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  • 101
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 155-160 
    ISSN: 0268-2605
    Keywords: tungsten trioxide ; electrochromism ; thin films ; chemical vapor deposition (CVD) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Crystalline and amorphous thin films of tungsten(VI) oxide can be prepared by chemical vapor deposition using a variety of volatile precursors below 500 °C. Deposition parameters for preparation of WO3 films from tungsten hexacarbonyl [W(CO)6], tungsten hexafluoride (WF6), tungsten ethoxides [W(OEt)x, x = 5, 6] and tetra(allyl)tungsten [W(η3-C3H5)4] are summarized. The electrochromic behavior of these films is comparable with that observed for WO3 films prepared by evaporation, sputtering and electrodeposition. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 2 Ill.
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  • 102
    ISSN: 0268-2605
    Keywords: chemical vapor deposition ; platinum ; palladium ; rhodium ; heterogeneous catalysts ; fluidized bed ; MOCVD ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new one-step method, entitled fluidized-bed metal-organic chemical vapor deposition (FBMOCVD) of preparing highly dispersed metal-supported catalysts is reported. The following complexes were studied and used as CVD precursors in presence of H2: [Rh(μ-Cl)(CO)2]2, Rh(allyl)3, Rh(acac)(CO)2, Pd(allyl)(hfac), Pd(allyl)(Cp), Pt(COD)(CH3)2. (acac, acetylacetonato; hfac, hexafluoroacetylacetonato; Cp, cyclopentadienyl; COD, cyclooctadienyl). In a first approach, depositions on planar substrates were carried out to establish the best experimental conditions to obtain good-quality deposits. X-ray diffraction, X-ray photo-electron spectroscopy and electron microprobe studies were realized on the resulting thin films. Analyses of the products contained in the gas phase after and during deposition were performed by mass spectrometry and GC-MS. Finally, catalysts prepared by FBMOCVD were characterized by transmission electron microscopy-energy dispersion spectroscopy (TEM-EDS), metal-loading determinations and specific-surface measurements (BET). Dispersed nanosized aggregates were obtained, showing high activities in alkene hydrogenation and alcohol hydrocarbonylation. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 7 Ill.
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  • 103
    ISSN: 0268-2605
    Keywords: Metal-organic chemical vapor deposition (MOCVD) ; precursors ; titanium ; vanadium ; carbonitride ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ceramic thin films containing titanium, vanadium, carbon, oxygen and nitrogen were obtained on steel substrates at 873 K, under nitrogen and helium gases and at low pressure, by chemical vapor deposition (CVD) from two organometallic precursors, CpTiCl2N(SiMe3)2 and Cp2VMe2 (Cp, cyclopentadienyl). Independent TG-DTA-MS and CVD studies of the two precursors showed their ability to co-decompose within compatible temperature and pressure domains. The mechanism of the reactions occurring inside the CVD apparatus was also approached by GC-MS and NMR analyses of the condensed decomposition products. CVD conducted under He gas confirmed that the formation of nitride resulted from the nitrogen atoms of the precursor, but the nitrogen content in the films remained lower than approx. 5%. Higher nitrogen contents (up to 12%) were only obtained when using ammonia as a carrier gas. Both precursors being air- and moisture-sensitive, high-purity CVD equipment was used to reduce oxycarbide formation. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 14 Ill.
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  • 104
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 189-199 
    ISSN: 0268-2605
    Keywords: single-source precursor ; tetrakis(diethylamido)chromium ; pyrolysis mechanism ; MOCVD ; low-temperature deposition ; chromium carbonitride thin films ; hard metallurgical coatings ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amorphous chromium carbonitride coatings with a low nitrogen content (3-8 at%) were deposited by low-pressure MOCVD in the temperature range 573-793 K using Cr(NEt2)4 as single-source precursor. This poor nitrogen incorporation is in agreement with the trends predicted by thermochemical calculations. XPS data, resistivity measurements and annealing experiments suggest that the films grown at 573 K are contaminated by organic species due to incomplete elimination of the ligands. The films deposited at higher temperature crystallize upon annealing at 873 K to form an orthorhombic ternary chromium carbonitride phase. The major volatile by-products of the MOCVD reaction were analyzed by 1H and 13C NMR. Their amount and the quasi-equimolar EtN=CHMe/HNEt2 ratio suggest that most of the NEt2 ligands are removed by a stepwise mechanism which probably occurs with other diethylamido complexes of transition metals when they are used as single-source precursors in MOCVD. The incorporation of the metalloid elements in the film is discussed in comparison with recent literature data. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 4 Ill.
