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991.
Estradiol extracted with an ODS minicolumn from serum (500 μl) is derivatized with 5-dimethylamino-1-naphthalenesulfonyl (dansyl) chloride at room temperature for 80 min, purified on the ODS minicolumn, separated on silica gel columns (150 × 1.9 mm i.d. and 100 × 1.9 mm i.d.) with n-hexane/chloroform/ethanol (70:30:0.1) as eluent at 3 ml min?1 and detected by the chemiluminescence emission produced in a post-column reaction with bis-(2,4,6-trichlorophenyl) oxalate (8 mM in chloroform containing 100 mM triethylamine) and hydrogen peroxide (600 mM in methanol containing 6% (v/v) sodium acetate buffer at pH 4.0). The overall recovery of estradiol from serum is ca. 90% and the detection limit is ca. 50 pg. 相似文献
992.
The inorganic-organic hybrid compound composed of the novel infinite-chain Pd(II) complex and the polyoxometalate ({[(en)Pd(p-bpy)]2[alpha-SiW12O40].8DMSO.4DMF}infinity (1a:1 with 8DMSO.4DMF; monoclinic P2(1)/c (No. 14), a = 15.0188(3) A, b = 15.6962(3) A, c = 26.9793(6) A, beta = 106.3580(10) degrees , V = 6102.6(2) A(3)) has been successfully synthesized by the reaction of [(en)Pd(OH2)2]2[alpha-SiW12O40] (2) with 4,4'-bipyridine (p-bpy). The treatment in dry N(2) at 50 degrees C or evacuation at room temperature forms {[(en)Pd(p-bpy)](2)[alpha-SiW(12)O(40)].6.0DMSO}(infinity) (1b:1 with 6DMSO) with a drastic reduction of the interlayer spacing, which is characterized by the powder diffraction analysis and the single-crystal analysis of 1c (1 with 4.5DMSO.3.5DMF; monoclinic P2(1)/a (No. 14), a = 14.200(9) A, b = 22.8865(8) A, c = 14.8558(5) A, beta = 114.7990(10) degrees , V = 4383.0(2) A(3)). Compound 1b reversibly sorbs the hydrophilic molecules with the maintenance of the intrinsic structure, which is much different from hydrophobic guest-inclusion properties reported in the other Pd-based supramolecular systems. 相似文献
993.
The Taft's substituent constant of the pentafluorophenyl group (sigma(C(6)F(5))) was reestimated to be 1.50 by correlation between IR spectral data (v(C)(=)(O)) and sigma constants for a series of esters (involving the pentafluorobenzyl group) of 3-phenylpropanoic acid and butanoic acid. The possibility of the disturbance of the correlation by the intramolecular pi-pi interaction between C(6)F(5) and C(6)H(5) groups in pentafluorobenzyl 3-phenylpropanoate was excluded by ab initio and DFT calculations of the stable conformations and their carbonyl frequencies. The reestimated sigma(C(6)F(5)) value was used for calculation of the pK(a) value of pentafluorobenzyl alcohol [14.5 (or 14.3)]. 相似文献
994.
Ken-ichiro Yamamoto Masayo Hayama Masato Matsuda Taiji Yakushiji Makoto Fukuda Takehiro Miyasaka Kiyotaka Sakai 《Journal of membrane science》2007
The tortuous capillary pore diffusion model (TCPDM) has been used for estimating diffusive and pure water permeability from simple structure parameters such as pore diameter, surface porosity, wall thickness and tortuosity. The validity of this model for evaluation of homogeneous membrane has been already confirmed. Recently, there is a trend toward the use of asymmetrical dialysis membranes made of synthetic polymer such as poly(acrylonitrile) (PAN), polysulfone (PS) and a polyethersulfone polyarylate (PEPA) blend polymer. The purpose of the present study is to apply the TCPDM to evaluation of commercially available hollow-fiber dialysis membranes with asymmetrical structures by simplifying them to a double-layer membrane. The TCPDM is capable of estimating pore tortuosity of asymmetrical dialysis membranes having skin and supporting layers from data on membrane thickness, pore diameter, pure water permeability and water content. Values for diffusive permeability obtained by the TCPDM are in a good agreement with experimental data. This TCPDM model is useful for evaluation of not only homogeneous membrane but also asymmetrical membrane. 相似文献
995.
Formation of ternary ion associates using diprotic acid dyes and its application to determination of cationic surfactants 总被引:1,自引:0,他引:1
A sensitive and selective method is described for the determination of cationic surfactants, such as benzethonium, benzalkonium, cetylpyridinium and trimethylstearylammonium, based on the formation and extraction of ternary ion associates with an acid dye (bromophenol blue or bromochlorophenol blue) and quinidine. Quinidine reacts with divalent anionic dyestuffs to form a bulky 11 complex anion, which is extractable into 1,2-dichloroethane as ternary ion associates with cationic surfactants in nearly neutral media. The ternary ion associate gives a blue product. Linearity of the calibration curve is improved and the extractability of the cationic surfactants is enhanced in the presence of quinidine. In addition, many other amines do not interfere with the determination. The blue ion associates can be used for the selective and sensitive spectrophotometric determination of cationic surfactants. 相似文献
996.
