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81.
Chikashi Shinagawa Yusuke Morikawa Shin-ichi Nishimura Hiroshi Ushiyama Atsuo Yamada Koichi Yamashita 《Journal of computational chemistry》2019,40(1):237-246
Na2FePO4F is a promising cathode material for a Na-ion battery because of its high electronic capacity and good cycle performance. In this work, first principle calculations combined with cluster expansion and the Monte Carlo method have been applied to analyze the charge and discharge processes of Na2FePO4F by examining the voltage curve and the phase diagram. As a result of the density functional theory calculation and experimental verification with structural analysis, we found that the most stable structure of Na1.5FePO4F has the P21/b11 space group, which has not been reported to date. The estimated voltage curve has two clear plateaus caused by the two-phase structure composed of P21/b11 Na1.5FePO4F and Pbcn Na2FePO4F or Na1FePO4F and separated along the c-axis direction. The phase diagram shows the stability of the phase-separated structure. Considering that Na2FePO4F has diffusion paths in the a- and c-axis directions, Na2FePO4F has both innerphase and interphase diffusion paths. We suggest that the stable two-phase structure and the diffusion paths to both the innerphase and interphases are a key for the very clear plateau. We challenge to simulate a nonequilibrium state at high rate discharge with high temperature by introducing a coordinate-dependent chemical potential. The simulation shows agreement with the experimental discharge curve on the disappearance of the two plateaus. © 2018 Wiley Periodicals, Inc. 相似文献
82.
Ferroelectric Coordination Polymers Self‐Assembled from Mesogenic Zinc(II) Porphyrin and Dipolar Bridging Ligands
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Dr. Joseph K.‐H. Hui Hiroyuki Kishida Keita Ishiba Kenta Takemasu Dr. Masa‐aki Morikawa Prof. Dr. Nobuo Kimizuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14213-14218
A new class of ferroelectric coordination‐based polymers has been developed by the self‐assembly of lipophilic zinc porphyrin ( ZnP ) and ditopic bridging ligands. The ligands contain dipolar benzothiadiazole or fluorobenzene units, which are axially coordinated to ZnP with the dipole moments oriented perpendicular to the coordination axes. The coordination‐based polymers show ferroelectric characteristics in the liquid crystalline state, as revealed by distinctive hysteresis in the polarization–electric field (P–E) loops and inversion current peaks in current–voltage (I–V) loops. The observed ferroelectric properties are explainable by flip–flop rotation of the dipolar axle ligands induced by the applied electric field, as demonstrated by the positive‐up–negative‐down (PUND) measurements. The present system provides a new operating principle in supramolecular ferroelectrics. 相似文献
83.
Tateki Morikawa Yusuke Uraguchi Shohei Sanda Satoshi Nakagawa Shigeki Sawayama 《Applied biochemistry and biotechnology》2018,184(1):80-91
Production of functional carotenoids using microalgae may facilitate the commercialization of anti-aging nutritional supplements. The green alga Chlamydomonas reinhardtii uses a non-mevalonate (MEP) pathway for isopentenyl diphosphate (IPP) synthesis. Two enzymes thought to play important roles in this MEP pathway to IPP synthesis are 1-deoxy-d-xylulose 5-phosphate synthase (DXS) and reductase (DXR). DnaJ-like chaperone (Orange protein) is thought to support phytoene synthase, a key enzyme in plant carotenoid synthesis. Genes for Orange (OR), DXS, and DXR were overexpressed via nuclear transformation into C. reinhardtii. CDS of OR, DXS, and DXR were amplified and connected with dual promoters of heat-shock protein 70A and ribulose bisphosphate carboxylase small chain 2. Compared with the parental strain, transformant CrOR#2 produced increased lutein and β-carotene (1.9-fold and 1.7-fold per cell, respectively). Transformant CrDXS#1 produced lutein and β-carotene at lower per-cell abundances than those for the parental strain. CrDXR#2 transformant produced lutein and β-carotene at higher per-cell abundances than their parental counterpart; however, these transformants produced lutein and β-carotene at lower per-medium abundances than their parental counterparts. These results suggest that OR protein supports phytoene synthase in C. reinhardtii and that the phytoene synthesis step is rate-limiting in carotenoid synthesis. 相似文献
84.
Masanari Kimura 《Tetrahedron letters》2018,59(14):1295-1300
β-Keto carboxylic acids are key intermediates in organic syntheses, used for the development of fine chemicals, natural products, and various biologically relevant molecules. Their utilities stem from the structural features and facile bond formations, e.g., asymmetric reduction of carbonyl groups for the synthesis of β-hydroxy carboxylic acids and conjugated addition reactions through decarboxylative enolate nucleophiles, which utilize the amphiphilic reactivity of β-keto carboxylic acids. Despite their versatility and utilities, development of efficient and straightforward synthetic methods for β-keto carboxylic acids has not attracted considerable attention owing to their instability. As efficient synthetic strategies for β-keto carboxylic acids and their derivatives, reactions of α-diazoesters, acylation of malonate anions, cross-coupling reactions, and CO2 insertion reactions are summarized in this review. 相似文献
85.
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87.
