Hideki Furutachi

Kanazawa University, Kanazawa, Ishikawa, Japan

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Publications (49)268.73 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A mononuclear peroxocarbonato-iron(III) complex [Fe(6Me-pic)2(O2C(O)O)]− (1-O2C(O)O) with bidentate ligands (6Me-pic), prepared by the reaction of a carbonato-iron(III) complex [Fe(6Me-pic)2(CO3)]− (1-CO3) with H2O2, was fully characterized. 1-O2C(O)O showed reversible O-O bond cleavage and reformation of the peroxo group under CO2 at 25 °C. 1-O2C(O)O is capable of not only oxidizing the C=C bond of cyclooctene but also the C-H bond of toluene. As for cyclooctene, epoxidation is favorable under CO2 in the presence of H2O, while cis-dihydroxylation precedes under N2, indicating that the oxidation reactivity of 1-O2C(O)O toward cyclooctene can be tuned by changing the concentration of CO2 and H2O.
    Chemistry Letters 01/2015; 44(3):330-332. DOI:10.1246/cl.141058 · 1.23 Impact Factor
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    ABSTRACT: Low-frequency vibrational modes of peroxo-bridged high-spin biferric complexes have been observed using nuclear resonance vibrational spectroscopy (NRVS; see picture, PVDOS=partial vibrational density-of-states) and assigned using DFT calculations. Correlations between the spectral features and the structure of peroxo-bridged cores form a basis for structural elucidation of enzyme-peroxo intermediates.
    Angewandte Chemie International Edition 01/2013; 52(4). DOI:10.1002/anie.201208240 · 11.26 Impact Factor
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    ABSTRACT: A mononuclear peracetatoiron(III) complex [Fe(6Me(2)-BPP)(CH3C(O)O-2)](+) (2) with a tripodal ligand (6Me(2)-BPP) was prepared in the reaction of an iron(II) complex [Fe(6Me(2)-BPP)(H2O)](+) (1) with peracetic acid. 2 is the first example of a structurally and spectroscopically well-defined non-heme type peracetatoiron(III) complex and has modest oxidation ability toward triphenyl phosphine, some olefins, and the tertiary C-H bond of adamantane.
    Chemistry Letters 05/2011; 40(5):515-517. DOI:10.1246/cl.2011.515 · 1.23 Impact Factor
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    ABSTRACT: A (mu-eta(2):eta(2)-peroxo)dicopper(II) complex, [Cu-2(H-L)(O-2)](2+) (1-O-2), supported by the dinucleating ligand 1, 3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]benzene (H-L) is capable of initiating C-H bond activation of a variety of external aliphatic substrates (SHn): 10-methyl-9,10-dihydroacridine (AcrH(2)), 1,4-cyclohexadiene (1,4-CHD), 9,10-dihydroanthracene (9,10-DHA), fluorene, tetralin, toluene, and tetrahydrofuran (THF), which have C-H bond dissociation energies (BDEs) ranging from similar to 75 kcal mol(-1) for 1,4-CHD to similar to 92 kcal mol(-1) for THF. Oxidation of SHn afforded a variety of oxidation products, such as dehydrogenation products (SH(n-2)), hydroxylated and further-oxidized products (SH(n-1)OH and SH(n-2)=O), dimers formed by coupling between substrates (H(n-1)S-SH(n-1)) and between substrate and H-L (H-L-SH(n-1)). Kinetic studies of the oxidation of the substrates initiated by 1-O-2 in acetone at-70 degrees C revealed that there is a linear correlation between the logarithms of the rate constants for oxidation of the C-H bonds of the substrates and their BDEs, except for THF. The combination of this correlation and the relatively large deuterium kinetic isotope effects (KIES), k(2)(H)/k(2)(D) (13 for 9,10-DHA, >= 29 for toluene, and similar to 34 for THF at-70 degrees C and similar to 9 for AcrH(2) at -94 degrees C) indicates that H-atom transfer (HAT) from SHn (SDn) is the rate-determining step. Kinetic studies of the oxidation of SHn by cumylperoxyl radical showed a correlation similar to that observed for 1-O-2, indicating that the reactivity of 1-O-2 is similar to that of cumylperoxyl radical. Thus, 1-O-2 is capable of initiating a wide range of oxidation reactions, including oxidation of aliphatic C-H bonds having BDEs from similar to 75 to similar to 92 kcal mol(-1), hydroxylation of the m-xylyl linker of H-L, and epoxidation of styrene (Matsumoto, T.; et al. J. Am. Chem. Soc. 2006, 128, 3874).
