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101.
Kazuhiko Ohashi Masaharu Nishiguchi Yoshiya Inokuchi Hiroshi Sekiya Nobuyuki Nishi 《Research on Chemical Intermediates》1998,24(7):755-764
Electronic spectra of a homo-molecular dimer cation, (C6H5CN)2
+, are measured by photodissociation spectroscopy in the gas phase. Broad features appeared in the 450–650 nm region are characteristic
of π3 → πCN transitions of the C6H5CN+ chromophore. No intense band is observed in the 650–1300 nm region, where other aromatic dimer cations usually show charge
resonance bands. Two component molecules of (C6H5CN)2
+ cannot take a parallel sandwich configuration suitable for the resonance interaction, because of geometrical constraints
due to other stronger interactions. 相似文献
102.
Summary Kinetics and mechanism of formation of a 113 mixed cyano-complex from [FeIII (Par)2]– (where Par represents 4-(2-pyridylazo)resorcional) and cyanide ion has been studied spectrophotometrically at 720 nm [max=Fe(III)(Par)
2
–
], pH=10.0±0.02, temp=25±0.1°C and 1=0.1 M (NaClO4). The order with respect to cyanidevaries from one to two at high and low cyanide concentrations respectively. The rate constants for respective reactions are k1=10.8±0.6×10–2 M–1 s–1, k2=7.7±0.5 M–2 s–1. The reverse reaction does not occur at a measurable rate even in presence of large excess of par. These observations suggest that FeIII (Par)
2
–
forms a mixed complex, [FePar(CN)3]2-, in presence of an excess of cyanide ions. A three-step mechanism consistent with these results is proposed. The activation parameters for the reaction have been derived and used to support the proposed mechanism. The effect of ionic strength lends further support to the mechanism. 相似文献
103.
Inatomi Y Inada A Murata H Nishi M Nakanishi T 《Chemical & pharmaceutical bulletin》2000,48(12):1930-1934
From a whole plant of a fern, Diplazium subsinuatum, three new hopane-triterpene lactone glycosides, diplaziosides V-VII (1-3), were isolated, together with a new monoacetyl derivative (4) of diplazioside VII (3). Compounds 1-3 were defined as the respective 3-O-[beta-D-glucopyranosyl-(1-->2)]-beta-D-glucopyranosides of 3beta,24-dihydroxyhopan-28,22-olide (1), of 3beta,17,24-trihydroxyhopan-28,22-olide (2), and of (22R)-3beta,24,30-trihydroxyhopan-28,22-olide (3), and 4 as the 6"-O-acetate of 3, respectively, on the basis of spectral evidence. 1-3 are new in their glycoside structures but also in their triterpene structures. Furthermore, in compounds 1-4, the coupling between the 24-hydroxy proton and one of the 24-methylene protons showed a very large J-value (11.4 Hz); based on this 1H-NMR evidence, etc., preferred conformations of the 24-hydroxymethylene groups in 1-4 are also inferred. In a similar manner, 1H-NMR coupling patterns of the 24-hydroxymethylene in the monoglucoside (2a) and aglycone (2b), derived from 2, are also reported and discussed here. 相似文献
104.
Multiphoton ionization (MPI) fragmentation pattern of p-xylene is investigated as a function of laser power at 193 and 248 nm. The mass pattern at 193 nm suggests the presence of two reaction sequences and the occurrence of drastic rearrangement in the parent ion and also in the superexcited xylene before fragmentation. 相似文献
105.
A sensitive and selective liquid chromatographic (LC) assay was developed to determine the concentration of pyrimethamine in animal tissue and egg by fluorescent derivative. Animal samples were extracted with acetonitrile, centrifuged, and purified by hexane. Fluorescent derivatization was performed by reacting pyrimethamine with chloroacetaldehyde and subjected to LC with fluorescence detection (excitation wavelength 300 nm, emission wavelength 420 nm). The limit of detection was 10 ng/g (10 ppb) and the standard calibration curve was linear in the range of 1-100 ppb (0.01-1 ng/10 microL). Recoveries from samples fortified at levels of 0.1 and 1 ppm (microg/g) were 61.0-77.4 and 65.5-81.2%, respectively. The method was applied to the monitoring of marketed samples. Pyrimethamine was not determined in any of the 70 samples: 20 swine muscle; 20 chicken muscle; 10 chicken liver; and 20 egg. 相似文献
106.
