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951.
Hiroshi Tatewaki Kiyoshi Tanaka Fukashi Sasaki Shigeru Obara Kimio Ohno Megumu Yoshimine 《International journal of quantum chemistry》1979,15(5):533-545
Configuration-interaction calculations, with an extended basis, are carried out on the ground and lower excited states of O2 and O2+ at and near the equilibrium internuclear distance (R = 2.3 a.u.) of the ground state of O2. Particular attention has been paid to the two lowest 3Σu? states, and the mixing of the valence and Rydberg characters in these states are studied. The lowest 3Σu? state is a Rydberg-type state for R < 2.3 a.u., but becomes valence-type for R ? 2.3 a.u. The second 3Σu? state, which is 1.6 eV above the lowest 3Σu? at R = 2.3 a.u., changes its character from Rydberg to valence, valence to Rydberg, and then to valence again when R increases from 1.9 to 3.1 a.u. Satisfactory agreement between the calculated and experimental vertical excitation energies is obtained. 相似文献
952.
T. Ichino S. Sasaki T. Matsuura S. Nishi 《Journal of polymer science. Part A, Polymer chemistry》1990,28(2):323-331
A series of new polyimides containing fluorinated alkoxy side chains are prepared from novel fluorinated alkoxy diamines. The dieletric constant at 1 kHz in the fluorinated polyimides decreases from 3.3 to 2.6 as fluorine content increases. The refractive index also changes from 1.58 to 1.48, dependent on the fluorine content. In addition, the fluorinated polyimides exhibit lower water absorption than the reference polyimides prepared from m-phenylenediamine. 相似文献
953.
Masayuki Kato Hiroyuki Nishide Eishun Tsuchida Takashi Sasaki 《Journal of polymer science. Part A, Polymer chemistry》1981,19(7):1803-1809
Poly(1-vinylimidazole) (PVI) resin was prepared with Ni2+, Co2+, or Zn2+ as a template to study the adsorption of metal ions. The metal-1-vinylimidazole complex was copolymerized and crosslinked with 1-vinyl-2-pyrrolidone by γ-ray irradiation and the template metal ion was removed by treating the polymer complex with an acid. These PVI resins adsorbed metal ions more effectively than the PVI resin prepared without the template. The number of adsorption sites (As) and the stability constant (K) of Ni2+ complex were larger for the PVI resin prepared with the Ni ion template, caused by the smaller dissociation rate constant of Ni ion from the resin. The composition of the Ni2+ complex in the resin remained constant. This suggests that the complexation proceeded via a one-step mechanism. 相似文献
954.
Hiroshi Nishihara Munehisa Fujita Hirofumi Takahashi Taro Saito Yukiyoshi Sasaki 《Transition Metal Chemistry》1980,5(1):98-101
Summary Cocondensation of buta-1,3-diene with cobalt vapor followed by addition of triethylphosphine gave a new complexsyn-Co(C4H7)(C4H6)(PEt3) (1) in 43% yield. The reaction pathway leading to (1) was investigated by matrix isolation i.r. spectroscopy. The monodentate butadiene, which was found as a reaction intermediate in the –196 toca. 0° temperature range, rearranges into a -butenyl or bidentate butadiene. The reaction of (1) with bromoethane gave cycloocta-1,5-diene and 4-vinylcyclohex-1-ene in quantitative yield. Complex (1) catalyzes the cyclotrimerization of phenylacetylene to 1,3,5-triphenylbenzene. 相似文献
955.
Summary A highly sensitive and selective Spectrophotometric method has been developed for the determination of yttrium in aluminium base alloys. The method is based on the red water-insoluble complex formed when yttrium and 1-[(5-methyl-2-pyridyl)azo]-2-naphthol (5-Me--PAN) react in a pH 9.5–11.2 solution. This complex could be extracted into ether (absorption maximum, 530 nm). Beer's law is obeyed up to 1 p. p. m. of yttrium and the molar absorptivity is 6.4 · 104 l · mole–1 · cm–1 at 530 nm.
