Radoske, T.*; Kloditz, R.*; Fichter, S.*; Mrz, J.*; Kaden, P.*; Patzschke, M.*; Schmidt, M.*; Stumpf, T.*; Walter, O.*; Ikeda, Atsushi
Dalton Transactions (Internet), 49(48), p.17559 - 17570, 2020/12
Journal of Nuclear and Radiochemical Sciences (Internet), 20, p.28 - 31, 2020/06
Motokawa, Ryuhei; Kobayashi, Toru; Endo, Hitoshi; Mu, J.*; Williams, C. D.*; Masters, A. J.*; Antonio, M. R.*; Heller, W. T.*; Nagao, Michihiro*
ACS Central Science, 5(1), p.85 - 96, 2019/01
Kozai, Naofumi; Sakamoto, Fuminori; Tanaka, Kazuya; Onuki, Toshihiko; Sato, Takahiro*; Kamiya, Tomihiro*; Grambow, B.
Chemosphere, 196, p.135 - 144, 2018/04
Transformation of heavy elements by microbes such as bacteria and fungi has been an intense research subject; however, little is known about that of protozoa. This study investigated interaction of a representative protozoa, , with heavy elements (Eu(III), Pb(II), U(VI)). Non-destructive elemental analysis by micro-PIXE hardly detected those elements on living cells after sorption experiments but clearly detected on the cells that were killed with a fixative beforehand. Chromatographic analysis of aquatic species of those heavy elements after the sorption experiments revealed a fraction of those elements bound to a glycoprotein dissolved from the cell surface of living cells to form soluble pseudocolloid. These findings suggest that complexation of heavy elements with the dissolved surface glycoprotein reduced the sorption of those heavy elements on living cells.
Motokura, Ken*; Fukuda, Takuma*; Uemura, Yohei*; Matsumura, Daiju; Ikeda, Marika*; Nambo, Masayuki*; Chun, W.-J.*
Catalysts, 8(3), p.106_1 - 106_8, 2018/03
Kaneko, Masashi; Watanabe, Masayuki; Miyashita, Sunao*; Nakashima, Satoru*
Radioisotopes, 66(8), p.289 - 300, 2017/08
Scalar-relativistic density functional calculations applied to some trivalent europium complexes. Five Eu(III) complexes whose Eu Mssbauer isomer shifts vary from -1.8 to 0.5 mm/s are referred by previously reported results. Geometrical optimizations of their complexes reproduces the experimental coordination structures. Single-point calculations are applied to their optimized geometries at three density functionals, namely, BP86, B3LYP, and B2PLYP, to obtain their electron densities at Eu nucleus. A comparison of the linearity between the electron densities and the corresponding Eu Mssbauer isomer shifts reveals that B2PLYP functional shows the best linearity. Electron population and bond analyses indicate that d- and f-orbital electrons of Eu ion in the complexes are found to be correlated to the experimental Eu Mssbauer isomer shifts. This indicates that the d- and f-orbital electrons are involved in the covalent interaction of the coordination bond between the Eu ion and the ligands.
Hosha Kagaku, (35), p.36 - 39, 2017/03
This paper is an article for research introduction by winner of the Japan Society of Nuclear and Radiochemical Sciences Encouragement Price 2016. It was mentioned about the achievements which revealed the spin transition behavior of iron complex and the separation mechanism of actinides from lanthanides.
Nakashima, Satoru*; Kaneko, Masashi
Advances in Chemistry Research, Vol.36, p.171 - 195, 2017/01
Spin-crossover (SCO) phenomena of the assembled coordination polymers are introduced. When the bridging ligand is flexible like 1,2-bis(4-pyridyl)ethane, 1,3-bis(4-pyridyl)propane, a variety of assembled structure can be obtained, depending on the conformer of the ligand and the guest molecules. Guest-dependent SCO phenomena of the assembled iron complexes are shown. Density functional theory is applied to know the cause of guest-dependent SCO phenomena. The validity of an iron mono-nucleus model is evaluated for the coordination polymers. It is shown that SCO occurs or not depends on the local structure around iron ion.