    Journal of the American Chemical Society 07/2009; 131(26):9258-67. DOI:10.1021/ja809822c · 12.11 Impact Factor
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    ABSTRACT: In the nick(el) of time: Bis(mu-oxo) dinickel(III) complexes 2 (see scheme), generated in the reaction of 1 with H(2)O(2), are capable of hydroxylating the xylyl linker of the supporting ligand to give 3. Kinetic studies reveal that hydroxylation proceeds by electrophilic aromatic substitution. The lower reactivity than the corresponding mu-eta(2):eta(2)-peroxo dicopper(II) complexes can be attributed to unfavorable entropy effects.
    Angewandte Chemie International Edition 04/2009; 48(18):3304-7. DOI:10.1002/anie.200900222 · 11.26 Impact Factor
  • Galyna G. Dubinina · Hideki Furutachi · David A. Vicic
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 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.
    ChemInform 11/2008; 39(47). DOI:10.1002/chin.200847073
  • Source
    Galyna G Dubinina · Hideki Furutachi · David A Vicic
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    ABSTRACT: The first examples of isolable and structurally characterized Cu(I)-CF3 complexes are reported. N-Heterocyclic carbene (NHC)-supported copper tert-butoxide complexes reacted with Me3Si-CF3 to afford new (NHC)Cu-CF3 complexes whose structures were dependent on whether or not the C4-C5 positions of the five-membered NHC rings were saturated. In situ generated (SIiPr)Cu-CF3 cleanly transferred its trifluoromethyl group to a number of organic halides under mild conditions.
    Journal of the American Chemical Society 08/2008; 130(27):8600-1. DOI:10.1021/ja802946s · 12.11 Impact Factor
  • Journal of the American Chemical Society 02/2007; 129(1):2-3. DOI:10.1021/ja063987z · 12.11 Impact Factor
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    ABSTRACT: New hexadentate dinucleating ligands having a xylyl linker, X–L–R, were synthesized, where X–L–R = 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2,4,6-trimethybenzene (Me2–L–Me) and 1,3-bis[bis(6-methyl-2-pyridylmethyl)aminomethyl]-2-fluorobenzene (H–L–F). They form dinuclear copper(I) complexes, [Cu2(X–L–R)]2+ (Me2–L–Me (1) and H–L–F (2)). The copper(I) complexes in acetone at −78 °C react with O2 to produce intra- and intermolecular (μ-η2:η2-peroxo)dicopper(II) species depending on the concentrations of the complexes: both complexes generate intramolecular (μ-η2:η2-peroxo)dicopper(II) species [Cu2(O2)(X–L–R)]2+ (1-O2 and 2-O2) at the concentrations below ∼5 mM, whereas at ∼60 mM, both complexes produce intermolecular (μ-η2:η2-peroxo)dicopper(II) species, which were confirmed by the electronic and resonance Raman spectroscopies. The electronic spectrum of 1-O2 in acetone at concentrations below ∼5 mM showed an absorption band at (λmax = 442 nm, ε = 5600 M−1 cm−1) assignable to the πσ∗(O–O)-to-Cu(II) ((dx2-y2+dx2-y2)(dx2-y2+dx2-y2) component) LMCT transition in addition to an intense band attributable to the πσ∗(O–O)-to-Cu(II) ((dx2-y2-dx2-y2)(dx2-y2-dx2-y2) component) LMCT transition (λmax = 359 nm, ε = 21000 M−1 cm−1), indicating that the (μ-η2:η2-peroxo)Cu(II)2 core of 1-O2 takes a butterfly structure. Decomposition of 1-O2 resulted in hydroxylation of the 2-position of the xylyl linker with 1,2-methyl migration (NIH shift), suggesting that the hydroxylation reaction proceeds via a cationic intermediate as proposed for closely related (μ-η2:η2-peroxo)Cu(II)2 complexes having a xylyl linker. Kinetic study of the decomposition (hydroxylation of the xylyl linker) of 1-O2 suggests that a stereochemical effect of the methyl group in the 2-position of the xylyl linker has a significant influence on a transition state for decomposition (hydroxylation of the xylyl linker).
