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Mn
Co
Ni
Cu
)VO
Yamamoto, Hajime*; Tsuji, Takuya; Matsumura, Daiju; 16 of others*
Inorganic Chemistry, 64(34), p.17496 - 17502, 2025/08
Times Cited Count:0 Percentile:0.00(Chemistry, Inorganic & Nuclear)He, X.*; Kagi, Hiroyuki*; Komatsu, Kazuki*; Sano, Asami; Abe, Jun*; Fukuyama, Ko*; Shimmei, Toru*; Nakano, Satoshi*
Inorganic Chemistry, 63(47), p.22349 - 22360, 2024/11
Times Cited Count:3 Percentile:43.45(Chemistry, Inorganic & Nuclear)Brucite, Mg(OH)
, is a key material for studying hydrogen bonds in solid hydroxides. This study explored how fluorine (F) substitution affects hydrogen-bonding in hydrogenated and deuterated brucite under ambient and high-pressure conditions using neutron powder diffraction, Raman, and IR spectroscopy. At ambient conditions, F substitution shortened donor- acceptor distances and elongated hydroxyl bonds, strengthening hydrogen bonds, as evidenced by red shifts in hydroxyl stretching modes. High-pressure experiments showed that F doping suppressed pressure-induced hydrogen-bond strengthening, reducing changes in hydroxyl bond length, bond angle, and cone angle. Spectroscopic measurements confirmed that F substitution limits pressure-induced hydroxyl elongation.
O
/U
O
redox equilibrium in [emim]Tf
N-based liquid electrolytes towards uranium redox-flow batteryTakao, Koichiro*; Ouchi, Kazuki; Komatsu, Atsushi; Kitatsuji, Yoshihiro; Watanabe, Masayuki
European Journal of Inorganic Chemistry, 27(14), p.e202300787_1 - e202300787_7, 2024/05
Times Cited Count:2 Percentile:29.80(Chemistry, Inorganic & Nuclear)Electrochemical behavior of U
O
/U
O
in 1-ethyl-3-methylimidazolium bis(trifluoromethyl)sulfonylamide ([emim]Tf
N) ionic liquid was studied to clarify what are required to attain its redox reversibility for utilizing depleted U as an electrode active material in a redox flow battery. As a result, reversibility of the U
O
/U
O
redox reaction was successfully achieved in use of a glassy carbon working electrode under presence of Cl
in [emim]Tf
N. To improve diffusivity of solutes, [emim]Tf
N diluted with an auxiliary molecular solvent, N,N-dimethylformamide (DMF). We have succeeded in demonstrating a reversible redox reaction of [U
O
Cl
]
+ e
= [U
O
Cl
]
in the 50:50 v/v [emim]Tf
N-DMF liquid electrolyte containing Cl
.
O
-75MoO
binary glasses composed of isolated MoO

Masuno, Atsunobu*; Munakata, Sae*; Okamoto, Yoshihiro; Yaji, Toyonari*; Kosugi, Yoshihisa*; Shimakawa, Yuichi*
Inorganic Chemistry, 63(12), p.5701 - 5708, 2024/03
Times Cited Count:5 Percentile:63.07(Chemistry, Inorganic & Nuclear)Transparent and brown La
O
-MoO
binary glasses were prepared in bulk form using a levitation technique. The glass-forming range was limited, with the primary composition being approximately 25 mol% La
O
. This glass exhibited a clear crystallization at 546
C, while determining its glass transition temperature was difficult. Notably, despite its amorphous nature, the glass possessed a density and packing density comparable to those of crystalline La
Mo
O
. X-ray absorption fine structure and Raman scattering analyses revealed that the glass structure closely resembles La
Mo
O
due to the presence of isolated MoO
units, whereas disordered atomic arrangement around La atoms was confirmed. The glass demonstrated transparency ranging from 378 to 5500 nm, and the refractive index at 1.0
m was estimated to be 2.0. The optical bandgap energy was 3.46 eV, which was slightly smaller than that of La
Mo
O
. Additionally, the glass displayed a transparent region ranging from 6.5 to 8.0
m. This occurrence results from the decreased diversity of MoO
units and connectivity of Mo-O-Mo, which resulted in the reduced overlap of multiphonon absorption. This glass formation, with its departure from conventional glass-forming rules, resulted in distinctive glasses with crystal-like atomic arrangements.
