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341.
Let Ek(z) be the Eisenstein series with weight k for the modulargroup SL(2, ). We prove that the zeros of Ek(ei) interlace withthe zeros of Ek+12(ei) on /2 < < 2/3. That is, any zeroof Ek(ei) lies between two consecutive zeros of Ek+12(ei) on/2 < < 2/3. 相似文献
342.
Hiroshi Nozaki Ken-ichiro Hayashi Kazuyuki Kakumoto Nobuyasu Matsuura Daisuke Takaoka Yukihiro Akao 《Tetrahedron letters》2007,48(47):8290-8292
Pauferrol A (1), a unique chalcone derivative was isolated from the stems of Caesalpinia ferrea Mart, and the structure was determined on the basis of 2D-NMR spectroscopy to be a chalcone trimer fused by a cyclobutane ring. This new chalcone trimer showed potent inhibitory activity against human topoisomerase II, with an IC50 value of 2.1 μM, and cell proliferation inhibitory activity through the induction of apoptosis in human leukemia HL60 cells, with an IC50 value of 5.2 μM. To our knowledge, this is the first report of the isolation and structure of this chalcone trimer and its biological activity. 相似文献
343.
344.
The reactions of zinc(II) acetate with a variety of 2-substituted benzothiazolines afforded tetrahedral mononuclear complexes with a N 2S 2 donor set, [Zn(RPhC(H) NC 6H 4 S) 2]. The obtained zinc(II) complexes can be divided into three groups based on the characteristics of the absorption spectra; Group 1 (R = 2,4,6-triMe ( 1), 2,6-diCl ( 2)) showing an intense band at 250-300 nm and a weak band at 400-450 nm, Group 2 (R = 4-Cl ( 3), H ( 4), 4-Et ( 5), 4-OMe ( 6)) showing two intense bands at 250-300 nm and a weak band at 400-450 nm, and Group 3 (R = 4-NMe 2 ( 7), 4-NEt 2 ( 8)) showing an intense band at 250-300 nm and two very intense bands at 350-450 nm. The Group 2 and Group 3 complexes exhibited a strong emission on irradiating with ultraviolet light while the Group 1 complexes were not emissive at room temperature. However, all the zinc(II) complexes were luminescent in CH 2Cl 2/toluene glass at 77 K, and their emission peak energies were found to correlate with the Hammett constant of the substituent at para position of a pendent phenyl ring in each complex. Similar reactions of cadmium(II) acetate with 2-substituted benzothiazolines were also carried out to synthesize corresponding cadmium(II) complexes. While [Cd(RPhC(H) NC 6H 4 S) 2] (R = 2,4,6-triMe ( 9)) with bulky substituents at ortho positions of a pendent phenyl ring had a tetrahedral mononuclear structure, other cadmium(II) complexes [Cd 2(RPhC(H) NC 6H 4 S) 4] (R = 4-Et ( 10), 4-OMe ( 11), 4-NMe 2 ( 12)) possessed S-bridged dinuclear structures. These cadmium(II) complexes, which are assumed to have a mononuclear structure in solution, showed photophysical properties similar to those of the corresponding zinc(II) complexes. 相似文献
345.
Nakamura A Munakata K Kochi T Nozaki K 《Journal of the American Chemical Society》2008,130(26):8128-8129
An alternating copolymer of methyl acrylate with carbon monoxide has been synthesized for the first time via coordination polymerization using palladium complexes of phosphine-sulfonic acid as catalysts. The highly controlled head-to-tail structure of the copolymer was confirmed by NMR spectra. Subsequent insertion of carbon monoxide and methyl acrylate to methylpalladium species provided gamma-ketoalkylpalladium 2. The present system apparently conquered the difficulty in coordination-insertion of CO to 2. 相似文献
346.
