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Takaaki Taguchi Masaki Yabe Hitomi Odaki Miki Shinozaki Mikko Metsä-Ketelä Takao Arai Susumu Okamoto Koji Ichinose 《Chemistry & biology》2013,20(4):510-520
Highlights? ActVA-ORF5 is a flavin-dependent monooxygenase required for actinorhodin biosynthesis ? ActVA-ORF5 and its three close homologs were functionally dissected ? ActVA-ORF5 and Gra-21 are bifunctional at C-6/C-8, while Med-7 acts only for C-6 ? AlnT exhibits different regiospecificity for oxidation of tricyclic substrates 相似文献
64.
Tetsuya Tsuda Susumu Kuwabata Gery R. Stafford Charles L. Hussey 《Journal of Solid State Electrochemistry》2013,17(2):409-417
The electrochemistry of Hf(IV) and the electrodeposition of Al–Hf alloys were examined in the Lewis acidic 66.7–33.3 mol% aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt containing HfCl4. When cyclic staircase voltammetry was carried out at a platinum disk electrode in this melt, the deposition and stripping waves for Al shifted to negative and positive potentials, respectively, suggesting that aluminum stripping is more difficult due to the formation of Al–Hf alloys. Al–Hf alloy electrodeposits containing ~13 at.% Hf were obtained on Cu rotating wire and cylinder electrodes. The Hf content in the Al–Hf alloy deposits depended on the HfCl4 concentration in the melt, the electrodeposition temperature, and the applied current density. The deposits were composed of dense crystals and were completely chloride-free. The chloride-induced pitting corrosion potential of the resulting Al–Hf alloys was approximately +0.30 V against pure aluminum when the Hf content was above 10 at.%. 相似文献
65.
Susumu Ohira 《合成通讯》2013,43(3-4):561-564
Dimethyl (1-diazo-2-oxopropyl) phosphonate (3) was transformed to dimethyl (diazomethyl)—phosphonate (4), which was used for the synthesis of enol ether or alkyne without isolation. 相似文献
66.
Tetsuyuki Taniai Sachiko Wakasugi Susumu Hashimoto Ai Shimada Tatsuya Urabe Kazuya Takahashi 《International journal of environmental analytical chemistry》2013,93(5):601-612
To obtain information on the environmental impact of materials eluted from volcanic ashes of Mt. Oyama, Miyake Island, which erupted in July 2000, the dissolution behaviours of heavy metals and rare-earth elements from the volcanic ashes were examined. The most important characteristic of the Mt. Oyama eruption is that sulphur dioxide (SO2) gas has been continuously released, and all persons living on Miyake Island have been required to evacuate. To estimate in terms of the volcanic eruption using SO2 gas, the ash nature in Mt. Usu, Hokkaido, was also examined and compared with that in Mt. Oyama. When rain water mixed the ashes, the water from the ashes of Mt. Oyama became acidic because of the sulphuric acid. Therefore, SO2 gas in Mt. Oyama can accelerate the dissolution of protons and heavy metals in the ashes, whereas the rain water in Mt. Usu was not acidic and the dissolution of the heavy metals was not so evident compared with that in the case of Mt. Oyama. With this sulphuric acid, heavy metals such as As, Cd, Pb and Hg in the ashes in Mt. Oyama easily dissolved owing to the low pH. The ashes in Mt. Oyama had been released for eight years and the amount of fallen ashes was estimated to be 33 billion tons. The weights of the harmful heavy metals in the volcanic ashes, such as As, Cd, Pb and Hg, were estimated to be 3.8?×?102, 1.3?×?103, 1.1?×?103 and 29?kg, respectively, and these heavy metals were dissolved and diluted in seawater. Therefore, the concentration and species (chemical form) of these metals should be carefully monitored in the future. Moreover, SO2 gas, which has a direct effect on human health and has been monitored continuously, causes other effects, such as facilitation of metal ion elution and rock aeration. 相似文献
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Mark Kristan Espejo Cabello Dr. Yuta Uetake Dr. Yu Yao Prof. Dr. Susumu Kuwabata Prof. Dr. Hidehiro Sakurai 《化学:亚洲杂志》2021,16(16):2280-2285
An aqueous colloidal dispersion of Pt nanoparticles (NPs) stabilized by fullerenol C60(OH)12 (Pt:C60(OH)12) was successfully synthesized via liquid-phase chemical reduction. The subsequent pyrolysis of Pt:C60(OH)12 at different temperatures was conducted to afford Pt-doped carbon with different chemical compositions (Pt:C60n). X-ray absorption spectroscopy (XAS) and Infrared (IR) absorption spectroscopy and thermogravimetric measurements revealed that the thus-prepared nanocomposite consists of Pt NPs and high valent Pt-C60(OH)12 complex. One distinct feature of C60(OH)12 matrix as catalyst support is the suppression of size growth of Pt NPs during the pyrolysis up to 300 °C. Electrochemical experiments using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were performed to find that Pt:C60300 (pyrolyzed at 300 °C) exhibited higher activity than others, that was attributed to the π-extended feature of the as-obtained carbon. 相似文献
69.
