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71.
Kentaro Iwasa 《Journal of organometallic chemistry》2009,694(23):3775-8128
Treatment of [Cp′MH(CO)3] (M = Mo, W; Cp′ = η5-C5H5 (Cp), η5-C5Me5 (Cp*)) with 1/8 equiv of S8 in THF, followed by the reaction with dppe under UV irradiation, gave new mono(hydrosulfido) complexes [Cp′M(SH)(CO)(dppe)] (Cp′ = Cp: M = Mo (5), W (6); Cp′ = Cp*: M = Mo (7), W (8); dppe = Ph2PCH2CH2PPh2). When 5 and 6 dissolved in THF were allowed to react with [RhCl(PPh3)3] in the presence of base, heterodinuclear complexes with bridging S and dppe ligands [CpM(CO)(μ-S)(μ-dppe)Rh(PPh3)] (M = Mo (9), W(10)) were obtained. Semi-bridging feature of the CO ligands were also demonstrated. Upon standing in CH2Cl2 solutions, 9 and 10 were converted further to the dimerization products [(CpM)2{Rh(dppe)}2(μ2-CO)2(μ3-S)2] (M = Mo (13), W). Detailed structures of mononuclear 7 and 8, dinuclear 9 and tetranuclear 13 have been determined by the X-ray diffraction. 相似文献
72.
Yamamoto C Nishikawa H Nihei M Shiga T Hedo M Uwatoko Y Sawa H Kitagawa H Taguchi Y Iwasa Y Oshio H 《Inorganic chemistry》2006,45(25):10270-10276
Reactions of K1.62[Pt(ox)2].2H2O and [Cu(bpy)(H2O)3](NO3)2 yielded partially oxidized one-dimensional (1D) bis(oxalato)platinates of [Cu(bpy)(H2O)n]6[Pt(ox)2]7.7H2O (n = 2, 3, or 4) (1) and [Cu(bpy)(H2O)n]8[Pt(ox)2]10.8H2O (n = 3 or 4) (2). The average oxidation numbers of the platinum ions in 1 and 2 are +2.29 and +2.40, respectively. Complexes 1 and 2 crystallize in the triclinic P and monoclinic C2/c space groups, respectively, and the [Pt(ox)2]n- anions are stacked along the crystallographic b axis with 7-fold periodicity for 1 and 10-fold periodicity for 2. In 1, an oxalato ligand in the platinum chain directly coordinates to a paramagnetic [Cu(bpy)(H2O)3]2+ ion, whereas no such direct coordination was observed for 2. The electrical conductivity of 2 at room temperature along the platinum chain is approximately 3 orders of magnitude smaller (sigma||= 1.3 x 10(-3) S cm(-1)) than that of 1 (sigma|| = 0.9-0.5 S cm(-1)), and the activation energies of 1 and 2 are 29 and 67 meV, respectively. The longest inter-platinum distances in 1 and 2 are 2.762 and 3.0082 A, respectively, and this is responsible for the lower electrical conductivity of 2. An X-ray oscillation photograph taken along the b axis of 1 reveals the 7-fold periodicity in the 1D chain, consistent with the period of the Peierls distortion estimated from the degree of partial oxidation. The semiconducting state of 1 can therefore be regarded as a commensurate Peierls state. The magnetoresistance of 1 at ambient pressure indicates no interaction between conduction electrons in the platinum chain and local spins of the paramagnetic CuII ions. Application of hydrostatic pressures of up to 3 GPa enhances electrical conduction, as is often seen as the usual pressure effect on the electrical conductivity, which is due to enhanced orbital (Pt-5dz2) overlap by pressure application. 相似文献
73.
Inokuchi E Narumi T Niida A Kobayashi K Tomita K Oishi S Ohno H Fujii N 《The Journal of organic chemistry》2008,73(10):3942-3945
A novel stereoselective synthetic approach to (Z)-trifluoromethylalkene dipeptide isosteres (CF(3)-ADIs) is described. Starting from readily available N-Boc-L-phenylalanine, Phe-Gly type CF(3)-ADIs were obtained through palladium-catalyzed carbonylation of allylic carbonates under CO. While the reaction of N-Boc derivatives proceeds in excellent yields but lower stereoselectivity (E: Z = 62:38-43:57), the reaction of the N, N-diBoc derivative exclusively affords the desired (Z)-isomer in 61% yield. We also present a highly stereoselective synthesis of several Phe-Gly type trisubstituted alkene dipeptide isosteres by palladium-catalyzed carbonylation. 相似文献
74.
