Toshio Takayama

Kanagawa University, Yokohama, Kanagawa, Japan

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Publications (18)23.75 Total impact

  • [Show abstract] [Hide abstract]
    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.
    Applied Organometallic Chemistry 01/2009; 23(4):154-160. · 2.01 Impact Factor
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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.
    Journal of Inorganic Biochemistry 11/2006; 100(10):1653-9. · 3.20 Impact Factor
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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)].
    Journal of Inorganic Biochemistry 11/2003; 97(2):240-8. · 3.20 Impact Factor
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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.
    Journal of Inorganic Biochemistry 08/2000; 81(1-2):49-55. · 3.20 Impact Factor
  • Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1999; 72(4):715-723.
  • Masanobu Watanabe, Masaru Sato, Toshio Takayama
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    ABSTRACT: The reaction of biruthenocene with excess p-benzoquinone and boron trifluoride−diethyl ether produced the title complex (1) in good yield. Single-crystal X-ray analysis revealed that 1 is the 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 CpRuIIFvRuII (C5H4P+Ph3) (3), respectively.
    Organometallics 01/1999; 18(25):5201-5203. · 4.15 Impact Factor
  • Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1998; 71(5):1071-1079.
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    Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1998; 71(9):2127-2136.
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    ABSTRACT: The conformation of the oxidation product (A) of biruthenocene (RcRc) with p-benzoquinone containing boron trifluoride diethylether complex is [RcRcC6H4O2]2+(BF4−)2 in which p-benzoquinoen is ligated to the RuIV center. The recrystallization of A from the mixture of nitromethhane containing small amount of acetonitrile or pyrazine gives mixed-valence cations formulated as [RuIICp(C5H4C5H4)CpRuIVL]2+ (L = acetonitrile 1 and pyrazine 2), in which L is coordinated to the RuIV center. The crystal of 1 formulated as [RuIICp(C5H4C5H4)CpRuIVNCCH3]2+ (BF4−)2. CH3NO2 (1), is found to be orthorhombic, space group Pbca, and the final R = 0.054 and Rw = 0.059. The similar pyrazine salt 2 formulated as [RuIICp(C5H4C5H4)CpRuIVN(CH)4N]2+ (BF4−)2(CH3NO2)2is found to be triclinic, space group P, , α = 89.45(1)°, β = 86.10(3)°, γ = 87.85(2)°, V = 4991(2), Z = 2, and the final R = 0.077 and RW = 0.090. The unit cell has three independent molecules (2A, 2B, 2C). The Ru(IV)-N distances (2.15(1) Å for 2A, 2.11(1) for 2B and 2.15(1) for 2C) are longer by ca. 0.1 Å than that of 1 because of bulky molecule of pyrazine. Both cations (1,2) have wedge-sharp structure due to the RuN bond, the dihedral angles between the Cp and C5H4 rings of the [LRuIVCp(C5H4)]2+ moiety are 38.70° for 1, 38.77° (2A), 40.84° (2B) and 41.67° (2C) for 2. The nucleophilicity to the RuIV increases in the order Cl− > pyrazine > acetoritrile > p-benzoquinone and unlike the case of mixed-valence halobiruthenocenium cations ([RcRcX]+: X  Cl, Br, I), no temperature dependent 1H - and 13C-NMR spectra were observed for 1 and 2 in solution, implying the absence of two-electron exchange reaction between the RuII and RuIV.
    Journal of Organometallic Chemistry 12/1997; 549(s 1–2):13–23. · 2.00 Impact Factor
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    ABSTRACT: Two new dipeptide complexes of the form H[Pt(digly)Cl] (2) (H2digly = glycylglycine) and H[Pt(Hdigly)Cl2] (4) were newly prepared, and K[Pt(Hdigly)Cl2] (3) was isolated. Complex 1, K[Pt(digly)Cl], crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 25.77(1) Å, b = 4.09(2) Å, c = 16.432(9) Å, β = 103.74(4)°, and Z = 8. Complex 3 crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 8.892(5) Å, b = 11.387(4) Å, c = 9.974(4) Å, β = 105.45(4)°, Z = 4. Complex 4 crystallizes in the monoclinic space group P21/c with unit cell dimensions a = 9.311(6) Å, b = 7.737(8), c = 15.627(4) Å, β = 105.92(3)°, Z = 4. Complex 4 has the rare iminol type H2digly coordinating to Pt. The 15N chemical shifts and the coupling constants