Yoshio Nishi 《International Journal of Infrared and Millimeter Waves》1987,8(9):1189-1210
The author reports that TEA-CO2 with an intra-cavity etalon is a useful pumping source which can deliver widely tunable beam (tunable range 1 GHz) with accurate oscillation frequencies and with high power compared to a tunable wave guide laser.The source is applied to the excitations of CH3OH and the FIR emissions from it are well assigned for there absorption transitions and FIR emissions. This proves that the source display not only usefulness for development of new FIR emissions but also for molecular spectroscopy. 相似文献
107.
Morphology and performance of unsaturated polyester nanocomposites modified with organoclay and thermoplastic polyurethane 总被引:1,自引:0,他引:1
<正>Unsaturated polyester(UPR)/thermoplastic polyurethane(TPU)/organoclay nanocomposites were prepared by melt compounding of thermoplastic polyurethane and unsaturated polyester prepolymer,and then mixing with the hybrids of styrene monomers and organoclay at ambient temperature.The crosslinking reaction eventually occurred through the unsaturated polyester prepolymer and styrene monomer.The morphology of the composites was investigated by scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results show that the impact strength of UPR/TPU/organoclay nanocomposites increases obviously;the cure shrinkage decreases markedly,the glass transition temperature is enhanced and an elastic response to the deformation is prominent at the temperature above 10℃. 相似文献
108.
Iron-catalyzed synthesis of glycine derivatives via carbon-nitrogen bond cleavage using diazoacetate
Treatment of tertiary amines with diazoacetate in the presence of a catalytic amount of an iron salt, FeCl(3), in ethanol gave glycine derivatives. In this reaction, a carbon-nitrogen single bond of the amine was cleaved. 相似文献
109.
A single-stranded DNA, readily extracted from industrial discarded salmon milt, was used to prepare hydrogels and complex gels by cross-linking with gelatin and kappa-carrageenan, for the oral delivery of probiotic bacteria. The complex gels showed a higher protective capability over the hydrogels for approximately one log scale. However, the hydrogels were more stable during storage at 4 degrees C. The Lactobacillus and Lactococcus due to protection of the hydrogels could better tolerate to acid than the Bifidobacterium. Furthermore, food-graded hydrogels were prepared and optimized to a similar protective capability for future applications. 相似文献
110.
Haruko Ikeuchi Mitsuhiro Kanakubo Shin Okuno Rika Sato Koichi Fujita Manatsu Hamada Nobuhiro Shoda Kenta Fukui Koji Okada Hikaru Kanazawa Akira Iimori Daisaku Miyake Takeshi Takeda Gen P. Satô 《Journal of solution chemistry》2010,39(10):1428-1453
The densities and the viscosities of tris(acetylacetonato)cobalt(III) solutions in acetonitrile, dichloromethane, chloroform, tetrachloromethane, benzene, toluene, ethylbenzene, and p-xylene were measured in the dilute concentration regions at several temperatures ranging from 278 to 313 K under ambient pressure. The partial molar volumes of the solvents and solute were calculated. They are independent of concentration and increase slightly as the temperature increases. The viscosity A- and B-coefficients of the Jones-Dole equation were obtained. The A-coefficients were found to be zero within experimental error. The B-coefficients are positive and decrease as the temperature increases. Thermodynamic quantities of activation for viscous flow were calculated on the basis of Eyring’s viscosity equation. From the quantities obtained in this study, along with some information from the literature, it is suggested that structure-making interactions occur between the segments of the complex and the solvent molecules. These interactions include electrostatic interactions between the local charge on the complex and the dipole moment of the solvent in solutions of acetonitrile and dichloromethane, interlocking packing interactions along C 3-axis of the complex with solvent in solutions of chloroform and tetrachloromethane, and π-electron interactions between the chelate ring of the complex and the solvent in solutions of benzene, toluene, ethylbenzene, and p-xylene. 相似文献