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1.
Feng Cheng Shuqi Wu Wenwei Zheng Shengqun Su Takumi Nakanishi Wenhuang Xu Pritam Sadhukhan Hibiki Sejima Shimon Ikenaga Kaoru Yamamoto Kaige Gao Shinji Kanegawa Prof. Osamu Sato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(59):e202202161
The crystallization of a complex having electron transfer properties in a polar space group can induce the polarization switching of a crystal in a specific direction, which is attractive for the development of sensors, memory devices, and capacitors. Unfortunately, the probability of crystallization in a polar space group is usually low. Noticing that enantiopure compounds crystallize in Sohncke space groups, this paper reports a strategy for the molecular design of non-ferroelectric polarization switching crystals based on the use of intramolecular electron transfer and chirality. In addition, this paper describes the synthesis of a mononuclear valence tautomeric (VT) cobalt complex bearing an enantiopure ligand. The introduction of enantiomer enables the crystallization of the complex in the polar space group (P21). The polarization of the crystals along the b-axis direction is not canceled out and the VT transition is accompanied by a change in the macroscopic polarization of the polar crystal. Polarization switching via electron transfer is realized at around room temperature. 相似文献
2.
In situ chemically cross‐linkable hydrogels composed of hexyl group–modified Alaska pollock–derived gelatin (C6‐ApGltn) and poly(ethylene glycol)‐based four‐armed cross‐linker is developed. Water droplets are quickly absorbed into the C6‐ApGltn hydrogel in the first 10 s compared with original ApGltn (Org‐ApGltn), and the final contact angle on C6‐ApGltn is significantly lower than that on Org‐ApGltn. Using a fluorescent probe, an increase in fluorescence intensity on C6‐ApGltn compared to that on Org‐ApGltn is found, indicating the formation of a hydrophobic pocket. Moreover, the promotion of cell migration into the C6‐ApGltn hydrogel is observed in vitro and in vivo compared with Org‐ApGltn hydrogel, despite no significant difference in elastic modulus. Therefore, the C6‐ApGltn hydrogel could potentially be used as a supporting material for cell transplantation and tissue/organ engineering. 相似文献
3.
Kentarou Sakamoto Dr. Misao Akishiba Takahiro Iwata Dr. Kazuya Murata Dr. Seiya Mizuno Dr. Kenichi Kawano Dr. Miki Imanishi Prof. Dr. Fumihiro Sugiyama Prof. Dr. Shiroh Futaki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20165-20173
Endocytic pathways are practical routes for the intracellular delivery of biomacromolecules. Along with this, effective strategies for endosomal cargo release into the cytosol are desired to achieve successful delivery. Focusing on compositional differences between the cell and endosomal membranes and the pH decrease within endosomes, we designed the lipid-sensitive and pH-responsive endosome-lytic peptide HAad. This peptide contains aminoadipic acid (Aad) residues, which serve as a safety catch for preferential permeabilization of endosomal membranes over cell membranes, and His-to-Ala substitutions enhance the endosomolytic activity. The ability of HAad to destabilize endosomal membranes was supported by model studies using large unilamellar vesicles (LUVs) and by increased intracellular delivery of biomacromolecules (including antibodies) into live cells. Cerebral ventricle injection of Cre recombinase with HAad led to Cre/loxP recombination in a mouse model, thus demonstrating potential applicability of HAad in vivo. 相似文献
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Prof. Shinji Toyota Dr. Eiji Tsurumaki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(28):6878-6890
Saturn-like systems consisting of nanoscale rings and spheres are fascinating motifs in supramolecular chemistry. Several ring molecules are known to include spherical molecules at the center of the cavity via noncovalent attractive interactions. In this Minireview, we generalize the molecular design, the structural features, and the supramolecular chemistry of such “nano-Saturns”, which consist of monocyclic rings and fullerene spheres (mainly C60), on the basis of previous experimental and theoretical studies. Ring molecules are classified into three types (loop, belt, and disk) according to their shapes and possible interactions. Whereas typical belt-shaped rings tend to form tight complexes due to the wide contact area via π–π interactions, flat disk-shaped rings generally form weak complexes due to the narrow contact area mainly via CH–π interactions. In spite of the small association energies, disk-shaped rings are attractive because such rings can mimic the planet Saturn precisely as exemplified by an anthracene cyclic hexamer–C60 complex. 相似文献
7.