Dr. Xuelin Yao Dr. Heng Zhang Fanmiao Kong Dr. Antoine Hinaut Dr. Rémy Pawlak Prof. Dr. Masanari Okuno Dr. Robert Graf Dr. Peter N. Horton Prof. Dr. Simon J. Coles Prof. Dr. Ernst Meyer Prof. Dr. Lapo Bogani Prof. Dr. Mischa Bonn Prof. Dr. Hai I. Wang Prof. Dr. Klaus Müllen Prof. Dr. Akimitsu Narita 《Angewandte Chemie (International ed. in English)》2023,62(46):e202312610
Structurally defined graphene nanoribbons (GNRs) have emerged as promising candidates for nanoelectronic devices. Low band gap (<1 eV) GNRs are particularly important when considering the Schottky barrier in device performance. Here, we demonstrate the first solution synthesis of 8-AGNRs through a carefully designed arylated polynaphthalene precursor. The efficiency of the oxidative cyclodehydrogenation of the tailor-made polymer precursor into 8-AGNRs was validated by FT-IR, Raman, and UV/Vis-near-infrared (NIR) absorption spectroscopy, and further supported by the synthesis of naphtho[1,2,3,4-ghi]perylene derivatives ( 1 and 2 ) as subunits of 8-AGNR , with a width of 0.86 nm as suggested by the X-ray single crystal analysis. Low-temperature scanning tunneling microscopy (STM) and solid-state NMR analyses provided further structural support for 8-AGNR . The resulting 8-AGNR exhibited a remarkable NIR absorption extending up to ∼2400 nm, corresponding to an optical band gap as low as ∼0.52 eV. Moreover, optical-pump TeraHertz-probe spectroscopy revealed charge-carrier mobility in the dc limit of ∼270 cm2 V−1 s−1 for the 8-AGNR . 相似文献
88.
Morikawa T Funakoshi K Ninomiya K Yasuda D Miyagawa K Matsuda H Yoshikawa M 《Chemical & pharmaceutical bulletin》2008,56(7):956-962
The methanolic extract from the rhizomes of Boesenbergia rotunda (Zingiberaceae) was found to show inhibitory effect on tumor necrosis factor-alpha (TNF-alpha)-induced cytotoxicity in L929 cells (IC(50)=6.1 microg/ml). By bioassay-guided separation, four new prenylcalcones, (+)-krachaizin A (1a), (-)-krachaizin A (1b), (+)-krachaizin B (2a), and (-)-krachaizin B (2b), and four new prenylflavanones, rotundaflavones Ia (3a), Ib (3b), IIa (4a), and IIb (4b), were isolated together with 18 known constituents (5a-7b and 8-19). The structures of eight new compounds were elucidated on the basis of physicochemical evidence. Among them, (+)-krachaizin B (2a), (-)-krachaizin B (2b), (+)-4-hydroxypanduratin A (6a), (-)-4-hydroxypanduratin A (6b), (+)-isopanduratin A (7a), (-)-isopanduratin A (7b), alpinetin (10), cardamonin (14), and 2,6-dihydroxy-4-methoxydihydrochalcone (15) significantly inhibited TNF-alpha-induced cytotoxicity in L929 cells at 10 microM. In addition, 2a, 2b, (+)-panduratins A (5a), (-)-panduratin A (5b), 6a, 7b, and geranyl-2,4-dihydroxy-6-phenylbenzoate (17) were found to show strong inhibitory effects on aminopeptidase N activity. 相似文献
89.
Morikawa T Xie H Wang T Matsuda H Yoshikawa M 《Chemical & pharmaceutical bulletin》2008,56(10):1438-1444
From the methanolic extract of the whole plant of Sinocrassula indica (Crassulaceae), six new flavonol glycosides, sinocrassosides B(4) (1), B(5) (2), C(1) (3), D(1) (4), D(2) (5), and D(3) (6), were isolated together with 30 compounds. The structures of 1-6 were elucidated on the basis of chemical and physicochemical evidence. In addition, several constituents were found to show inhibitory effects on aminopeptidase N and aldose reductase. 相似文献
90.
Kimura M Horino Y Mori M Tamaru Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(34):9686-9702
The Calpha==Cbeta double bond of allene carbamates 1 serves as an electron acceptor similar to the double bond of conjugated enones by means of a through-space interaction with the N--SO2 bond; the carbamate double bond is thus subject to nucleophilic addition for a wide variety of nucleophiles, which proceeds under mild conditions by heating at 70-100 degrees C. Depending on the kind of nucleophiles, 1 displays three different reaction modes: 1) Typically enol ethers and allylsilanes promote 1,3-sulfonyl migration of 1 and undergo the inverse electron demand Diels-Alder reaction with the 1-aza-1,3-butadiene intermediates II thus formed to furnish bicyclic 2-alkoxy-5-sulfonyltetrahydropyridines 2 and 2-silylmethyl-5-sulfonyltetrahydropyridines 3, respectively, with high regio- and stereoselectivity and retention of configuration of the double bonds of these electron-rich alkenes; 2) silanes (RnSiH4-n, n=1-3) and thiols deliver the hydride and the thiolate at the Cbeta carbon and promote the 1,3-sulfonyl migration, followed by protonation of the thus-formed carbamate anion (Z)-III to provide, for example, (Z)-4 a and (Z)-4 j, respectively; 3) alcohols simply add to the Calpha==Cbeta double bond and provide (E)-6. Usually, the reaction with alcohols is accompanied by the second pathway, giving rise to, for example, (Z)-4 b in addition to (E)-6 b. Phenol engages in the third pathway and provides (E)-6 g exclusively. Heteroaromatics, such as furans and benzofurans follow the first pathway, however, in a different regioselectivity from enol ethers and allylsilanes, delivering the oxygen atom at the 3-position of 5-sulfonyltetrahydropyridines (2 g and 2 h). Indoles, on the other hand, show a dichotomy, equally enjoying the first and the third pathways and provide mixtures of (E)-7 and (E)-8, respectively. 相似文献