - Dinuclear niobium(III) complexes [{NbCl2(L)}(2)(mu-Cl)(2)(mu-L)] (L = tetrahydrothiophene, dimethyl sulfide): Preparation, molecular structures, and the catalytic activity for the regioselective cyclotrimerization of alkynes
Masaki Kakeya; Takashi Fujihara; Takashi Kasaya; Akira Nagasawa
ORGANOMETALLICS, 巻：25, 号：17, 開始ページ：4131, 終了ページ：4137, 2006年08月, ［査読有り］
Dinuclear niobium complexes [ {NbCl2L}(2)( mu-Cl)(2)( mu-L)] ( L) tetrahydrothiophene C4H8S, THT ( 1a)) have been prepared by the reaction of diniobium( V) decachloride ( Nb2Cl10) with magnesium in THT. The structure of 1a was determined by X-ray crystallography to have a Nb-Nb bond, which is consistent with that of 1b ( L) dimethyl sulfide, Me2S). The reaction of 1a, as well as 1b, with alkyne ( R1C CR2) at room temperature gave a head-to-tail cycloadded alkyne trimer, 1,3,5-( R-1)(3)-2,4,6-( R-2)(3)-benzene ( R-1) H, R-2) Ph ( 2); R-1) p-tolyl, R-2) H ( 3); R-1) R-2) CH2Cl ( 4); R-1) R-2) COOEt ( 5); R-1) n-Pr, R-2) Me ( 6); R-1) n-Bu, R-2) H ( 7); R-1) Me3Si, R-2) H ( 8), R-1) R-2) Et ( 9), R-1) R-2) n-Pr ( 10)), regioselectively in high yields. The cyclotrimerization is found to be catalyzed by complexes 1a and 1b, since only 1/600 equiv of the complex to the alkynes can lead to the corresponding product in high yields. The reactions of 1a with 6 equiv of 3-hexyne and 4-octyne gave a mononuclear byproduct, NbCl3( eta(2)-RC CR-RC=CR) ( R) Et ( 11), Pr ( 12)), besides 9 and 10, respectively. The reactions of 11 or 12 with an excess of original alkyne, however, resulted exclusively in the formation of the corresponding benzene derivative, in equimolar amount to 1,2,3,4-( R) 4- 5,6-( R')(2)-benzene ( R) R') Et ( 9), R) R') Pr ( 10), R) Et, R') Pr ( 13), R) n-Pr, R') Et ( 14)). This observation suggests that the mononuclear species does not behave as a catalyst, and the regioselectivity may be due to a dinuclear structure of the niobium complexes.
AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/om0601100
DOI ID：10.1021/om0601100, ISSN：0276-7333, Web of Science ID：WOS:000239536800016 - 4,4′-Dinonyl-2,2′-bipyridine
Takashi Fujihara; Hajime Suzuki; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：61, 号：6, 開始ページ：o1867, 終了ページ：o1868, 2006年06月, ［査読有り］
The title compound, C28H44N2, is one of the precursors of the amphiphilic heteroleptic ruthenium(II) sensitizer for DSC (dye-sensitized solar cells), and its molecule has a crystallographically imposed centre of symmetry. A segregated packing structure between the alkyl chain layers and pyridine rings is observed. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536805015849
DOI ID：10.1107/S1600536805015849, ISSN：1600-5368, SCOPUS ID：32244448004 - (E)-1-Mercapto-1-(p-tolylsulfanyl)-N-(p-tosylmethyl) methanimine: A two-dimensional supramolecular network of S - H⋯O and C - H⋯π interactions
Masaki Kakeya; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：62, 号：4, 開始ページ：o1384, 終了ページ：o1386, 2006年04月, ［査読有り］
In the crystal structure of the title compound, C16H 17NO2S3, the dihedral angle between the mean planes of the two benzene rings is 70.8 (1)°. There are intermolecular S - H⋯O and C - H⋯π interactions, and molecules are linked into a two-dimensional network. The layers are further linked together by weak C - H⋯O interactions. © 2006 International Union of Crystallography All rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S160053680600849X
DOI ID：10.1107/S160053680600849X, ISSN：1600-5368, SCOPUS ID：33744921060 - Di-mu-chloro-mu-(dimethyl sulfide)-bis[dichloro(dimethyl sulfide) niobium(III)]
M Kakeya; T Fujihara; A Nagasawa
ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 巻：62, 開始ページ：M553, 終了ページ：M554, 2006年03月, ［査読有り］
The title compound, [Nb2Cl6(C2H6S)(3)], contains an Nb-III=Nb-III double bond [2.6880 (3)angstrom]. Each Nb atom has a distorted octahedral coordination environment formed by two terminal and two bridging Cl- ions, and one monodentate and one bridging Me2S ligands.
