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21.
Wolfgang A. Herrmann Cornelia Weber Manfred L. Ziegler Orhan Serhadli 《Journal of organometallic chemistry》1985,297(2):245-254
The diazoolefines of composition N2CCR2 (R/R = CH3/CH3 and(-CH2-)5) are suitable precursors of the corresponding vinylidene ligands CCR2. Thus, treatment of the RhRh complex [(η5-C5Me5)Rh(μ-CO)]2 (1) with the N-nitrosourethanes 2a and 2b, resp., in the presence of lithium t-butoxide yields the otherwise inaccessible μ-vinylidene complexes (μ-CCR2)[(η5-C5Me5)Rh(CO)]2 (R = CH3 (3a), R,R = (-CH2-)5 (3b)). The analogous cobalt compound (μ-CCMe2)[(η5-C5Me5)Co(CO)]2 (5a) is obtained similarly. This procedure extends the well-documented diazoalkane method for the synthesis of μ-alkylidene complexes to the less stable diazoalkenes. A single-crystal X-ray diffraction study of the dimethylvinylidene derivative 3a shows the CMe2 ligand to adopt an almost symmetrically metal-bridging position (d(RhC) 197.8(1) and 204.3(1) pm), with a rhodium-rhodium single bond completing a three-membered Rh2C-metallacycle (d(RhRh) 268.4(0) pm) analogous with cyclopropane. 相似文献
22.
Hamilton BH Cardon TB Lorigan GA Ziegler CJ 《Dalton transactions (Cambridge, England : 2003)》2005,(17):2941-2944
Metal-organic frameworks based on the Pb[B(Im)(4)](+) unit form layered structures analogous to those observed in clays and double layered hydroxide minerals. These layers can act as scaffolds for the organization of anionic organic guests. In this report, we use this scaffold to assemble TEMPO and PROXYL carboxylates in the interlayer spacings of Pb[B(Im)(4)](4-carboxy-TEMPO) 1 and Pb[B(Im)(4)](3-carboxy-PROXYL)(H(2)O)2, respectively. The resultant materials are paramagnetic, and the organization of the radical units differs between the two compounds. This results in changes in electronic structure of the radical unit, as observed by EPR spectroscopy. 相似文献
23.
ODIN, a non-empirical INDO-MO scheme, has been used to determine the ground state electronic configurations for the tetrahedral molecules, VCl4 and VBr4. A 2
E ground state was obtained for both molecules. The Photoelectron spectrum and the electronic spectrum have been calculated for VCl4, and a satisfactory correlation with the corresponding experimental data was made. Also, ODIN was employed to evaluate electronic transition energies and the photoelectron spectrum of VBr4. 相似文献
24.
Zusammenfassung Beim Erhitzen von Betain mit Phenylisocyanat (12) auf 140–160° entsteht Diphenylimidazolidin-dion-(2,4) (I).
Diphenylimidazolidine-dion-2,4 (I) was obtained by the reaction of betaine with phenylisocyanate (12) at 140–160°.相似文献
25.
Time-dependent density functional theory (TD-DFT) is applied to the CD spectra of Lambda(deltadeltadelta)-(+)-[Co(S-pn)n(en)(3-n)]3+ (n = 1, 2, 3) and Lambda(deltadeltadelta)-(+)-[Co(en)3]3+ as well as the stereoisomers Delta-((delta)n(lambda)(3-n))-(-)-[Co(S-pn)n(en)(3-n)]3+ (n = 1, 2, 3) and Delta(deltadeltadelta)-(-)-[Co(en)3]3+. Theory is able to reproduce the major differences in the CD spectra of the species with a Lambda-configuration and their isomers with a Delta-configuration in both the d-d and ligand-to-metal CT region. It is further possible to rationalize the trend in terms of a larger azimuthal distortion away from the octahedral geometry in the Lambda-conformation compared to the Delta-configuration. Considerations were also given to the CD spectra of the lel3-isomer, Delta(lambdalambdalambda)-(-)-[Rh(R-pn)3]3+ and the ob-isomer, Lambda(lambdalambdalambda)-(+)-[Rh(S-pn)3]3+. 相似文献
26.