Kitamura Y Mori K Yamamoto M Nozaki A Saito M Tsukamoto I Mifune M Saito Y 《Chemical & pharmaceutical bulletin》2008,56(9):1364-1366
In order to explore the capability of metal porphyrins as an alternative of horseradish peroxidase (HRP), HRP-like activity of three manganese-porphyrins (Mn-Ps) and three Mn-octabromo-porphyrins (Mn-OBPs) was examined in both aqueous and immobilized states. It was found that Mn(3+)-octabromotetrakis(1-methyl-pyridinium-4yl)porphine (Mn-OBTMPyP) has an activity of at least 90% of HRP in an aqueous solution. Mn-OBTMPyP exhibited a catalytic activity even in the presence of hydrogen peroxide without suicide reaction. In addition, Mn-OBTMPyP was revealed to function as an alternative to HRP in the quantitative determination of serum uric acid. These results are of great interest because they indicate that metal-octabromo-porphyrins possibly include promising candidates of artificial enzyme capable of substituting for HRP. 相似文献
347.
348.
Dr. Shuhei Kusumoto Toshiumi Tatsuki Prof. Dr. Kyoko Nozaki 《Angewandte Chemie (International ed. in English)》2015,54(29):8458-8461
Hydroformylation, a reaction that adds carbon monoxide and dihydrogen across an unsaturated carbon–carbon multiple bond, has been widely employed in the chemical industry since its discovery in 1938. In contrast, the reverse reaction, retro‐hydroformylation, has seldom been studied. The retro‐hydroformylation reaction of an aldehyde into an alkene and synthesis gas (a mixture of carbon monoxide and dihydrogen) in the presence of a cyclopentadienyl iridium catalyst is now reported. Aliphatic aldehydes were converted into the corresponding alkenes in up to 91 % yield with concomitant release of carbon monoxide and dihydrogen. Mechanistic control experiments indicated that the reaction proceeds by retro‐hydroformylation and not by a sequential decarbonylation–dehydrogenation or dehydrogenation–decarbonylation process. 相似文献
349.
Nozaki and Taya (ASME J. Appl. Mech. 64 (1997) 495–502) analyzed the elastic field in a convex polygonal inclusion in an infinite body. By numerical analysis, they
found that, when the shape of the inclusion is a regular polygon, “the strain at the center of inclusion” and “the strain
energy per unit volume of inclusion” have strange and remarkable properties: these values are the same as those of a circular
inclusion and are invariant for inclusion's orientation if the shape of the inclusion is not a square. In this paper, we first derive a simple, exact expression of the Eshelby tensor for an arbitrary polygonal inclusion. Using
the expression, we then show a mathematical explanation why these special properties appear.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
350.
K Nozaki H Komaki Y Kawashima T Hiyama T Matsubara 《Journal of the American Chemical Society》2001,123(4):534-544
The regioselectivity of styrene insertion to an acyl-Pd bond was studied by NMR in (i) a stoichiomeric reaction and (ii) a copolymerization with CO. In the stoichiometric reaction of styrene with [(CH(3)CO)Pd(CH(3)CN)[(R,S)-BINAPHOS]].[B[3,5-(CF(3))(2)C(6)H(3)](4)], both 1,2- and 2,1-products were given. To mimic the real polymerization conditions, a polyketone-substituted complex [[CH(3)(CH(2)CHCH(3)CO)(n)]Pd[(R,S)-BINAPHOS]].[B(3,5-(CF(3))(2)C(6)H(3))(4)] (n approximately 14) was prepared. When this polymer-attached Pd species was treated with styrene, the 1,2-insertion product was the only detectable species. Thus, exclusive 1,2-insertion is demonstrated to be responsible for the styrene-CO copolymerization, in sharp contrast to the predominant 2,1-insertion with conventional nitrogen ligands. Chain-end analysis revealed that beta-hydride elimination took place from the 2,1-complex but not from the 1,2-complex. Thus, once 2,1-insertion occurs, rapid beta-hydride elimination proceeds to terminate the polymerization, as is common to the other phosphorus-ligand systems. The resulting Pd-H species re-initiates the copolymerization, as was proven by MALDI-TOF mass analysis of the product copolymers. 相似文献