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581.
Kenichi Maruyama Yuji Mishima Keiji Minagawa Junko Motonaka 《Journal of Electroanalytical Chemistry》2001,510(1-2)
A transition metal complex as an electrochemical probe of a DNA sensor must have an applicable redox potential, high binding affinity and chemical stability. Some complexes with the dipyrido[3,2-a:2′,3′-c]phenazine (DPPZ) ligand have been reported to have high binding affinity for DNA. However, it was difficult to detect the targeted DNA electrochemically using these complexes because of the relatively high redox potential. In this work, a combination of bipyridine ligands with functional groups (---NH2, ---CH3 and ---COOH) and the DPPZ ligand were studied. The introduction of electron-donating groups was effective for controlling the redox potential of the DPPZ-type osmium complex. The [Os(DA-bpy)2DPPZ]2+ complex (DA-bpy; 4,4′-diamino-2,2′-bipyridine) had a lower half-wave potential (E1/2) of 147 mV (vs. Ag AgCl) and higher binding affinity with DNA {binding constant, K=3.1×107 M−1 in 10 mmol dm−3 Tris–HCl buffer with 50 mmol dm−3 NaCl (pH 7.76)} than those of other complexes. With the single stranded DNA (ssDNA) modified gold electrode, the hybridization signal (ΔI) of the [Os(DA-bpy)2DPPZ]2+ complex was linear in the concentration range of 1.0 pg ml−1–0.12 μg ml−1 for the targeted DNA with a regression coefficient of 0.999. The detection limit was 0.1 pg ml−1. 相似文献
582.
Masashi Ozaki Ai Shimazaki Mina Jung Yumi Nakaike Naoki Maruyama Shinya Yakumaru Alwani Imanah Rafieh Takahiro Sasamori Norihiro Tokitoh Piyasiri Ekanayake Yasujiro Murata Richard Murdey Atsushi Wakamiya 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(28):9489-9493
A high‐purity methylammonium lead iodide complex with intercalated dimethylformamide (DMF) molecules, CH3NH3PbI3?DMF, is introduced as an effective precursor material for fabricating high‐quality solution‐processed perovskite layers. Spin‐coated films of the solvent‐intercalated complex dissolved in pure dimethyl sulfoxide (DMSO) yielded thick, dense perovskite layers after thermal annealing. The low volatility of the pure DMSO solvent extended the allowable time for low‐speed spin programs and considerably relaxed the precision needed for the antisolvent addition step. An optimized, reliable fabrication method was devised to take advantage of this extended process window and resulted in highly consistent performance of perovskite solar cell devices, with up to 19.8 % power‐conversion efficiency (PCE). The optimized method was also used to fabricate a 22.0 cm2, eight‐cell module with 14.2 % PCE (active area) and 8.64 V output (1.08 V/cell). 相似文献
583.
Hollow giant lipid vesicles were prepared in a single step by coaxially electrospraying separate solutions of phospholipid and a degradable polyelectrolyte. We synthesized a hydrolytically degradable cationic polyelectrolyte, poly(β-amino esters) (PBAE), and employed it as a degradable microgel template to form giant vesicles. Droplets of the phospholipid solution and the degradable polyelectrolyte solution were electrosprayed from coaxial double needles into a receiving solution. The PBAE formed a microgel by crosslinking with multivalent anions in the receiving solution, and the phospholipids formed bilayers on the microgel. Hollow giant lipid vesicles were successfully obtained and the mean diameters were 7.6 μm (C.V. 58 %). Substrates (calcein, dextran, and polymeric microparticles) were successfully encapsulated in the giant vesicles. Microscopic observations of microparticle mobility inside a giant vesicle indicated the fluidity of its aqueous interior. Investigations using fluorescently labeled PBAE also suggested the degradation of PBAE, and the release of fluorescent PBAE fragments from the encapsulated microgel, to form hollow giant lipid vesicles. 相似文献
584.
Dr. Alexander G. O'Brien Dr. Akinobu Maruyama Dr. Yasuhide Inokuma Prof. Makoto Fujita Prof. Phil S. Baran Prof. Donna G. Blackmond 《Angewandte Chemie (International ed. in English)》2014,53(44):11868-11871
Electrochemical reactions are shown to be effective for the C? H functionalization of a number of heterocyclic substrates that are recalcitrant to conventional peroxide radical initiation conditions. Monitoring reaction progress under electrochemical conditions provides mechanistic insight into the C? H functionalization of a series of heterocycles of interest in medicinal chemistry. 相似文献
585.
High‐Power Electrochemical Energy Storage System Employing Stable Radical Pseudocapacitors 下载免费PDF全文
Hitoshi Maruyama Dr. Hideyuki Nakano Dr. Masaaki Nakamoto Prof. Dr. Akira Sekiguchi 《Angewandte Chemie (International ed. in English)》2014,53(5):1324-1328
The development of electrical energy storage devices that can operate at high charge and discharge rates is fundamentally important, however although electrochemical capacitors (ECs) can charge and discharge at high rates, their electrochemical storage capacity remains an order of magnitude lower than that of conventional lithium‐ion batteries. Novel pseudocapasitors are developed, based on the stable persilyl‐susbtituted free radicals of the heavy group 14 elements, (tBu2MeSi)3E. [E=Si ( 1 ), Ge ( 2 ), and Sn ( 3 )], as anode materials for energy storage system. Such systems showed a remarkable cycle stability without significant loss of power density, in comparison with similar characteristics of the known organic radical batteries, the dual carbon cell, and the electrochemical capacitor. Particularly important is that these novel electrochemical energy storage systems employing stable heavy group 14 element radicals are lithium‐free. The electrochemical properties and structures of the reduced and oxidized species were studied by the cyclic voltammetry (CV), electron paramagnetic resonance (EPR) spectroscopy, and X‐ray diffraction (XRD). 相似文献
586.