    Journal of Organometallic Chemistry 01/2007; 692(1-3):111-121. DOI:10.1016/j.jorganchem.2006.05.068 · 2.17 Impact Factor
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    ABSTRACT: Stufenweise herab: Die Reaktion von [Cu(Me2-tpa)]+ (Me2-tpa=Bis(6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amin) mit H2O2 führt unter regioselektiver Oxidation einer Methylgruppe des Liganden zum Alkylperoxokupfer(II)-Komplex [Cu(Me-tpa-CH2OO)]+, der weiter zu Aldehyd- und Alkoholkupfer(I)-Komplexen sowie Alkoxo- und Carboxylkupfer(II)-Komplexen abgebaut wird (siehe Schema; blau N, grün Cu, rot O).
    Angewandte Chemie International Edition 10/2006; 45(41):6911-4. DOI:10.1002/anie.200602477 · 11.26 Impact Factor
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    ABSTRACT: The reaction of [Ni2(OH)2(Me2-tpa)2]2+ (1) (Me2-tpa = bis(6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine) with H2O2 causes oxidation of a methylene group on the Me2-tpa ligand to give an N-dealkylated ligand and oxidation of a methyl group to afford a ligand-based carboxylate and an alkoxide as the final oxidation products. A series of sequential reaction intermediates produced in the oxidation pathways, a bis(mu-oxo)dinickel(III) ([Ni2(O)2(Me2-tpa)2]2+ (2)), a bis(mu-superoxo)dinickel(II) ([Ni2(O2)2(Me2-tpa)2]2+ (3)), a (mu-hydroxo)(mu-alkylperoxo)dinickel(II) ([Ni2(OH)(Me2-tpa)(Me-tpa-CH2OO)]2+ (4)), and a bis(mu-alkylperoxo)dinickel(II) ([Ni2(Me-tpa-CH2OO)2]2+ (5)), was isolated and characterized by various physicochemical measurements including X-ray crystallography, and their oxidation pathways were investigated. Reaction of 1 with H2O2 in methanol at -40 degrees C generates 2, which is extremely reactive with H2O2, producing 3. Complex 2 was isolated only from disproportionation of the superoxo ligands in 3 in the absence of H2O2 at -40 degrees C. Thermal decomposition of 2 under N2 generated an N-dealkylated ligand Me-dpa ((6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine) and a ligand-coupling dimer (Me-tpa-CH2)2. The formation of (Me-tpa-CH2)2 suggests that a ligand-based radical Me-tpa-CH2* is generated as a reaction intermediate, probably produced by H-atom abstraction by the oxo group. An isotope-labeling experiment revealed that intramolecular coupling occurs for the formation of the coupling dimer. The results indicate that the rebound of oxygen to Me-tpa-CH2* is slower than that observed for various high-valence bis(mu-oxo)dimetal complexes. In contrast, the decomposition of 2 and 3 in the presence of O2 gave carboxylate and alkoxide ligands, respectively (Me-tpa-COO- and Me-tpa-CH2O-), instead of (Me-tpa-CH2)2, indicating that the reaction of Me-tpa-CH2* with O2 is faster than the coupling of Me-tpa-CH2* to generate ligand-based peroxyl radical Me-tpa-CH2OO*. Although there is a possibility that the Me-tpa-CH2OO* species could undergo various reactions, one of the possible reactive intermediates, 4, was isolated from the decomposition of 3 under O2 at -20 degrees C. The alkylperoxo ligands in 4 and 5 can be converted to a ligand-based aldehyde by either homolysis or heterolysis of the O-O bond, and disproportionation of the aldehyde gives a carboxylate and an alkoxide via the Cannizzaro reaction.