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  • 105
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 201-220 
    ISSN: 0268-2605
    Keywords: MOCVD ; molybdenum oxycarbide ; chromium oxycarbide ; coating ; kinetics ; microstructure ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A review of the coating kinetics of molybdenum and chromium oxycarbides and a study on the properties of deposited films are reported. Molybdenum carbonyl, chromium carbonyl and their mixture were used to prepare coatings at temperatures between 170 and 450 °C on SS304 or SiC substrates by a process of metal-organic chemical vapor deposition (MOCVD). The processing parameters of the coatings, such as the evaporation of precursors, coating pressure and temperature, are discussed along with the coating rates, compositions and other microstructural information, so to reveal the kinetics of the coating process on two different substrates. In addition, the chemical composition, crystalline phases and microstructure of the coatings obtained in various conditions are presented with the evidence interpreted by various electron-microscopic and spectroscopic techniques, including XRD, EDS, EPMA and XPS. The dependence of some properties, such as hardness, adhesive strength and corrosive resistance of the coatings on SS 304, on their composition and the deposited phases, i.e. as a function of coating temperature and pressure, is reviewed. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 14 Ill.
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  • 106
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 221-236 
    ISSN: 0268-2605
    Keywords: MOCVD ; barium ; liquid delivery ; mixed-metal species ; aerosol-assisted CVD ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Conventional MOCVD techniques require molecules displaying volatility and constant vapor pressure. Metal oxide precursors, i.e., β-diketonates, or classical or functionalized metal alkoxides are mostly solids. The various approaches used to tailor volatility are discussed with barium derivatives as an example. The relationships between sublimation temperature and molecular weight suggest that volatility can be optimized on the basis of molecular weight.   Aerosol-assisted CVD (AACVD) can use a larger range of precursors since volatility is no longer crucial. The solvent is an undesired ballast in a CVD process. High solubility of the precursors in the selected solvent is thus desirable. ‘Stability’ here includes the absence of precipitation which would change the stoichiometry of the feed solution for multicomponent oxides. Precipitation is often promoted by hydrolysis; stability toward moisture is thus desirable. The use of mixtures of precursors based on different ligands (β-diketonates, β-ketoesterates, alkoxides) can lead to ligand exchange reactions giving homometallic species, sometimes of low solubility, or mixed-metal species by self-assembly, thus improving solubility and stability toward moisture. These aspects are illustrated in compositions related to high-Tc superconductors. Novel copper, yttrium, cerum(IV), barium-copper, yttrium-copper and praseodynium-copper species are reported. © 1998 John Wiley & Sons, Ltd.
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  • 107
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 293-293 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 108
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 109
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 294-294 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 110
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 111
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 295-296 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 112
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 296-296 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 113
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 114
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 296-297 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 115
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 297-297 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 116
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 117
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 298-298 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 118
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 237-241 
    ISSN: 0268-2605
    Keywords: tin ; iodomethane ; solubilization ; methyltin species ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dissolution of tin metal by iodomethane-water mixtures has been studied and the influence of several parameters on both the extent and rate of reaction investigated. The rate-determining step shows a pseudo-first-order dependence on iodomethane (CH3I). The reaction is strongly dependent upon both water and oxygen. The activation energy of only 16 kJ mol-1 is interpreted in terms of a facile bond-breaking and making process at the metal surface, generating methyltin species. Analysis by hydride generation and GC-AA confirmed the formation of methylated species ranging from monomethyl- to tetramethyl-tin; inorganic tin (from hydrolysis) was the major form, however. These findings are similar to those made earlier by us on the solubilization of arsenic from GaAs by alkyl halide-water mixtures, and a similar multi-step scheme is proposed. © 1998 John Wiley & Sons, Ltd.