Prof. Dr. Toshiaki Murai Kenta Morikawa Toshifumi Maruyama 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(39):13112-13119
The sequential addition of aromatic Grignard reagents to O‐alkyl thioformates proceeded to completion within 30 s to give aryl benzylic sulfanes in good yields. This reaction may begin with the nucleophilic attack of the Grignard reagent onto the carbon atom of the O‐alkyl thioformates, followed by the elimination of ROMgBr to generate aromatic thioaldehydes, which then react with a second molecule of the Grignard reagent at the sulfur atom to form arylsulfanyl benzylic Grignard reagents. To confirm the generation of aromatic thioaldehydes, the reaction between O‐alkyl thioformates and phenyl Grignard reagent was carried out in the presence of cyclopentadiene. As a result, hetero‐Diels–Alder adducts of the thioaldehyde and the diene were formed. The treatment of a mixture of the thioformate and phenyl Grignard reagent with iodine gave 1,2‐bis(phenylsulfanyl)‐1,2‐diphenyl ethane as a product, which indicated the formation of arylsulfanyl benzylic Grignard reagents in the reaction mixture. When electrophiles were added to the Grignard reagents that were generated in situ, four‐component coupling products, that is, O‐alkyl thioformates, two molecules of Grignard reagents, and electrophiles, were obtained in moderate‐to‐good yields. The use of silyl chloride or allylic bromides gave the adducts within 5 min, whereas the reaction with benzylic halides required more than 30 min. The addition to carbonyl compounds was complete within 1 min and the use of lithium bromide as an additive enhanced the yields of the four‐component coupling products. Finally, oxiranes and imines also participated in the coupling reaction. 相似文献
587.
A tungsten trioxide (WO3) film was prepared by calcination from a precursor paste including suspended ammonium tungstate and polyethylene glycol (PEG). The ammonium tungstate suspension was yielded by an acid-base reaction of tungstic acid and an ammonium solution followed by deposition with ethanol addition. Thermogravimetric (TG) analysis showed that the TG profile of PEG is significantly influenced by deposited ammonium tungstate, suggesting that PEG is interacting strongly with deposited ammonium tungstate in the suspension paste. X-ray diffraction (XRD) data indicated that the WO3 film is crystallized by sintering over 400 °C. The scanning electron microscopic (SEM) measurement showed that the film is composed of the nano-structured WO3 platelets. The semiconductor properties of the film were examined by Mott-Schottky analysis to give flat band potential EFB=0.30 V vs. saturated calomel reference electrode (SCE) and donor carrier density ND=2.5×1022 cm−3, latter of which is higher than previous WO3 films by two orders of magnitude. The higher ND was explained by the large interfacial heterojunction area caused by the nano-platelet structure, which apparently increases capacitance per a unit electrode area. The WO3 film sintered at 550 °C produced 3.7 mA cm−2 of a photoanodic current at 1.2 V vs. SCE under illumination with a 500 W xenon lamp due to catalytic water oxidation. This photocurrent was 4.5-12.8 times higher than those for the other control WO3 films prepared by similar but different procedures. The high catalytic activity could be explained by the nano-platelet structure. The photocurrent was generated on illumination of UV and visible light below 470 nm, and the maximum incident photon-to-current conversion efficiency (IPCE) was 47% at 320 nm at 1.2 V. Technically important procedures for preparation of nano-structured platelets were discussed. 相似文献
588.
Yoshinori Yamamoto Hidetaka Yatagai Yuji Ishihara Norihiko Maeda Kazuhiro Maruyama 《Tetrahedron》1984,40(12):2239-2246
The reaction of crotyltrialkylstannanes (1) with aldehydes in the presence of BF3,OEt2, produces the corresponding erythro homoallyl alcohols (2) predominantly regardless of the geometry of the double bond. Further, the Lewis acid mediated reaction exhibits the enhanced Cram selectivity in comparison with other allylic organometallic reactions which proceed in the absence of Lewis acids. Use of AlCl3-i-PrOH as the Lewis acid entirely changes the reaction course; the linear adduct (12) is produced rather than the branched adduct (13). The reaction of 1-BF3,OEt2 system is applied to the short and stereoselective synthesis of the (±) Prelog-Djerassi lactonic acid (16) and (-) verrucarinolactone (19). 相似文献
589.
Zirconium enolates, prepard from lithium enolates and bis(cyclopentadienyl)zirconium dichloride, undergo a facile aldol condensation with aldehydes to give predominantly the erythro product regardless of the geometry of the starting enolates. 相似文献
590.
The solutions of carrier-free125mTe(VI) have been prepared by oxidizing125mTe(IV) with bromine. Using carrier-free125mTe(VI) as a tracer, the effects of pH, NaCl concentration, and tellurium(VI) concentration on the adsorption and colloidal properties of tellurium(VI) in NaCl solution have been studied. It has been found that traces of tellurium(VI) are adsorbed on filter paper and show colloidal behavior in the basic region. A method has been devised for the separation of carrier-free125mTe from its parent nuclide125Sb, based on the adsorption properties of125mTe(VI) in basic solutions. 相似文献