Toshio Takayama

Gifu University, Gihu, Gifu, Japan

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Publications (43)89.95 Total impact

  • Isao Hasegawa · Yasutaka Nakane · Toshio Takayama
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    No preview · Article · Aug 2010 · ChemInform
  • Yoshito Takeuchi · Toshio Takayama
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    No preview · Article · Apr 2010 · ChemInform
  • Yoshito Takeuchi · Toshio Takayama

    No preview · Chapter · Dec 2009
  • Yoshito Takeuchi · Toshio Takayama

    No preview · Chapter · Dec 2009
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    ABSTRACT: We report fast, high-yield syntheses of a series of [Pt(C∧N)(HC∧N)X] complexes, where HC∧N is 2-phenylpyridine (Hppy) or 2-p-tolylpyridine (Htopy) and X− is Cl−, Br−, I−, ONO2−, NO2− or SCN−. The structure of [Pt(topy)(Htopy)(ONO2)] was analyzed by single-crystal X-ray diffraction. Substitution of Cl− with Br− or I− in our complexes shifted the 195Pt NMR peaks upfield in the order Cl− < Br− < I−, but the magnitudes of their shifts were one-tenth those observed for non-cyclometalated platinum(II) complexes. As the two nitrato complexes showed strong emissions in acetonitrile solution—three to six times those of other complexes—they were used to fabricate OLEDs. Although their emissions were not particularly strong, devices fabricated with platinum(II) complexes containing bulky ligands emitted green light with a short lifetime (τ). Copyright © 2009 John Wiley & Sons, Ltd.
    No preview · Article · Apr 2009 · Applied Organometallic Chemistry
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    ABSTRACT: We prepared platinum(IV) complexes containing dipeptide and diimine or diamine, the [PtCl(dipeptide-N,N,O)(diimine or diamine)]Cl complex, where -N,N,O means dipeptide coordinated as a tridentate chelate, dipeptide=glycylglycine (NH(2)CH(2)CON(-)CH(2)COO(-), digly, where two protons of dipeptide are detached when the dipeptide coordinates to metal ion as a tridentate chelate), glycyl-L-alanine (NH(2)CH(2)CON(-)CHCH(3)COO(-), gly-L-ala), L-alanylglycine (NH(2)CH CH(3)CON(-)CH(2)COO(-), L-alagly), or L-alanyl-L-alanine (NH(2)CHCH(3)CON(-)CHCH(3)COO(-), dil-ala), and diimine or diamine=bipyridine (bpy), ethylenediamine (en), N-methylethylenediamine (N-Me-en), or N,N'-dimethylethylenediamine (N,N'-diMe-en). In the complexes containing gly-L-ala or dil-ala, two separate peaks of the (195)Pt NMR spectra of the [PtCl(dipeptide-N,N,O)(diimine or diamine)]Cl complexes appeared in, but in the complexes containing digly or L-alagly, one peak which contained two overlapped signals appeared. One of the two complexes containing gly-L-ala and bpy, [PtCl(gly-L-ala-N,N,O)(bpy)]NO(3), crystallized and was analyzed. This complex has the monoclinic space group P2(1)2(1)2(1) with unit cell dimensions of a=9.7906(3)A, b=11.1847(2)A, c=16.6796(2)A, Z=4. The crystal data revealed that this [PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex has the near- (Cl, CH(3)) configuration of two possible isomers. Based on elemental analysis, the other complex must have the near- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) configuration. The (195)Pt NMR chemical shifts of the near- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex and the far- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex are 0 ppm and -19 ppm, respectively (0 ppm for the Na(2)[PtCl(6)] signal). The additive property of the (195)Pt NMR chemical shift is discussed. The (195)Pt NMR chemical shifts of [PtCl(dipeptide-N,N,O)(bpy)]Cl appeared at a higher field when the H attached to the dipeptide carbon atom was replaced with a methyl group. On the other hand, the (195)Pt NMR chemicals shifts of [PtCl(dipeptide-N,N,O)(diamine)] appeared at a lower field when the H attached to the diamine nitrogen atom was replaced with a methyl group, in the order of [PtCl(digly-N,N,O)(en)]Cl, [PtCl(digly-N,N,O)(N-Me-en)]Cl, and [PtCl(digly-N,N,O)(N,N'-diMe-en)]Cl.
