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Hideyuki Higashimura

Bio: Hideyuki Higashimura is an academic researcher from Sumitomo Chemical. The author has contributed to research in topics: Polymerization & Catalysis. The author has an hindex of 26, co-authored 144 publications receiving 2889 citations. Previous affiliations of Hideyuki Higashimura include National Institute of Advanced Industrial Science and Technology & Okayama University of Science.


Papers
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TL;DR: In this paper, the authors describe the hydrogen production from an aqueous medium over amino-functionalized Ti(IV) metal-organic framework (Ti-MOF-NH2) under visible-light irradiation.
Abstract: The present article describes the hydrogen production from an aqueous medium over amino-functionalized Ti(IV) metal–organic framework (Ti-MOF-NH2) under visible-light irradiation. Ti-MOF-NH2, which employs 2-amino-benzenedicarboxylic acid as an organic linker, has been synthesized by a facile solvothermal method. Pt nanoparticles as cocatalysts are then deposited onto Ti-MOF-NH2 via a photodeposition process (Pt/Ti-MOF-NH2). The XRD and N2 adsorption measurements reveal the successful formation of a MOF framework structure and its remaining structure after deposition of Pt nanoparticles. The observable visible-light absorption up to ∼500 nm can be seen in the DRUV–vis spectrum of Ti-MOF-NH2, which is associated with the chromophore in the organic linker. Ti-MOF-NH2 and Pt/Ti-MOF-NH2 exhibit efficient photocatalytic activities for hydrogen production from an aqueous solution containing triethanolamine as a sacrificial electron donor under visible-light irradiation. The longest wavelength available for the ...

520 citations

Journal ArticleDOI
TL;DR: Results demonstrate that this organometallic polycondensation proceeds through a chain-growth polymerization mechanism from an initiator unit derived from the catalyst.
Abstract: Palladium-catalyzed polycondensation of 2-(7-bromo-9,9-dioctyl-9H-fluoren-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1a) with tBu3PPd(Ph)Br (2) via Suzuki−Miyaura coupling reaction was investigated. The polymerization in a mixture of THF and 2 mol/L aqueous solution of Na2CO3 proceeded smoothly at room temperature and afforded well-defined polyfluorenes with narrow molecular weight distributions. MALDI-TOF mass spectroscopy showed that the obtained polymers have a phenyl group at one end. The relationships of conversion to number-average molecular weight (Mn) and feed ratio to Mn were linear. These results demonstrate that this organometallic polycondensation proceeds through a chain-growth polymerization mechanism from an initiator unit derived from the catalyst.

286 citations

Journal ArticleDOI
TL;DR: An overview on recent developments of oxidative polymerizations of phenols, particularly focusing on the coupling selectivity, can be found in this article, where three reaction mechanisms are discussed: coupling of free phenoxy radicals, coupling of the phenoxonium cation coordinated to catalyst complexes, and coupling through the phenoxide cation.

269 citations

Journal ArticleDOI
TL;DR: In this paper, a Pt-deposited amino-functionalised Ti(IV) metal-organic framework (Pt/Ti-MOF-NH2) was used for hydrogen production and photocatalytic reduction of nitrobenzene under visible-light irradiation.

186 citations

Journal ArticleDOI
TL;DR: A new class of macrocyclic metal-N(4) complexes [MN(4)](n) (M = Co and Fe) were designed and synthesized based on a triangular ligand that provides a high density of active sites and facilitates the reduction of dioxygen via a four-electron pathway.
Abstract: A new class of macrocyclic metal-N4 complexes [MN4]n (M = Co and Fe) were designed and synthesized based on a triangular ligand. Their unique triangular trinuclear structure provides a high density of active sites and facilitates the reduction of dioxygen via a four-electron pathway. Among them, a [CoN4]3/C catalyst (20 wt %) exhibits high catalytic activity and long-time stability for the oxygen reduction reaction (ORR) in alkaline conditions, superior to the commercial Pt/C catalyst. Such structurally well-defined [MN4]n complexes provide a platform for a new generation of nonprecious metal catalysts (NPMCs) for fuel cell applications.

