Co-reporter:Takahiro Matsumoto, Takahiro Kishima, Takeshi Yatabe, Ki-Seok Yoon, and Seiji Ogo
Organometallics October 23, 2017 Volume 36(Issue 20) pp:3883-3883
Publication Date(Web):October 9, 2017
DOI:10.1021/acs.organomet.7b00471
We present a mechanistic investigation for the activation of H2 and O2, induced by a simple ligand effect within [NiFe] models for O2-tolerant [NiFe]hydrogenase. Kinetic study reveals Michaelis–Menten type saturation behaviors for both H2 and O2 activation, which is the same behavior as that found in O2-tolerant [NiFe]hydrogenase. Such saturation behavior is caused by H2 complexation followed by heterolytic cleavage of H2 by an outer-sphere base, resulting in the formation of a hydride species showing hydridic character.
Co-reporter:Hidetaka Nakai;Masafumi Kuyama;Juncheol Seo;Takahiro Goto;Takahiro Matsumoto
Dalton Transactions 2017 vol. 46(Issue 28) pp:9126-9130
Publication Date(Web):2017/07/18
DOI:10.1039/C7DT01388D
Taking advantage of the outstanding oxygen-sensitive luminescence properties of the previously synthesised Tb(III) complex [{(MeMeArO)3tacn}LnIII(THF)] (1Tb, Ln = Tb), herein, we have prepared an oxygen sensor based on 1Tb embedded in polystyrene film (1Tb/PS) and found that 1Tb/PS shows the highest sensitivity (I0/I100 = 14.9) and the fastest response (response/recovery time = 1.9 s/2.9 s), among the lanthanide(III)-based oxygen sensors with f–f emission. Moreover, we have prepared the lanthanide(III)-based colorimetric luminescent oxygen sensor (1TbSm/PS) with green–yellow–red responses, by using 1Tb and a newly synthesised oxygen-insensitive Sm(III) complex (1Sm, Ln = Sm; Φ = 0.010 and τ = 12.2 μs).
Co-reporter: Seiji Ogo;Yuki Mori;Dr. Tatsuya Ando;Dr. Takahiro Matsumoto;Dr. Takeshi Yatabe;Dr. Ki-Seok Yoon;Dr. Hideki Hayashi;Dr. Masashi Asano
Angewandte Chemie International Edition 2017 Volume 56(Issue 33) pp:9723-9726
Publication Date(Web):2017/08/07
DOI:10.1002/anie.201704864
AbstractThe ability to catalyze the oxidation of both H2 and CO in one reaction pot would be a major boon to hydrogen technology since CO is a consistent contaminant of H2 supplies. Here, we report just such a catalyst, with the ability to catalyze the oxidation of either or both H2 and CO, based on the pH value. This catalyst is based on a NiIr core that mimics the chemical function of [NiFe]hydrogenase in acidic media (pH 4–7) and carbon monoxide dehydrogenase in basic media (pH 7–10). We have applied this catalyst in a demonstration fuel cell using H2, CO, and H2/CO (1/1) feeds as fuels for oxidation at the anode. The power density of the fuel cell depends on the pH value in the media of the fuel cell and shows a similar pH dependence in a flask. We have isolated and characterized all intermediates in our proposed catalytic cycles.
Co-reporter: Seiji Ogo;Yuki Mori;Dr. Tatsuya Ando;Dr. Takahiro Matsumoto;Dr. Takeshi Yatabe;Dr. Ki-Seok Yoon;Dr. Hideki Hayashi;Dr. Masashi Asano
Angewandte Chemie International Edition 2017 Volume 56(Issue 33) pp:9627-9627
Publication Date(Web):2017/08/07
DOI:10.1002/anie.201705755
A [NiIr]-based catalyst turns the table on CO poisoning by exploiting the gas as a fuel. The system is able to act as a H2 oxidizing catalyst at low pH and as a CO oxidizing catalyst at high pH. At pH 7, there is a crossover where both oxidations are catalyzed simultaneously. In their Communication on page 9723 ff., S. Ogo et al. report a proof-of-concept fuel cell that functioned on a 50:50 supply of H2 and CO. The double function is depicted above as a two-headed bird.
