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171.
A method for the determination of copper(II) complexes with humic acids was developed by batch operation with the cation exchanger sulphopropyl-Sephadex C-25 (C-25). The copper-binding ability (conditional stability constants and copper-complexing capacities) of humic acids which were extracted from peat in Hokkaido was evaluated. A solution containing copper(II) ions and humic acids was shaken with the C-25 exchanger. The copper-humic acid complexes remained in the supernatant and the uncomplexed free copper ion was retained on the C-25. The copper-humic acid complexes were determined by flame atomic absorption spectrometry. The copper-binding ability of nitrilotriacetic acid (NTA) as a model ligand was similarly determined with a Scatchard plot. The conditional stability constant obtained at pH 4.5 was in good agreement with the reported value. The copper-binding abilities of the humic acids from peat were estimated using a Scatchard plot adopting a two-site model. The functional groups in the humic acids which contribute to the complexation with copper were investigated by conductimetric and pH titration, and the relationship between the copper-binding sites and functional groups in the humic acids was investigated. 相似文献
172.
Toshio Kinoshita Yukihiro Watanabe Setsuko Nakao Sunao Furukawa 《Journal of heterocyclic chemistry》1992,29(7):1785-1788
The following 5-nitro-2,4(1H,3H)-pyrimidinediones possessing bromo substituted side chains at the 1- and 6-positions were prepared by bromination of 3,6-dimethyl-1-(ω-hydroxyalkyl)-5-nitro-2,4(1H,3H)-pyrimidinediones 4a and 4b and its nitrates 2a and 2b . The three of mono-bromo derivatives are: 1-(ω-acetoxyalkyl and ω-hydroxyalkyl)-6-bromomethyl-3-methyl. 6a, 6b, 7a and 7b and 1-(ω-bromoalkyl)-3,6-dimethyl-2,4(1H,3H)- pyrimidinediones 8a and 8b . The one type dibromo derivatives are: 1-(ω-bromoalkyl)-6-bromomethyl-3-methyl-2,4(1H,3H)-pyrimidinediones 5a and 5b . 相似文献
173.
Takeshi Hara Yasutaka Kayama Hisashi Fukushima 《Journal of heterocyclic chemistry》1981,18(6):1089-1093
The reaction of trans-3a,4,5,9b-tetrahydronaphth[1,2-d]imidazoline-2-thiones ( 8 ) with α-bromoketones gave, depending upon the structure of the α-bromoketones, reaction solvent and reaction temperature, the hydrobromides of tetrahydronaphth[1,2-d]imidazolin-2-ylthiomethyl ketone ( 10 ), hexahydro-8-hydroxynaphth[1′,2′:4,5]imidazo[2,1-b]thiazoles ( 5, 11, 19 and 20 ) or tetrahydronaphth[1′,2′:4,5]imidazo[2,1-b]-thiazoles ( 12 and 16 ). Structural determinations based on ir and nmr spectroscopies are discussed. 相似文献
174.
175.
176.
177.
Raman spectra of the Li+, Na+, K+, NH+4, Mg2+, Ca2+, Sr2+, Ba2+, Pb2+ complexes of 12-crown-4 and also 12-crown-4 in various states are observed. The spectra of 12-crown-4 change remarkably by complex formation with cations. Normal vibration calculations of various conformations of 12-crown-4 are carried out. On the basis of the observed spectra and the results of the calculations, the conformation of 12-crown-4 in the Li+, Na+, K+, NH+4, Mg2+ complexes is found to have approximate D2d symmetry, while that in the Ca2+, Sr2+, Ba2+ complexes is found to have approximate C2V symmetry. 相似文献
178.
Takeshi Fukushima Emi Naka-aki Famei Li Willy R.G. Baeyens Toshimasa Toyo’oka 《Analytica chimica acta》2004,522(1):99-104
Fluoxetine (FLX) and the N-desmethyl metabolite, norfluoxetine (NFLX) in rat brain microdialysis samples were determined by high-performance liquid chromatography (HPLC) with fluorescence detection using pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). In vitro experiment showed that the relative recovery of FLX across microdialysis membrane was enhanced by adding β-cyclodextrin (β-CD) or β-CD polymer to microdialysis perfusion fluid. The perfusion fluid containing β-CD polymer, which has polymeric glyceryl linkers attached to the hydroxyl group, gave the better recovery with satisfactory precisions. Using 1% β-CD polymer in Ringer’s solution as the perfusate, in vivo rat brain microdialysis experiment on intraperitoneal administration of FLX (10 mg/kg) to rats was carried out. The fluorescence peaks of FLX and NFLX appeared later than 30 min after the administration of FLX, and then, gradually increased with time. Two hours later, FLX reached a plateau level, but NFLX slowly increased, and at 24-48 h, NFLX levels were higher than FLX levels. These data suggest that long distributions of FLX and the potent metabolite, NFLX, in brain contributed to the long-term drug actions in vivo. 相似文献
179.
Incorporation of imidazolium ion functionalities into the paraffinic side-chain termini of a triphenylene derivative resulted in stabilization of a columnar mesophase of its liquid crystalline assembly, which was retained over a wider temperature range down to 4 degrees C by an externally added imidazolium-based ionic liquid. 相似文献
180.
Yoshiaki Fukushima Shinji Inagaki 《Journal of inclusion phenomena and macrocyclic chemistry》1987,5(4):473-482
Natural montmorillonite, fractionated from bentonite produced in Yamagata, Japan, was ion-exchanged for NH
3
+
–(CH2)11–COOH, NH
3
+
–(CH2)5–COOH, Al3+, Cu2+, Mg2+, Co2+, Li+, K+ and H+. The mixtures of the ion-exchanged montmorillonite and -caprolactam were heated at 263°C in glass ampoules for various periods. The intercalated compounds before and after the heating were examined by X-ray powder diffraction, DSC and GPC. Although -caprolactam was not polymerized without montmorillonite, it was polymerized at 263°C in the presence of montmorillonite. The polymerization rate varied with the interlayer cations in the order of NH
3
+
–(CH2)11–COOH>Al3+>NH
3
+
–(CH2)5–COOH>H+>Cu2+>Mg2+>Co2+>Li+>K+. After heating at 263°C for 5 h, the mean number-average molecular weight was about 1.5×104. Although the interlayer distance of NH
3
+
–(CH2)11–COOH type montmorillonite/-caprolactam compound increased from 2.85 nm to 4.90 nm by heating at temperatures above the melting point of -caprolactam, those of other compounds were not changed. After heating at 263°C, an intercalated compound of montmorillonite and 6-polyamide, whose interlayer distance was more than 10 nm, was obtained. It is concluded that montmorillonite acts as a Brönsted acid and initiates the open ring polymerization of -caprolactam and that the driving force of swelling is the polymerization energy.Presented at the Fourth International Symposium on Inclusion Phenomena and the Third International Symposium on Cyclodextrins, Lancaster, U.K., 20–25 July 1986. 相似文献