    Inorganic Chemistry 05/2006; 45(7):2873-85. DOI:10.1021/ic0514243 · 4.76 Impact Factor
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    ABSTRACT: A discrete (mu-eta2:eta2-peroxo)Cu(II)2 complex, [Cu2(O2)(H-L)]2+, is capable of performing not only intramolecular hydroxylation of a m-xylyl linker of a dinucleating ligand but also intermolecular epoxidation of styrene via electrophilic reaction to the C=C bond and hydroxylation of THF by H-atom abstraction.
    Journal of the American Chemical Society 04/2006; 128(12):3874-5. DOI:10.1021/ja058117g · 12.11 Impact Factor
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    ABSTRACT: The structure and dioxygen-reactivity of copper(I) complexes R supported by N,N-bis(6-methylpyridin-2-ylmethyl)amine tridentate ligands L2R[R (N-alkyl substituent)=-CH2Ph (Bn), -CH2CH2Ph (Phe) and -CH2CHPh2(PhePh)] have been examined and compared with those of copper(I) complex (Phe) of N,N-bis[2-(pyridin-2-yl)ethyl]amine tridentate ligand L1(Phe) and copper(I) complex (Phe) of N,N-bis(pyridin-2-ylmethyl)amine tridentate ligand L3(Phe). Copper(I) complexes (Phe) and (PhePh) exhibited a distorted trigonal pyramidal structure involving a d-pi interaction with an eta1-binding mode between the metal ion and one of the ortho-carbon atoms of the phenyl group of the N-alkyl substituent [-CH2CH2Ph (Phe) and -CH2CHPh2(PhePh)]. The strength of the d-pi interaction in (Phe) and (PhePh) was weaker than that of the d-pi interaction with an eta2-binding mode in (Phe) but stronger than that of the eta1 d-pi interaction in (Phe). Existence of a weak d-pi interaction in (Bn) in solution was also explored, but its binding mode was not clear. Redox potentials of the copper(I) complexes (E1/2) were also affected by the supporting ligand; the order of E1/2 was Phe>R>Phe. Thus, the order of electron-donor ability of the ligand is L1Phe<L2R<L3Phe. This was reflected in the copper(I)-dioxygen reactivity, where the reaction rate of copper(I) complex toward O2 dramatically increased in the order of R<R<R. The structure of the resulting Cu2/O2 intermediate was also altered by the supporting ligand. Namely, oxygenation of copper(I) complex R at a low temperature gave a (micro-eta2:eta2-peroxo)dicopper(II) complex as in the case of Phe, but its O-O bond was relatively weakened as compared to the peroxo complex derived from Phe, and a small amount of a bis(micro-oxo)dicopper(III) complex co-existed. These results can be attributed to the higher electron-donor ability of L2R as compared to that of L1Phe. On the other hand, the fact that Phe mainly afforded a bis(micro-oxo)dicopper(III) complex suggests that the electron-donor ability of L2R is not high enough to support the higher oxidation state of copper(III) of the bis(micro-oxo) complex.
