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91.
92.
Karl Hensen Bjrn Spangenberg Michael Bolte 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):208-210
The crystal and molecular structures of two phenanthroline hydrochlorides have been determined at 173 K. 1,10‐Phenanthrolin‐1‐ium chloride, C12H9N2+·Cl?, crystallizes in two stacks of exactly planar molecules. Both stacks are approximately parallel to the (02) plane and the planes composing the different stacks enclose an angle of 13.29 (3)°. Tris(1,10‐phenanthrolin‐1‐ium) dichloride (hydrogen chloride) chloride chloroform solvate, 3C12H9N2+·2Cl?·HCl·Cl?·CHCl3, displays an interesting network of Cl? mediated hydrogen bonds between the two different phenanthrolinium moieties and between a phenanthrolinium and the chloroform solvate. In addition, a hydrogen bond between the HCl and the third Cl? ion is formed. The C—N—C angle at the protonated N atoms is, in all phenanthrolinium units of both structures, significantly larger than the C—N—C angle at the non‐protonated N atom. 相似文献
93.
The 13C spectra of 5,6,9,10-tetradehydrocyclodeca[1,2,3,4-def]-benzo [7,8]biphenylene, 1, and 5,6,9,10-tetradehydrocyclodeca [1,2,3,4-def]-naphtho [2,3-7,8]biphenylene, 2, are reported as are those of a number of simpler acetylenic hydrocarbons used as spectral references. Most of the shifts can be assigned unambiguously. The acetylenic shift assignments were verified by ortho-proton, sp-carbon (1H(1)-13Csp(3)) decoupling experiments. A simple additive shift correlation is found for the hydrocarbons containing unstrained acetylenic groups. However, significant discrepencies are found for the 13C shifts for the strained hydrocarbons 1, 2, 1,2-bis(phenylethynyl)-benzene, 12, and 2,3-bis(phenylethynyl)-naphthalene, 13. The discrepencies are particularily large for carbons near the triple bonds and are attributed to a combination of strain, rehybridization, and other proximity effects related to the interaction between the ortho-substituted acetylenic carbons. 相似文献
94.
Zusammenfassung In Vorstehendem wurde zunächst die Ausführung der von einem von uns ausgearbeiteten Schwefelsäuretitration mittelst Benzidinchlorhydrats nochmals genau beschrieben, sodann wurden die Bedingungen festgestellt, unter denen verschiedene Schwefelsäuremengen am genauesten zu bestimmen waren. Es hat sich dabei herausgestellt, dass die Schwefelsäure bis zu 0,01g H2SO4 herunter nach der beshriebenen Methode auf 1–2 genau bestimmt werden kann. Die Anwendung der Methode auf verschiedene Fälle (Ammoniumsulfat, Alaun, Zinksulfat-heptahydrat, Mohr'sches Salz, Mangansulfat-tetrahydrat), wobei die Metalle in einigen Fällen vorher ausgefällt wurden, bestätigten die zuvor festgestellten Regeln; ausserdem wurde gezeigt, dass beim Ausfällen von Zink, Eisen und Mangan nach dem angegebenen Verfahren Schwefelsäure nicht mitgerissen wird. Die Zeit, welche eine derartige Bestimmung, auch wenn die beschriebenen Ausfällungen vorgenommen werden müssen, bei einiger Uebung erfordert, ist sehr kurz, weil alles Auswaschen und so weiter in Fortfall kommt, so dass auch hier ein Vortheil gegenüber dem gewichtsanalytischen Verfahren vorhanden ist. 相似文献
95.
Karl Hassler 《Monatshefte für Chemie / Chemical Monthly》1982,113(4):421-425
A simple preparation of the title compounds is achieved by reacting Na3P/K3P with stoichiometric mixtures of chlorotriphenylsilane and chlorotrimethylsilane.31P- and29Si-NMR-Data as well as Ir and Raman spectra of the compounds are reported. 相似文献
96.
Sommermann T Kim BG Peters K Peters EM Linker T 《Chemical communications (Cambridge, England)》2004,(22):2624-2625
Only three steps are required for the convenient synthesis of 2-C-branched glyco-amino acids from glycals with good yields and stereoselectivities. 相似文献
97.
Franzén J Marigo M Fielenbach D Wabnitz TC Kjaersgaard A Jørgensen KA 《Journal of the American Chemical Society》2005,127(51):18296-18304
The development of a general organocatalyst for the alpha-functionalization of aldehydes, via an enamine intermediate, is presented. Based on optically active alpha,alpha-diarylprolinol silyl ethers, the scope and applications of this catalyst for the stereogenic formation of C-C, C-N, C-F, C-Br, and C-S bonds are outlined. The reactions all proceed in good to high yields and with excellent enantioselectivities. Furthermore, we will present mechanistic insight into the reaction course applying nonlinear effect studies, kinetic resolution, and computational investigations leading to an understanding of the properties of the alpha,alpha-diarylprolinol silyl ether catalysts. 相似文献
98.
99.
Thermochemical Investigations of the Systems Ti/Ni and Ti/Co By treatment of solid Ni or Co with a H2/TiCl4-gas mixture at sufficient high temperature (T ≥ 900°C) the intermetallic phases TiNi3 and TiCo3, resp., are formed. The conversion grade depends on the H2/TiCl4-ratio. From the experimentally determined conversion grades and the known thermodynamic data of all other species existing in equilibrium the free enthalpies and the heats of formation of TiN3 and TiCo3 have been calculated (TiNi3: ΔH(298) = ?133.3 ± 6 kJ/mol; TiCo3: ΔH(298) = ?104.7 ± 6 kJ/mol). 相似文献
100.
Adsorption of CF4 on the internal and external surfaces of opened single-walled carbon nanotubes: a vibrational spectroscopy study 总被引:1,自引:0,他引:1
Byl O Kondratyuk P Forth ST FitzGerald SA Chen L Johnson JK Yates JT 《Journal of the American Chemical Society》2003,125(19):5889-5896
Infrared spectroscopy has been used to make the first experimental discrimination between molecules bound by physisorption on the exterior surface of carbon single-walled nanotubes (SWNTs) and molecules bound in the interior. In addition, the selective displacement of the internally bound molecules has been observed as a second adsorbate is added. SWNTs were opened by oxidative treatment with O(3) at room temperature, followed by heating in a vacuum to 873 K. It was found that, at 133 K and 0.033 Torr, CF(4) adsorbs on closed SWNTs, exhibiting its nu(3) asymmetric stretching mode at 1267 cm(-1) (red shift relative to the gas phase, 15 cm(-1)). Adsorption on the nanotube exterior is accompanied by adsorption in the interior in the case of opened SWNTs. Internally bound CF(4) exhibits its nu(3) mode at 1247 cm(-1) (red shift relative to the gas phase, 35 cm(-1)). It was shown that, at 133 K, Xe preferentially displaces internally bound CF(4) species, and this counterintuitive observation was confirmed by molecular simulations. The confinement of CF(4) inside (10,10) single-walled carbon nanotubes does not result in the production of lattice modes that are observed in large 3D ensembles of CF(4). 相似文献