Toshio Morikawa Xuezheng Li Eriko Nishida Seikou Nakamura Kiyofumi Ninomiya Hisashi Matsuda Yoshimi Oda Osamu Muraoka Masayuki Yoshikawa 《Helvetica chimica acta》2010,93(3):573-586
The MeOH extract from the flowers of Bellis perennis was found to show pancreatic‐lipase inhibitory activity (IC50 455 μg/ml). From the extract, seven new triterpene saponins named perennisaponins G ( 1 ; IC50 163 μM ), H ( 2 ; 137 μM ), I ( 3 ; 147 μM ), J ( 4 ; 148 μM ), K ( 5 ; 223 μM ), L ( 6 ; 81.4 μM ), and M ( 7 ; 195 μM ) were isolated as pancreatic lipase inhibitors. The stereostructures of 1 – 7 were elucidated on the basis of chemical and spectroscopic evidence. 相似文献
75.
Koichi Machida Megumi Yamauchi Eriko Kurashina Masao Kikuchi 《Helvetica chimica acta》2010,93(11):2164-2175
Four new tetrahydrofuranoid lignan glycosides, (7S,8R,7′R,8′S)‐4,9,4′,7′‐tetrahydroxy‐3,3′‐dimethoxy‐7,9′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 2 ), (7R,8S,7′S,8′R)‐4,9,4′,7′‐tetrahydroxy‐3,3′‐dimethoxy‐7,9′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 3 ), (7R,8S,7′R,8′S)‐4,9,4′,9′‐tetrahydroxy‐3,3′‐dimethoxy‐7,7′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 4 ), and rel‐(7R,8S,7′S,8′R)‐4,9,4′,9′‐tetrahydroxy‐3,3′‐dimethoxy‐7,7′‐epoxylignan 9‐O‐β‐D ‐glucopyranoside ( 5 ), and ten known lignan glycosides, 1 and 6 – 14 , were isolated from the leaves of Osmanthus fragrans Lour. var. aurantiacus Makino . Their structures were established on the basis of spectral and chemical studies. 相似文献
76.
Shin-ichiro Fujita Nobuhiro Iwasa Hiroaki Tani Wataru Nomura Masahiko Arai Nobutsune Takezawa 《Reaction Kinetics and Catalysis Letters》2001,73(2):367-372
For the title reaction, Cu/ZnO catalysts prepared from aurichalcite were more active than those prepared from other precursors.
Selectivity to ethyl acetate over Cu/ZnO was much higher than that over Cu/SiO2
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
77.
78.
Yoshiumi Kohno Eriko Haga Keiko Yoda Masashi Shibata Choji Fukuhara Yasumasa Tomita Yasuhisa Maeda Kenkichiro Kobayashi 《Journal of Physics and Chemistry of Solids》2014
Because of its non-toxicity, naturally occurring anthocyanin is potentially suitable as a colorant for foods and cosmetics. To the wider use of the anthocyanin, the immobilization on the inorganic host for an easy handling as well as the improvement of the stability is required. This study is focused on the adsorption of significant amount of the natural anthocyanin dye onto mesoporous silica, and on the stability enhancement of the anthocyanin by the complexation. The anthocyanin has successfully been adsorbed on the HMS type mesoporous silica containing small amount of aluminum. The amount of the adsorbed anthocyanin has been increased by modifying the pore wall with n-propyl group to make the silica surface hydrophobic. The light fastness of the adsorbed anthocyanin has been improved by making the composite with the HMS samples containing aluminum, although the degree of the improvement is not so large. It has been proposed that incorporation of the anthocyanin molecule deep inside the mesopore is required for the further enhancement of the stability. 相似文献
79.
Ayumi Takizawa Eriko Doi Akio Murai Hidetoshi Kawai Takanori Suzuki 《Tetrahedron》2006,62(31):7408-7435
Convergent synthesis of the common FGHI-ring part (54) of ciguatoxins was achieved via the following key steps: (i) the Nozaki-Hiyama-Kishi reaction connecting the F-ring part (6) with the I-ring part (7); (ii) regio- and stereoselective epoxidation; (iii) the 6-exo-epoxide opening reaction forming simultaneously the H-ring and the quaternary asymmetric center at C30; (iv) inversion of the C29 stereocenter by a two-step oxidation/reduction process, where the successful inversion depended on proper management of the steric environment of the substrate; and (v) final reductive cyclization constructing the G-ring. 相似文献
80.
Manabu Iwasa 《Annals of the Institute of Statistical Mathematics》1991,43(4):657-665
This paper discusses -admissiblility and d-admissiblity which are important concepts in studying the performance of statistical tests for composite hypotheses. A sufficient condition for -admissibility is presented. When =1/m, the Nomakuchi-Sakata test, which is uniformly more powerful than the likelihood ratio test for hypotheses min (1, 1) = 0 versus min (1, 1) > 0, is generalized for a class of distributions in an exponential family, and its unbiasedness and -admissibility are shown. Finally, the case of 1/m is discussed in brief. 相似文献