Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Atsushi Tahara Last modified date:2018.08.30

Assistant Professor / Department of Applied Molecular Chemistry / Institute for Materials Chemistry and Engineering

1. Tamer Shubair, Osama Eljamal, Ahmed M. E. Khalil, Atsushi Tahara, Nobuhiro Matsunaga, Novel application of nanoscale zero valent iron and bimetallic nano-Fe/Cu particles for the treatment of cesium contaminated water, Journal of Environmental Chemical Engineering, 6, 4, 4253-4264, 2018.06, Following the accident at the Fukushima Daiichi Nuclear Power Plant in 2011, radioactive cesium was released
into the environment in large amounts and heavily contaminated drinking water in Fukushima and neighboring
prefectures. In this research, the capability of nanoscale zero valent iron (nZVI) and bimetallic nano-Fe/Cu
particles for cesium removal from aqueous solutions was evaluated for the first time. The nanoparticles were
characterized by TEM, XRD, SEM-EDS and BET-N2 adsorption. The effect of several variables such as initial
cesium concentration, contact time, pH, temperature, competing cations and dosage of the nanoparticles on the
sorption behavior of cesium was studied using a batch technique. The obtained results showed that nZVI and
nano-Fe/Cu particles displayed effective performance for removal of cesium. For both nanoparticles, the removal
efficiency exceeded 99% at initial cesium concentration of 1 mg/L and 1 g/L doses. The experimental data were
well fitted to the pseudo-second-order kinetic model, which means that the overall rate constant of cesium
sorption process was controlled by chemisorption. The rate constant of nano-Fe/Cu particles was larger than that
of nZVI, indicating a faster kinetic sorption by nano-Fe/Cu particles. The thermodynamic parameters indicated
exothermic and spontaneous nature of the sorption process. The Langmuir, Freundlich and Redlich-Peterson
isotherm models were also used to fit the equilibrium data. nZVI and nano-Fe/Cu particles exhibited excellent
selective sorption toward cesium in the simulated contaminated water after Fukushima accident. The current
work demonstrated that nZVI and nano-Fe/Cu particles can be considered as promising materials for cesium
removal from contaminated waters..
2. Yusuke Sunada, Hajime Ogushi, Taiji Yamamoto, Shoko Uto, Mina Sawano, Atsushi Tahara, Hiromasa Tanaka, Yoshihito Shiota, Kazunari Yoshizawa, Hideo Nagashima, Disilaruthena- and Ferracyclic Complexes Containing Isocyanide Ligands as Effective Catalysts for Hydrogenation of Unfunctionalized Sterically Hindered Alkenes, Journal of the American Chemical Society, 10.1021/jacs.8b00812, 140, 11, 4119-4134, 2018.03, Disilaferra- and disilaruthenacyclic complexes containing mesityl isocyanide as a ligand, 3′ and 4′, were synthesized and characterized by spectroscopy and crystallography. Both 3′ and 4′ showed excellent catalytic activity for the hydrogenation of alkenes. Compared with iron and ruthenium carbonyl analogues, 1′ and 2′, the isocyanide complexes 3′ and 4′ were more robust under the hydrogenation conditions, and were still active even at higher temperatures (∼80 °C) under high hydrogen pressure (∼20 atm). The iron complex 3′ exhibited the highest catalytic activity toward hydrogenation of mono-, di-, tri-, and tetrasubstituted alkenes among currently reported iron catalysts. Ruthenium complex 4′ catalyzed hydrogenation under very mild conditions, such as room temperature and 1 atm of H2. The remarkably high catalytic activity of 4′ for hydrogenation of unfunctionalized tetrasubstituted alkenes was especially notable, because it was comparable to the activity of iridium complexes reported by Crabtree and Pfaltz, which are catalysts with the highest activity in the literature. DFT calculations suggested two plausible catalytic cycles, both of which involved activation of H2 assisted by the metal-silicon bond through σ-bond metathesis of late transition metals (oxidative hydrogen migration). The linear structure of M C≡N - C (ipso carbon of the mesityl group) played an essential role in the efficient hydrogenation of sterically hindered tetrasubstituted alkenes..
