A5066627191- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Metal complexes synthesis and properties
- Electrocatalysts for Energy Conversion
- Magnetism in coordination complexes
- CO2 Reduction Techniques and Catalysts
- Advanced Photocatalysis Techniques
- Crystal structures of chemical compounds
- Metalloenzymes and iron-sulfur proteins
- Porphyrin and Phthalocyanine Chemistry
- Crystallography and molecular interactions
- Metal-Catalyzed Oxygenation Mechanisms
- Organometallic Complex Synthesis and Catalysis
- Advanced battery technologies research
- Metal-Organic Frameworks: Synthesis and Applications
- Asymmetric Synthesis and Catalysis
- Ammonia Synthesis and Nitrogen Reduction
- Oxidative Organic Chemistry Reactions
- Catalytic Processes in Materials Science
- Lanthanide and Transition Metal Complexes
- Electrochemical Analysis and Applications
- Polyoxometalates: Synthesis and Applications
- Synthetic Organic Chemistry Methods
- Asymmetric Hydrogenation and Catalysis
- Carbon dioxide utilization in catalysis
Kyushu University
2016-2025
Toho University
2023-2024
Tohoku University
2002-2023
Hitotsubashi University
2023
Japanese Society for Dialysis Therapy
2022
Waseda University
1988-2021
Tokyo University of Science
1999-2021
Institute for Molecular Science
2014-2021
Université de Montréal
2021
Nagoya University
2016
A photo-hydrogen-evolving molecular device made up of a tris(2,2'-bipyridine)ruthenium(II) derivative and dichloro(2,2'-bipyridine)platinum(II) has been found to serve as the first effective model "molecular device" which evolves hydrogen from water in presence sacrificial electron donor (EDTA), under visible-light illumination.
Three water-soluble cobalt porphyrins have been investigated as water oxidation catalysts via photo-initiation using RuII(bpy)32+/Na2S2O8. The pH dependence of the turnover frequency revealed maximum activity at 11. Based on second order catalyst concentration for rate oxidation, we suggest a bimolecular radical coupling process determining step.
This article summarizes the ongoing studies on photo-hydrogen-evolving molecular devices (PHEMDs) made up of polypyridyl Ru(II) photosensitizers and Pt(II)-based catalysts, carried out in authors' group last two decades. The H(2)-evolving activities catalysts demonstrated by various experimental evidences are first described. Then structure-activity relationship, some important factors required for higher catalytic activity, several insights into mechanism photochemical H(2) evolution...
The performance of a water-soluble cobalt porphyrin ([{meso-tetra(4-sulfonatophenyl)porphyrinato}cobalt(III)], CoTPPS) as catalyst for the photoreduction CO2 in fully aqueous media has been investigated under visible light irradiation using [Ru(bpy)3]2+ photosensitizer and ascorbate sacrificial electron donor. CO is selectively produced (>82%) with high efficiency (926 TONCO; TONCO = turnover number CO). Upon optimization, selectivities at least 91% are achieved. Efficiencies up to 4000 2400...
Zweifach über Kreuz: Der Einsatz von Prolin als organischem Katalysator ermöglicht eine direkte gekreuzte Eintopf-Mannich-Reaktion zwischen zwei unterschiedlichen Aldehyden und 4-Methoxyanilin, die hochgradig syn-diastereo- enantioselektiv abläuft.
Abstract Experiments show that [Ru(terpy)(bpy)(OH2)]2+ is highly active as a catalyst toward oxidation of water into molecular oxygen in spite the mononuclear character complex, while [Ru(terpy)(bpy)Cl]+ shows no activity at all. It also confirmed fairly stable under strongly oxidizing conditions presence cerium(IV) ammonium nitrate, Ce(NH4)2(NO3)6, which was evidenced by spectrophotometric, mass spectrometric, and gas chromatographic analysis.
Salen's lot: Meerwein–Ponndorf–Verley reduction of [Ti(salen)(OiPr)2] (salen=bis(salicylidene)ethylenediaminato) complexes followed by treatment with water leads to the synthesis pseudo-heterochiral and homochiral di-μ-oxotitanium dimers. These dimers, in particular (aR,S,Δ, aR,S,Δ)-dimer 1, efficiently catalyze epoxidation simple olefins using aqueous hydrogen peroxide (see scheme) ee values up 99 % turnover numbers 4600.
The Mo-based polyoxometalates containing mono- and dicobalt(III) catalyst cores, [CoMo(6)O(24)H(6)](3-) [Co(2)Mo(10)O(38)H(4)](6-), were found to serve as O(2)-evolving catalysts in a system consisting of tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)) sodium persulfate (S(2)O) an aqueous borate buffer solution at pH 8.0. Kinetics O(2) evolution reveals that the higher cobalt nuclearity is not necessary attain highly active nature catalyst.
Without using precious elements, a highly efficient and selective molecular-based photocatalytic system for CO2-to-CO conversion in fully aqueous media has been developed. Our copper(I)-based water-soluble photosensitizer (CuPS) preserves its luminescent long-lived excited state even media. The CuPS-driven CO2 reduction catalyzed by cobalt porphyrin possessing four N-methylpyridinium acceptors at the meso positions (CoTMPyP) achieves highest catalytic activity among those reported systems:...