BLACKWELL PUBLISHING, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536806005149
DOI ID：10.1107/S1600536806005149, ISSN：1600-5368, Web of Science ID：WOS:000235681100069 - Tetra-n-propylammonium perchlorate
Takashi Fujihara; Masaru Kato; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：61, 号：5, 開始ページ：o1439, 終了ページ：o1440, 2005年05月, ［査読有り］
The crystallographic analysis of the title compound, C12H 28N+·ClO4 -, (I), shows that intermolecular C-H⋯O interactions stabilize the crystal structure. The compound is isomorphous with tetra-n-propylammonium iodide, whose structure has been described by Yoshida et al. [Acta Cryst. (1994). C50, 1758-1760]. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536805012006
DOI ID：10.1107/S1600536805012006, ISSN：1600-5368, SCOPUS ID：18544384488 - Di-μ-chloro-bis[diacetonitriledichloro-niobium(III)] acetonitrile disolvate
Masaki Kakeya; Takashi Fujihara; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：60, 号：7, 開始ページ：m893, 終了ページ：m894, 2004年07月, ［査読有り］
The title compound, [Nb2(μ-Cl)2Cl 4(CH3CN)4]·2CH3CN, is a centrosymmetric dinuclear niobium complex containing an NbIII = NbIII double bond [2.8577 (9) Å]. The Nb atom has a distorted octahedral coordination environment formed by two terminal Cl atoms [Nb-Cl = 2.3761 (14) and 2.3853 (15) Å], two acetonitrile ligands [Nb-N = 2.301 (4) and 2.309 (4) Å] and two μ-Cl atoms [Nb-Cl = 2.3356 (13) and 2.3358 (13) Å]. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536804012760
DOI ID：10.1107/S1600536804012760, ISSN：1600-5368, SCOPUS ID：18444402217 - N,N,N′,N′-Tetrakis(2-pyridiniomethyl)-1,3-diaminopropane tetraperchlorate monohydrate
Takashi Fujihara; Miki Saito; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：60, 号：7, 開始ページ：o1126, 終了ページ：o1128, 2004年07月, ［査読有り］
The cation of the title compound H4tptn4+· 4ClO4 -·H2O, where H4tptn 4+ is N,N,N′,N′-tetrakis(2-pyridiniomethyl)-1,3- diaminopropane (C27H34N6 4+), contains an intramolecular N - H⋯N hydrogen bond, and the average ring angle at the N atoms in the pyridinium rings is 123.6 (1)°. Intermolecular N - H⋯O and O - H⋯O hydrogen bonds are also found in the crystal structure. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536804011961
DOI ID：10.1107/S1600536804011961, ISSN：1600-5368, SCOPUS ID：18444401757 - Fac-Triaqua[tris(2-pyridyl)amine-κ3N]chromium(III) tris(trifluoromethanesulfonate)
Yukiko Terasaki; Takashi Fujihara; Akira Nagasawa; Sumio Kaizaki
Acta Crystallographica Section E: Structure Reports Online, 巻：60, 号：6, 開始ページ：m854, 終了ページ：m856, 2004年06月, ［査読有り］
In the title compound, fac-[Cr(tpa)(H2O)3](CF 3SO3)3 [tpa is tris(2-pyridyl)amine
C 15H12N4], the CrIII ion is coordinated by the symmetry-related N atoms of tpa, which acts as a tripodal ligand, and O atoms of water
a threefold rotation axis passes through the Cr and amine N atoms, with Cr-Npyridyl and CrO distances of 2.0403 (12) and 1.9815 (11) A, respectively. A three-dimensional network is formed by intermolecular O-H⋯O hydrogen bonds between coordinated water molecules and sulfonate groups of the anions. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536804011912
DOI ID：10.1107/S1600536804011912, ISSN：1600-5368, SCOPUS ID：18444388004 - Tetrakis(1,3-dimethylimidazolidinium-2-dithiocarboxylate-κS)zinc(II) diperchlorate
Takashi Fujihara; Tomoaki Sugaya; Akira Nagasawa; Juzo Nakayama
Acta Crystallographica Section E: Structure Reports Online, 巻：60, 号：3, 開始ページ：m282, 終了ページ：m284, 2004年03月, ［査読有り］