of the deprotonated coordinated amide N were obtained for the first time for these complexes. These amide peaks showed almost no coordination shift compared with the large coordination shift of the amine nitrogen. The coupling constants between Pt and deprotonated nitrogen for K[Pt(Hdipep)Cl2] were larger than those for K[Pt(dipep)Cl]. The growth inhibition assays of K[Pt(digly)Cl], K[Pt(Hdigly)Cl2], and cis-diamminedichloroplatinum(II) (cisplatin) against methylcholanthrene-induced Meth A fibrosarcoma (Meth A) solid tumor transplanted in BALB/c mice were measured. In mice, 35.9% of slight growth inhibition was observed in the group administered with K[Pt(digly)Cl] (dose of 26 mg/kg/day), and 40.6% in the group administered with K[Pt(Hdigly)Cl2] (dose of 52 mg/kg/day), and 45.3% cisplatin (dose of 10 mg/kg/day). The side effects related to the decrease in body weight are milder than that of cisplatin. Their toxicity against normal mouse bone marrow cells was measured. All of them exhibited toxicity against bone marrow cells, but K[Pt(digly)Cl] and K[Pt(Hdigly)Cl2] had only 1/10 the toxicity of cisplatin.
    Inorganic Chemistry - INORG CHEM. 01/1997; 36(19):4195-4201.
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    ABSTRACT: The conformation of the oxidation product (A) of biruthenocene (RcRc) with p-benzoquinone containing boron trifluoride diethylether complex is [RcRcC6H4O2]2+(BF4−)2 in which p-benzoquinoen is ligated to the RuIV center. The recrystallization of A from the mixture of nitromethhane containing small amount of acetonitrile or pyrazine gives mixed-valence cations formulated as [RuIICp(C5H4C5H4)CpRuIVL]2+ (L = acetonitrile 1 and pyrazine 2), in which L is coordinated to the RuIV center. The crystal of 1 formulated as [RuIICp(C5H4C5H4)CpRuIVNCCH3]2+ (BF4−)2. CH3NO2 (1), is found to be orthorhombic, space group Pbca, a = 14.255(7), b = 37.105(10), c = 10.051(4) Å, V = 5316(4), Z = 8 and the final R = 0.054 and Rw = 0.059. The similar pyrazine salt 2 formulated as [RuIICp(C5H4C5H4)CpRuIVN(CH)4N]2+ (BF4−)2(CH3NO2)2is found to be triclinic, space group P1, a = 9.006(2), b = 19.233(4), c = 28.907(10) Å, α = 89.45(1)°, β = 86.10(3)°, γ = 87.85(2)°, V = 4991(2), Z = 2, and the final R = 0.077 and RW = 0.090. The unit cell has three independent molecules (2A, 2B, 2C). The Ru(IV)-N distances (2.15(1) Å for 2A, 2.11(1) for 2B and 2.15(1) for 2C) are longer by ca. 0.1 Å than that of 1 because of bulky molecule of pyrazine. Both cations (1,2) have wedge-sharp structure due to the RuN bond, the dihedral angles between the Cp and C5H4 rings of the [LRuIVCp(C5H4)]2+ moiety are 38.70° for 1, 38.77° (2A), 40.84° (2B) and 41.67° (2C) for 2. The nucleophilicity to the RuIV increases in the order Cl− > pyrazine > acetoritrile > p-benzoquinone and unlike the case of mixed-valence halobiruthenocenium cations ([RcRcX]+: X  Cl, Br, I), no temperature dependent 1H - and 13C-NMR spectra were observed for 1 and 2 in solution, implying the absence of two-electron exchange reaction between the RuII and RuIV.
    North-Holland Mathematics Studies 01/1997; 549(1):13-23.
  • Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1996; 69(6):1579-1586.
  • Masanobu Watanabe, Izumi Motoyama, Toshio Takayama
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    ABSTRACT: Oxidations of biruthenocene (RcRc) and ferrocenylruthenocene (FcRc) with an equivalent amount of iodine or iodoruthenocenium +Y− ([RcHI]+Y−), Y  BF4− and PF6−) gave monocationic halometallocenium salts formulated as [M11Cp(C5H4C5H4)CpRuIVI]+Y− (M  Ru, Y  I3 1, BF42; M  Fe, Y  I33, BF44, PF65). The crystal structure of 1, 3 and 4 were analyzed by single-crystal X-ray diffraction. The crystal of 1 is monoclinic, space group P21c, a = 10.737(3), b = 23.957(3), c = 9.936(3) Å, β = 110.96(2)°, Z = 4, final R = 0.084. The crystal of 3 is monoclinic, space group P21c, a = 10.575(3), b = 9.902(4) å, β = 110.85(3)°, Z = 4, final R = 0.049. The crystal of 4 is orthorhombic, space group P212121, a = 9.871(10), b = 25.581(10), c = 7.810(3) Å, Z = 4, final R = 0.094. The most interesting structural difference between the I3− (1.3) and other salts (2, 4, 5) is found in the direction of the RuIV−1 bond with respect to the remaining half of the M11Cp(C5H4) (M  Ru, Fe) moiety. Because one end of