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951.
Yuichi Momoi Dr. Kei‐ichiro Okuyama Dr. Hiroki Toya Dr. Kenji Sugimoto Dr. Kentaro Okano Prof. Dr. Hidetoshi Tokuyama 《Angewandte Chemie (International ed. in English)》2014,53(48):13215-13219
The enantiocontrolled total synthesis of (?)‐haouamine B pentaacetate was accomplished via an optically active indane‐fused β‐lactam, which was prepared by a newly developed Friedel–Crafts reaction. Subsequent cleavage of the β‐lactam and an intramolecular McMurry coupling reaction provided the core indane‐fused tetrahydropyridine, which led to the elucidation of the structure, as proposed by Trauner and Zubía. 相似文献
952.
Enhancement of Host–Guest Interactions Using Rationally Designed Macrocyclic Boronic Esters with a Naphthalene Core 下载免费PDF全文
Yuji Kikuchi Dr. Hiroki Takahagi Dr. Kosuke Ono Prof. Dr. Nobuharu Iwasawa 《化学:亚洲杂志》2014,9(4):1001-1005
Efficient inclusion of electron‐deficient aromatic guest molecules in an organic solvent utilizing π‐stacking interactions was achieved by using two kinds of macrocyclic boronic esters, 1,4‐naph‐ [2+2] and 1,5‐naph‐ [2+2] , which were easily prepared by self‐assembly of 1,4‐naphthalenediboronic acid ( 3 ) or 1,5‐naphthalenediboronic acid ( 4 ) and racemic tetrol 1 with an indacene framework in a protic solvent. The X‐ray crystallographic analyses revealed that the tilt angles of the two naphthalene rings are different: that of 1,4‐naph‐ [2+2] is about 15° and that of 1,5‐naph‐ [2+2] is about 0°. Owing to the parallel alignment of two aromatic rings, 1,5‐naph ‐[2+2] has a much higher binding ability than 1,4‐naph‐ [2+2] . This knowledge could be useful for the design of the new host molecules in organic solvents. 相似文献
953.
Fabrication of NIR‐Excitable SERS‐Active Composite Particles Composed of Densely Packed Au Nanoparticles on Polymer Microparticles 下载免费PDF全文
Masaaki Kanahara Hiroki Satoh Takeshi Higuchi Atsushi Takahara Hiroshi Jinnai Koji Harano Satoshi Okada Eiichi Nakamura Yasutaka Matsuo Hiroshi Yabu 《Particle & Particle Systems Characterization》2015,32(4):441-447
A simple fabrication method is demonstrated for surface‐enhanced Raman scattering (SERS)‐active plasmonic nanoballs, which consisted of Au nanoparticles (NPs) and core–shell polystyrene and amino‐terminated poly(butadiene) particles, by heterocoagulation and Au NP diffusion. The amount of Au NPs introduced into the core–shell particles increases with the concentration of Au NPs added to the aqueous dispersion of the core–shell particles. When the amount of Au NPs increases, closely packed, three‐dimensionally arranged and close‐packed Au NPs arrays are formed in the shells. Strong SERS signals from para‐mercaptophenol adsorbed onto composite particles with multilayered Au NPs arrays are obtained by near‐infrared (NIR) light illumination. 相似文献
954.
The oxirane ring cleavage with dilithiated secondary amides was accelerated by the addition of boron trifluoride-etherate to afford γ-hydroxyamides, which were transformed into 5-alkylsubstituted γ-lactams via an intramolecular N-alkylation reaction. 相似文献
955.
956.