Motokawa, Ryuhei; Kobayashi, Toru; Endo, Hitoshi*; Ikeda, Takashi; Yaita, Tsuyoshi; Suzuki, Shinichi; Narita, Hirokazu*; Akutsu, Kazuhiro*; Heller, W. T.*
Journal of Nuclear Science and Technology, 53(8), p.1205 - 1211, 2016/08
Iida, Yoshihisa; Barr, L.; Yamaguchi, Tetsuji; Hemmi, Ko
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(1), p.3 - 8, 2016/06
Thorium (Th)-229 is one of the important radionuclides for the performance assessment calculations for high-level radioactive waste repositories. The sorption behavior of Th onto montmorillonite and illite were investigated by batch sorption experiments. Experiments were carried out under variable pH and carbonate concentrations. The sorbability of montmorillonite was higher than that of illite. Distribution coefficients, (m kg), decreased with increased carbonate concentrations and showed the minimal value at around pH 10. The sorption behaviors of Th were analyzed by the non-electrostatic surface complex model with PHREEQC computer program. The model calculations were able to explain the experimental results reasonably well. The decreases of was likely due to the stabilization of aqueous species by hydroxo-carbonate complexations in the solutions.
Takagi, Shigeyuki*; Iijima, Yuki*; Sato, Toyoto*; Saito, Hiroyuki; Ikeda, Kazutaka*; Otomo, Toshiya*; Miwa, Kazutoshi*; Ikeshoji, Tamio*; Aoki, Katsutoshi*; Orimo, Shinichi*
Angewandte Chemie; International Edition, 54(19), p.5650 - 5653, 2015/05
Even, J.*; Yakushev, A.*; Dllmann, Ch. E.*; Haba, Hiromitsu*; Asai, Masato; Sato, Tetsuya; Brand, H.*; Di Nitto, A.*; Eichler, R.*; Fan, F. L.*; et al.
Science, 345(6203), p.1491 - 1493, 2014/09
A new superheavy element complex, a seaborgium carbonyl, has been successfully synthesized, and its adsorption property has been studied using a cryo-thermochromatography and -detection apparatus COMPACT. Nuclear reaction products of short-lived Sg preseparated with a gas-filled recoil ion separator GARIS at RIKEN were directly injected into a gas cell filled with He/CO mixture gas, and chemical reaction products of volatile carbonyl complexes were trasported to COMPACT. The Sg carbonyl complex detected with COMPACT was found to be very volatile with adsorption enthalpy of 50 kJ/mol, from which we have concluded that this complex should be a Sg hexacarbonyl Sg(CO). This is the first synthesis of organometallic compounds of transactinide elements for which only simple inorganic comounds have been synthesized so far.
Ueda, Masato; Sakamoto, Yoshiaki*
Genshiryoku Bakkuendo Kenkyu, 12(1-2), p.31 - 39, 2006/03
no abstracts in English
Ishimori, Kenichiro*; Watanabe, Masayuki; Kimura, Takaumi; Yaita, Tsuyoshi; Yamada, Takashi*; Kataoka, Yumiko*; Shinoda, Satoshi*; Tsukube, Hiroshi*
Chemistry Letters, 34(8), p.1112 - 1113, 2005/08
Stereochemical substitution on tripod ligand significantly offered efficient separation of trivalent actinides from trivalent lanthanides. Liquid-liquid extraction using chiral tris(2-pyridylmethyl)amine ligands as an extractant exhibited high efficiency and selectivity for trivalent actinides. A combination of chiral ligand and 2-bromodecanoic acid further enhanced extraction performance for trivalent actinides.