The title compound, [Zn(C6H10N2S 2)4](ClO4)2, containing four inner-salt ligands, is considered to retain an inner-salt structure in the crystal structure, where the planes of the carbenium and the dithiocarboxylate moieties are nearly perpendicular to each other [85 (2)°]. The asymmetric unit consists of one-half of the complex molecule, as the complex has twofold crystallographic symmetry. The backbone C-C bond length [N2C-CS 2 = 1.488 (7) Å] is significantly shorter than that of a normal C-C single bond. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S160053680400217X
DOI ID：10.1107/S160053680400217X, ISSN：1600-5368, SCOPUS ID：18444387406 - Bis(tetraethylammonium) 2,2′-bipyridine-4,4′-dicarboxylate tetrahydrate
Takashi Fujihara; Atsuo Kobayashi; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：60, 号：3, 開始ページ：o353, 終了ページ：o355, 2004年03月, ［査読有り］
The title compound, 2C8H20N+·C 12H6N2O4 2-·4H 2O, which is one of the precursors of the dye for DSC (dye-sensitized solar cells), consists of tetraethylammonium cations, 2,2′-bipyridine-4, 4′-dicarboxylate anions and water molecules. The anion has a centre of symmetry and the pyridine ring is inclined to the carboxylate group by 7.9 (3)°. A two-dimensional network is formed through intermolecular O-H⋯O hydrogen bonds between water molecules and the carboxylate groups of the anions. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536804002910
DOI ID：10.1107/S1600536804002910, ISSN：1600-5368, SCOPUS ID：18444378422 - N,N,N′,N′-Tetrakis(2-pyridylmethyl)-1,2-diaminoethane: A multidentate ligand
Takashi Fujihara; Miki Saito; Akira Nagasawa
Acta Crystallographica Section E: Structure Reports Online, 巻：60, 号：2, 開始ページ：o262, 終了ページ：o263, 2004年02月, ［査読有り］
The reaction of 1,2-diaminoethane and 2-pyridinecarboxyaldehyde in the presence of a reducing agent, sodium triacetoxyborohydride, leads to the title compound, C26H28N6. The molecule has a centre of symmetry. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1107/S1600536804001254
DOI ID：10.1107/S1600536804001254, ISSN：1600-5368, SCOPUS ID：18444392694 - A series of [Cr2(μ-OH)n(μ-RCO2) 3-n(bispma)2] type chromium (III) dinuclear complexes (n = 1, 2) with tridentate bis (2-pyridylmethyl)amine (bispma): Synthesis, crystal structure, and magnetic properties
Takashi Fujihara; Akira Fuyuhiro; Sumio Kaizaki
Inorganica Chimica Acta, 巻：278, 号：1, 開始ページ：15, 終了ページ：23, 1998年08月, ［査読有り］
A series of chromium (III) dinuclear complexes with general formula [Cr2(μ-OH)n(μ-RCO2) 3-n(bispma)2]Xm·yH2O(bispma = bis(2-pyridylmethyl)amine
n = 1, m = 3, R = H, Me, Et, CH2Cl, CH2ClCH2
m = 4, R = CH2NH3, CH2CH2NH3, CH2CH2CH2NH3, CH(CH3)NH3, CH(OH)NH3
n = 2, m = 3, R = CH3, H) was prepared and characterized by elemental analysis, UV-Vis, IR absorption and 2H NMR spectra, magnetic susceptibility measurements, and X-ray crystal structure analysis. The crystal of [Cr2(μ-OH)2(μ-HCO2)(bispma)2] [ClO4]3· 0.5H2O was orthorhombic with space group Pnma, a = 14.771 (3), b= 12.346(6), c = 19.054(4) Å, U = 3474(1) Å3, Z = 4. Two complexes for R = H and CH2Cl were found to exhibit alternating magnetic properties from antiferromagnetic to ferromagnetic interaction with change of counter ions. This anomalous magnetism was examined by comparison with the reported magneto-structural relationship. © 1993 Elsevier Science S.A. All rights reserved.