Yusaku Hioki Hiroki Kuyama Chikako Hamana Kohei Takeyama Koichi Tanaka 《Journal of mass spectrometry : JMS》2013,48(11):1217-1223
We describe here an optimization study of the sample preparation conditions for sensitive detection of peptides by matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). Among many factors in the conditions, we varied the percent acetonitrile in the peptide solution, the percent acetonitrile in the matrix solution and the α‐cyano‐4‐hydroxycinnamic acid (CHCA) concentration in the matrix solution. CHCA was chosen because it is the most frequently used matrix for analyzing peptides. The well‐established dried‐droplet method was employed for sample deposition. The examined range of the concentration of CHCA was from 0.01 to 10 mg/ml, and the MeCN content of the solvent for matrix/analyte was 10% to 50%. The indicator for the detection sensitivity was the S/N ratio of the peaks of peptides used. Highly increased sensitivity (100‐ to 1000‐fold) was observed for the optimal CHCA concentration of 0.1 mg/ml in 20% MeCN/0.1% aq. trifluoroacetic acid (TFA), as compared with the conventional concentration (10 mg/ml) in 50% MeCN/0.1% aq. TFA. For example, the limit of detection of human ACTH 18–39 was 10 amol/well for the optimal condition but 10 fmol/well for the conventional condition. The optimal condition (0.1 mg/ml CHCA in 20% MeCN/0.1% aq. TFA) was verified with five model peptides and provided significant improvement in sensitivity (by two to three orders of magnitude) compared with the conventional conditions. Optimizing the CHCA concentration and solvent composition significantly improved the detection sensitivity in the analysis of peptides by MALDI‐MS. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
957.
958.
Wen Wen Yin‐Shan Meng Cheng‐Qi Jiao Qiang Liu Hai‐Lang Zhu Ya‐Ming Li Hiroki Oshio Tao Liu 《Angewandte Chemie (International ed. in English)》2020,59(38):16393-16397
It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal‐to‐metal charge transfer (MMCT) and spin‐crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a FeII‐triazole moiety and generates a mixed‐valence complex {[(Tp4‐Me)FeIII(CN)3]9[FeII4(trz‐ph)6]}?[Ph3PMe]2?[(Tp4‐Me)FeIII(CN)3] ( 1 ; trz‐ph=4‐phenyl‐4H‐1,2,4‐triazole). Moreover, MMCT occurs between FeIII and one of the FeII sites after heat treatment, resulting in the generation of a new phase, {[(Tp4‐Me)FeII(CN)3][(Tp4‐Me)FeIII(CN)3]8 [FeIIIFeII3(trz‐ph)6]}? [Ph3PMe]2?[(Tp4‐Me)FeIII(CN)3] ( 1 a ). Structural and magnetic studies reveal that MMCT can tune the two‐step SCO behavior of 1 into one‐step SCO behavior of 1 a . Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin‐transition materials with accessible multi‐electronic states. 相似文献
959.
Nano‐ to micrometer‐scale surface roughness contributes to the hydrophobicity of materials as discussed often in terms of superhydrophobicity. We report here that as little as 1 wt% of α, β, and γ‐cyclodextrins (CDs) can disperse carbon nanohorn aggregates (CNHa) as surfactants in water by binding on their pointed tips. The binding mode was visually demonstrated using single‐molecule atomic resolution real‐time electron microscopy (SMART‐EM). The SMART‐EM data provided an estimation of the equilibrium constant of the CD binding to be close to that of adamantane ammonium chloride to β‐CD. A qualitative study on the rate of decomplexation of α, β, and γ‐CDs from CNHa suggests a substantial mechanistic difference in their binding mode to the CNH tips. A sequence of α‐CD complexation and decomplexation allows us to purify CNHa by selectively removing graphitic ball‐shaped impurity (GB). Upon treatment with NaNH2, the purified CNHa produce GB‐free amino‐CNHa where the tips are functionalized with NH2 groups. 相似文献
960.
Electrochemical impedance spectroscopy has been widely used to understand the chemistry and physics of battery systems. This review covers electrochemical impedance spectroscopy used for the interpretation of impedance data of lithium-ion batteries (LIBs) from advanced equivalent circuit models to the mathematical model, which is developed by John Newman. In addition, as a method to realize an energy-sustainable society using diagnostics based on the combination of LIBs and electrochemical impedance spectroscopy, on-board diagnostics of battery packs are achieved based on an input signal generated by a power controller in a battery management system instead of the conventionally used frequency response analyzer. The diagnostic system is applicable to energy management systems which are installed in homes, buildings, and communities, accumulating the impedance data on state of health of LIBs. Finally, a future possibility regarding the diagnostics of battery packs coupled with the machine learning of impedance data is introduced. 相似文献