名古屋大学 · 材料科学
山田靖之教授の研究室は、機能性分子の自己組織化と超分子相互作用を核に、高機能性金属錯体や酸化還元反応を制御する新規分子センサーや高効率な酸化触媒の開発を進めています。特に、ポルフィリン・フタロシアニン系キチムカルのスターバック構造とイオン・π相互作用を活用した多スケールな分子アセンブリーや、高価な触媒の効率化に寄与する超分子的活性化戦略が特徴です。また、高温超伝導体の微細構造と臨界電流密度の関係についても、材料の物性制御の観点から深く分析しています。
Figures are computed from collected data and may differ slightly.
Microstructural properties and their influence on Jc have been studied in detail on Ag-sheathed (Bi,Pb)2Sr2Ca2Cu3Ox tapes prepared by the powder-in-tube method. The present study centres on two important factors for the achievement of high Jc values: (1) The liquid phase reaction during the (2223) phase formation at 847 degrees C for the composition Bi1.72Pb0.34Sr1.83Ca1.97Cu3.13Ox leads to better connectivity between the (2223) platelets, thus considerably improving Jc (77 K, 0 T): single phase
Firmly tied: A four-fold rotaxane was prepared from a porphyrin unit with four alkylammonium chains and a phthalocyanine unit with four peripheral crown ethers. In a dinuclear Cu2+ complex of the four-fold rotaxane, the Cu2+–porphyrin and the Cu2+–phthalocyanine moieties were stacked efficiently on one another to afford spin–spin communication. The spin states were switched reversibly (see picture). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Suc
We report the preparation and crystal structure of a triply stacked metal complex array in which a Cu-phthalocyanine is sandwiched between different Cu-porphyrins. The discrete heterogeneous assembly was prepared through formation of a fourfold rotaxane from a tetradactyl porphyrin with alkylammonium moieties and a phthalocyanine bearing four crown ethers and the subsequent formation of an ionic complex between the fourfold rotaxane and a tetraanionic porphyrin. The tetraanionic porphyrin, Cu-TP
Back and forth. Redox potential sensors that consist of a flavin unit, a bora-3a,4a-diaza-s-indacene (BODIPY) moiety, and a L-proline linker are presented. While reduced forms of these fluorescent sensors are almost nonfluorescent, their oxidized forms exhibit bright emissions under control of the redox status of the flavin unit. It is also shown that these changes are reversible in aqueous solutions and living cells, as illustrated in the figure. Supporting information for this article is avail
Phase relationship in the [(K 1/2 Bi 1/2 ) 1- y (Na 1/2 Bi 1/2 ) y ](Ti 1- x B x )O 3 system with B=Zr, Fe 1/2 Nb 1/2 , Zn 1/3 Nb 2/3 or Mg 1/3 Nb 2/3 has been investigated by dielectric measurement and X-ray diffractometry. All of the bi-binary systems were solid-soluble throughout the entire composition range. With increasing y and x , ferroelectric Curie point decreased and the ε - T curve became flat. Composition dependence of the transition temperature was examined by varying x or y . Phase
Development of supramolecular methods to further activate a highly reactive intermediate is a fascinating strategy to create novel potent catalysts for activation of inert chemicals. Herein, a supramolecular approach to enhance the oxidizing ability of a high-valent oxo species of a nitrido-bridged iron porphyrinoid dimer that is a known potent molecular catalyst for light alkane oxidation is reported. For this purpose, a nitrido-bridged dinuclear iron complex of porphyrin-phthalocyanine heterod
To generate integrated organized molecular properties, multiple molecular components are required to be assembled into the molecular system with sequential and spatial accuracy in accordance with the design of the molecular assembly. Herein, we present a novel programmable synthesis of a cofacially stacked porphyrin array via repetitive construction of a peptide duplex. We designed and synthesized a novel porphyrin having two artificial amino acid moieties at the trans meso-positions. The amino
μ-Nitrido- and μ-carbido-bridged iron phthalocyanine dimers, when used as cathode-active materials for rechargeable lithium batteries, showed four stable redox waves in cyclic voltammetry studies in solution and a stable discharge capacity of approximately 60 mAh g<sup>-1</sup> after 200 cycles. These results indicate that μ-heteroatom-bridged iron phthalocyanine dimers are good platforms for designing novel phthalocyanine-based electrode-active materials.
A stacked assembly composed of a porphyrin and two phthalocyanines was prepared through fourfold rotaxane formation. Two phthalocyanine molecules, bearing four 24-crown-8 units, were assembled onto a porphyrin template incorporating four sidechains with two dialkylammonium ions each through pseudorotaxane formation between crown ether units and ammonium ions. The Staudinger phosphite reaction, as the stoppering reaction, resulted in the formation of the stacked heterotrimer composed of a porphyr
Catalytic CH<sub>4</sub>oxidation using a μ-nitrido-bridged iron porphyrinoid dimer was successfully activated by supramolecular complexation.
We present a novel strategy to synthesize multi-molecular arrays in a programmable way by stepwise elongation based on repetition of two-fold rotaxane formation and construction of threads. A cofacially triply stacked porphyrin array was obtained via the repetitive two-fold rotaxane formation.
Preparation of an accurate assembly of phthalocyanines is rather difficult because of the high aggregation property of phthalocyanines. In this study, a novel discrete phthalocyanine dimer was prepared in which the relative configuration of each component was tightly and accurately fixed in an H-aggregate form by a rigid U-shaped linker. Electrochemical measurements showed that there were strong intramolecular electronic interactions between the two phthalocyanines.
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