Dr. Yasufumi Takahashi  Dr. Yu Kobayashi  Dr. Ziqian Wang  Dr. Yoshikazu Ito  Masato Ota  Dr. Hiroki Ida  Dr. Akichika Kumatani  Dr. Keisuke Miyazawa  Prof. Takeshi Fujita  Prof. Hitoshi Shiku  Yuri E. Korchev  Dr. Yasumitsu Miyata  Prof. Takeshi Fukuma  Prof. Mingwei Chen  Prof. Tomokazu Matsue 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3629-3636

High-resolution scanning electrochemical cell microscopy (SECCM) is used to image and quantitatively analyze the hydrogen evolution reaction (HER) catalytically active sites of 1H-MoS₂ nanosheets, MoS₂, and WS₂ heteronanosheets. Using a 20 nm radius nanopipette and hopping mode scanning, the resolution of SECCM was beyond the optical microscopy limit and visualized a small triangular MoS₂ nanosheet with a side length of ca. 130 nm. The electrochemical cell provides local cyclic voltammograms with a nanoscale spatial resolution for visualizing HER active sites as electrochemical images. The HER activity difference of edge, terrace, and heterojunction of MoS₂ and WS₂ were revealed. The SECCM imaging directly visualized the relationship of HER activity and number of MoS₂ nanosheet layers and unveiled the heterogeneous aging state of MoS₂ nanosheets. SECCM can be used for improving local HER activities by producing sulfur vacancies using electrochemical reaction at the selected region.  相似文献   

    

Koichi Mitsudo  Ren Matsuo  Toki Yonezawa  Haruka Inoue  Hiroki Mandai  Seiji Suga 《Angewandte Chemie (International ed. in English)》2020,59(20):7803-7807

The first electrochemical dehydrogenative C?S bond formation leading to thienoacene derivatives is described. Several thienoacene derivatives were synthesized by dehydrogenative C?H/S?H coupling. The addition of ⁿBu₄NBr, which catalytically promoted the reaction as a halogen mediator, was essential.  相似文献   

    

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 Fe^II‐triazole moiety and generates a mixed‐valence complex {[(Tp^4‐Me)Fe^III(CN)₃]₉[Fe^II₄(trz‐ph)₆]}?[Ph₃PMe]₂?[(Tp^4‐Me)Fe^III(CN)₃] ( 1 ; trz‐ph=4‐phenyl‐4H‐1,2,4‐triazole). Moreover, MMCT occurs between Fe^III and one of the Fe^II sites after heat treatment, resulting in the generation of a new phase, {[(Tp^4‐Me)Fe^II(CN)₃][(Tp^4‐Me)Fe^III(CN)₃]₈ [Fe^IIIFe^II₃(trz‐ph)₆]}? [Ph₃PMe]₂?[(Tp^4‐Me)Fe^III(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   

    

Hiroki Hanayama  Junya Yamada  Koji Harano  Eiichi Nakamura 《化学:亚洲杂志》2020,15(10):1549-1552

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   

    

Masao Yoshino  Karol Bartosiewicz  Takahiko Horiai  Kei Kamada  Akihiro Yamaji  Yasuhiro Shoji  Yuui Yokota  Shunsuke Kurosawa  Yuji Ohashi  Hiroki Sato  Satoshi Toyoda  Romana Kucerkova  Vitezslav Jary  Martin Nikl  Akira Yoshikawa 《physica status solidi b》2020,257(8):1900504

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Makoto Miyoshi  Hiroki Harada  Takashi Egawa  Tetsuya Takeuchi 《physica status solidi (a)》2020,217(3)

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Dr. Toshio Nishino  Dr. Colin J. Martin  Hiroki Takeuchi  Florence Lim  Dr. Kazuma Yasuhara  Yohan Gisbert  Dr. Seifallah Abid  Dr. Nathalie Saffon-Merceron  Dr. Claire Kammerer  Prof. Dr. Gwénaël Rapenne 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(52):12010-12018

The design and synthesis of a new family of nanocars is reported. To control their motion, we integrated a dipole which can be tuned thanks to strategic donor and acceptor substituents at the 5- and 15-positions of the porphyrin backbone. The two other meso positions are substituted with ethynyltriptycene moieties which are known to act as wheels. Full characterization of nine nanocars is presented as well as the electrochemistry of these push-pull molecules. DFT calculations allowed us to evaluate the magnitude of the dipoles and to understand the electrochemical behavior and how it is affected by the electron donating and accepting groups present. An X-ray crystal structure of one nanocar has also been obtained.  相似文献   

    

Hiroki Fukunaga  Dr. Wataru Kosaka  Honoka Nemoto  Dr. Kouji Taniguchi  Dr. Shogo Kawaguchi  Dr. Kunihisa Sugimoto  Prof. Dr. Hitoshi Miyasaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(70):16755-16766

The insertion of “sandwiched spins” between magnetic layers could efficiently affect the interlayer magnetic correlations, but doing so increases the complexity in the interlayer spin alignment because of competition between the inserted spin-layer interaction J_NNI and the interlayer through-space interaction J_NNNI if the magnitude of J_NNI is of the same order as J_NNNI with reciprocal signs of the respective interactions. Herein, systematic tuning of the magnetic phase variations by J_NNI and J_NNNI in two kinds of metal-variable isostructural series of supramolecular pillared layer magnets [MCp*₂][{Ru₂^II,II(2,3,5,6-F₄CO₂)₄}₂(TCNQ)] ⋅ 2 DCE (M=Co, Fe, Cr; 2,3,5,6-F₄PhCO₂⁻=2,3,5,6-tetrafluorobenzoate; TCNQ=7,7,8,8-tetracyano-p-quinodimethane; DCE=1,2-dichloroethane) and their DCE-free series, in which [MCp*₂]⁺ (Cp*=η⁵-C₅Me₅) species with S=0, 1/2, and 3/2 for M=Co, Fe, Cr, respectively, are sandwiched between ferrimagnetic layers of [{Ru₂}₂(TCNQ)]⁻, is demonstrated. The results showed that the flexible magnetic natures of these magnets are changeable in dependence on J_NNI and J_NNNI, as well as on interlayer inserted spins M.  相似文献   

    

Zhujun Zhang  Dr. Hiroki Nagashima  Prof. Takashi Tachikawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(23):9132-9139

Significant charge recombination that is difficult to suppress limits the practical applications of hematite (α-Fe₂O₃) for photoelectrochemical water splitting. In this study, Ti-modified hematite mesocrystal superstructures assembled from highly oriented tiny nanoparticle (NP) subunits with sizes of ca. 5 nm were developed to achieve the highest photocurrent density (4.3 mA cm⁻² at 1.23 V vs. RHE) ever reported for hematite-based photoanodes under back illumination. Owing to rich interfacial oxygen vacancies yielding an exceedingly high carrier density of 4.1×10²¹ cm⁻³ for super bulk conductivity in the electrode and a large proportion of ultra-narrow depletion layers (<1 nm) inside the mesoporous film for significantly improved hole collection efficiency, a boosting of multihole water oxidation with very low activation energy (E_a=44 meV) was realized.  相似文献   

    

Cecilia Cerretani  Hiroki Kanazawa  Tom Vosch  Jiro Kondo 《Angewandte Chemie (International ed. in English)》2019,58(48):17481-17481

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