    No preview · Article · Nov 2006 · Journal of Inorganic Biochemistry
  • Isao Hasegawa · Tatsuya Niwa · Toshio Takayama
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    ABSTRACT: The reaction of Si8O20[Si(CH3)2H]8 with X(CH3)2SiCl (X = CH3, CH2Cl, CH2Br) in a hexane/acetic acid solution gave Si8O20[Si(CH3)2X]8 in ⩾90% isolation yield, indicating that the dimethylsilyl group of Si8O20[Si(CH3)2H]8 can be substituted for another silyl group with retaining the double eight-membered ring silicate core.
    No preview · Article · Feb 2005 · Inorganic Chemistry Communications
  • Yoshito Takeuchi · Toshio Takayama
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    ABSTRACT: Recent advances in 73Ge NMR spectroscopy are reviewed. Following the introduction (Section 1), Section 2 describes recently determined chemical shifts and linewidths for a variety of organogermanium compounds which range from normal (tetravalent) to hypercoordinated (up to heptavalent) species. The role of linewidth as evidence for hypercoordination is discussed. In Section 3, coupling constants, relaxation times and relaxation mechanisms are discussed in detail, showing that in some cases a mechanism other than quadrupolar is involved. In the last section, high-resolution solid-state 73Ge NMR spectroscopy is covered which has not been treated in previous reviews.
    No preview · Article · Dec 2004 · ChemInform
  • Isao Hasegawa · Wataru Imamura · Toshio Takayama
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    ABSTRACT: Si8O20[Si(CH3)2H]8 reacts with methanol or H2O, resulting in fission of the SiO–Si(CH3)2H bond. The double eight-membered ring silicate core of Si8O20[Si(CH3)2H]8 is retained during the reactions. Si8O20[Si(CH3)3]8 undergoes neither alcoholysis nor hydrolysis under the same reaction conditions, indicating that stability of the Si–O–Si bond depends on the type of functional groups attached to a Si atom.
    No preview · Article · Apr 2004 · Inorganic Chemistry Communications
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    ABSTRACT: The preparation of platinum(II) complexes containing L-serine using K(2)[PtCl(4)] and KI as raw materials was undertaken. The cis-trans isomer ratio of the complexes in the reaction mixture differed significantly depending on whether KI was present or absent in the reaction mixture. One of the two [Pt(L-ser-N,O)(2)] complexes (L-ser=L-serinate anion) prepared using KI crystallizes in the monoclinic space group P2(1)2(1)2(1) with unit cell dimensions a=8.710(2) A, b=9.773(3) A, c=11.355(3) A, Z=4. The crystal data revealed that this complex has a cis configuration. The other [Pt(L-ser-N,O)(2)] complex also crystallizes in the monoclinic space group P2(1)2(1)2(1) with unit cell dimensions a=7.0190(9) A, b=7.7445(6) A, c=20.946(2) A, Z=4. The crystal data revealed that this complex has a trans configuration. The 195Pt NMR chemical shifts of trans-[Pt(L-ser-N,O)(2)] and cis-[Pt(L-ser-N,O)(2)] complexes are -1632 and -1832 ppm, respectively. 195Pt NMR and HPLC measurements were conducted to monitor the reactions of the two [Pt(L-ser-N,O)(2)] complexes with HCl. Both 195Pt NMR and HPLC showed that the reactivities of cis- and trans-[Pt(L-ser-N,O)(2)] toward HCl are different: coordinated carboxyl oxygen atoms of trans-[Pt(L-ser-N,O)(2)] were detached faster than those for cis-[Pt(L-ser-N,O)(2)].
    No preview · Article · Nov 2003 · Journal of Inorganic Biochemistry
  • Yoshito Takeuchi · Toshio Takayama
