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81.
The reaction of anhydrous YbCl3 with 1 equiv, of Li2Me2Si(NPh)2 in THF, after workup, yielded a ytterbium(Ⅲ) chloride [{Me2Si(NPh)2Yb}(μ2-CI)(TMEDA)]2·3PhMe (1) (TMEDA=tetramethylethanediamine). The same reaction followed by treatment with Na-K alloy afforded a new ytterbium(H) complex supported by a bridged diamide with four coordinated LiC1 molecules, [{Me2Si(NPh)2Yb(THF)2}(μ3-CI)(μ4-CI){Li(THF)}2]2·2THF (2) in high yield. Both complexes were structurally characterized by X-ray analysis to be dimers. Complex 1 was a chlorine-bridged dimer with ytterbium in a distorted octahedral geometry. In complex 2 two [Me2Si(NPh)2Yb(THF)2]- (μ3-CI)[Li(THF)]2 moieties were connected with each other by two μ4-CI bridges to form a "chair-form" framework. 相似文献
82.
83.
Line positions and molecular constants for the 0-0, 1-0, 2-0, 0-1, 2-1, 3-1, 0-2, 1-2, and 4-2 bands of the C2 Phillips system () are reported. Among them, five bands have not been reported previously. Rotational perturbations have been observed in the previously unobserved v = 1 level of the state. This state is perturbed by the state which was discovered by Ballik and Ramsay. These observations provide new information regarding the perturbing state. In particular, the minimum of the potential energy for the state has been found to be at 9227.4 cm?1 instead of 13 310 cm?1, which was the previous Te value for this electronic state. 相似文献
84.
85.
N. YA. Turova E. P. Turevskaya V. G. Kessler M. I. Yanovskaya 《Journal of Sol-Gel Science and Technology》1994,2(1-3):17-23
X-ray structural analysis of crystalline alkoxides in many cases reveals that along with OR-groups their molecules also contain oxo-ligands. The following possible reactions leading to formation of oxoalkoxides have been discussed: hydrolysis, pyrolysis (frequently uncontrollable), ether elimination, oxidation of OR-groups (which exist in solutions of alkali, alkaline-earth and rare earth elements), or alkoxides of the lower oxidation states (which are formed by reduction of M(OR)
n
on cathode during electrolysis or by hydrogen in statu nascendi). Oligomeric oxoalkoxides differ from the polymeric alkoxides M(OR)
n
in considerably higher solubility and reactivity. The most important role of oxoalkoxides in the processes of formation of oxides has been demonstrated using as an example preparation of BaTiO3 from alkoxides. 相似文献
86.
Yu. G. Osokin M. YA. Grinberg V. Sh. Feldblyum O. A. Yasinskii V. V. Plachtinskii E. R. Kofanov V. A. Ustinov G. S. Mironov 《Reaction Kinetics and Catalysis Letters》1978,9(2):189-192
The isomerization kinetics of 5-vinylbicyclo [2,2,1]-hept-1ene to 5-enthylidenbicyclo [2,2,1] hept-2-ene in the presence of iron pentacarbonyl and parasubstituted anilines has been investigated. The kinetic data correlate with -constants of the substitutes according to Jaffe.
5- [2,2,1]-2- 5- [2,2,1] -2- - . - .相似文献
87.
The paper considers the dynamic process of contact interaction of infinite impulse-loaded strips arranged with a gap. The
behavior of the strips is described by linear elastic dynamics equations. The contact problem is solved by the collocation
method. The process of impact of two and three strips is analyzed. The calculation results are compared with data obtained
by using the finite-element method. 相似文献
88.
89.
90.
反相高效液相色谱法测定棒柄花中反式-4-(1-丙烯基)苯酚-β-D-吡喃葡萄糖苷 总被引:1,自引:1,他引:0
用反相高效液相色谱法建立棒柄花中反式-4-(1-丙烯基)苯酚-β-D-吡喃葡萄糖苷的含量测定方法,并测定其含量。色谱柱Reliasil-C18(250 mm×4.6 mm,5μm),流动相乙腈-水(体积比22∶78),流速1.0mL/m in,检测波长257 nm。结果待测组分在0.080 4~0.281 4μg范围内与峰面积线性关系良好,相关系数为0.999 5,平均加标回收率为98%,RSD为1.8%(n=6)。本法简便、快速、重复性好、结果准确可靠。 相似文献