Co-reporter: Seiji Ogo;Yuki Mori;Dr. Tatsuya Ando;Dr. Takahiro Matsumoto;Dr. Takeshi Yatabe;Dr. Ki-Seok Yoon;Dr. Hideki Hayashi;Dr. Masashi Asano
Angewandte Chemie 2017 Volume 129(Issue 33) pp:9855-9858
Publication Date(Web):2017/08/07
DOI:10.1002/ange.201704864
AbstractThe ability to catalyze the oxidation of both H2 and CO in one reaction pot would be a major boon to hydrogen technology since CO is a consistent contaminant of H2 supplies. Here, we report just such a catalyst, with the ability to catalyze the oxidation of either or both H2 and CO, based on the pH value. This catalyst is based on a NiIr core that mimics the chemical function of [NiFe]hydrogenase in acidic media (pH 4–7) and carbon monoxide dehydrogenase in basic media (pH 7–10). We have applied this catalyst in a demonstration fuel cell using H2, CO, and H2/CO (1/1) feeds as fuels for oxidation at the anode. The power density of the fuel cell depends on the pH value in the media of the fuel cell and shows a similar pH dependence in a flask. We have isolated and characterized all intermediates in our proposed catalytic cycles.
Co-reporter: Seiji Ogo;Yuki Mori;Dr. Tatsuya Ando;Dr. Takahiro Matsumoto;Dr. Takeshi Yatabe;Dr. Ki-Seok Yoon;Dr. Hideki Hayashi;Dr. Masashi Asano
Angewandte Chemie 2017 Volume 129(Issue 33) pp:9755-9755
Publication Date(Web):2017/08/07
DOI:10.1002/ange.201705755
Ein [NiIr]-basierter Katalysator bietet der CO-Vergiftung die Stirn, indem er das Gas als Brennstoff verwendet. Das Katalysatorsystem kann H2 bei niedrigen pH-Werten und CO bei hohen pH-Werten oxidieren. Bei pH 7 werden beide Oxidationen zugleich katalysiert. In der Zuschrift auf S. 9855 berichten S. Ogo et al. über einen Brennstoffzellenprototyp, der mit einem 50:50-Vorrat an H2 und CO betrieben wurde. Die doppelte Funktion ist als zweiköpfiger Vogel dargestellt.
Co-reporter:Hidetaka Nakai, Kengo Matsuba, Masataka Akimoto, Tomonori Nozaki, Takahiro Matsumoto, Kiyoshi Isobe, Masahiro Irie and Seiji Ogo
Chemical Communications 2016 vol. 52(Issue 23) pp:4349-4352
Publication Date(Web):19 Feb 2016
DOI:10.1039/C6CC00059B
Rod-like millimetre-size crystals of a newly prepared rhodium dithionite complex with n-pentyl moieties bend upon photoirradiation and return to the initial shape upon heating; the roles of the flexible n-pentyl moieties as well as the photoreactive dithionite unit (μ-O2SSO2) are disclosed by single crystal X-ray diffraction.
Co-reporter:Hidetaka Nakai, Juncheol Seo, Kazuhiro Kitagawa, Takahiro Goto, Kyoshiro Nonaka, Takahiro Matsumoto, and Seiji Ogo
Inorganic Chemistry 2016 Volume 55(Issue 13) pp:6609
Publication Date(Web):June 21, 2016
DOI:10.1021/acs.inorgchem.6b00800
Coordination environment of the Tb3+ ion in oxygen-sensitive luminescent complexes can be successfully controlled through the size of alkyl substituents on ligands {(RMeArOH)4cyclen} (R = tBu or Me; cyclen = 1,4,7,10-tetraazacyclododecane); a newly prepared eight-coordinate complex 1tBu shows higher oxygen sensitivity (KSV = 17 600) and lower luminescence quantum yield (Φ = 0.67 under N2) than those of the previously reported seven-coordinate analogues 1Me and [{(MeMeArO)3tacn}TbIII(THF)] (KSV = 12 600 and 8300, Φ = 0.91 and 0.91 under N2, respectively; tacn = 1,4,7-triazacyclononane; THF = tetrahydrofuran). The oxygen-sensitive mechanism is discussed on the basis of the photophysical properties of the corresponding Gd(III) complexes.