Abstract Enabling the production of solar fuels on a global scale through artificial photosynthesis requires development water oxidation catalysts with significantly improved stability. The stability photosystems is often reduced owing to attack by singlet oxygen, which produced during light harvesting. Here, we report photochemical CoFPS , fluorinated Co‐porphyrin designed resist oxygen. exhibits relative its non‐fluorinated analogue, as shown large increase in turnover numbers. This...
To stop global warming and climate changes, substantial efforts have been made to diminish CO2 emission. Photocatalytic electrocatalytic reduction into fuels has thus become a highly important topic. Our recent interest develop earth-abundant environmentally friendly photocatalytic systems consisting of non-precious-metal molecular catalyst combined with subcomponents, especially using aqueous conditions without any organic solvents. However, in water suffers from drawback decreasing its...
Improving the photocatalytic efficiency of a fully noble-metal-free system for CO2 reduction remains fundamental challenge, which can be accomplished by facilitating electron delivery as consequence exploiting intermolecular interactions. Herein, we have designed two Cu(I) photosensitizers with different pyridyl pendants at phenanthroline moiety to enable dynamic coordinative interactions between sensitizers and cobalt macrocyclic catalyst. Compared parent photosensitizer, one...
A series of novel emissive Ir(III) complexes having the coordination environments [Ir(N--N--N)2]3+, [Ir(N--N--N)(N--N)Cl]2+, and [Ir(N--N--N)(N--C--N)]2+ with 2,6-bis(1-methyl-benzimidazol-2-yl)pyridine (L1, N--N--N), 1,3-bis(1-methyl-benzimidazol-2-yl)benzene (L2H, N--C--N), 4'-(4-methylphenyl)-2,2':6',2' '-terpyridine (ttpy, 2,2'-bipyridine (bpy, N--N) have been synthesized their photophysical electrochemical properties studied. The exhibited phosphorescent emissions in 500-600 nm region,...
The mechanism of O(2) evolution from water catalyzed by a series mononuclear aquaruthenium complexes, [Ru(terpy)(bpy)(OH(2))](2+), [Ru(tmtacn)(R(2)bpy)(OH(2))](2+) (R=H, Me, and OMe; R(2)bpy=4,4'-disubstituted-2,2'-bipyridines), [Ru(tpzm)(R(2)bpy)(OH(2))](2+) OMe), is investigated, where terpy=2,2':6',2''-terpyridine, bpy=2,2'-bipyridine, tmtacn=1,4,7-trimethyl-1,4,7-triazacyclononane, tpzm=tris(1-pyrazolyl)methane. kinetics investigated as function either the catalyst concentration or...
The photo-hydrogen-evolving activity (activity to enhance the photochemical EDTA-reduction of water into molecular hydrogen) was evaluated for three different Ru(II)Pt(II) dimers with a general formula [(bpy)2Ru(micro-bridge)PtCl2]2+(bpy = 2,2'-bipyridine; bridge 4,4'-bis(N-(3-aminopropyl)carbamoyl)-2,2'-bipyridine (L1), 2,3-bis(2-pyridyl)pyrazine (L2), and 4,4'-bis(N-(4-pyridyl)methylcarbamoyl)-2,2'-bipyridine (L3); EDTA ethylenediaminetetraacetic acid disodium salt). A new complex,...
The Ru(V)==O species and other intermediates in O(2) evolution from water catalyzed by [Ru(terpy)(bpy)(OH(2))](2+) were spectrophotometrically characterized, the spectral components observed identified based on TD-DFT calculations. Moreover, important insights into rapid paths after RDS given DFT studies.
The one-electron-reduced form of methylviologen (MV(+*)), generated in situ by bulk electrolysis (MV(2+)), was for the first time reacted with various Pt(II) complexes aqueous media without light irradiation to reveal that thermal reduction water into molecular hydrogen is indeed highly promoted Pt(II)-based catalysts.
Supramolecular photosynthetic systems made up of the [Ir(ppy)2(bpy)]+ and [Co(bpy)3]2+ cores (ppy = 2-phenylpyridinate, bpy 2,2′-bipyridine) are in situ self-assembled aqueous media to generate H2 upon visible light irradiation, where one them recorded a relatively high turnover number 20.
A series of asymmetrical bis-tridentate cyclometalated complexes including [Ru(Mebib)(Mebip)](+), [Ru(Mebip)(dpb)](+), [Ru(Mebip)(Medpb)](+), and [Ru(Mebib)(tpy)](+) two noncyclometalated [Ru(Mebip)(2)](2+) [Ru(Mebip)(tpy)](2+) were prepared characterized, where Mebib is bis(N-methylbenzimidazolyl)benzene, Mebip bis(N-methylbenzimidazolyl)pyridine, dpb 1,3-di-2-pyridylbenzene, Medpb 4,6-dimethyl-1,3-di-2-pyridylbenzene, tpy 2,2':6',2″-terpyridine. The solid-state structure...
A nickel pyrazinedithiolate ([Ni(dcpdt)2 ]2- ; dcpdt=5,6-dicyanopyrazine-2,3-dithiolate), bearing a NiS4 core similar to the active center of [NiFe] hydrogenase, is shown serve as an efficient molecular catalyst for hydrogen evolution reaction (HER). This shows effectively low overpotentials HER (330-400 mV at pH 4-6). Moreover, turnover number catalysis reaches 20 000 over 24 h electrolysis with high Faradaic efficiency, 92-100 %. The electrochemical and DFT studies reveal that diprotonated...