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121.
Matsuda Y Hoki K Maeda S Hanaue K Ohta K Morokuma K Mikami N Fujii A 《Physical chemistry chemical physics : PCCP》2012,14(2):712-719
Ionization dynamics of acetone and its dimer in supersonic jets is investigated by a combination of experimental and theoretical techniques, both of which have recently been developed. In experiments, the neutral and the cationic structures are explored by infrared predissociation spectroscopy with the vacuum-ultraviolet photoionization detection schemes. Reaction paths following the one-photon ionization of the acetone monomer and its dimer have been studied by the joint use of several theoretical methods including the ab initio molecular dynamics, the global reaction route mapping, the intrinsic reaction coordinate, and the artificial force induced reaction calculations. Upon one-photon ionization, the dimer isomerizes to the H-bonded form, in which the enol cation of acetone is bound to the neutral molecule, while this enolization is energetically forbidden in the acetone monomer. The enolization of the dimer cation occurs through a two-step proton-transfer from the methyl group of the ionized moiety, and is catalyzed by the neutral moiety within the dimer cation. 相似文献
122.
Isao Kagomiya Yusuke Hayashi Ken-ichi Kakimoto Kazuyoshi Kobayashi 《Journal of magnetism and magnetic materials》2012
The particulate and the multilayer CoFe2O4(CFO)–BaTiO3(BT) composites were prepared by the conventional solid state reaction method and the tape casting method, respectively. Both the prepared composites were simultaneously ferroelectric and ferromagnetic at room temperature. For the multilayer composite sample, a piezoelectric resonance frequency remarkably depended on the applied DC magnetic field, while no remarkable magnetic field dependence was observed for the particulate composite samples. An uniform magnetostriction of the CFO phase in the multilayer composite contributes to piezoelectric effect of the BT phases, resulting in the modulation of the piezoelectric resonance frequency. 相似文献
123.
9,10-Dicyanoanthracene-sensitized photo-oxygenation of 2,2-diaryl-3-(2,2-diarylvinyl)oxiranes 3 in acetonitrile did not afford the corresponding 1,2,4-trioxepines 4, but 1,2,4-trioxolanes 7. The structural assignment of 7 was reported, and the mechanism of the formation of 7 was proposed. 相似文献
124.
A nonlinear iterative learning algorithm is proposed to make a voltage waveform in the secondary coil sinusoidal in this paper. The algorithm employs a globally convergent Jacobian-free quasi-Newton type solver that has a BFGS-like structure. This method functions well, and it is demonstrated using typical soft magnetic materials. 相似文献
125.
Ken-ichi Iwamoto Masako Hamaya Naoki Hashimoto Hitomi Kimura Yumiko Suzuki Masayuki Sato 《Tetrahedron letters》2006,47(40):7175-7177
Benzoin reactions are catalyzed by N,N-dialkylbenzimidazole to yield α-hydroxy ketones; the reaction proceeds in water as an aqueous medium under mild conditions. The utility of these salts as pre-catalysts in these reactions has been demonstrated. 相似文献
126.
Kazunobu Toshima Ken-ichi Kasumi Kanako Kawahara Shuichi Matsumura 《Tetrahedron》2004,60(25):5331-5339
Novel α- and β-stereocontrolled glycosidations using a heterogeneous solid acid, sulfated zirconia (SO4/ZrO2), as an activator have been developed. The glycosidations of manno- and 2-deoxyglucopyranosyl α-fluorides with several alcohols using SO4/ZrO2 in MeCN proceeded α-stereoselectively, while those with the same activator in the presence of MS 5A in Et2O occurred with β-stereoselectivity. Thus, both the α- and β-manno- and 2-deoxyglucopyranosides were effectively obtained by the present glycosidations. 相似文献
127.
The adsorbed state of nitrogen on Ru catalysts was studied by a TPD technique combined with an isotopic technique. (1) A molecular and an atomic species on Ru powder, (2) a molecular and three atomic species on Raney-Ru, and (3) two molecular and probably three atomic species on Raney-Ru/K were identified, respectively. Relations between the adsorbed states and those reactivities for an isotopic equilibration reaction of N2 were discussed. 相似文献
128.
Toshiki Aoki Tomoyuki Fukuda Ken-ichi Shinohara Takashi Kaneko Masahiro Teraguchi Masayuki Yagi 《Journal of polymer science. Part A, Polymer chemistry》2004,42(18):4502-4517
To develop better polymeric materials for optical-resolution membranes, we synthesized nine chiral phenylacetylenes containing pinanyl groups. We used them to investigate the effects of chemical structures, including the number and position of the chiral groups in the monomers, on the induction of chirality in the main chain during polymerization and on the degree of enantioselectivity in the permeation of the polymeric membranes. The monomers included six new chiral p-(oligomethylpinanylsiloxanyl)phenylacetylenes. The homopolymerizations of these nine monomers with a Rh complex produced high-molecular-weight polymers (molecular weight = 105–106). Of the five polymers with a chiral pinanyl group at the 1-position of each oligosiloxanyl group, all except for two polymers showed high molar ellipticity in the main-chain region in the circular dichroism spectra. This finding indicated that these polymers had a chiral helical main chain. The membranes fabricated from all the polymers synthesized in this study were high-quality, except for two polymers. All these membranes showed enantioselective permeabilities for two amino acids and an alcohol. The membranes from the polymers with a chiral helical backbone, a high content of pinanyl groups, no oligodimethylsiloxane moieties, or a combination of these showed good enantioselectivities (= 1.7–640) in permeation. We propose that the sense of the main-chain helicity determined the selectivity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4502–4517, 2004 相似文献
129.
Sulfonic acid group-functionalized amorphous silica acts as a highly effective and reusable catalyst for acetalization of various carbonyl compounds with methanol and tetrahydropyranylation of alcohols. 相似文献
130.
Ken-ichi Yamada 《Tetrahedron letters》2004,45(35):6595-6597
Cycloalkyl radicals were directly generated from cycloalkanes via C-H bond cleavage by the action of dimethylzinc-air and underwent an addition reaction with N-tosylimines, giving aminoalkylation products in fair to high yields. 相似文献