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41.
A rigid terpyridine ligand containing chiral alkyl chains has been synthesized, characterized and subsequently complexed with ruthenium(II) ions. The product was characterized by MALDI-TOF-MS, UV-vis and NMR. Circular dichroism showed the appearance of extended helical columnar aggregates. 相似文献
42.
Cyclic α-trimethylsilylketones are synthesized from cyclic vinyltrimethylsilanes via the epoxides , and the alcohols . 相似文献
43.
Formation of CoAl3Cl11 at higher Al2Cl6 Pressures The reaction of CoCl2,f with Al2Cl6,g (≈ 3 atm) is investigated considering every component of the gas phase (Al2Cl6, AlCl3, Al3Cl9, CoAlCl5, CoAl2Cl8, CoAl3Cl11) and the deviation from the ideal behaviour. The conclusion is derived that at 600 K from CoCl2,s and larger pressures of Al2Cl6 besides CoAl2Cl8 a small amount of CoAl3Cl11 is formed. 相似文献
44.
Kai Li Harald D. H. Stver 《Journal of polymer science. Part A, Polymer chemistry》1993,31(10):2473-2479
Narrow disperse microparticles are formed by dispersion polymerization of commercial divinylbenzene in acetonitrile or ethanol solution in the presence of 2,2′-azobis(2-methylpropionitrile) initiator and polyvinylpyrrolidone stabilizer. The particles have average diameters between 1 and 9 μm depending on monomer concentration, solvent, and temperature. While the smaller particles are relatively smooth, surface texture increases with diameter to give popcorn shapes at 9 μm diameter. High crosslinker concentration is shown to be essential for particle formation. © 1993 John Wiley & Sons, Inc. 相似文献
45.
Gaseous Acetates Thermoanalytical and mass-spectrometrical observations are undertaken with some acetates and oxiacetates. The volatilization of copper(I) acetate takes place like that of the silver acetate as M2Ac2+ (besides the deposition of Ag). On the volatilization of the anhydrous compounds Cu2Ac4, Cr2Ac4, Rh2Ac4, and Mo2Ac4 in the vacuum of a mass spectrometer is observed that Cu2Ac4 vaporizes dissociative as Cu2Ac2+ (+ 2 “Ac”), while the other compounds vaporize as M2Ac4+ and simultaneously is formed an oxidic (e.g. Cr2O4) or metallic residue. PdAc2 vaporizes in the mass spectrometer as a trimeric molecule Pd3Ac6. M4OAc6, which is formed from the dihydrates, vaporizes in a mass spectrometer with M ? Co, Mn as M4OAc6+. Other complexes of the same type appear as Be4OAc5+, Mg4OAc5+, and Zn4OAc5+. 相似文献
46.
Harald Greger Otmar Hofer Andreas Werner 《Monatshefte für Chemie / Chemical Monthly》1985,116(2):273-277
In addition to the well known affinin [=spilanthol, (2E,6Z,8E)-deca-2,6,8-trienoic acid isobutylamide (1)], the corresponding 2-methyl-butylamide (2), and two new acetylenic alkamides were isolated fromSpilanthes oleracea L. by reversed phase medium pressure chromatography: (Z)-non-2-en-6,8-diynoic acid isobutylamide (3) and (Z)-dec-2-en-6,8-diynoic acid isobutylamide (4). The structures and their stereochemistries were elucidated by1H-NMR,13C-NMR (2 and3), MS, UV, IR, and CD (2). The chemotaxonomic significance of the distribution of alkamides within theCompositae tribeHeliantheae is briefly discussed.
Neue Amide ausSpilanthes oleracea (Kurze Mitteilung)
Zusammenfassung AusSpilanthes oleracea wurden neben dem seit langem bekannten Affinin [=Spilanthol, (2E,6Z,8E)-Deca-2,6,8-triensäureisobutylamid (1)] durch Umkehrphasen-Mitteldruckchromatographie das entsprechende 2-Methylbutylamid (2) und zwei neue acetylenische Alkamide isoliert: (Z)-Non-2-en-6,8-diinsäure-isobutylamid (3) und (Z)-Dec-2-en-6,8-diinsäure-isobutylamid (4). Die Strukturen und deren Stereochemie wurden mittels1H-NMR,13C-NMR (2 und3), MS, UV, IR und CD (2) aufgeklärt. Die chemotaxonomische Bedeutung der Verbreitung von Alkamiden innerhalb der Compositen-TribusHeliantheae wird kurz diskutiert.相似文献
47.
Alkynylxenon(II) fluorides, RCC(triple bond)XeF, have been prepared from the reactions of the corresponding trimethyl(alkynyl)silanes, Me3(-)SiC(triple bond)CR, and XeF2 in the presence of [NMe4F in common organic solvents at low temperature. The existence of the linear unit C(triple bond)C-Xe-F was proved for PhC(triple bond)CXeF by the 19F-13C NMR correlation method using the HMBC pulse sequence. 相似文献
48.
An easy to handle and stable racemization catalyst for secondary alcohols is obtained by an in situ mixture of readily available [Ru(cymene)Cl2]2 with chelating aliphatic diamines. Optimization of the reaction revealed that N,N,N′,N′-tetramethyl-1,3-propanediamine as ligand racemizes aromatic alcohols completely within 5 h. This easy to handle and stable catalytic system is combined with a lipase-catalyzed resolution to provide an efficient dynamic kinetic resolution of secondary alcohols. 相似文献
49.
The reaction of linear (Si(n)Cl(2)(n)(+2); n = 3-5) and cyclic (Si(5)Cl(10)) perchloropolysilanes with 1 or 2 equiv of LiN(SiMe(3))(2) results in the formation of the bis(trimethylsilyl)amino derivatives (Me(3)Si)(2)NSi(3)Cl(7) (1), (Me(3)Si)(2)NSi(4)Cl(9) (2), (Me(3)Si)(2)N(SiCl(2))(n)N(SiMe(3))(2) (n = 3, 4; n = 4, 5; n = 5, 6), cyclo-(Me(3)Si)(2)NSi(5)Cl(9) (7), and cyclo-[(Me(3)Si)(2)N](2)Si(5)Cl(8) (8). 1-8 easily can be hydrogenated with LiAlH(4) to give the corresponding amino and diamino polysilanyl hydrides. The monosubstituted and cyclic compounds 1, 2, 7, and 8 additionally afford Si-Si bond scission products, which cannot be separated in all cases. Chloro- and dichloro derivatives of Si(3)H(8), n-Si(4)H(10), and n-Si(5)H(12) are obtained from the corresponding aminosilanes and dry HCl. All compounds were characterized by standard spectroscopic techniques. For Si-H derivatives the coupled (29)Si NMR spectra were analyzed to obtain an unequivocal structural proof. 相似文献
50.
France S Shah MH Weatherwax A Wack H Roth JP Lectka T 《Journal of the American Chemical Society》2005,127(4):1206-1215
We report a mechanistically based study of bifunctional catalyst systems in which chiral nucleophiles work in conjunction with Lewis acids to produce beta-lactams in high chemical yield, diastereoselectivity, and enantioselectivity. Chiral cinchona alkaloid derivatives work best when paired with Lewis acids based on Al(III), Zn(II), Sc(III), and, most notably, In(III). Homogeneous bifunctional catalysts, in which the catalyst contains both Lewis acidic and Lewis basic sites, were also studied in detail. Mechanistic evidence allows us to conclude that the chiral nucleophiles form zwitterionic enolates that react with metal-coordinated imines. Alternative scenarios, which postulated metal-bound enolates, were disfavored on the basis of our observations. 相似文献