Elsevier S.A., 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/S0020-1693(97)06169-0
DOI ID：10.1016/S0020-1693(97)06169-0, ISSN：0020-1693, SCOPUS ID：0001894294 - Preparative Study and Characterization of the Cis-Diamminetetranitrocobaltate(III) Ion. A Missing Link in the Ammine-Nitro Cobalt(III) Series.
Fujita Miho; Fujihara Takashi; Kojima Masaaki; YOSHIKAWA Yuzo; YAMASAKI Kazuo
Proceedings of the Japan Academy, Series B, 巻：73, 号：8, 開始ページ：161, 終了ページ：164, 1997年
The preparative conditions and stability of cis-[Co(NO2)4(NH3)2]-, which had been a missing link in the ammine-nitro cobalt(III) series until recently, were studied using 59Co NMR spectroscopy. The reaction of Na3[Co(NO2)6] with liquid ammonia mainly gave cis-[Co(NO2)4(NH3)2]- together with mer- and fac-[Co(NO2)3(NH3)3] and cis-[Co(NO2)2(NH3)4]+; the formation of trans-[Co(NO2)4(NH3)2]- was not observed. The reaction of aqueous [Co(NO2)6]3- with aqueous ammonia also gave the cis isomer as a major product. On the contrary, the cis isomer did not form during the conventional preparation from CoCl2 in an aqueous solution. The cis isomer was very stable in the solid state, but the isomer slowly isomerized in water (t1/2>5 days at room temperature, ca. 0.1mol dm-3) to the trans isomer. The reaction was accompanied by the formation of fac-[Co(NO2)3(NH3)3] which then isomerized to the mer isomer, and by the formation of several unknown species.
The Japan Academy, 英語
DOI：https://doi.org/10.2183/pjab.73.161
DOI ID：10.2183/pjab.73.161, ISSN：0386-2208, CiNii Articles ID：130000903006, CiNii Books ID：AA00785485 - Correlation of 13C, 15N and 59Co nuclear magnetic resonance chemical shifts with ligand-field parameters for pentacyanocobaltate(III) complexes
Takashi Fujihara; Sumio Kaizaki
Journal of the Chemical Society, Dalton Transactions, 号：8, 開始ページ：1275, 終了ページ：1279, 1993年, ［査読有り］
The 13C, 15N and 59Co NMR spectra of 15 pentacyanocobaltate(III) complexes revealed a common tendency for the chemical shift to vary with the identity of the sixth co-ordinated ligand. These chemical shifts were found to correlate with ligand-field parameters, including the nephelauxetic ratio, among them the reduction parameter having a significant effect.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/DT9930001275
DOI ID：10.1039/DT9930001275, ISSN：1472-7773, SCOPUS ID：37049082943 - Diamagnetic behaviour of high-resolution nitrogen-14 nuclear magnetic resonance spectra for co-ordinated nitrogens in paramagnetic chromium(III) diamine complexes
Takashi Fujihara; Sumio Kaizaki
Journal of the Chemical Society, Dalton Transactions, 号：16, 開始ページ：2521, 終了ページ：2524, 1993年, ［査読有り］