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  • 119
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 243-251 
    ISSN: 0268-2605
    Keywords: arsenic ; speciation ; algae ; Fucus gardneri ; arsenosugar ; high-performance liquid chromatography (HPLC) ; inductively coupled plasma-mass spectrometry (ICP-MS) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsenic speciation in a brown alga, Fucus gardneri, collected in Vancouver, B.C., Canada, was carried out by using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). Hydride generation-atomic absorption spectrometry (HG-AAS) was used for total arsenic determination. The relative amounts of some arsenosugars 1 in growing tips are found to be different in comparison with the remainder of the plant. Fucus samples collected in summer contain 9 ppm of total arsenic. Most of the arsenic species are extractable. Fucus samples collected in winter contain relatively higher amounts of arsenic, 16-22 ppm, but only low amounts of this are extractable. © 1998 John Wiley & Sons, Ltd.
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  • 120
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 253-256 
    ISSN: 0268-2605
    Keywords: disilane ; gas source MBE ; synchrotron radiation ; silicon hydride ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Surface hydrogen and growth mechanisms are investigated for synchrotron radiation (SR)-assisted gas source molecular beam epitaxy (SR-GSMBE) using Si2H6 on the Si(100) surface in the low-temperature region. The surface silicon hydrides (deuterides) are monitored in situ during the epitaxial growth by means of infrared reflection absorption spectroscopy with a Si(100) substrate and a CoSi2 buried metal layer. It is concluded that the chemisorption of gas-phase reactive species such as SiHn and H generated by SR irradiation and the subsequent hydrogen desorption are the key mechanisms of SR-GSMBE at low substrate temperatures. © 1998 John Wiley & Sons, Ltd.
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  • 121
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 257-264 
    ISSN: 0268-2605
    Keywords: Rochow reaction ; cesium chloride ; rubidium chloride ; silicon impurities ; action of promoters ; scanning electron microscopy (SEM) ; energy-dispersive X-ray spectroscopy (EDX) ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Cesium chloride- and rubidium chloride-promoted Rochow contact masses based on both technical-grade and highly pure silicon have been investigated in the Rochow reaction and by REM/EDX surface analysis. The alkali-salt promoters seem to act analogously to the well-known zinc promoter, by localizing the reaction to distinct reactive areas and keeping free the surface area for the reaction, probably for the formation of catalytically active Cu-Si surface species. The alkali salts exhibited their promoting action only in combination with the impurities within the technical-grade silicon. Otherwise, they acted as blocking poisons. The promoter action of alkali chlorides in contact masses based on technical-grade silicon is possibly connected with the formation of salt melts, containing alkali chlorides and impurities. These melts, analogously to zinc chloride, could dissolve oxidic impurities from the silicon surface which otherwise would enhance the blocking of potentially active surface by extensive copper deposition. © 1998 John Wiley & Sons, Ltd.
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  • 122
    ISSN: 0268-2605
    Keywords: carbohydrate surfactants ; wetting behaviour ; siloxane ; silane ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The wetting behaviour of carbohydrate surfactants bearing siloxane, carbosilane, polysilane or silane moieties has been investigated. By static surface tension (γlv, σ) and wetting tension (γsv-γsl, α) measurements on a non-polar perfluorinated surface (FEP®), the contact angles of aqueous surfactant solutions above the critical micelle formation concentration (cmc) were determined. Surface tension and wetting tension react independently on defined changes in the chemical structure of the surfactant molecules. Siloxane surfactants reduce the surface tension most effectively, whereas for a neopentyl-substituted silane derivative the lowest solid/liquid interfacial tension was found. The data for isomeric siloxanes, carbosilanes and silanes suggest that donor-acceptor forces at solid interfaces have a maximum range of about 4.5 Å. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 8 Ill.