3. Konoka Hoshi, Atsushi Tahara, Yusuke Sunada, Hironori Tsutsumi, Ryoko Inoue, Hiromasa Tanaka, Yoshihito Shiota, Kazunari Yoshizawa, Hideo Nagashima, σ-CAM mechanisms for the hydrogenation of alkenes by cis- and trans- disilametallacyclic carbonyl complexes (M = Fe, Ru, Os)
Experimental and theoretical studies, Bulletin of the Chemical Society of Japan, 10.1246/bcsj.20170004, 90, 5, 613-626, 2017.01, The hydrogenation of alkenes catalyzed by disilametallacyclic carbonyl complexes of iron, ruthenium or osmium was studied experimentally and theoretically. The disilaruthenacycle 2 with two CO ligands in the trans-configuration was prepared, characterized, and its ability to catalyze hydrogenation was studied. Similar to the corresponding iron analogue 1 in which the CO ligands are in the cis-configuration, 2 contains a H2MSi4 core with SiHSi SISHA (secondary interaction of silicon and hydrogen atoms) and catalyzed the hydrogenation of several alkenes under mild conditions. DFT calculations of 1 and 2 with cis- and trans-CO configurations (cis-1, trans-1, cis-2 and trans-2) revealed that the mechanism of ethylene hydrogenation comprises three catalytic cycles, and a key step involves the H-H bond of H2 being activated by an M-Si bond through oxidative hydrogen migration. These mechanisms are a variety of α-CAM (complex-assisted metathesis) mechanisms. Further calculations suggest that these catalytic cycles can apply to the catalytic hydrogenation of ethylene by osmium analogues of 1 and 2 (cis-3 and trans-3). Some of the elementary reactions in the cycles are dependent on the metal, and the osmium complexes show different performance from the iron and ruthenium analogues due to the characteristic natures of the third-row transition metals..
4. Atsushi Tahara, Hiromasa Tanaka, Yusuke Sunada, Yoshihito Shiota, Kazunari Yoshizawa, Hideo Nagashima, Theoretical Study of the Catalytic Hydrogenation of Alkenes by a Disilaferracyclic Complex
Can the Fe-Si σ-Bond-Assisted Activation of H-H Bonds Allow Development of a Catalysis of Iron?, Journal of Organic Chemistry, 10.1021/acs.joc.6b01961, 81, 22, 10900-10911, 2016.11, The mechanisms associated with the hydrogenation of alkenes catalyzed by the iron complex Fe(cis-CO)2{o-(SiMe2)2C6H4}2(H)2 (1) were investigated by DFT calculations. The complex 1 has a structure in which the iron center is bonded to four silicon atoms and two hydrides. Secondary Si···H···Si interactions were also observed. The exchange of a 1,2-bis(dimethylsilyl)benzene ligand with ethylene and hydrogen gives a disilaferracycle bearing η2-(CH2=CH2) and η2-H2 ligands. The catalytic cycle initiated from the disilaferracycle involves cleavage of a H-H linkage assisted by an Fe-Si bond to form Fe-H and η1-(H-Si) moieties (step 1), hydrogen migration from the Fe-H group to the η2-(CH2=CH2) ligand which accomplishes the insertion of ethylene into the Fe-H bond (step 2), and reaction of the resulting β-agostic ethyl moiety with the η2-(H-Si) group to form ethane on the iron atom (step 3). The octahedral geometry of 1 as well as the presence of π-acidic CO ligands and Fe-Si σ-bonds contributes to all of the catalytic intermediates and the transition states being in the low-spin state. Steps 1 and 3 correspond to the σ-complex-assisted metathesis (σ-CAM) mechanisms proposed by Perutz and Sabo-Etienne, suggesting that these mechanisms can assist in the design of iron-based hydrogenation catalysts operating under mild conditions..
5. Daisuke Noda, Atsushi Tahara, Yusuke Sunada, Hideo Nagashima, Non-Precious-Metal Catalytic Systems Involving Iron or Cobalt Carboxylates and Alkyl Isocyanides for Hydrosilylation of Alkenes with Hydrosiloxanes, Journal of the American Chemical Society, 10.1021/jacs.5b11311, 138, 8, 2480-2483, 2016.03, A mixture of an iron or a cobalt carboxylate and an isocyanide ligand catalyzed the hydrosilylation of alkenes with hydrosiloxanes with high efficiency (TON >103) and high selectivity. The Fe catalyst showed excellent activity for hydrosilylation of styrene derivatives, whereas the Co catalyst was widely effective in reaction of alkenes. Both of them catalyzed the reaction with allylic ethers. Chemical modification and cross-linking of silicones were achieved by choosing the right catalyst and reaction conditions..
6. Atsushi Tahara, Yasumitsu Miyamoto, Ryuta Aoto, Keisuke Shigeta, Yuta Une, Yusuke Sunada, Yukihiro Motoyama, Hideo Nagashima, Catalyst Design of Vaska-Type Iridium Complexes for Highly Efficient Synthesis of π-Conjugated Enamines, Organometallics, 10.1021/acs.organomet.5b00636, 34, 20, 4895-4907, 2015.10, The appropriate design of a ligand (L) in IrCl(CO)(L)2 (4) realized the efficient synthesis of π-conjugated enamines possessing hole-transport properties. The iridium complex with electron-withdrawing phosphorus ligands catalyzed the hydrosilylation of amides to the corresponding silylhemiaminals, which were transformed to the enamines by heat or by treatment with acids. High catalytic efficiency (TON > 10,000) was achieved, which made it possible for the residual iridium in the enamine product to be below 20 ppb..