Diamagnetic behaviour in the chemical shift and linewidth of high-resolution nitrogen-14 NMR spectra for paramagnetic chromium(III) diamine complexes was investigated in comparison with that for the corresponding diamine dihydrochlorides and the diamagnetic cobalt(III) complexes. The NMR signals can be assigned to each inequivalent nitrogen ligating atom of unsymmetic diamines in the chromium(III) complexes. The 14N NMR spectra are affected by the diamine chelate ring conformations of the tris(diamine) complexes, but hardly sensitive to the ligand replacement in trans- and cis-[CrX2(diamine)2] type complexes.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1039/DT9930002521
DOI ID：10.1039/DT9930002521, ISSN：1472-7773, SCOPUS ID：0008325301
- 層状構造 銅及びコバルト桂皮酸錯体の磁性
市村奏絵; 藤原隆司; 木田孝則; 萩原政幸; 鎌田憲彦; 本多善太郎
日本磁気学会学術講演概要集, 巻：44th, 2020年
ISSN：1882-2959, J-Global ID：202102250230299548 - 一次元金属錯体M(sba)(H2O)2・H2O(M=Co,Cu)の磁気異方性
野本尚之; 藤原隆司; 澤田祐也; 木田孝則; 萩原政幸; 鎌田憲彦; 本多善太郎
日本磁気学会学術講演概要集, 巻：43rd, 2019年
ISSN：1882-2959, J-Global ID：202002284951988664 - H2Oを架橋配位子とする1次元構造金属錯体の磁性
野本尚之; 藤原隆司; 澤田祐也; 木田孝則; 萩原政幸; 鎌田憲彦; 本多善太郎
日本磁気学会学術講演概要集, 巻：42nd, 開始ページ：124, 2018年08月28日
日本語
ISSN：1882-2959, J-Global ID：201802236748914308 - Synthesis and phase structures of novel pi-acceptor discotic liquid crystalline compounds having a pyrenedione core
Mikio Yasutake; Takashi Fujihara; Akira Nagasawa; Keiichi Moriya; Takuji Hirose
巻：2008, 号：24, 開始ページ：4120, 終了ページ：4125, 2008年08月
Several pi-acceptor discotic liquid crystalline compounds were synthesized by using a pyrenedione unit as a core. Terrace-like and band-like structures were revealed by polarized optical microscopy (POM) observations and XRD measurements. In conjunction with the results of the single-crystal structure analysis of analogous crystalline compounds, all of the liquid crystalline compounds were confirmed to form a discotic lamellar phase D(L2). ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).
英語
DOI：https://doi.org/10.1002/ejoc.200800360
DOI ID：10.1002/ejoc.200800360, ISSN：1434-193X, CiNii Articles ID：80019737426, Web of Science ID：WOS:000258808000006 - (-)(545)-fac-Delta-Tris(L-prolinato)cobalt(III) trihydrate
Masaru Kato; Miho Hayashi; Takashi Fujihara; Akira Nagasawa
巻：64, 開始ページ：M684, 終了ページ：U621, 2008年05月
The absolute configuration of the octahedral fac-CoN3O3 title complex, [Co(C5H8NO2)(3)]center dot 3H(2)O, has been determined by single-crystal X- ray analysis. A three-dimensional network of hydrogen bonds is observed between the proline carboxylate groups and the three uncoordinated water molecules.
英語
DOI：https://doi.org/10.1107/S1600536808010246
DOI ID：10.1107/S1600536808010246, ISSN：1600-5368, Web of Science ID：WOS:000255450100061 - (-)545-fac -Δ- Tris(l-prolinato)cobalt(III) trihydrate
Masaru Kato; Miho Hayashi; Takashi Fujihara; Akira Nagasawa
巻：64, 号：5, 開始ページ：m684, 2008年04月30日
The absolute configuration of the octa-hedral fac-CoN3O3 title complex, [Co(C5H8NO2)3]·3H2O, has been determined by single-crystal X-ray analysis. A three-dimensional network of hydrogen bonds is observed between the proline carboxyl-ate groups and the three uncoordinated water mol-ecules.