    Dalton Transactions 11/2005; DOI:10.1039/b500202h · 4.20 Impact Factor
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    ABSTRACT: Dinuclear metal(II) complexes of 2,6-bis(N-[(2-dimethylamino)ethyl]iminomethyl)-4-methylphenol (HL), [Mn-2(L)(ACO)(2)(NCS)] (1), [Co-2(L)(AcO)(2)]BPh4 (2), [Ni-2(L)(AcO)(2)(MeOH)]BPh4 (3), and [Zn-2(L)(AcO)(2)]BPh4 (4), have been examined as regards their hydrolytic activity toward tris(p-nitrophenyl) phosphate (TNP) and hydrogen bis(p-nitrophenyl) phosphate (HBNP) by means of mass spectrometric methods as well as UV-visible spectroscopic methods. All the complexes hydrolyze TNP to BNP- in the relative activity of 4 > 2 > I >> 3. It is found that one AcO- group Of [M-2(L)(AcO)(2)](+) is replaced with BNP-, arising from the hydrolysis of TNP, affording [M-2(L)(AcO)(bnp)](+) in an equilibrium with [M-2(L)(AcO)(2)](+): [M-2(L)(AcO)(2)](+) + BNP- reversible arrow [M-2(L)(AcO)(bnp)]+ + AcO-. In the reaction of HBNP with 1-4, [M-2(L)(AcO)(bnp)](+) is produced in the equilibrium with [M-2(L)(AcO)(2)](+), and the bound BNP- is slowly hydrolyzed in the case of M = Mn and Co. The bound BNP- of [Ni-2(L)(AcO)(bnp)]+ is barely hydrolyzed and the bound BNP- of [Zn-2(L)(AcO)(bnp)](+) is practically not hydrolyzed. The relevance of the complexes to phosphotriesterase and phosphodiesterase is discussed.
    Bulletin of the Chemical Society of Japan 10/2005; 78(10-10):1795-1803. DOI:10.1246/bcsj.78.1795 · 2.21 Impact Factor
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    ABSTRACT: A mononuclear iron(III) complex containing a peroxocarbonate ligand, [Fe(qn)2(O2C(O)O)]- (qn = quinaldinate), underwent the reversible O-O bond cleavage and reformation of the peroxo group via the formation of FeIV=O or FeV=O species, which was confirmed by the resonance Raman and ESI-TOF/MS measurements.
    Journal of the American Chemical Society 05/2005; 127(13):4550-1. DOI:10.1021/ja0427202 · 12.11 Impact Factor
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    ABSTRACT: A new tetradentate tripodal ligand (L3) containing sterically bulky imidazolyl groups was synthesized, where L3 is tris(1-methyl-2-phenyl-4-imidazolylmethyl)amine. Reaction of a bis(mu-hydroxo)dicopper(II) complex, [Cu2(L3)2(OH)2]2+ (1), with H2O2 in acetonitrile at -40 degrees C generated a (mu-1,1-hydroperoxo)dicopper(II) complex [Cu2(L3)2(OOH)(OH)]2+ (2), which was characterized by various physicochemical measurements including X-ray crystallography. The crystal structure of 2 revealed that the complex cation has a Cu2(mu-1,1-OOH)(mu-OH) core and each copper has a square pyramidal structure having an N3O2 donor set with a weak ligation of a tertiary amine nitrogen in the apex. Consequently, one pendant arm of L3 in 2 is free from coordination, which produces a hydrophobic cavity around the Cu2(mu-1,1-OOH)(mu-OH) core. The hydrophobic cavity is preserved by hydrogen bondings between the hydroperoxide and the imidazole nitrogen of an uncoordinated pendant arm in one side and the hydroxide and the imidazole nitrogen of an uncoordinated pendant arm in the other side. The hydrophobic cavity significantly suppresses the H/D and 16O/18O exchange reactions in 2 compared to that in 1 and stabilizes the Cu2(mu-1,1-OOH)(mu-OH) core against decomposition. Decomposition of 2 in acetonitrile at 0 degrees C proceeded mainly via disproportionation of the hydroperoxo ligand and reduction of 2 to [Cu(L3)]+ by hydroperoxo ligand. In contrast, decomposition of a solid sample of 2 at 60 degrees C gave a complex having a hydroxylated ligand [Cu2(L3)(L3-OH)(OH)2]2+ (2-(L3-OH)) as a main product, where L3-OH is an oxidized ligand in which one of the methylene groups of the pendant arms is hydroxylated. ESI-TOF/MS measurement showed that complex 2-(L3-OH) is stable in acetonitrile at -40 degrees C, whereas warming 2-(L3-OH) at room temperature resulted in the N-dealkylation from L3-OH to give an N-dealkylated ligand, bis(1-methyl-2-phenyl-4-imidazolylmethyl)amine (L2) in approximately 80% yield based on 2, and 1-methyl-2-phenyl-4-formylimidazole (Phim-CHO). Isotope labeling experiments confirmed that the oxygen atom in both L3-OH and Phim-CHO come from OOH. This aliphatic hydroxylation performed by 2 is in marked contrast to the arene hydroxylation reported for some (mu-1,1-hydroperoxo)dicopper(II) complexes with a xylyl linker.