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  • 123
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 277-284 
    ISSN: 0268-2605
    Keywords: carboxylation ; methane ; carbon monoxide ; ytterbium(III) acetate ; manganese(II) acetate ; sodium hypochlorite ; acetic acid ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method of synthesis of acetic acid in water has been developed from the carboxylation of methane with carbon monoxide using lanthanide catalysts. Ytterbium(III) acetate has been found to be the most active catalyst among the compounds of the lanthanide series in the carboxylation reaction of methane with carbon monoxide. Sodium hypochlorite or hydrogen peroxide was used as the oxidant in this reaction. Sodium hypochlorite exhibited more favorable activity than hydrogen peroxide in the reaction. The catalytic activity was improved by the addition of transition-metal salts such as manganese(II) acetate. The best result has been found at a ratio of manganese(II) acetate to ytterbium(III) acetate of 1:10. The optimum reaction conditions (reaction temperature, 40 °C; time, 20 h; methane, 20 atm; carbon monoxide, 5 atm) have been obtained. © 1998 John Wiley & Sons, Ltd.
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  • 124
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 298-299 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 125
    ISSN: 0268-2605
    Keywords: Nickel-σ-organyl complexes ; dispersed atomic Ni(0) ; Ni(I) ions ; silica ; EPR ; FMR ; spectrum calculation ; strain ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dispersed atomic nickel(0) is formed during the reaction of the nickel-σ-organyl complexes with silanol groups at temperatures below 373 K. That nickel is oxidized to Ni(I) by protons of the silanol groups in a consecutive step. The Ni(I) portion amounts to about 70% w/w of the Ni used. Six different Ni(I) species are detected by electron paramagnetic resonance. They are stabilized by interaction with the silica surface and the organic moieties; they act as anchor ions for the Ni(0) atoms. Ni(0) crystallites stabilized in this way are about 0.5 nm in diameter after a treatment at 373 K. The influence of the Ni(I) ions on the collective, magnetic properties of the clusters is revealed by calculation of ferromagnetic resonance (FMR) spectra using the independent-grain approach according to Schlömann and Kotyukov. A strain of about 10 GPa is brought about in the nickel crystallites by the interaction with Ni(I) ions. © 1998 John Wiley & Sons, Ltd.
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  • 126
    ISSN: 0268-2605
    Keywords: magnetization reversal ; iron oxide particles ; SQUID ; atomic force microscopy ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report first measurements of the magnetization reversal of monodisperse 30 nm and 50 nm ferromagnetic Fe3O4 particles. These particles are produced in a carrier gas as an aerosol by spray pyrolysis. After production and size selection, they are precipitated on a silicon chip with a niobium SQUID (superconducting quantum interference device) incorporated on its surface. By changing a magnetic field in the plane of the SQUID, we can measure the magnetization reversal of the particles by the flux they induce into the SQUID. The angular dependence of this reversal is determined by rotating the magnetic field around the SQUID. Scanning electron microscope (SEM) images have confirmed the particle size and revealed the position of the collected particles. If the particle concentration is too high, we cannot detect changes in the magnetic moment of a single particle, but measure the magnetic properties of the whole assembly. If only a few particles are found on the SQUID loop the angular dependence of the magnetic reversal of a single particle can be measured; this result is compared with a simple model of magnetization reversal. © 1998 John Wiley & Sons, Ltd.
