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841.
The resolved structure of the lowest-energy oxo to osmium charge-transfer absorption band of trans-[OsO2(malonate)2]2- is analyzed on the basis of the exact molecular Ci symmetry determined from the structure of a crystal used for spectroscopy. The multiple progressions observed in the polarized spectra are rationalized in terms of the deviations from idealized D4h point group symmetry and compared to the spectra observed for complexes with D2h symmetry such as trans-[OsO2(oxalate)2]2- that show only a single dominant progression for this transition. 相似文献
842.
E. G. Le Roux M. Peisach C. A. Pineda M. A. B. Pougnet 《Journal of Radioanalytical and Nuclear Chemistry》1988,120(1):97-104
The split-root technique was used to study the effect of varying the growth media on the elemental content of nutrient elements in the roots of grape vines. The varieties 2-1 (R99 x Jacquez) and Sauvignon blanc (Vitis vinifera) were grown in Hoagland water culture with and without added aluminium. The elemental concentrations of Mg, Al, Si, P. S, Cl, K and Ca in the dried roots were determined by PIXE. Roots grown in Al-rich media were deficient in Mg and Ca, but enriched in Al. There was a correlation between Al and Si but the uptake differed in the two varieties. 相似文献
843.
B. Schuh C. Neureiter H. Jäger L. Windholz 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1996,37(2):149-153
Laserspectroscopic investigations were performed on a collimated atomic beam of barium (natural isotope abundance). The metastable ground levels (3D1,2,3 and 1D2) of the investigated lines were populated by a discharge burning in barium vapour directly in front of the oven hole. We could investigate 14 spectral lines between 580 and 690 nm. The tensor polarizabilities of the upper and the lower level as well as the differences in the scalar polarizabilities could be determined. Spectra in magnetic fields up to 0.03 Tesla showed no deviation from the pattern resulting from a simple Russell-Sounders coupling. 相似文献
844.
Condensations of 2,2,2-trifluorodiazoethane with pentanal, cyclohexancarboxaldehyde and benzaldehyde have been performed in presence of antimony pentachloride or boron trifiuoride. These reactions lead mainly to homologated aldehydes or ketones α substituted by a trifluoromethyl group. 相似文献
845.
The addition of perfluoroalkyliodes CF3(CF2)nl (n= 3, 5, 7) to isocyanides 2 produces perfluoroalkylimidoyl iodides 3 under thermal conditions when the isocyanide nitrogen substituent is n-butyl or cyclohexyl, but fails when it is t-butyl or 2,6-dimethylphenyl. The same reaction can be induced at room temperature by the addition of decimolar quantity of copper powder. This type of metal-catalyzed condensation is general for all perfluoroalkyliodides and isocyanides studied. The perfluoroalkylimidoyl-iodides 3 have been transformed into a variety of perfluorocarboxylic acid derivatives (amides, amidines. imidates, imidoylfluorides) and perfluoroalkylamines. 相似文献
846.
The preparation of 2-amino-5-nitrothiophene, 2-formamido-5-nitrothiophene, 2-acetamido-5-nitrothiophene and 2-t-butyloxycarbonylamino-5-nitrothiophene are described. Abnormal values of the coupling constants J3.4 had been observed in the 1H-nmr spectra of compounds obtained. 相似文献
847.
NMR spectra have been measured of the Li+, Na+ and K+ ion pairs of the indenyl carbanion in 1,2-dimethoxyethane and tetrahydrofuran as a function of temperature. The changes of the chemical shifts are explained in terms of the detailed structure of the ion pairs. The results in both solvents strongly suggest that in indenyl-Li+ the counterion is predominantly located over the six-membered ring. In THF the preferred position of the cations Na+ and K+ in the contact ion pairs seems to be the five-membered ring. 相似文献
848.
H Moriya C Moriwaki S Akimoto K Yamaguchi M Iwadare 《Chemical & pharmaceutical bulletin》1967,15(11):1662-1668
849.
850.