    Journal of the American Chemical Society 05/2005; 127(14):5212-23. DOI:10.1021/ja047437h · 12.11 Impact Factor
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    ABSTRACT: (mu-Hydroxo or oxo)(mu-1,2-peroxo)diiron(III) complexes having a tetradentate tripodal ligand (L) containing a carboxylate sidearm [Fe2(mu-OH or mu-O)(mu-O2)(L)2]n+ were synthesized as models for peroxo-intermediates of non-heme diiron proteins and characterized by various physicochemical measurements including X-ray analysis, which provide fundamental structural and spectroscopic insights into the peroxodiiron(III) complexes.
    Journal of the American Chemical Society 02/2005; 127(3):826-7. DOI:10.1021/ja045594a · 12.11 Impact Factor
  • Jaeheung Cho · Hideki Furutachi · Shuhei Fujinami · Masatatsu Suzuki
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    ABSTRACT: A radical approach: The reaction of [Ni2(OH)2(Me 2-tpa)2]2+ with H2O2 resulted in the peroxidation of a methyl group of the Me2-tpa ligand to produce a bis(μ-alkylperoxo)dinickel(II) complex (see ORTEP diagram) as a reaction intermediate for further oxidation to carboxylato and alkoxo complexes [Ni(Mel-tpa-COO)]+ and [Ni2(Me1-tpa-CH 2O)2]2+. Me2-tpa=bis[(6-methyl-2- pyridyl)methyl] [(2-pyridyl)methyl]amine.
    Angewandte Chemie International Edition 06/2004; 43(25):3300-3. DOI:10.1002/anie.200353637 · 11.26 Impact Factor
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    ABSTRACT: Oxygenation of copper(I) with tetradentate tripodal ligands (L) comprised of a tris(aminoethyl)amine (tren) skeleton having sterically bulky substituent(s) on the terminal nitrogens has been investigated, where L = tris(N-benzylaminoethyl)amine (L-H,L-Bn), tris(N-benzyl-N-methylaminoethyl)amine (L-Me,L-Bn), or tris(N,N-dimethylaminoethyl)amine (L-Me,L-Me). All the copper(I) complexes reacted with dioxygen at low temperatures to produce superoxocopper(II) and/ or trans-(mu-1,2-peroxo)-dicopper(II) complexes depending on the steric bulkiness of the terminal nitrogens and the reaction conditions. The reaction of a copper(I) complex [Cu(L-H,L-Bn)](+) at -90 degreesC in acetone resulted in the formation of a superoxo complex [Cu(L-H,L-Bn)(O-2)](+) as a less stable species and a peroxo complex [{Cu(L-H,L-Bn))(2)(O-2)](2+) as a stable species. The structures of [Cu(L-H,L-Bn)]ClO4 and [(Cu(L-H,L-Bn)}(2)(O-2)](BPh4)(2).8(CH3)(2)CO were determined by X-ray crystallography. [[Cu(L-H,L-Bn))(2)(O-2)](2+) has a trans-(mu-1,2-peroxo)-dicopper(II) core with a trigonal bipyramidal structure. The O-O bond distance is 1.450(5) Angstrom with an intermetallic Cu...Cu separation of 4.476(2) Angstrom. The resonance Raman spectrum of [{Cu(L-H,L-Bn)](2)(O-2)](2+) measured at -90 degreesC in acetone-d(6) showed a broad v(O-O) band at 837-834 cm(-1) (788 cm(-1) for an O-18 labeled sample) and two v(Cu-O) bands at 556 and 539 cm(-1), suggesting the presence of two peroxo species in solution. [Cu(L-Me,L-Bn)](+) also produced both superoxo and trans-mu-1,2-peroxo species, [Cu(L-Me,L-Bn)(O-2)](+) and [{Cu(L-Me,L-Bn))(2)(O-2)](2+). At a lower concentration of [Cu(L-Me,L-Bn)](+) (similar to0.24 mM) and higher dioxygen concentration (P(O-2) = similar to1 atm), the superoxo species is predominantly formed, whereas at a higher