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排序方式: 共有231条查询结果,搜索用时 437 毫秒
81.
82.
Shota Ooi Takayuki Tanaka Takahisa Ikeue Kazuhisa Yamasumi Kento Ueta Daiki Shimizu Masatoshi Ishida Hiroyuki Furuta Atsuhiro Osuka 《化学:亚洲杂志》2019,14(10):1771-1776
Copper complexes of corroles have recently been a subject of keen interest due to their ligand non‐innocent character and unique redox properties. Here we investigated bis‐copper complex of a triply‐linked corrole dimer that serves as a pair of divalent metal ligands but can be reduced to a pair of trivalent metal ligands. Reaction of triply‐linked corrole dimer 2 with Cu(acac)2 (acac=acetylacetonate) gave bis‐copper(II) complex 2Cu as a highly planar molecule with a mean‐plane deviation value of 0.020 Å, where the two copper ions were revealed to be divalent by ESR, SQUID, and XPS methods. Oxidation of 2Cu with two equivalents of AgBF4 gave complex 3Cu , which was characterized as a bis‐copper(II) complex of a dicationic triply‐linked corrole dimer not as the corresponding bis‐copper(III) complex. In accord with this assignment, the structural parameters around the copper ions were revealed to be quite similar for 2Cu and 3Cu . Importantly, the magnetic spin–spin interaction differs depending on the redox‐state of the ligand, being weak ferromagnetic in 2Cu and antiferromagnetic in 3Cu . 相似文献
83.
The formation of deeply-bound antikaonic nuclear states in nuclear (K−,N) reactions is investigated theoretically within a distorted-wave impulse approximation (DWIA), considering the isospin properties of the Fermi-averaged elementary amplitudes. We calculate the formation cross sections of the deeply-bound states by the (K−,N) reactions on the nuclear targets, 12C and 28Si, at incident K− lab momentum pK−=1.0 GeV/c and θlab=0°, introducing a complex effective nucleon number Neff for unstable bound states in the DWIA. The results show that the deeply-bound states can be populated dominantly by the (K−,n) reaction via the total isoscalar ΔT=0 transition owing to the isospin nature of the amplitudes, and that the cross sections described by ReNeff and ArgNeff enable to deduce the structure of the nuclear states; the calculated inclusive nucleon spectra for a deep -nucleus potential do not show distinct peak structure in the bound region. The few-body and states formed in (K−,N) reactions on s-shell nuclear targets, 3He, 3H and 4He, are also discussed. 相似文献
84.
Dan Phuong Nguyen Se-Young O Chan-Woo Park Keesam Shin Chan-Gyu Lee Toshitada Shimozaki Takahisa Okino 《Journal of magnetism and magnetic materials》2008,320(14):e264-e267
[Fe(0.5 nm)/Pt(0.5 nm)]40, [Fe(1 nm)/Pt(1.5 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 multilayer were prepared by DC magnetron sputtering. By conventional furnace annealing (CA) at 270–600 °C for various time, all of the films still remained the disordered structure with the soft magnetic phase. By rapid thermal annealing (RTA) at 500 °C for various time, we obtained the [Fe(1 nm)/Pt(1.5 nm)]20 and [Fe(3 nm)/Pt(3 nm)]10 films with L12 ordered FePt3 phase which was almost ferromagnetic at room temperature. However, the [Fe(0.5 nm)/Pt(0.5 nm)]40 films was still disordered state even under RTA. Compared with CA, RTA exposed an outstanding effect on accelerating the phase transition when the film thickness is over [Fe(0.5 nm)/Pt(0.5 nm)]40. 相似文献
85.
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87.
The change of the carbon structure with electrochemical intercalation of lithium has been investigated by X-ray diffraction (XRD) method. Graphitized carbons showed the first and the second stage structures clearly during the intercalation process. However, the layer spacing corresponding to the 1st stage structure of graphitized carbon was smaller than that of graphite. This is because the first stage structure of graphitized carbon is the mixed structure of lithiated graphite crystallites and lithiated turbostratic disordered layers. The lithium is mainly intercalated into turbostratic disordered layers above 0.1 V versus Li/Li+, and intercalated into graphite crystallites rather than turbostratic disordered layers below 0.1 V versus Li/Li+. 相似文献
88.
Kuroyanagi M Shimomae M Nagashima Y Muto N Okuda T Kawahara N Nakane T Sano T 《Chemical & pharmaceutical bulletin》2005,53(12):1519-1523
In the course of research on the bioactive constituents of woody plants in the Cyugoku area of Japan, a methanol extract of the leaves of Alnus japonica were found to have strong antioxidative activity. Ethyl acetate soluble and n-buthanol soluble fractions of the methanol extract had a potent antioxidative effect. Both fractions were purified by silica gel column chromatography and HPLC using an ODS column to give four new diarylheptanoids along with known diarylheptanoids and flavonoids. These new compounds were elucidated to be 7-(3,4-dihydroxyphenyl)-5-hydroxy-1-(4-hydroxyphenyl)-3-heptanone-5-O-beta-D-xylopyranoside (1), 1-(3,4-dihydroxyphenyl)-5-hydroxy-7-(4-hydroxyphenyl)-3-heptanone-5-O-beta-D-xylopyranoside (2), 1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxy-3-heptanone-5-O-[2-(2-methylbutenoyl)]-beta-D-xylopyranoside (3) and 1,7-bis-(3,4-dihydroxyphenyl)-5-methoxy-3-heptanone (4) using spectral methods and especially 1H-, 13C-NMR and 2D-NMR measurements. The isolated compounds including their main constituent, oregonin (5), were tested for antioxidative activity. Some of these compounds having two catechol structures showed potent antioxidative activity. Compounds having one catechol structure showed moderate antioxidative activity, but a peracetate of 5 having no catechol structure exhibited no antioxidative activity. Thus the catechol structure of the diarylheptanoids is indispensable for antioxidative activity. 相似文献
89.
Kim TH Ito H Hayashi K Hasegawa T Machiguchi T Yoshida T 《Chemical & pharmaceutical bulletin》2005,53(6):641-644
A phytochemical investigation of the polar constituents in the heartwood of Indian Santalum album L. resulted in the isolation of three new neolignans (1-3) and a new aromatic ester (4), along with 14 known components. The structures of the new compounds (1-4) were established using spectroscopic methods. 相似文献
90.
Cationic polymeric flocculants in water are determined spectrophotometrically with the anionic compound 3-(2-hydroxy-3-carboxyanilide-1-azonaphthalene)-4-hydroxybenzenesulfonic acid at pH 10 by flow injection analysis. The calibration graph at 680 nm is rectilinear from 0 to 20 mg l?1 under optimal conditions. The relative standard deviation for 20 injections of Cat-Floc (10 mg l?1) was 1.2%; the sample throughput was 60 h?1. 相似文献