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51.
The reactions between ammonium fluoride, hydrazinium(1+) fluoride, hydrazinium(2+) fluoride and XeF2 or XeF6 were studied. It was found that Xe, HF, N2 were formed in these reactions. Interestingly enough, beside of these gases nitrogen fluorides in different quantities were formed also. The courses and the products of the above reactions are compared with analogous reactions with KrF2. 相似文献
52.
František Kopecký Božena Kopecká Pavol Kaclík 《Journal of inclusion phenomena and macrocyclic chemistry》2001,39(3-4):215-217
The solubility of nimodipine was measured in aqueous solutions of the following cyclodextrins: -cyclodextrin (-CD), hydroxypropyl--CD (HP--CD), -cyclodextrin (-CD), random substituted methyl--CD (M--CD), three hydroxypropyl--CDs (HP--CD) with mutually different average degree of substitution, and hydroxypropyl--cyclodextrin (HP--CD). From the determined linear solubility diagrams the values of the binding constant K11 of the inclusion complexes of nimodipine with the respective CDs were evaluated. The -CDs efficiently solubilized sparingly soluble nimodipine, the highest value of K11 was found for M--CD (1680 M-1), followed by -CD (550 M-1) and HP--CDs, where the higher degree of substitution lowered K11. Only slight solubilization of nimodipine was observed in the solutions of the -CDs and HP--CD. 相似文献
53.
Amidines can be prepared on a solid support by reducing polymer-bound amidoximes with SnCl2·2H2O. The method has proved to be straightforward and highly efficient. Amidoximes attached to the solid support are readily available by treating resin-bound nitriles with hydroxylamine. 相似文献
54.
M. Kabešová I. Vargová T. Šramko J. Gažo 《Journal of Thermal Analysis and Calorimetry》1978,13(1):65-70
The influence of the position of the CH3 group in picoline and lutidine ligands on the degree of chemical change of the NCS groups in coordination compounds of the type Cu(NCS)2L2 (whereL=2-, 3- and 4-picoline, and 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-lutidine) is dealt with. The most marked effect of the CH3 group is found to be exerted in position 4. This effect of the methyl group on the degree of chemical change points to the mutual influence of the ligands in coordination compounds of Cu(II).
Zusammenfassung Der Artikel befaßt sich mit dem Einfluß der Lage der CH3 Gruppe in Pikolinen und Lutidinen als Liganden auf den Grad der chemischen Änderungen der Gruppen NSC in Koordinationsverbindungen des Typs Cu(NCS)2L2 (L=2-, 3- und 4-Pikoline, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- und 3,5-Lutidine). Der ausgeprägteste Effekt der CH3 Gruppe wurde in der Position 4 beobachtet. Dieser Einfluß der Methylgruppe auf das Ausmaß der chemischen Änderungen deutet auch auf die gegenseitige Wirkung der Liganden in Koordinationsverbindungen von Cu(II).
Résumé L'article a trait à l'influence de la position du groupe CH2 dans les picolines et lutidines, en tant que ligands, sur le degré des changements chimiques des groupes SCN dans les composés de coordination du type Cu(SCN)2L2 (L=2-, 3 et 4-picoline, 2,3-, 2,4-,2,5-, 2,6-, 3,4- et 3,6-lutidine). L'effet le plus prononcé du groupe CH3 s'observe en position 4. Cette influence du groupe méthyle sur le degré des changements chimiques indique aussi l'influence mutuelle des ligands dans les composés de coordination du Cu(II).
- , , NCS Cu(NCS)2,L2, L=2-, 3- 4- , 2.3-, 2.4-, 2.5-, 2.6-, 3.4- 3.5-. , 4. Cu(II).相似文献
55.