-MoO
whiskers in
Mo/
Tc radioisotope production and
Mo/
Tc extraction using hot atomsNgo, M. C.*; Fujita, Yoshitaka; Suzuki, Tatsuya*; Do, T. M. D.*; Seki, Misaki; Nakayama, Tadachika*; Niihara, Koichi*; Suematsu, Hisayuki*
Inorganic Chemistry, 62(32), p.13140 - 13147, 2023/08
Times Cited Count:6 Percentile:51.65(Chemistry, Inorganic & Nuclear)Technetium-99m (
Tc) is one of the most important radioisotopes for diagnostic radio-imaging applications.
Tc is a daughter product of the
Mo isotope. There are two methods used to produce
Mo/
Tc: the nuclear fission (n,f) and the neutron capture (n,
) methods. Between them, the (n,f) method is the main route, used for approximately 90% of the world's production. However, the (n,f) method faces numerous problems, including the use of highly enriched uranium, the release of highly radioactive waste, and nonproliferation problems. Therefore, the (n,
) method is being developed as a future replacement for the (n,f) method. In this work,
-MoO
whiskers prepared by the thermal evaporation method and
-MoO
particles were irradiated in a nuclear reactor to produce
Mo/
Tc via neutron capture. The irradiated targets were dispersed into water to extract the
Mo/
Tc. As a result,
-MoO
whisker yielded higher
Mo extraction rate than that from
-MoO
. In addition, by comparing the dissolved
Mo concentrations in water, we clarified a prominent hot-atom of
-MoO
whiskers. This research is the first demonstration of
-MoO
being used as an irradiation target in the neutron capture method. On the basis of the results,
-MoO
is considered a promising irradiation target for producing
Mo/
Tc by neutron capture and using water for the radioisotope extraction process in the future.
Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
Times Cited Count:4 Percentile:28.77(Chemistry, Inorganic & Nuclear)Yamagata, Kazuhito*; Ouchi, Kazuki; Marumo, Kazuki*; Tasaki-Handa, Yuiko*; Haraga, Tomoko; Saito, Shingo*
Inorganic Chemistry, 62(2), p.730 - 738, 2023/01
Times Cited Count:3 Percentile:26.91(Chemistry, Inorganic & Nuclear)The inert NpO
complex with a fluorescein-modified phenanthroline-2,9-dicarboxylic acid was found by kinetic selection using polyacrylamide gel electrophoresis (PAGE) from a small chemical library. The small spontaneous dissociation rate constant of 8
10
s
(the half-life of 23 hours) was determined. This is the singly-charged NpO
complex exhibiting unusual kinetic inertness in aqueous solution, one million times slower than widely accepted fast kinetics of neptunyl complexes. Selective fluorescence detection of NpO
was achieved in PAGE with a detection limit of 68 pmol dm
(17 fg). This system was successfully applied to simulated spent nuclear fuel and high-level radioactive waste samples.
Zheng, X.*; Kato, Masaru*; Uemura, Yohei*; Matsumura, Daiju; Yagi, Ichizo*; Takahashi, Kiyonori*; Noro, Shinichiro*; Nakamura, Takayoshi*
Inorganic Chemistry, 62(3), p.1257 - 1263, 2023/01
Times Cited Count:11 Percentile:75.69(Chemistry, Inorganic & Nuclear)
-edge to assess the U(V) electronic structure in FeUO
Yomogida, Takumi; Akiyama, Daisuke*; Ouchi, Kazuki; Kumagai, Yuta; Higashi, Kotaro*; Kitatsuji, Yoshihiro; Kirishima, Akira*; Kawamura, Naomi*; Takahashi, Yoshio*
Inorganic Chemistry, 61(50), p.20206 - 20210, 2022/12
Times Cited Count:10 Percentile:62.39(Chemistry, Inorganic & Nuclear)FeUO
was studied to clarify the electronic structure of U(V) in a metal monouranate compound. We obtained the peak splitting of HERFD-XANES spectra utilizing high-energy-resolution fluorescence detection-X-ray absorption near edge structure (HERFD-XANES) spectroscopy at the U L
-edge, which is a novel technique in the U(V) compounds. Theoretical calculations revealed that the peak splitting was caused by splitting the 6d orbital of U(V). Such distinctive electronic states are of major interest to researchers and engineers working in various fields, from fundamental physics to the nuclear industry and environmental sciences for actinide elements.
O
-pentadentate planar ligands designed for the strongest and selective capture of uranium from seawaterMizumachi, Takumi*; Sato, Minami*; Kaneko, Masashi; Takeyama, Tomoyuki*; Tsushima, Satoru*; Takao, Koichiro*
Inorganic Chemistry, 61(16), p.6175 - 6181, 2022/04
Times Cited Count:10 Percentile:62.39(Chemistry, Inorganic & Nuclear)Based on unique 5-fold equatorial coordination of UO
, water-compatible pentadentate planar ligands, H
saldian and its derivatives, were designed as strong and selective capture of UO
in seawater. In the simulated seawater condition (0.5 M NaCl + 2.3 mM HCO
/CO
, pH 8), saldian
shows the strongest complexation with UO
to form UO
(saldian) (log
= 28.05
0.07), which is more than 10 order of magnitude greater than amidoxime-based or -inspired ligand systems most commonly employed for U capture from seawater. Good selectivity for UO
from other metal ions coexisting in seawater was also demonstrated.