Tomoe Sanada Kazuhiro Yamamoto Kazuo Kojima Noriyuki Wada 《Journal of Sol-Gel Science and Technology》2007,41(3):237-243
To obtain red luminants, MgO-GeO2 gel glasses and glass ceramics doped with manganese ions were prepared by a sol-gel method and their properties were investigated
by measuring X-ray diffraction (XRD), electron spin resonance (ESR), and luminescence and excitation spectra. Under UV irradiation
at 254 nm, the gel glasses and glass ceramics showed red luminescence at 620–665 nm, the intensity of which became strong
with increasing the heat-treatment temperature. A glass ceramic with the composition 1.0MnO-25MgO-75GeO2 heat treated at 1000°C exhibited the strongest red luminescence at 661 nm. From the results of XRD and ESR, this luminescence
is found to be due to the transition from the 4T1g to the 6A1g state of octahedrally coordinated Mn2+ ions located in MgGeO3 polycrystals. The luminescence wavelength of the glass ceramics (∼665 nm) is long compared with Eu3+-containing phosphors (612 nm), therefore the glass ceramics can be expected for red luminants. 相似文献
997.
Kazuaki Kanamoto Koreyoshi Imamura Nobuhide Kataoka Jun Oshitani Hiroyuki Imanaka Kazuhiro Nakanishi 《Colloids and surfaces. A, Physicochemical and engineering aspects》2009,350(1-3):79-86
The cathodic electrolysis of H2O2 (H2O2 + e− → OH− + OH) on a metal surface in the presence of calcium and phosphate ions results in the formation of calcium phosphate deposits on the metal surface. In this study, the deposits formed under various treatment conditions (pHs, concentrations and ratios of calcium/phosphate ions, and so on) were characterized by scanning electron spectroscopy (SEM), and X-ray diffractometry. The exclusive formation of hydroxyapatite, HAP, was observed under comparatively narrow conditions (pH 3–4, [Ca+]/[PO43−] = 25 mM/15 mM), which is clearly different from the reported conditions for the deposition of HAP on titanium substrates. HAP was deposited in the form of a layer, comprised of morphologically amorphous HAP flakes that were less than 20 nm thick. SEM and FTIR analyses of the deposit at different stages of H2O2-electrolysis revealed that a few dozen nanometer-sized spheres of amorphous calcium phosphate were formed in the first step and then fused with each other to form ribbon-like flakes of HAP or broken glass-like brushite, depending on the pH. The pH for HAP formation on a stainless steel surface was markedly lower than that used for titanium, and the observed process by which amorphous calcium phosphate is converted to HAP was markedly different from that for the electrochemical deposition (electrolysis of water) of HAP on a titanium substrate. 相似文献
998.
Fujiwara S Okada K Shikano Y Shimizu Y Shin-Ike T Terao J Kambe N Sonoda N 《The Journal of organic chemistry》2007,72(1):273-276
N-Carbonylation of less nucleophilic nitrogen compounds was achieved by the reaction of the lithium azaenolates with carbon monoxide and selenium. This reaction proceeds in the cases of amides, formamides, ureas, and carbamates, leading to the formation of the corresponding carbamoselenoates in good to high yields after trapping with BuI. 相似文献
999.
Development of novel chiral hemilabile Segphos P-P=O ligands is described. The ligands are examined for enantioselective Pd-catalyzed allylic alkylation of cyclic allylic acetates. 相似文献
1000.
Ishiuchi S Miyazaki M Sakai M Fujii M Schmies M Dopfer O 《Physical chemistry chemical physics : PCCP》2011,13(6):2409-2416
Electronic excitation spectra of the S(1)← S(0) transition obtained by resonance-enhanced two-photon ionization (REMPI) are analysed for phenol-Ar(n) (PhOH-Ar(n)) clusters with n≤ 4. An additivity rule has been established for the S(1) origin shifts upon sequential complexation at various π binding sites, which has allowed for the identification of two less stable isomers not recognized previously, namely the (2/0) isomer for n = 2 and the (2/1) isomer for n = 3. Infrared (IR) spectra of neutral PhOH-Ar(n) and cationic PhOH(+)-Ar(n) clusters are recorded in the vicinity of the OH and CH stretch fundamentals (ν(OH), ν(CH)) in their S(0) and D(0) ground electronic states using IR ion dip spectroscopy. The small monotonic spectral redshifts Δν(OH) of about -1 cm(-1) per Ar atom observed for neutral PhOH-Ar(n) are consistent with π-bonded ligands. In contrast, the IR spectra of the PhOH(+)-Ar(n) cations generated by resonant photoionization of the neutral precursor display the signature of H-bonded isomers, suggesting that ionization triggers an isomerization reaction, in which one of the π-bonded Ar ligands moves to the more attractive OH site. The dynamics of this isomerization reaction is probed for PhOH(+)-Ar(3) by picosecond time-resolved IR spectroscopy. Ionization of the (3/0) isomer of PhOH(+)-Ar(3)(3π) with three π-bonded Ar ligands on the same side of the aromatic ring induces a π→ H switching reaction toward the PhOH(+)-Ar(3)(H/2π) isomer with a time constant faster than 3 ps. Fast intracluster vibrational energy redistribution prevents any H →π back reaction. 相似文献