Co-reporter:Hidetaka Nakai, Kazuhiro Kitagawa, Juncheol Seo, Takahiro Matsumoto and Seiji Ogo
Dalton Transactions 2016 vol. 45(Issue 29) pp:11620-11623
Publication Date(Web):12 May 2016
DOI:10.1039/C6DT01303A
This paper presents a gadolinium(III) complex that shows blue phosphorescence in the crystalline state at room temperature under air atmosphere; color of the crystals can be changed to pale-green from blue by doping of 1-naphthol.
Co-reporter:Hidetaka Nakai, Juncheol Seo, Kazuhiro Kitagawa, Takahiro Goto, Takahiro Matsumoto and Seiji Ogo
Dalton Transactions 2016 vol. 45(Issue 23) pp:9492-9496
Publication Date(Web):04 May 2016
DOI:10.1039/C6DT01057A
This paper presents the first dysprosium(III) complex, [{(MeMeArO)3tacn}DyIII(THF)] (1Dy), that shows oxygen-sensitive luminescence. The synthesis, structure and oxygen-sensitive luminescence properties of 1Dy are reported (Φ = 0.050 and τ = 17.7 μs under N2, Φ = 0.011 and τ = 4.1 μs under O2 and KSV = 305 M−1 in THF; KSV = 0.0077%−1 in polystyrene film). The oxygen sensitive mechanism of 1Dy is discussed based on the photophysical properties of the corresponding gadolinium(III) complex, [{(MeMeArO)3tacn}GdIII(THF)].
Co-reporter:Viet-Ha Tran, Takeshi Yatabe, Takahiro Matsumoto, Hidetaka Nakai, Kazuharu Suzuki, Takao Enomoto, Takashi Hibino, Kenji Kaneko and Seiji Ogo
Chemical Communications 2015 vol. 51(Issue 63) pp:12589-12592
Publication Date(Web):08 Jul 2015
DOI:10.1039/C5CC04286K
We report an acid-stable Si oxide-doped Ir oxide film (IrSi oxide film), made by metal organic chemical vapour deposition (MOCVD) of an IrV complex for electrochemical water-oxidation. This is a successful improvement of catalytic ability and stability depending upon the pH of Ir oxide by doping of Si oxide. The turnover frequency (TOF) of the electrochemical water-oxidation by the IrSi oxide film is the highest of any Si oxide-doped Ir oxide materials and higher even than that of Ir oxide in acidic media.
Co-reporter:Harutaka Nakamori, Takahiro Matsumoto, Takeshi Yatabe, Ki-Seok Yoon, Hidetaka Nakai and Seiji Ogo
Chemical Communications 2014 vol. 50(Issue 86) pp:13059-13061
Publication Date(Web):15 Sep 2014
DOI:10.1039/C4CC06055E
Herein, we report the first crystal structure of a monomeric p-semiquinonato d-block complex and its reactivity toward dioxygen, closely associated with a biological system of an oxygen evolving centre of photosystem II.
Co-reporter:Nga T. Nguyen, Yuki Mori, Takahiro Matsumoto, Takeshi Yatabe, Ryota Kabe, Hidetaka Nakai, Ki-Seok Yoon and Seiji Ogo
Chemical Communications 2014 vol. 50(Issue 87) pp:13385-13387
Publication Date(Web):19 Sep 2014
DOI:10.1039/C4CC05911E
We report the decomposition of formic acid to hydrogen and carbon dioxide, catalysed by a NiRu complex originally developed as a [NiFe]hydrogenase model. This is the first example of H2 evolution, catalysed by a [NiFe]hydrogenase model, which does not require additional energy.
Co-reporter:Hidetaka Nakai, Kihun Jeong, Takahiro Matsumoto, and Seiji Ogo
Organometallics 2014 Volume 33(Issue 17) pp:4349-4352
Publication Date(Web):August 19, 2014
DOI:10.1021/om500647h
A new class of efficient catalyst, the Rh(I) complex [(η5-C5Me5)RhI(bpy)] (1; bpy = 2,2′-bipyridine), for the C–F bond hydrogenolysis of fluoroaromatics (C6F5CF3, C6F6, C6F5H, and C6F5CH3) is presented. The best turnover number of 380 for C6F6 is afforded by using 0.1 mol % of 1, 0.8 MPa of H2, and 2 equiv of Et2NH in CH3CN at 25 °C. The successful isolation of the C–F bond cleavage product [(η5-C5Me5)RhIII(bpy)(C6F5)](F) as a plausible intermediate of the catalytic hydrogenolysis of C6F6 by 1 is also described.