Mafra L Paz FA Shi FN Rocha J Trindade T Fernandez C Makal A Wozniak K Klinowski J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,12(2):363-375
A compound formulated as (C4H12N2)[Ge2(pmida)2(OH)2] x 4 H2O (where pmida(4-) = N-(phosphonomethyl)iminodiacetate and C4H12N2(2+) = piperazinedium cation), containing the anionic [Ge2(pmida)2(OH)2]2- complex, has been synthesised by the hydrothermal approach and its structure determined by single-crystal X-ray diffraction analysis. Several high-resolution solid-state magic-angle spinning (MAS) NMR techniques, in particular two-dimensional 1H-X(13C,31P) heteronuclear correlation (HETCOR) and 1H-1H homonuclear correlation (HOMCOR) experiments incorporating a frequency-switched Lee-Goldburg (FS-LG) decoupling scheme, have been employed for the first time in such a material. Using these tools in tandem affords an excellent general approach to study the structure of other inorganic-organic hybrids. We assigned the NMR resonances with the help of C...H and P...H internuclear distances obtained through systematic statistical analyses of the crystallographic data. The compound was further characterised by powder X-ray diffraction techniques, IR and Raman spectroscopy, and by elemental and thermal analyses (thermogravimetric analysis and differential scanning calorimetry). 相似文献
56.
The Beckmann fragmentation product, 3-methoxy-17-oxo-16,17-secoestra-1,3,5(10)-trien-16-nitrile (2) has been reduced by LAH giving the expected 3-methoxy-17-hydroxy-16,17-secoestra-1,3,5(10-trien-16-amine hydrochloride (3) and 3-methoxy-17-oxa-D-homoestra-1,3,5(10)-trien-16-ol (4), by a presumed neighbouring group participation of 17-OH group in the intermediary formed 16-imino derivative (A). The structure of 4 has been proved by an alternative synthetic route by reducing 3-methoxy-17-oxa-D-homoestra-1,3,5(10)-trien-16-one (7) with di-iso-butylaluminium hydride. 相似文献
57.
A. Paulenová P. Rajec M. Ježíková 《Journal of Radioanalytical and Nuclear Chemistry》1998,228(1-2):119-122
The ultrafiltration preconcentration of Cd2+ using micellar extraction with 8-hydroxyquinoline (8-HQ), solubilized in anionic micelles of sodium dodecylsulphate (SDS)) were studied. The n-butanol was used as a co-surfactant. Ultrafiltration yields (R, %) on cellulose acetate membranes (wet, 20000 MW-CO) under 400 kPa pressure were determined. Distribution ratios (D) of cadmium between bulk liquid phase and micellar pseudophase were estimated. The constants (app.) for the cadmium-sodium exchange on SDS micelles surface at pH values of 4.8 and 5.3 (3.36 and 3.86, respectively) were determined. It was found, that the values of ultrafiltration yields of the cadmium (at constant concentration of 8-HQ) are influenced not only by the pH and by the concentration values, but also by the ratio of the concentrations of the metal and the anionic surfactant. 相似文献
58.
[reaction: see text] A simple procedure for the cleavage of triethylsilyl (TES) ethers in the presence of 10 wt % Pd/C in methanol or 95% ethanol is reported. This method allows selective removal of alkyl TES ethers in the presence of aromatic TES ethers or tert-butyldimethylsilyl (TBS) protecting groups. 相似文献
59.
A. Paulenová P. Rajec M. Ježíková J. Kučera 《Journal of Radioanalytical and Nuclear Chemistry》1996,211(1):145-152
The preconcentration of cadmium from aqueous colloid solution containing 8-hydroxyquinoline as extractant, laurylsulphate natrium as surfactant,n-butanol as co-surfactant was performed using micellar ultrafiltration technique. Filters with different pore size and materials were used to achieve a separation from liquid solutions. The cadmium recoveries depending on different conditions (pH, concentration of surfactant) were determined and the results are explained in the terms of colloidal parameters in the compare with the classical solvent extraction. 相似文献
60.
Born—Oppenheimer potential surfaces for a bridged three-site electron-transfer system are calculated. The adiabatic potentials depend upon both the vibrational sum and difference coordinates. Along the vibrational difference coordinate, the ground-state surface has single-minimun form when the through-bridge electronic coupling is strong, and double-minimum form for weak through-bridge coupling. The results are compared to those previously reported for two-site models. 相似文献