Yaita, Tsuyoshi; Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro; Shimada, Asako*; Assefa, Z.*; Haire, R. G.*
Physica Scripta, T115, p.302 - 305, 2005/00
The structural parameter and the electronic structure of the complex between cerium and N,N'-dimethyl-N,N'-diphenylpyridine-2,6-carboxyamide(DMDPhPDA) was investigated by XAFS, photo luminescence and excitation spectra. The DMDPhPDA is one of the promising ligands for separation of trivalent actinides from lanthanides. The Ce-K XAFS spectra were measured at BL11XU of SPring-8. The bond distances between the carbonyl oxygens and cerium, and between the pyridyl nitrogen and cerium are 253pm and 264pm, respectively. The bond angle of the plane consisting of the two carbonyl oxygens and nitrogen with cerium was about 180 degree. This complex was a yellow color unique for the DMDPhPDA-lanthanide complexes. The photo absorption peak for the complex was extremely broad, and the peak position was at a higher wavenumber as compared with those for the other lanthanide complexes. The peak in the highest wavenumber of this band may be attributed to the transition between f and d orbitals, which are greatly influenced by the ligand field of the DMDPhPDA. The XANES spectrum of the cerium complex clearly showed that cerium was trivalent.
Nagame, Yuichiro; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Akiyama, Kazuhiko; Ishii, Yasuo; Sato, Tetsuya; Hirata, Masaru; Nishinaka, Ichiro; Ichikawa, Shinichi; et al.
Radiochimica Acta, 93(9-10), p.519 - 526, 2005/00
no abstracts in English
Yoshida, Takahiro; Ozaki, Takuo; Onuki, Toshihiko; Francis, A. J.*
Radiochimica Acta, 92(9-11), p.749 - 753, 2004/12
Accumulation of Fe(III)-, Eu(III)-, Hf(IV)-, and Pu(IV)-desferrioxamine B (DFO) complexes by aerobic bacterium, (ATCC 55241) was studied in order to elucidate stability of DFO complexes on biosorption. When Eu(III)-DFO complex was incubated with bacteria in 0.1 M Tris-HCl buffer (pH = 7.2), the metals were removed from solution, with no change in DFO concentration in solution. On the other hand, Fe(III)-, Hf(IV)-, and Pu(IV)-DFO complexes were not accumulated to bacteria. Metals with high charge to ionic radius ratio (Z/r) suppress the dissociation of complexes, leading small bacterial accumulation.
Watanabe, Masayuki; Mirvaliev, R.*; Tachimori, Shoichi; Takeshita, Kenji*; Nakano, Yoshio*; Morikawa, Koshi*; Chikazawa, Takahiro*; Mori, Ryohei*
Solvent Extraction and Ion Exchange, 22(3), p.377 - 390, 2004/06
The synergistic extraction with N,N,N',N'-tetrakis(2-methylpyridyl)-ethylenediamine (TPEN) and di(2-ethylhexyl)phosphoric acid (D2EHPA) demonstrates a good selectivity for Am(III) over macro amount of Ln(III) in 1-octanol. The maximum apparent separation factor, which is defined as the ratio of the distribution ratio of Am(III) to that of Eu(III), is ca. 80 while the molar fraction between D2EHPA and TPEN is 2.0. This ratio is corresponding to the result of the spectrophotometric titration, which indicates that TPEN and D2EHPA form an aggregate in 1-octanol and two D2EHPA molecules coordinate to Eu(III) TPEN complex, [Eu(TPEN)]. In the present study, the association of D2EHPA and TPEN is one of the most important factors for the synergistic extraction and the complexation of TPEN and D2EHPA with Eu(III).
Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Akiyama, Kazuhiko; Nishinaka, Ichiro; Hirata, Masaru; Yaita, Tsuyoshi; Ichikawa, Shinichi; Nagame, Yuichiro; et al.
Journal of the American Chemical Society, 126(16), p.5219 - 5224, 2004/04
Fluoride complexation of element 104, rutherfordium (Rf), produced in the Cm(O,5n)Rf reaction has been studied by anion-exchange chromatography on an atom-at-a-time scale. The anion-exchangechromatographic behavior of Rf was investigated in 1.9-13.9 M hydrofluoric acid together with those of the group-4 elements Zr and Hf produced in the O-induced reactions on Ge and Gd targets, respectively. It was found that the adsorption behavior of Rf on anion-exchange resin is quite different from those of Zr and Hf, suggesting the influence of relativistic effect on the fluoride complexation of Rf.
Dai-5-Han Jikken Kagaku Koza 22; Kinzoku Sakutai, Seni Kinzoku Kurasuta, p.200 - 209, 2004/03
no abstracts in English