Amine‐Responsive Adaptable Nanospaces: Fluorescent Porous Coordination Polymer for Molecular Recognition 下载免费PDF全文
Ritesh Haldar Prof. Ryotaro Matsuda Prof. Susumu Kitagawa Prof. Subi J. George Prof. Tapas Kumar Maji 《Angewandte Chemie (International ed. in English)》2014,53(44):11772-11777
Flexible and dynamic porous coordination polymers (PCPs) with well‐defined nanospaces composed of chromophoric organic linkers provide a scaffold for encapsulation of versatile guest molecules through noncovalent interactions. PCPs thus provide a potential platform for molecular recognition. Herein, we report a flexible 3D supramolecular framework {[Zn(ndc)(o‐phen)]?DMF}n (o‐phen=1,10‐phenanthroline, ndc=2,6‐napthalenedicarboxylate) with confined nanospaces that can accommodate different electron‐donating aromatic amine guests with selective turn‐on emission signaling. This system serves as a molecular recognition platform through an emission‐readout process. Such unprecedented tunable emission with different amines is attributed to its emissive charge‐transfer (CT) complexation with o‐phen linkers. In certain cases this CT emission is further amplified by energy transfer from the chromophoric linker unit ndc, as evidenced by single‐crystal X‐ray structural characterization. 相似文献
70.
Selective Generation of Formamides through Photocatalytic CO2 Reduction Catalyzed by Ruthenium Carbonyl Compounds 下载免费PDF全文
Dr. Katsuaki Kobayashi Dr. Takashi Kikuchi Prof. Susumu Kitagawa Prof. Koji Tanaka 《Angewandte Chemie (International ed. in English)》2014,53(44):11813-11817
The selective formation of dialkyl formamides through photochemical CO2 reduction was developed as a means of utilizing CO2 as a C1 building block. Photochemical CO2 reduction catalyzed by a [Ru(bpy)2(CO)2]2+ (bpy: 2,2′‐bipyridyl)/[Ru(bpy)3]2+/Me2NH/Me2NH2+ system in CH3CN selectively produced dimethylformamide. In this process a ruthenium carbamoyl complex ([Ru(bpy)2(CO)(CONMe2)]+) formed by the nucleophilic attack of Me2NH on [Ru(bpy)2(CO)2]2+ worked as the precursor to DMF. Thus Me2NH acted as both the sacrificial electron donor and the substrate, while Me2NH2+ functioned as the proton source. Similar photochemical CO2 reductions using R2NH and R2NH2+ (R=Et, nPr, or nBu) also afforded the corresponding dialkyl formamides (R2NCHO) together with HCOOH as a by‐product. The main product from the CO2 reduction transitioned from R2NCHO to HCOOH with increases in the alkyl chain length of the R2NH. The selectivity between R2NCHO and HCOOH was found to depend on the rate of [Ru(bpy)2(CO)(CONR2)]+ formation. 相似文献