Hirao Shigekazu Kakiuchi Hideki Akata Naofumi Tamari Toshiya Sugihara Shinji Shima Nagayoshi Yokoyama Sumi Tanaka Masahiro 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(7):3077-3083
Journal of Radioanalytical and Nuclear Chemistry - This paper discusses the spatiotemporal variation in atmospheric tritiated water (HTO) concentration near the Fukushima Daiichi Nuclear Power... 相似文献
8.
Salt‐Free Reduction of Nonprecious Transition‐Metal Compounds: Generation of Amorphous Ni Nanoparticles for Catalytic C–C Bond Formation 下载免费PDF全文
Dr. Taiga Yurino Yohei Ueda Dr. Yoshiki Shimizu Dr. Shinji Tanaka Haruka Nishiyama Prof. Dr. Hayato Tsurugi Prof. Dr. Kazuhiko Sato Prof. Dr. Kazushi Mashima 《Angewandte Chemie (International ed. in English)》2015,54(48):14437-14441
A salt‐free procedure for the generation of a wide variety of metal(0) particles, including Fe, Co, Ni, and Cu, was achieved using 2,3,5,6‐tetramethyl‐1,4‐bis(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene ( 1 ), which reduced the corresponding metal precursors under mild conditions. Notably, Ni particles formed in situ from the treatment of Ni(acac)2 (acac=acetylacetonate) with 1 in toluene exhibited significant catalytic activity for reductive C? C bond‐forming reactions of aryl halides in the presence of excess amounts of 1 . By examination of high‐magnification transmission electron microscopy images and electron diffraction patterns, we concluded that amorphous Ni nanoparticles (Ni aNPs) were essential for the high catalytic activity. 相似文献
9.
Prof. Dr. Mingoo Jin Satsuki Matsuura Hikaru Yamamoto Prof. Dr. Motohiro Mizuno Prof. Dr. Hajime Ito 《European journal of organic chemistry》2023,26(12):e202201468
We report multidynamic molecular rotations in crystals using a concave-shape N-heterocyclic carbene (NHC) binuclear Au(I) complex rotor bearing pyrazine and tetrahydrofuran (THF) molecules as multicomponent rotators. Single-crystal X-ray diffraction (XRD) measurements revealed that two THF molecules are located near the central pyrazine encapsulated by two bulky NHC ligands. From 2H solid-state NMR analysis, it was observed that the pyrazine rotated in a 2-fold site exchange with a 180° rotational angle and a 31 kJ mol−1 energy barrier, while the THF molecules showed a 23°-38° libration with a lower energy barrier (14 kJ mol−1). Interestingly, the pyrazine rotation was accelerated when the THF molecules rotated in fast site exchange with a large angle of libration, suggesting that the rotators exhibit multidynamics in a correlated manner. 相似文献
10.
Takahiro Takayama Toshiki Mochizuki Kenichiro Todoroki Jun Zhe Min Hajime Mizuno Koichi Inoue Hiroyasu Akatsu Ichiro Noge Toshimasa Toyo'oka 《Analytica chimica acta》2015
Chiral metabolites are found in a wide variety of living organisms and some of them are understood to be physiologically active compounds and biomarkers. However, the overall analysis of chiral metabolomics is quite difficult due to the high number of metabolites, the significant diversity in their physicochemical properties, and concentration range from metabolite-to-metabolite. To solve this difficulty, we developed a novel approach for chiral metabolomics fingerprinting and chiral metabolomics extraction, which is based on the labeling of a pair of enantiomers of chiral derivatization reagents (i.e., DMT-(S,R)-Pro-OSu and DMT-3(S,R)-Apy) and precursor ion scan chromatography of the derivatives. The multivariate statistics is also required for this strategy. The proposed procedures were evaluated by the detection of a diagnostic marker (i.e., d-lactic acid) using the saliva of diabetic patients. This method was used for the determination of biomarker candidates of chiral amines and carboxyls in Alzheimer's disease (AD) brain homogenates. As the results, l-phenylalanine (L-Phe) and l-lactic acid (L-LA) were identified as the decreased and increased biomarker candidates in the AD brain, respectively. Therefore, the proposed approach seems to be helpful for the determination of non-target chiral metabolomics possessing amines and carboxyls. 相似文献