Helga Wittmann W. Dreveny E. Ziegler 《Monatshefte für Chemie / Chemical Monthly》1968,99(3):1205-1216
Zusammenfassung 1,8-Trimethylenchinisatin-hydrat (TMCH) reagiert mit Aminosäuren zum farblosen Bis-(2-oxo-4-hydroxy-1,8-trimethylen-1,2-dihydro-3-chinolinyl)-amin (2). Da2 bei der Dehydrierung in das Farbsalz5 übergeht, welches eine dem Ruhemann-Purpur analoge Struktur aufweist, ergeben sich neuartige Aspekte zur Deutung des Mechanismus der Ninhydrin-Reaktion.
1.8-Trimethylenequinisatin hydrate (TMCH) reacts with amino acids yielding the colorless bis-(2-oxo-4-hydroxy-1.8-trimethylene-1.2-dihydro-3-quinolyl)-amine (2). Upon dehydrogenation of2 the dye salt5 is obtained. Because of the close relationship between5 and Ruhemann's purple a re-interpretation of the mechanism of the ninhydrin reaction could be made.相似文献
27.
Synthesis and Characterization of cis- and trans-Bis(benzonitrile)dichloroplatinum(II). X-Ray Structure Analysis of Both the cis- and trans-Species The compounds cis- and trans-(C6H5CN)2PtCl2 were synthesized and characterized by means of IR and Raman spectroscopy and by X-Ray structure analysis. The trans-species crystallizes triclinic, C—1 , the cis-compound monoclinic, C—P21/c. 相似文献
28.
Zusammenfassung Polyäthyleniminzellulosen sorbieren Cu2+ durch koordinative Bindung als Zentralion des sekundären Stickstoffs des Polyäthylenimins im PH-Bereich 3,5 bis 4,5 selektiv aus verd. Lösungen. 10g Kupfer können von 105fachen Überschüssen anderer Übergangsmetalle separiert, mit verd. Salzsäure eluiert und mit Diäthyldithiocarbamat photometrisch bestimmt werden. Das Verfahren eignet sich zur Erfassung von 0,001% Kupfer in Zink, Mangan, Kobalt, Nickel, Cadmium und Aluminium sowie aus Lösungen, deren Kupfergehalt 0,02 ppm beträgt.
Selectivation of small amounts of copper with polyethyleneimine-cellulose
Summary Polyethyleneimine celluloses selectively sorb Cu2+ from dilute solutions through coordinative bonding as central ion of the secondary nitrogen of polyethyleneimine in the pH-range of 3.5–4.5. 10g of copper may be separated from 105-fold excesses of other transition metals, then eluted with dilute hydrochloric acid and determined photometrically with diethyldithiocarbamate. The method is suitable for determining 0.001% copper in zinc, manganese, cobalt, nickel, cadmium, and aluminium as well as in solutions whose coppercontent is 0.02 ppm.相似文献
29.
Max Ziegler und Walter Rittner 《Fresenius' Journal of Analytical Chemistry》1958,164(3):310-313
Zusammenfassung Die Trennung der Thioglykolsäurekomplexe des Molybdäns von dem des Vanadiums verläuft mit einer Molybdänausbeute von 99%. Das Vanadium kann im Durchlauf in bequemer Weise mittels Thioglykolsäure im pH-Bereich 4,5–8 bei guter Genauigkeit photometriert werden.Herrn Prof. Dr. O. Glemser, Direktor des Anorganisch-Chem.-Instituts, danken wir sehr für das stete Interesse und die Unterstützung, die er uns zuteil werden ließ.Dem Herrn Bundesminster für Atomkernenergie und Wasserwirtschaft sowie der Deutschen Forschungsgemeinschaft danken wir für apparative und finanzielle Hilfe. 相似文献
30.