Co-reporter:Dr. Takahiro Matsumoto;Shigenobu Eguchi;Dr. Hidetaka Nakai; Takashi Hibino;Dr. Ki-Seok Yoon; Seiji Ogo
Angewandte Chemie International Edition 2014 Volume 53( Issue 34) pp:8895-8898
Publication Date(Web):
DOI:10.1002/anie.201404701
Abstract
Reported herein is an electrode for dihydrogen (H2) oxidation, and it is based on [NiFe]Hydrogenase from Citrobacter sp. S-77 ([NiFe]S77). It has a 637 times higher mass activity than Pt (calculated based on 1 mg of [NiFe]S77 or Pt) at 50 mV in a hydrogen half-cell. The [NiFe]S77 electrode is also stable in air and, unlike Pt, can be recovered 100 % after poisoning by carbon monoxide. Following characterization of the [NiFe]S77 electrode, a fuel cell comprising a [NiFe]S77 anode and Pt cathode was constructed and shown to have a a higher power density than that achievable by Pt.
Co-reporter:Dr. Takahiro Matsumoto;Shigenobu Eguchi;Dr. Hidetaka Nakai; Takashi Hibino;Dr. Ki-Seok Yoon; Seiji Ogo
Angewandte Chemie International Edition 2014 Volume 53( Issue 34) pp:
Publication Date(Web):
DOI:10.1002/anie.201405392
Co-reporter:Dr. Takahiro Matsumoto;Shigenobu Eguchi;Dr. Hidetaka Nakai; Takashi Hibino;Dr. Ki-Seok Yoon; Seiji Ogo
Angewandte Chemie 2014 Volume 126( Issue 34) pp:9041-9044
Publication Date(Web):
DOI:10.1002/ange.201404701
Abstract
Reported herein is an electrode for dihydrogen (H2) oxidation, and it is based on [NiFe]Hydrogenase from Citrobacter sp. S-77 ([NiFe]S77). It has a 637 times higher mass activity than Pt (calculated based on 1 mg of [NiFe]S77 or Pt) at 50 mV in a hydrogen half-cell. The [NiFe]S77 electrode is also stable in air and, unlike Pt, can be recovered 100 % after poisoning by carbon monoxide. Following characterization of the [NiFe]S77 electrode, a fuel cell comprising a [NiFe]S77 anode and Pt cathode was constructed and shown to have a a higher power density than that achievable by Pt.
Co-reporter:Dr. Takahiro Matsumoto;Shigenobu Eguchi;Dr. Hidetaka Nakai; Takashi Hibino;Dr. Ki-Seok Yoon; Seiji Ogo
Angewandte Chemie 2014 Volume 126( Issue 34) pp:
Publication Date(Web):
DOI:10.1002/ange.201405392
Co-reporter:Seiji Ogo
The Chemical Record 2014 Volume 14( Issue 3) pp:
Publication Date(Web):
DOI:10.1002/tcr.201402010
Abstract
This article summarizes the development of a range of organometallic, biomimetic analogues of [NiFe]hydrogenases and their employment in a new generation of H2-O2 fuel cells. It begins with a summary of O2-sensitive and O2-tolerant enzyme chemistry before detailing the properties and functionality of our biomimetic complexes, including: the first ever fully functional model, selective H2 and O2 activation, and the first catalyst using only common metals. These systems are centered on Ni–Fe, Ni–Ru, Ir–Ir, and Rh–Rh cores and use a range of ligands that all follow a set of design principles described herein.