7. Atsushi Tahara, Regio- and stereoselective synthesis of multisubstituted enamides by treatment of ynamides with boronic acids, Yuki Gosei Kagaku Kyokaishi/Journal of Synthetic Organic Chemistry, 10.5059/yukigoseikyokaishi.73.749, 73, 7, 749-750, 2015.01, Addition of boronic acids to ynamides can be a useful method to obtain enamides, which have been considered as good prochiral precursors for the synthesis of optically active compounds bearing quaternary stereogenic centers. Although the regioselectivity for carbometalation should be required, recently, highly regio- and stereocontrolled addition reactions have been developed by using transition metal catalysts. In this review, three types of regio- and stereocontrolled synthesis of multisubstituted enamides are discussed..
8. 田原 淳士, Me2S-induced Highly Selective Reduction of Aldehydes in the Presence of Ketones Involving Aldehyde-selective Rate Enhancement: A Triruthenium Cluster-catalyzed Hydrosilylation, CHEMISTRY LETTERS, 10.1246/cl.140731, 43, 12, 1829-1831, 2014.12.
9. Atsushi Tahara, Mana Kajigaya, Toshiro Takao, Hiroharu Suzuki, Synthesis and dynamic properties of a triruthenium complex containing μ32(∥)-ethyne and μ3- methylidyne ligands
Equilibrium of an ethyne-hydrido complex with a nonclassical μ3-Vinyl complex, Organometallics, 10.1021/om301064y, 32, 1, 260-271, 2013.01, A triruthenium complex containing μ32(∥) -ethyne and μ3-methylidyne ligands, (CpRu) 332(∥)-HCî-≡CH} (μ3-CH)(μ-H)2 (2a), was synthesized via the treatment of {Cp*Ru(μ-H)}33-H)2 (3) (Cp* = η5-C5Me5) with propene. In the low-temperature region, VT 1H NMR spectra showed that complex 2a is in equilibrium with a nonclassical μ3-vinyl complex, (CpRu)3322-HC= CH2)(μ3-CH)(μ-H) (5a), which features an interaction between one of the β-vinyl protons and a Ru center. The presence of the unusual 3c-2e interaction of the β-C-H bond of the vinyl group is strongly supported by the small JC-H value (98 Hz) found for the β-carbon as well as the small JH-H value for the α-vinyl proton. Treatment of the equilibrated mixture of phenyl-substituted complexes (CpRu)332(∥)-HCî- ≡CPh}(μ3-CH)(μ-H)2 (2b) and (CpRu) 3322-HC=CHPh) (μ3-CH)(μ-H) (5b) with tBuNC afforded a μ-styryl complex, (CpRu)3(μ-η2-HC=CHPh)(μ3-CH) (μ-tBuNC)(μ-H) (6), while analogous treatment of 2a and 5a resulted in the formation of μ3-dimetalloallyl complex (CpRu)333-CHCHCN(H)tBu}(μ3-CH)(μ-H) (7). These results imply that the coordinatively saturated μ3- η2(∥)-alkyne-μ3-alkylidyne complex can generate a vacant site via the migration of a hydrido ligand onto an alkyne ligand to yield a μ-vinyl intermediate..
10. Atsushi Tahara, Mana Kajigaya, Makoto Moriya, Toshiro Takao, Hiroharu Suzuki, Metathesis reaction of hydrocarbyl ligands across the triruthenium plane, Angewandte Chemie - International Edition, 10.1002/anie.201002235, 49, 34, 5898-5901, 2010.08, Trains and boats and planes: The thermolysis of a tri ruthenium complex having H3-pentylidyne and μ3-pentyne ligands on each face of the tri metallic plane exclusively afforded the μ3- ethylidyne-nroctyne complex. In this reaction, a C3 fragment migrated from one face of the Ru3 planeto the other. This corresponds to the selective redistribution of two C5 molecules into C2 and C8 molecules. (Figure Presented).
11. Makoto Moriya, Atsushi Tahara, Toshiro Takao, Hiroharu Suzuki, Arylation of hydrocarbyl ligands formed from n-alkanes through C-H bond activation of benzene using a triruthenium cluster, European Journal of Inorganic Chemistry, 10.1002/ejic.200900519, 23, 3393-3397, 2009.08, Triruthenium complex 2 containing a perpendicularly coordinated 1-pentyne ligand, which is one of the key intermediates of the reaction of triruthenium pentahydrido complex 1 with n-pentane, reacts with benzene to yield μ3-benzyne-μ3-pentylidyne complex 5 by C-H bond activation. β-H elimination form the μ3-penytylidyne ligand occurred upon heating to yield μ3-pentenylidene complex 6, which was followed by the formation of closo-ruthenacyclopentadiene complex 8 by the connection of the two hydrocarbyl moieties placed on each face of the triruthenium plane with partial metal-metal bond breaking. Treatment of 8 with pressurized hydrogen resulted in exclusive liberation of n-pentylbonzene, which is difficult to synthesize by conventional Friedel-Crafts alkylation. These sequential transformations correspond to the formation of linear alkylbenzene by the reaction of pentane with benzene on a trimetallic plane..