Zusammenfassung Eine hochempfindliche und selektive spektrophotometrische Methode zur Bestimmung von Yttrium in Aluminiumlegierungen wurde ausgearbeitet. Sie beruht auf der Bildung der roten, wasserlöslichen Komplexverbindung des Yttriums mit 1-[(5-Methyl-2-pyridyl)azo]-2-naphthol(5-Me--PAN) bei pH 9,5–11,2. Diese Verbindung läßt sich mit Äther extrahieren und hat ein Absorptionsmaximum bei 530 nm. Das Beersche Gesetz ist bis zu 1 ppm Yttrium erfüllt. Die molare Extinktion beträgt 6,4 · 104 1 · Mol–1 cm–1 bei 530 nm.相似文献
956.
Kaname Sasaki 《Tetrahedron letters》2006,47(51):9039-9043
A novel class of ‘armed’ glycosyl donors containing a double bond at the C-2 position was designed by mimicking the mechanism of lysozyme-initiated hydrolysis. These donors were used to achieve chemoselective glycosidation of hex-2-enopyranosyl acetate and hexopyranosyl acetate, and synthesis of O-glycosidic linkages between highly deoxygenated sugars and tertiary alcohols. 相似文献
957.
Hidetsugu Abe Tadayosi Yoshimura Shigehiko Kanaya Yoshimasa Takahashi Yoshikatsu Miyashita Shin-Ichi Sasaki 《Analytica chimica acta》1987
Although odor is an inherent characteristic of chemical substances, no methods to measure or identify odor objectively have been available. A computerized method for classification and identification of odor is reported. Odors are detected by using eight semiconductor gas-sensor elements which have different sensing properties for gases; the output from the odor-detecting apparatus for a gas sample is represented by an 8-dimensional vector. The vectors for 30 substances were examined by clustering analysis and four obvious clusters were observed. These clusters corresponded to ethereal, etherealminty, ethereal-pungent and pungent substances. 相似文献
958.
Liu Z Ma R Osada M Takada K Sasaki T 《Journal of the American Chemical Society》2005,127(40):13869-13874
We report on the controlled synthesis of single-crystal platelets of alpha- and beta-Co(OH)2 via homogeneous precipitation using hexamethylenetetramine as a hydrolysis agent. The alpha- and beta-Co(OH)2 hexagonal platelets of several micrometers in width and about 15 nm in thickness were reproducibly yielded in rather dilute CoCl2 solutions in the presence and absence of NaCl at 90 degrees C, respectively. The phase and size control of the products were achieved by varying both CoCl2 and NaCl concentrations. Polarized optical microscope observations revealed clear liquid crystallinity of colloidal suspensions of these high aspect-ratio platelets. The as-prepared alpha-Co(OH)2 containing interlayer chloride ions was intercalated with various inorganic or organic anions, keeping its high crystallinity and hexagonal platelike morphology. 相似文献
959.
Shigeru Sasaki 《Tetrahedron letters》2004,45(50):9193-9196
Crowded triarylphosphines carrying 2,6-diarylphenyl and 2,4,6-trialkylphenyl groups were synthesized by the reaction of arylcopper(I) reagent with the chlorophosphines. The triarylphosphines had large bond angles and lengths around the phosphorus and were reversibly oxidized at significantly low potentials. X-ray crystallography of bis(2,4,6-triisopropylphenyl)[4-methyl-2,6-di(1-naphthyl)phenyl]phosphine revealed that two 1-naphthyl groups took anti conformation in the crystal. 相似文献
960.
Palladium-catalyzed cyclization-methoxycarbonylation of (2R,3S)-3-methylpenta-4-yne-1,2-diol (6) derived from (2R,3S)-epoxy butanoate 7 followed by methylation gave the tetrahydro-2-furylidene acetate (−)-10, which was converted to the left-half aldehyde (+)-3. A Wittig reaction between (+)-4 and the phosphoranylide derived from the bithiazole-type phosphonium iodide 4 using lithium bis(trimethylsilyl)amide afforded the (+)-cystothiazole A (2). 相似文献