Co-reporter:Makoto Takenaka, Ki-Seok Yoon, Takahiro Matsumoto, Seiji Ogo
Bioresource Technology (March 2017) Volume 227() pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.biortech.2016.12.051
•PFOR was anaerobically purified from Citrobacter sp. S-77.•Ceramic hydroxyapatite acted as a stable matrix of PFORS77 in alginate hydrogels.•Efficient acetyl-CoA production by the immobilized PFOR was achieved.•The PFORS77-HA hydrogels had remarkable reusability under anaerobic conditions.Pyruvate ferredoxin oxidoreductase from Citrobacter sp. S-77 (PFORS77) was purified in order to develop a method for acetyl-CoA production. Although the purified PFORS77 showed high O2-sensitivity, the activity could be remarkably stabilized in anaerobic conditions. PFORS77 was effectively immobilized on ceramic hydroxyapatite (PFORS77-HA) with an efficiency of more than 96%, however, after encapsulation of PFORS77-HA in alginate, the rate of catalytic acetyl-CoA production was highly reduced to 36% when compared to that of the free enzyme. However, the operational stability of the PFORS77-HA in alginate hydrogels was remarkable, retaining over 68% initial activity even after ten repeated cycles. The results suggested that the PFORS77-HA hydrogels have a high potential for biotechnological application.Download high-res image (111KB)Download full-size image
Co-reporter:Seiji Ogo
Coordination Chemistry Reviews (1 March 2017) Volume 334() pp:
Publication Date(Web):1 March 2017
DOI:10.1016/j.ccr.2016.07.001
•This paper provides an overview of the structures and functions of H2ases and their models.•H2 and O2 activation mechanisms of [NiFe]H2ases and their models are described.•H2ase models are applied for fuel cell electrodes.H2 is an important compound from both a biological and a chemical industry perspective. Oxidation and reduction enable H2 to be used as a source of energy and as a raw material in the manufacture of a variety of useful substances. In nature, hydrogenases (H2ases) have been entrusted with the task of activating H2, making it responsible for part of the Earth’s energy circulation system since the birth of the planet. H2ases have distinctive active centers and their structures and electronic states can be controlled to produce specific functions. This paper provides an overview of the structures and functions of H2ases and their models.
Co-reporter:Koji Yoshimoto, Takeshi Yatabe, Takahiro Matsumoto, Viet-Ha Tran, Andrew Robertson, Hidetaka Nakai, Koichiro Asazawa, Hirohisa Tanaka and Seiji Ogo
Dalton Transactions 2016 - vol. 45(Issue 37) pp:NaN14627-14627
Publication Date(Web):2016/06/22
DOI:10.1039/C6DT01655C
We report the first example of a wholly inorganic mimic of a part of the FeMoco active centre of nitrogenases. We detail the synthesis, characterisation and reactivity of two related, transient hydride-containing inorganic clusters, a dihydride complex and a vinyl monohydride complex, which bear the [Fe2MoOS3] portion of FeMoco. The dihydride complex is capable of reducing acetylene to ethylene via the vinyl monohydride complex. In the reaction cycle, a transient low-valent complex was generated by the reductive elimination of H2 or ethylene from dihydride or vinyl monohydride complexes, respectively.
Co-reporter:Hidetaka Nakai, Masafumi Kuyama, Juncheol Seo, Takahiro Goto, Takahiro Matsumoto and Seiji Ogo
Dalton Transactions 2017 - vol. 46(Issue 28) pp:NaN9130-9130
Publication Date(Web):2017/06/14
DOI:10.1039/C7DT01388D
Taking advantage of the outstanding oxygen-sensitive luminescence properties of the previously synthesised Tb(III) complex [{(MeMeArO)3tacn}LnIII(THF)] (1Tb, Ln = Tb), herein, we have prepared an oxygen sensor based on 1Tb embedded in polystyrene film (1Tb/PS) and found that 1Tb/PS shows the highest sensitivity (I0/I100 = 14.9) and the fastest response (response/recovery time = 1.9 s/2.9 s), among the lanthanide(III)-based oxygen sensors with f–f emission. Moreover, we have prepared the lanthanide(III)-based colorimetric luminescent oxygen sensor (1TbSm/PS) with green–yellow–red responses, by using 1Tb and a newly synthesised oxygen-insensitive Sm(III) complex (1Sm, Ln = Sm; Φ = 0.010 and τ = 12.2 μs).