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    ABSTRACT: IntroductionNew Techniques Modern Pulse SequencesCombination of NMR and Other TechniquesNew Compounds Some Interesting CompoundsSilicenium IonsCompounds with Hypervalent Si NucleiOrganically Modified SilicatesNMR Parameters Theory of 29Si NMR ParametersCoupling ConstantsRelaxation Times and Exchange PhenomenaSolid-state 29Si NMR IntroductionNew TechniquesNMR and X-ray StudiesRelaxation TimesDynamicsHypervalent SiliconMiscellaneousReferences Modern Pulse SequencesCombination of NMR and Other Techniques Some Interesting CompoundsSilicenium IonsCompounds with Hypervalent Si NucleiOrganically Modified Silicates Theory of 29Si NMR ParametersCoupling ConstantsRelaxation Times and Exchange Phenomena IntroductionNew TechniquesNMR and X-ray StudiesRelaxation TimesDynamicsHypervalent SiliconMiscellaneous
    No preview · Article · Oct 2003
  • Yoshito Takeuchi · Toshio Takayama
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    ABSTRACT: Introduction Scope and LimitationChemical Shifts and Coupling ConstantsTheory of NMR Chemical Shifts of PolyenesRecent Applications Solution NMR Linear Conjugated DienesPolymers Containing PolyenesAntibiotic PolyenesMetal Bound PolyenesSolid State NMR 13C CP/MAS NMR2H Static NMRSpecial Topics AllenesSolitonsFullerenesReferences Scope and LimitationChemical Shifts and Coupling Constants Solution NMR Linear Conjugated DienesPolymers Containing PolyenesAntibiotic PolyenesMetal Bound PolyenesSolid State NMR 13C CP/MAS NMR2H Static NMR Linear Conjugated DienesPolymers Containing PolyenesAntibiotic PolyenesMetal Bound Polyenes 13C CP/MAS NMR2H Static NMR AllenesSolitonsFullerenes
    No preview · Article · Apr 2003
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    ABSTRACT: Lithium intercalation into coke carbon modified with mesophase-pitch and heat-treated at 800, 1000, and 3000°C was observed using solid-state 7Li-nuclear magnetic resonance (7Li-NMR) spectroscopy. It was found that the fully lithiated state charged to 0V in the modified coke heat-treated at 3000°C showed a peak at about 45ppm; on the other hand, two peaks appeared at about 45 and 16–17ppm in the modified coke heat-treated below 1000°C. The peak appearing at 45ppm indicated that Li-GIC is present in the first stage, and the peak at about 16–17ppm indicated that the lithium stored in the modified part has an ionic character greater than in the coke part and is not a lithium cluster. The lithiated states charged to 0.1 and 0.2V and discharged to 0.1, 0.2 and 1.5V from the charged state (0V) are also described.
    No preview · Article · Jul 2001 · Journal of Power Sources
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    ABSTRACT: Spin-lattice relaxation times (T-1) of Ge-73 nuclei of tetraphenylgermane (1) and some other organogermanes in solid state and metallic germanium were determined under the high-resolution condition. T-1 values were found in the order of s in agreement with the reported value for metallic germanium determined in the static condition.
    No preview · Article · Jun 2001 · Chemistry Letters
  • Yoshito Takeuchi · Toshio Takayama
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    No preview · Article · Jan 2001 · ChemInform
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    ABSTRACT: Three dipeptide complexes of the form K[M(dipeptide)Cl] (H2dipeptide=glycylbeta-alanine, beta-alanylglycine, beta-alanylbeta-alanine) and four dipeptide methyl ester complexes of the form K[M(dipeptideOMe)Cl2] (HdipeptideOMe=glycylalpha-alanine methyl ester, alpha-alanylglycine methyl ester, dialpha-alanine methyl ester) were newly prepared. The K[Pt(glybeta-ala)Cl] complex crystallizes in the monoclinic space group C2/c with unit cell dimensions of a=25.77(1) A, b=4.09(2) A, c= 16.432(9) A, beta=103.74(4) degrees, and Z=8. The K[Pt(glyalpha-alaOMe)Cl2] complex crystallizes in the monoclinic space group P1 with unit cell dimensions of a=7.195(2) A, b=7.977(5) A, c=10.326(3) A, alpha=72.49(3) degrees, beta=103.74(4) degrees, gamma=88.27(4) degrees and Z=2. The 195Pt NMR peaks of the complexes containing the beta-alanine moiety appeared significantly more upfield than those of the complexes containing diglycine. The ratios of the species of the platinum complexes containing the dipeptide ester in neutral solution were significantly different from those in alkaline solution at 40 degrees C for a short time.