英語
DOI：https://doi.org/10.1107/S1600536808010246
DOI ID：10.1107/S1600536808010246, ISSN：1600-5368, SCOPUS ID：43149094863 - 化学修飾によるナノサイズクラスター金属錯体の高機能化
藤原 隆司
総合研究機構研究プロジェクト研究成果報告書, 号：6(平成19年度), 2008年 - 化学修飾によるナノサイズクラスター金属錯体の高機能化
藤原 隆司
号：6(平成19年度), 2008年 - Anion influence on the coordination polymer structures of silver(I) complexes with 2-methylisothiazol-3(2H)-one
Masaru Kato; Takashi Fujihara; Daisaku Yano; Akira Nagasawa
巻：10, 号：10, 開始ページ：1460, 終了ページ：1466, 2008年
Silver(I) coordination polymers formed by self-assembly of ambidentate ligands, 2-methylisothiazol-3(2H)-one (MI) and 5-chloro-2-methylisothiazol-3(2H)-one (CMI), have been characterized by single crystal X-ray analysis. The structure of the cation in [Ag-I(mu-O-mi)(2)] X (X = ClO4- (1); SbF6- (2)) is a one-dimensional chain while that in the nitrate salt, [Ag-2(I)(mu-O-mi)](NO3)(2) (3), is a three-dimensional network. A silver(I) complex with CMI, [Ag-I(mu-O-cmi)(2)] ClO4 (4), has also been synthesized and the cation has a one-dimensional chain structure. Although both MI and CMI have both O-and S-donor moieties, the oxygen atom dominantly coordinates to the silver(I) centre. The anion influence on the chain structure is attributed to the competition for the coordination ability between anions and MI, and the flexibility of the coordination sphere of d(10) silver(I) ion.
英語
DOI：https://doi.org/10.1039/b810652p
DOI ID：10.1039/b810652p, ISSN：1466-8033, Web of Science ID：WOS:000259411200031 - ニオブ錯体触媒を用いたニトリル類の位置選択的環化反応
藤原 隆司
総合研究機構研究プロジェクト研究成果報告書, 巻：第5号(18年度), 開始ページ：537, 終了ページ：538, 2007年 - ニオブ錯体触媒を用いたニトリル類の位置選択的環化反応
藤原 隆司
巻：第5号(18年度), 開始ページ：537, 終了ページ：538, 2007年 - Syntheses and X-Ray Structures of Novel Phenoxo-Bridged Binuclear Complexes: Bis(μ-Phenoxo)Bis[bis(Acetylacetonato)Chromium(III)] Complex and its Para-Substituted Phenoxo Analogs
Manabu Nakahanada; Takashi Fujihara; Akira Fuyuhiro; Sumio Kaizaki
巻：31, 号：8, 開始ページ：1315, 終了ページ：1316, 1992年03月01日
英語, 速報，短報，研究ノート等（学術雑誌）
DOI：https://doi.org/10.1021/ic00034a003
DOI ID：10.1021/ic00034a003, ISSN：1520-510X, SCOPUS ID：0005790713
- 無機・有機ハイブリッドナノクラスターの協奏的レドックス機能
日本学術振興会, 科学研究費助成事業, 基盤研究(C), 2011年 - 2013年
藤原 隆司, 埼玉大学
配分額（総額）：5460000, 配分額（直接経費）：4200000, 配分額（間接経費）：1260000
双性イオン型配位子と種々の金属イオンを用いて新規な無機・有機ハイブリッドナノクラスターの合成を行った。合成したクラスターに関して，結晶構造・溶液内構造や電気化学的性質、分光学的性質について明らかにした。
得られた知見を元に，多電子レドックス系における配位子－金属イオン間や金属間の電子的な相互作用について検討を行った。併せて，計算科学の手法を用いて電子状態や構造の解析を行った。より複雑な多電子系レドックスを示す新規な双性イオン型配位子を開発した。これらの結果から，ナノマテリアルとしての機能性についての評価を試みた。
得られた結果の一部に関しては論文投稿を行い，成果の公表を行った。
課題番号：23510115 - 電子溜め機能を持つナノサイズクラスター金属錯体の有機化学的修飾による高機能化
日本学術振興会, 科学研究費助成事業, 基盤研究(C), 2008年 - 2010年
藤原 隆司, 埼玉大学
配分額（総額）：4420000, 配分額（直接経費）：3400000, 配分額（間接経費）：1020000
種々の新規な中心金属イオンと双性イオン型配位子を組み合わせたナノサイズクラスター金属錯体の合成を行った。得られた錯体の構造解析などを行い,さらにクラスター錯体を有機化学的手法を用いる化学修飾を試みた。反応によって得られた化合物の溶液内と固体での電気化学的性質から酸化還元特性を明らかにし,また電解生成物の紫外可視吸収の測定などを行い,固体状態や溶存状態の構造についての知見を得た。
課題番号：20510093 - -
競争的資金 - -
競争的資金