Co-reporter:Hidetaka Nakai, Kengo Matsuba, Masataka Akimoto, Tomonori Nozaki, Takahiro Matsumoto, Kiyoshi Isobe, Masahiro Irie and Seiji Ogo
Chemical Communications 2016 - vol. 52(Issue 23) pp:NaN4352-4352
Publication Date(Web):2016/02/19
DOI:10.1039/C6CC00059B
Rod-like millimetre-size crystals of a newly prepared rhodium dithionite complex with n-pentyl moieties bend upon photoirradiation and return to the initial shape upon heating; the roles of the flexible n-pentyl moieties as well as the photoreactive dithionite unit (μ-O2SSO2) are disclosed by single crystal X-ray diffraction.
Co-reporter:Hidetaka Nakai, Kazuhiro Kitagawa, Juncheol Seo, Takahiro Matsumoto and Seiji Ogo
Dalton Transactions 2016 - vol. 45(Issue 29) pp:NaN11623-11623
Publication Date(Web):2016/05/12
DOI:10.1039/C6DT01303A
This paper presents a gadolinium(III) complex that shows blue phosphorescence in the crystalline state at room temperature under air atmosphere; color of the crystals can be changed to pale-green from blue by doping of 1-naphthol.
Co-reporter:Hidetaka Nakai, Juncheol Seo, Kazuhiro Kitagawa, Takahiro Goto, Takahiro Matsumoto and Seiji Ogo
Dalton Transactions 2016 - vol. 45(Issue 23) pp:NaN9496-9496
Publication Date(Web):2016/05/04
DOI:10.1039/C6DT01057A
This paper presents the first dysprosium(III) complex, [{(MeMeArO)3tacn}DyIII(THF)] (1Dy), that shows oxygen-sensitive luminescence. The synthesis, structure and oxygen-sensitive luminescence properties of 1Dy are reported (Φ = 0.050 and τ = 17.7 μs under N2, Φ = 0.011 and τ = 4.1 μs under O2 and KSV = 305 M−1 in THF; KSV = 0.0077%−1 in polystyrene film). The oxygen sensitive mechanism of 1Dy is discussed based on the photophysical properties of the corresponding gadolinium(III) complex, [{(MeMeArO)3tacn}GdIII(THF)].
Co-reporter:Nga T. Nguyen, Yuki Mori, Takahiro Matsumoto, Takeshi Yatabe, Ryota Kabe, Hidetaka Nakai, Ki-Seok Yoon and Seiji Ogo
Chemical Communications 2014 - vol. 50(Issue 87) pp:NaN13387-13387
Publication Date(Web):2014/09/19
DOI:10.1039/C4CC05911E
We report the decomposition of formic acid to hydrogen and carbon dioxide, catalysed by a NiRu complex originally developed as a [NiFe]hydrogenase model. This is the first example of H2 evolution, catalysed by a [NiFe]hydrogenase model, which does not require additional energy.
Co-reporter:Harutaka Nakamori, Takahiro Matsumoto, Takeshi Yatabe, Ki-Seok Yoon, Hidetaka Nakai and Seiji Ogo
Chemical Communications 2014 - vol. 50(Issue 86) pp:NaN13061-13061
Publication Date(Web):2014/09/15
DOI:10.1039/C4CC06055E
Herein, we report the first crystal structure of a monomeric p-semiquinonato d-block complex and its reactivity toward dioxygen, closely associated with a biological system of an oxygen evolving centre of photosystem II.
Co-reporter:Viet-Ha Tran, Takeshi Yatabe, Takahiro Matsumoto, Hidetaka Nakai, Kazuharu Suzuki, Takao Enomoto, Takashi Hibino, Kenji Kaneko and Seiji Ogo
Chemical Communications 2015 - vol. 51(Issue 63) pp:NaN12592-12592
Publication Date(Web):2015/07/08
DOI:10.1039/C5CC04286K
We report an acid-stable Si oxide-doped Ir oxide film (IrSi oxide film), made by metal organic chemical vapour deposition (MOCVD) of an IrV complex for electrochemical water-oxidation. This is a successful improvement of catalytic ability and stability depending upon the pH of Ir oxide by doping of Si oxide. The turnover frequency (TOF) of the electrochemical water-oxidation by the IrSi oxide film is the highest of any Si oxide-doped Ir oxide materials and higher even than that of Ir oxide in acidic media.