    No preview · Article · Aug 2000 · Journal of Inorganic Biochemistry
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    ABSTRACT: Two water-soluble, silver(I) complexes showing a wide spectrum of effective antibacterial and antifungal activities, i.e., ([Ag(Hhis)].0.2EtOH)2 (1; H2his = L-histidine) and [Ag(Hpyrrld)]2 (3; H2pyrrld = (S)-(-)-2-pyrrolidone-5-carboxylic acid) were prepared. In aqueous solution 1 and 3 were present as dimers, whereas in the solid state they were polymers. Crystallization of 1 by slow evaporation and/or vapor diffusion gave water-insoluble crystals of [Ag(Hhis)]n (2) showing modest antimicrobial activities. The complex 1 in the solid state is a polymer formed by intermolecular hydrogen-bonding interactions between dimeric [Ag(Hhis)]2 cores, while 2 is a different polymer without a core complex. X-ray crystallography revealed that 2 was a left-handed helical polymer consisting of a bent, 2-coordinate silver(I) atom bonding to the Namino atom of one Hhis- ligand and the N pi atom of a different Hhis- ligand. Of particular note is the fact that Ocarboxyl atoms do not participate in the coordination. X-ray crystallography also revealed that 3 was a left-handed helical polymer formed by self-assembly of dimeric [Ag(Hpyrrld)]2 cores with an intramolecular metal(I)-metal(I) interaction (Ag-Ag distance, 2.9022(7) A). The FT-IR and the solid-state 13C and 15N NMR spectra showed that the dimeric core of 1 was formed through Ag-N bonds, while that of 3 was formed through Ag-O bonds. The molecular ions of 1 and 3 were detected by the positive-ion electrospray ionization (ESI) mass spectrometry. For 1-3, characterization by elemental analysis, TG/DTA, FT-IR, and variable-temperature solid-state 13C NMR and room-temperature 15N NMR measurements was performed, and for 1 and 3, that by solution molecular weight measurements and solution (109Ag, 1H, and 13C) NMR spectroscopies was also carried out. The antibacterial and antifungal activities of 1 and 3 were remarkable and comparable to those of the previous silver(I)-N-heterocycle complexes.
    Full-text · Article · Aug 2000 · Inorganic Chemistry
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    ABSTRACT: High-resolution solid-state MAS 73Ge NMR spectra of organogermanium compounds have been observed for the first time; the chemical shifts and half-widths of tetraphenylgermane and tetrabenzylgermane were recorded with and without high-power decoupling.
    No preview · Article · Apr 2000 · Chemical Communications
  • Masanobu Watanabe · Masaru Sato · Toshio Takayama
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    ABSTRACT: The reaction of biruthenocene with excess p-benzophenone/boron trifluoride produced complex 1 in good yield. Single-crystal X-ray analysis revealed that 1 is a Ru−fulvalene complex with the novel coordination mode μ2-η6:η6. The reaction of 1 with Br2 and PPh3 in CH3NO2 gave cations formulated as [BrCpRuIVFvRuIVCpBr]2+ (2) and CpRuIIFv(C5H4P+Ph3)RuII (3), respectively. The reaction of 1 with other nucleophiles, such as CH3CN, N(CH2CH2)2N, and NC5H5, gave the corresponding mixed-valence (RuIIRuIV) cations formulated as [CpRuIIFvRuIVCpL]2+.
    No preview · Article · Dec 1999 · Organometallics
  • Isao Hasegawa · Yoshiaki Fujii · Toshio Takayama · Keiko Yamada

    No preview · Article · Oct 1999 · Journal of Materials Science Letters

Publication Stats

475 Citations
89.95 Total Impact Points

Institutions

  • 2010
    • Gifu University
      • Faculty of Engineering
      Gihu, Gifu, Japan
  • 1984-2010
    • Kanagawa University
      • • Department of Chemistry
      • • Faculty of Engineering
      Yokohama, Kanagawa, Japan
  • 1998
    • Saitama University
      • Department of Chemistry
      Saitama, Saitama, Japan