174 citations


Cited by
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Journal ArticleDOI
TL;DR: This paper presents a meta-analyses of the chiral stationary phase transition of Na6(CO3)(SO4)2, Na2SO4, and Na2CO3 of the Na2O/Na2O 2 mixture at the stationary phase and shows clear patterns in the response of these two materials to each other.
Abstract: Jenny Schneider,*,† Masaya Matsuoka,‡ Masato Takeuchi,‡ Jinlong Zhang, Yu Horiuchi,‡ Masakazu Anpo,‡ and Detlef W. Bahnemann*,† †Institut fur Technische Chemie, Leibniz Universitaẗ Hannover, Callinstrasse 3, D-30167 Hannover, Germany ‡Faculty of Engineering, Osaka Prefecture University, 1 Gakuen-cho, Sakai Osaka 599-8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China

4,353 citations

Journal ArticleDOI
TL;DR: It is found that Fe(3)O(4)/N-GAs show a more positive onset potential, higher cathodic density, lower H(2)O-2) yield, and higher electron transfer number for the ORR in alkaline media than Fe( 3)O (4) NPs supported on N-doped carbon black or N- doped graphene sheets, highlighting the importance of the 3D macropores and high specific surface area of the GA support for
Abstract: Three-dimensional (3D) N-doped graphene aerogel (N-GA)-supported Fe3O4 nanoparticles (Fe3O4/N-GAs) as efficient cathode catalysts for the oxygen reduction reaction (ORR) are reported. The graphene hybrids exhibit an interconnected macroporous framework of graphene sheets with uniform dispersion of Fe3O4 nanoparticles (NPs). In studying the effects of the carbon support on the Fe3O4 NPs for the ORR, we found that Fe3O4/N-GAs show a more positive onset potential, higher cathodic density, lower H2O2 yield, and higher electron transfer number for the ORR in alkaline media than Fe3O4 NPs supported on N-doped carbon black or N-doped graphene sheets, highlighting the importance of the 3D macropores and high specific surface area of the GA support for improving the ORR performance. Furthermore, Fe3O4/N-GAs show better durability than the commercial Pt/C catalyst.

1,952 citations

Journal ArticleDOI
TL;DR: This review provides an overview of the significant advances in the development of diverse MOF composites reported till now with special emphases on the synergistic effects and applications of the composites.
Abstract: Metal–organic frameworks (MOFs), also known as porous coordination polymers (PCPs), synthesized by assembling metal ions with organic ligands have recently emerged as a new class of crystalline porous materials. The amenability to design as well as fine-tunable and uniform pore structures makes them promising materials for a variety of applications. Controllable integration of MOFs and functional materials is leading to the creation of new multifunctional composites/hybrids, which exhibit new properties that are superior to those of the individual components through the collective behavior of the functional units. This is a rapidly developing interdisciplinary research area. This review provides an overview of the significant advances in the development of diverse MOF composites reported till now with special emphases on the synergistic effects and applications of the composites. The most widely used and successful strategies for composite synthesis are also presented.

1,738 citations

Journal ArticleDOI
TL;DR: This review is expected to guide the design of stable MOFs by providing insights into existing structures, which could lead to the discovery and development of more advanced functional materials.
Abstract: Metal-organic frameworks (MOFs) are an emerging class of porous materials with potential applications in gas storage, separations, catalysis, and chemical sensing. Despite numerous advantages, applications of many MOFs are ultimately limited by their stability under harsh conditions. Herein, the recent advances in the field of stable MOFs, covering the fundamental mechanisms of MOF stability, design, and synthesis of stable MOF architectures, and their latest applications are reviewed. First, key factors that affect MOF stability under certain chemical environments are introduced to guide the design of robust structures. This is followed by a short review of synthetic strategies of stable MOFs including modulated synthesis and postsynthetic modifications. Based on the fundamentals of MOF stability, stable MOFs are classified into two categories: high-valency metal-carboxylate frameworks and low-valency metal-azolate frameworks. Along this line, some representative stable MOFs are introduced, their structures are described, and their properties are briefly discussed. The expanded applications of stable MOFs in Lewis/Bronsted acid catalysis, redox catalysis, photocatalysis, electrocatalysis, gas storage, and sensing are highlighted. Overall, this review is expected to guide the design of stable MOFs by providing insights into existing structures, which could lead to the discovery and development of more advanced functional materials.

1,721 citations

01 Feb 1995
TL;DR: In this paper, the unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio using DFT, MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set.
Abstract: : The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

1,652 citations