concentration of [Cu(L-Me,L-Bn)](+) (similar to1 mM) and lower dioxygen concentration (P(O-2) = similar to0.02 atm) the formation of the peroxo species is observed. The resonance Raman spectrum of [Cu(L-Me,L-Bn)(O-2)](+) (similar to1 mM) in acetone-d(6) at similar to-95 degreesC exhibited a v(O-O) band at 1120 cm(-1) (1059 cm(-1) for an O-18 labeled sample) and that of [(Cu(L-Me,L-Bn)](2)(O-2)](2+) (similar to3 mM) in acetone-d(6) at similar to-90 degreesC showed two v(O-O) bands at 812 and 797 cm(-1) (767 and 753 cm(-1) for an O-18 labeled sample), respectively. A similar observation was also made for [[Cu(L-Me,L-Me)}(2)(O-2)](2+). Relationships between the energies of the LMCT and d-d transitions and those of the v(O-O) and v(Cu-O) stretching vibrations and the steric constraints in the Cu(II)(O-2(2-))-Cu(II) core are discussed.
    Bulletin of the Chemical Society of Japan 01/2004; 77(1):59-72. DOI:10.1246/bcsj.77.59 · 2.21 Impact Factor
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    ABSTRACT: A new sterically hindered tetradentate tripodal ligand (Me2-etpy) and its labeled analogue having deuterated methylene groups (d4-Me2-etpy) were synthesized, where Me2-etpy is bis(6-methyl-2-pyridylmethyl)(2-pyridylethyl)amine. Copper(I) complexes [Cu(Me2-etpy or d4-Me2-etpy)]+ (1 and 1-d4, respectively) reacted with dioxygen at -80 degrees C in acetone to give bis(mu-oxo)dicopper(III) complexes [Cu2(O)2(Me2-etpy or d4-Me2-etpy)2](2+) (1-oxo and 1-d4-oxo, respectively), the latter of which was crystallographically characterized. Unlike a bis(mu-oxo)dicopper(III) complex with a closely related Me2-tpa ligand having a 2-pyridylmethyl pendant, 1-oxo possessing a 2-pyridylethyl pendant is not fully formed even under 1 atm of O2 at -80 degrees C and is very reactive toward the oxidation of the supporting ligand. Thermal decomposition of 1-oxo gave an N-dealkylated ligand in yield approximately 80% based on a dimer and a corresponding aldehyde. The deuterated ligand d4-Me2-etpy greatly stabilizes the bis(mu-oxo)dicopper(III) complex 1-d4-oxo, indicating that the rate determining step of the N-dealkylation is the C-H bond cleavage from the methylene group. The reversible conversion between 1-d4 and 1-d4-oxo in acetone is dependent on the temperature, and the thermodynamic parameters (DeltaH and DeltaS) of the equilibrium were determined to be -53 +/- 2 kJ mol(-1) and -187 +/- 10 J mol(-1) K(-1), respectively. The effect of the 2-pyridylethyl pendant in comparison with the 2-pyridylmethyl and 6-methyl-2-pyridylmethyl pendants on the physicochemical properties of the copper(I) and bis(mu-oxo)dicopper(III) species is discussed.
    Inorganic Chemistry 01/2004; 42(25):8534-44. DOI:10.1021/ic0345166 · 4.76 Impact Factor

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1k Citations
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  • 1998–2013
    • Kanazawa University
      • • School of Chemistry
      • • Graduate School of Natural Science and Technology
      Kanazawa, Ishikawa, Japan
  • 2008
    • Honolulu University
      Honolulu, Hawaii, United States
  • 1996–1999
    • Kyushu University
      • Department of Chemistry
      Hukuoka, Fukuoka, Japan
  • 1995
    • University of the Ryukyus
      Okinawa, Okinawa, Japan