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1.
2.
The new cluster [Bu4N]2[W6Cl8(OSO2CF3)6] (1) has been prepared and structurally characterized. This material is an effective precursor for the generation of cluster ions with the general formula [W6C18L6]n (L = Cl-, Br-, I-, NCS-, NCO-, NCSe-, and O=PPh3; n = 2- or 4+). The last three clusters are new. The products have been characterized by IR spectroscopy, NMR spectroscopy, and FAB mass spectrometry. In addition to 1, the products [Bu4N]2[W6C18(NCS)6] (5) and [Bu4N]2[W6C18(NCO)6] (7) were structurally characterized. Crystal data for 1: space group, P2(1/c) (No. 14); a = 11.116(5) A; b = 27.952(1) A; c = 24.516(1) A; beta = 95.182(9) degrees; V = 7586.3(5) A3; Z = 4. Crystal data for 5: space group, P2(1/n) (No. 14); a = 11.3323(9) A; b = 12.3404(9) A; c = 44.583(3) A; beta = 97.089(1) degrees ; V = 6187.1(7) A3; Z = 4. Crystal data for 7: space group, P1 (No. 2); a = 11.8009(8) A; b = 11.9332(8) A; c = 11.9522(8) A; alpha = 77.904(1) degrees; beta = 95.182(9) degrees; gamma = 62.574(1) degrees V = 1450.5(2) A3; Z = 1. 相似文献
3.
Complexes of poly(ethylene oxide) (PEO), with various alkali metal salts are known to exhibit ionic conductivities which exceed 10?5(Ωcm)?1 at moderate temperatures. We have employed IR and Raman spectroseopy to study well characterized samples of the following polymer-salt complexes: PEO·NaBr, PEO·NaI, PEO·NaSCN, PEO·NaBF4, PEO·NaCF3SO3, PEO·KSCN, PEO·RbSCN and PEO·CsSCN. Cation-dependent vibrational bands observed in the far IR and M-On symmetric stretching bands observed in the Raman support a cation-oxygen atom interaction, and indicate the polyether chain may wrap around the cations. In particular, NaX and KX complexes of PEO are believed to have a helical configuration for the polymer which differs from that of pure PEO. Some general rules are presented for polymer-salt complex formation. 相似文献
4.
J.I. McOmber D.F. Shriver M.A. Ratner J.R. Ferraro P.LaBonville Walling 《Journal of Physics and Chemistry of Solids》1982,43(9):903-909
High pressure Raman, electrical conductivity, and optical microscopic studies on the ternary fast ion conductor Cu2HgI4 were undertaken to delineate the pressure-temperature phase diagram. In addition, comparison of the pressure dependence of Raman shifts in Cu2HgI4 and Tl2ZnI4 was used to assist in making vibrational assignments whenever possible. 相似文献
5.
6.
A deep understanding of both guided propagating and evanescent waves is very essential for non-destructive evaluation. Guided propagating waves have received considerable attention, but the research on guided evanescent waves is quite limited, especially for functionally graded structures. This paper presents an analytical approach, based on the orthogonal function technique, to solve the evanescent waves in a spherical curved plate with functionally graded material in the radial direction. The proposed approach can obtain all the real, imaginary and complex solutions but without iterative process. The validity of the proposed approach is illustrated by comparison with available results. The convergence of the approach is also discussed through a numerical example. Dispersion characteristics of the guided waves in various graded spherical curved plates are studied and three dimensional dispersion curves are plotted in frequency-complex wavenumber space. The effects of different radius-thickness ratios and graded fields on the dispersion curves of the guided evanescent waves are illustrated. The displacement distributions are also discussed to analyze the characteristics of the guided evanescent waves. 相似文献
7.
Adduct formation on the oxygen of a bridging carbonyl causes a very small perturbation of metal—metal stretching frequencies of polynuclear carbonyls. This small shift contrasts with the large change in v(MM) when carbonyl groups are redistributed between terminal and bridging positions; therefore, using low frequency Raman spectroscopy, it is possible to infer the structural relation of C- and O-bonded adduct to the parent carbonyl. Structural inferences for Fe3(CO)12 · AlBr3, Ru3(CO)12 · AlBr3 and Fe2(CO)9 · AlBr3 are given. 相似文献
8.
Mykhaylo Dukh Pavel Drašar Ivan Černý VladimÍr Pouzar James A. Shriver VladimÍr Král 《Supramolecular chemistry》2013,25(2-3):237-244
Novel steroidal calix[4]pyrroles were prepared in excellent yields from commercially available cholic acid derivatives using an efficient synthetic sequence. Once in hand, it was found that these calix[4]pyrroles exist in the form of four different configurational isomers. Separation of these isomers was achieved readily using normal phase HPLC techniques. Once purified, the steroidal calix[4]pyrroles were screened via -FABMS analyses to judge their utility in effecting the enantioselective recognition of appropriate organic anions. Results that provided support for antipodal R > S selectivity were obtained in the case of both tartaric acid and mandelic acid. Direct extraction studies were then carried out and these confirmed the pattern of R > S selectivity observed by -FABMS. 相似文献
9.
The tosylate (p-toluenesulfonate) cluster [Bu4N]2[W6Cl8(p-OSO2C6H4CH3)6] (1) has been prepared and characterized by IR and NMR spectroscopy, elemental analysis, and an X-ray crystal structure. This cluster complex is shown to be a useful starting material for the preparation of pseudohalide clusters, [Bu4N]2[W6Cl8(NCQ)6] (Q = O (2), S (3), and Se (4)), in high yields. Cluster 1 also serves as a precursor to the new cluster compounds: [Bu4N]2[W6Cl8(O2CCH3)6] (5), [Bu4N]2[W6Cl8((mu-NC)Mn(CO)2(C5H5))6] (6), [W6Cl8((mu-NC)Ru(PPh3)2(C5H5))6][ p-OSO2C6H4CH3]4 (7), and [W6Cl8((mu-NC)Os(PPh3)2(C5H5))6][ p-OSO2C6H4CH3]4 (8). X-ray crystal structures are reported for 1, 4, and 5. 相似文献
10.
Recently, metal clusters supported on some solids which simultaneously exhibit many excellent properties of both metal clusters and supports have been intensively studled. Such surface organometallic chemistry, which concerns the synthesis, structure, reactivity and catalytic activity of surface-supported organometallfc compounds is a new 相似文献