the I3−1 anion sits above the C5H4 plane of the M11Cp(C5H4) moiety, the RuIV-I− bons is fixed in the trans position to the M11Cp(C5H4) moiety, avoiding steric hindrance between them when the I3− salts (1 and 3) are crystallized. In the case of the BF4− and PF6− salts, the RuIV-I− bond sits in the cis position to the M11Cp(C[in5H4) moiety, as shown in Scheme 1, and this conformation gives larger tilting angles between the two ν5-Cp and ν5-C5H4 on the RuIV side (e.g. tilting angles 42.4° and 39.21° for 2 and 4 respectively) than those of both I3− salts (31.08° for 1, 32.73° for 3) due to the van der Waals contact between I and the C5H4C5H4 plane. Such large conformational differences between the salts 1, 3 and 2, 4, 5 were observed from the results of 13C CP/MAS NMR and 57Fe-Mössbauer spectroscopic studies; i.e. large temperature dependent 57Fe-Mössbauer spectra were found for 4 and 5, unlike the case of 3, probably because of the delocalization of the higher positive [IRuIVCp(C5Hin4)]su1 charge to the Fe11Cp(C5H4) moiety for 4 and 5.
    Journal of Organometallic Chemistry 01/1996; 523(2):153-165. · 2.00 Impact Factor
  • Masanobu Watanabe, Izumi Motoyama, Toshio Takayama
    Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1996; 69(10):2877-2884.
  • Masanobu Watanabe, Izumi Motoyama, Toshio Takayama
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    ABSTRACT: The oxidation of [1.1]ferrocenylruthenocenophane (1) with bromo- or chlororuthenocenium +BF4− ([RcHX]+BF4−;X = Br, Cl) was carried out giving a diamagnetic salt2. The crystal form of2 is monoclinic, space groupP2i/n, a = 10.556(3), b = 13.634(3), c = 13.795(2)A˚, β = 107.27(2)°, V = 1896.0(8)A˚3, Z = 4, and the finalR = 0.045andRw = 0.040, based on the results of the single-crystal X-ray diffraction study. The distance between the Ru and Fe is ca. 4.495(2)A˚, which is much shorter than1 (4.792(2)A˚). The structure of the cation is illustrated as a resonance hybrid canonical structure of α,α-carbonium-type expressed as [Fe11(C5H4CH2C5H4)(C5H4CHC5H4)Ru]+ andη6-fulvalne-type as [Fe11(C5H4CH2C5H4)(C5H4CHC5H4)Ru]+. The two C5H4 rings on the Ru side are tilted greatly (the dihedral angle of the rings is 10.92°) owing to the RuCα+ bond formation (2.407(6)A˚), which gives the stability of the carbonium center -CH+-.57Fe Mo¨ssbauer,1H,13C and13C CP/MAS NMR spectroscopic studies support the above formula.
    Journal of Organometallic Chemistry 01/1996; 524:9-18. · 2.00 Impact Factor
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    ABSTRACT: The structure of iodo[1.1]ferrocenylruthenocenophanium+ BF4− (1), prepared by oxidation of [1.1]ferrocenylruthenocenophane ([1.1])FcRc) with iodoruthenocenium+ BF4− ([RcHI]+ BF4−) was analyzed by single-crystal X-ray diffraction. The crystal form of 1 is triclinic, space group P1, a = 9.794(2), b = 14.393(4), c = 7.777(2) Å, α = 101.62(4), β = 93.17(4), γ = 72.09(2)°, Z = 2, and the final R and Rw were both 0.052. The cation exists in a syn-conformation, as with other [1.1]metallocenophanes, and is given the formula [Fe(II)(C5H4CH2C5H4)2Ru(IV)I]+ with Ru(IV)-I bond (2.751(1) Å) formation in the solid. The distance between the Ru(IV) and Fe(II) atoms is 4.719(1) Å, which is slightly shorter than the value for [1.1]FcRc, and the bond angle of IRu(IV)Fe(II) is 91.50(1)°. The cation has two kinds of twisted C5H4CH2C5H4 systems. The cyclopentadienyl rings in the [Cp(C5H4)RuI]+ moiety are highly slanted (the dihedral angle between the Cp ring and fulvenide ligand is 33.87°) owing to the Ru(IV)-I bond. Large downfield shifts of the 13C CP/MAS NMR signals for the ruthenocene moiety are explained by the same fact.
    Journal of Organometallic Chemistry 01/1995; 496(1):87-92. · 2.00 Impact Factor
  • Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1995; 68(9):2559-2565.
  • Yoshio Koike, Toshio Takayama, Masatoshi Watabe
    Bulletin of The Chemical Society of Japan - BULL CHEM SOC JPN. 01/1984; 57(12):3595-3596.

Publication Stats

18 Citations
23.75 Total Impact Points

Institutions

  • 1995–2009
    • Kanagawa University
      • • Department of Material and Life Chemistry
      • • Faculty of Engineering
      • • Department of Chemistry
      Yokohama, Kanagawa, Japan
  • 2000–2006
    • Kogakuin University
      Edo, Tōkyō, Japan