Ta
O
Kimura, Kenta*; Yagi, Naoki*; Hasegawa, Shunsuke*; Hagihara, Masato; Miyake, Atsushi*; Tokunaga, Masashi*; Cao, H.*; Masuda, Takatsugu*; Kimura, Tsuyoshi*
Inorganic Chemistry, 60(20), p.15078 - 15084, 2021/10
Times Cited Count:6 Percentile:37.45(Chemistry, Inorganic & Nuclear)
Ir M
ssbauer spectroscopic parameters of Vaska's complexes and their oxidative adductsKaneko, Masashi; Nakashima, Satoru*
Inorganic Chemistry, 60(17), p.12740 - 12752, 2021/09
Times Cited Count:6 Percentile:37.45(Chemistry, Inorganic & Nuclear)In the present study, density functional theory (DFT) calculation was applied to Vaska's complexes of formula
-[IrCl(CO)(PPh
)
], and their oxidative adducts with small molecules (YZ) including H
, i.e.,
-[IrCl(YZ)(CO))(PPh
)
], to successfully correlate the electronic states of the complexes with the corresponding
Ir M
ssbauer spectroscopic parameters. After confirming the reproducibility of the DFT methods for elucidating the equilibrium structures and
Ir M
ssbauer isomer shifts of the octahedral Ir complexes, the isomer shifts and quadrupole splitting values of Vaska's complexes and their oxidative adducts were calculated. A bond critical point analysis revealed that the tendency in the isomer shifts was correlated with the strength of the covalent interaction in the coordination bonds. In an electric field gradient (EFG) analysis of the oxidative adducts, the sign of the principal axis was found to be positive for the complex with YZ = Cl
and negative for the complex with YZ = H
. This reversal of the sign of the EFG principal axis was caused by the difference in the electron density distribution for the coordination bonds between Ir and YZ, according to a density of states analysis.
Simonnet, M.; Kobayashi, Toru; Shimojo, Kojiro; Yokoyama, Keiichi; Yaita, Tsuyoshi
Inorganic Chemistry, 60(17), p.13409 - 13418, 2021/09
Times Cited Count:30 Percentile:91.31(Chemistry, Inorganic & Nuclear)Kwon, H.*; Pietrasiak, E.*; Ohara, Takashi; Nakao, Akiko*; Chae, B.*; Hwang, C.-C.*; Jung, D.*; Hwang, I.-C.*; Ko, Y. H.*; Kim, K.*; et al.
Inorganic Chemistry, 60(9), p.6403 - 6409, 2021/05
Times Cited Count:1 Percentile:4.88(Chemistry, Inorganic & Nuclear)Nakano, Satoshi*; Sano, Asami; Hattori, Takanori; Machida, Shinichi*; Komatsu, Kazuki*; Fujihisa, Hiroshi*; Yamawaki, Hiroshi*; Goto, Yoshito*; Kikegawa, Takumi*
Inorganic Chemistry, 60(5), p.3065 - 3073, 2021/03
Times Cited Count:15 Percentile:72.22(Chemistry, Inorganic & Nuclear)X-ray and neutron diffraction analyses of ammonia borane were conducted at ambient and high pressures. The H-H distance in dihydrogen bonds was shorter than twice the van der Waals radius (2.4
). The half of the dihydrogen bonds were broken on phase transition from AP to the first high pressure phase (HP1) at approximately 1.2 GPa as revealed by an increase in the H-H distances. On further pressure increase, all of the H-H distances became shorter than 2.4
again, implying the pressure-induced reformation of the dihydrogen bonds. Furthermore, the HP1 transformed to the second one with the structure of
(Z = 2) at about 11 GPa. In this phase transition, the inclination of the molecule axis became larger and the number of types of dihydrogen bonds increased from 6 to 11. Just before the third transition at 18.9 GPa, the shortest dihydrogen bond decreased to 1.65
. The present study experimentally first confirmed the breakage and reformation of the dihydrogen bonds by the structural change under pressure.
complexes of mixed N,O-donor ligands demonstrated on a 10-fold [Eu(TPAMEN)]
chelate complexSchnaars, K.; Kaneko, Masashi; Fujisawa, Kiyoshi*
Inorganic Chemistry, 60(4), p.2477 - 2491, 2021/02
Times Cited Count:6 Percentile:37.45(Chemistry, Inorganic & Nuclear)To reduce high-level radiotoxic waste generated by nuclear power plants, highly selective separation agents for minor actinides are mandatory. The mixed N,O-donor ligand
-tetrakis[(6-carboxypyridin-2-yl)methyl]ethylenediamine (H
TPAEN) has shown good performance as a masking agent in Am
/Eu
separation studies. In this work, we examine whether a decrease in O-donor basicity can promote the M
-N
interactions. Therefore, we replace the deprotonated "charged" carboxylic acid groups of TPAEN
by neutral amide groups and introduce
-tetrakis[(6-
-diethylcarbamoylpyridin-2-yl)methyl]ethylenediamine (TPAMEN) as a new ligand. TPAMEN was crystallized with Eu(OTf)
and Eu(NO
)
6H
O to form positively charged 1:1 [Eu(TPAMEN)]
complexes in the solid state. Alterations in the M-O/N bond distances are compared to [Eu(TPAEN)]
and investigated by DFT calculations to expose the differences in charge/energy density distributions at europium(III) and the donor functionalities of the TPAEN
and TPAMEN. On the basis of estimations of the bond orders, atomic charges spin populations, and density of states in the Eu and potential Am and Cm complexes, the specific contributions of the donor-metal interaction are analyzed. The prediction of complex formation energy differences for the [M(TPAEN)]
and [M(TPAMEN)]
(M
= Eu
, Am
) complexes provide an outlook on the potential performance of TPAMEN in Am
/Eu
separation.
Narita, Hirokazu*; Kasuya, Ryo*; Suzuki, Tomoya*; Motokawa, Ryuhei; Tanaka, Mikiya*
Encyclopedia of Inorganic and Bioinorganic Chemistry (Internet), 28 Pages, 2020/12
Tamain, C.*; Bonato, L.*; Aupiais, J.*; Dumas, T.*; Guillaumont, D.*; Barkleit, A.*; Berthon, C.*; Solari, P. L.*; Ikeda, Atsushi; Guilbard, P.*; et al.
European Journal of Inorganic Chemistry, 2020(14), p.1331 - 1344, 2020/04
Times Cited Count:4 Percentile:20.73(Chemistry, Inorganic & Nuclear)The molecular characterization based on multi-technique approach has led to major highlights on revealing the coordination environment of americium (Am) surrounded by citric acid (H
CitH). The structure of the different complexes at pH 1 and 3 are described. These characterizations are made possible by the comparison of the americium-citric acid system with the americium-tricarballylic acid (one analogue of the citric acid without the alpha-hydroxo group).
Ru M
ssbauer parameters of ruthenium-nitrosyl complexesKaneko, Masashi; Kato, Akane*; Nakashima, Satoru*; Kitatsuji, Yoshihiro
Inorganic Chemistry, 58(20), p.14024 - 14033, 2019/10
Times Cited Count:12 Percentile:52.12(Chemistry, Inorganic & Nuclear)We applied density functional theory calculations to ruthenium-nitrosyl complexes, which are known to exist in high-level radioactive waste, to give a theoretical correlation between
Ru M
ssbauer spectroscopic parameters (
and 
) and ligand field strength (
) for the first time. The structures of the series of complexes, [Ru(NO)L
] (L = Br
, Cl
, NH
, CN
), were modeled based on the corresponding single-crystal X-ray coordinates. The comparisons of the geometries and total energies between the different spin states suggested that the singlet spin state of [Ru(II)(NO
)L
] complexes were the most stable. The calculated results of both the
and 
values reproduced the experimental results by reported previously and increased in the order of L = Br
, Cl
, NH
, CN
. Finally, we estimated the ligand field strength (
) based on molecular orbitals, assuming C
symmetry and showed the increase of 
values in that order, being consistent with well-known spectrochemical series of ligands. The increase attributes to the strengthening of the abilities of
-donor and
-acceptor of the L-ligands to the Ru atom, resulting in the increase of the
values.
Narita, Hirokazu*; Nicolson, R. M.*; Motokawa, Ryuhei; Ito, Fumiyuki*; Morisaku, Kazuko*; Goto, Midori*; Tanaka, Mikiya*; Heller, W. T.*; Shiwaku, Hideaki; Yaita, Tsuyoshi; et al.
Inorganic Chemistry, 58(13), p.8720 - 8734, 2019/07
Times Cited Count:22 Percentile:75.40(Chemistry, Inorganic & Nuclear)