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  • 127
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 337-340 
    ISSN: 0268-2605
    Keywords: porous silicon ; luminescence ; light-assisted etching ; atomic force microscopy ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We present an investigation into a new technique for producing luminescent porous silicon with controlled lateral microstructure. The process is based on the effect of laser-assisted stain etching of silicon with hydrofluoric acid solution. With the further goal of preparing two-dimensional periodical arrays of luminescent microdots, we studied the accuracy of the technique by etching single submillimetre structures with a low-power laser. The size and exact position of the etched area are controlled by laser focusing and movement, respectively, with submillimetre accuracy. Samples exhibit orange luminescence when illuminated with UV or blue light.We have studied the dependence of the efficiency of the luminescence, the structure and the rate of etching on parameters such as the HF concentration, the intensity and wavelength of illumination and the doping level of the silicon wafer. Optimization of the process parameters, and consistency with assumed mechanisms of luminescence and etching process, are discussed. © 1998 John Wiley & Sons, Ltd.
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  • 128
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 341-346 
    ISSN: 0268-2605
    Keywords: silver halides ; nanoparticles ; pseudoisocyanine ; stability ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pseudoisocyanine (PIC) was adsorbed on colloidal silver halide nanoparticles where it formed aggregates (J-aggregates). The nanoparticles were prepared using a surfactant (AOT)/n-heptane/water microemulsion. The molecules of pseudoisocyanine replaced the molecules of surfactant (AOT) on the surface of the nanoparticles and caused an instability of the silver bromide dispersion. The stability could be improved by two methods: either by using an adsorption inhibitor (e.g. p-xylene) or by adding another surfactant (CTAB). The adsorption has also been carried out at low temperature: the stability of the particles was then improved, and the J-aggregates are smaller. © 1998 John Wiley & Sons, Ltd.
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  • 129
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 387-391 
    ISSN: 0268-2605
    Keywords: colloidal manganese ; ESR ; susceptibility ; antiferromagnetism ; superparamagnetism ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reduction of MnBr2·2THF (THF = tetrahydrofuran) using K[BEt3H] yields the organosol [Mn·0.3THF]x. According to the UV/Vis, ESR (electron spin resonance spectroscopy), HRTEM (high-resolution transmission electron microscopy), XPS (X-ray photoelectron spectroscopy) and XAS (X-ray absorption spectroscopy) data, this nanosized metal colloid consists of small THF-stabilized Mn0 particles which show, in susceptibility investigations, a diminished magnetic coupling as deduced from the Weiss temperature, Θ = 96 K. The Neél temperature TN is likewise strongly reduced in comparison with the bulk value (95 K). The THF-stabilized Mn0 particles exhibit superparamagnetism below 20 K, with a partial blocking at 10 K, and to our knowledge represent the first colloid consisting of particles of an elemental antiferromagnetic metal. © 1998 John Wiley & Sons, Ltd.
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  • 130
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    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 12 (1998), S. 305-314 
    ISSN: 0268-2605
    Keywords: mesoporous ; oxides ; nanostructures ; luminescence ; zeolites ; guest/host ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ordered porous inorganic compounds can now be synthesized with pore sizes between 0.3 nm and several tens of nanometers. The sharp pore size distribution of such materials and the ordered pore arrangement open possibilities for using them to organize matter on the nanometer scale. This overview highlights different aspects of this topic, using four selected examples: the spatial organization of molecules with high molecular hyperpolarizability to create a frequency-doubling element; the encapsulation of a laser dye which results in a new class of solid-state lasers; the encapsulation of small metal clusters in mesoporous ordered oxides; and the encapsulation of semiconductor clusters in such oxides. © 1998 John Wiley & Sons, Ltd.
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  • 131
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    Applied Organometallic Chemistry 12 (1998), S. 401-408 
    ISSN: 0268-2605
    Keywords: Metallocene ; Ziegler-Natta ; Polypropylene ; α-Olefins ; Catalysis ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of propylene using a mixture of racemic metallocenes and Ziegler-Natta catalysts was investigated. The polypropylene was obtained as a mixture of a fine powder and beads, with the powder being absorbed partially on the beads. The relative amount of the powder can be controlled by the concentration of the metallocene. The compatibility between the components of the mixed catalytic systems and the effect of the components on the rate of polymerization and on the properties of the new polymers were studied. The metallocene system dramatically affects the melt viscosity, isotacticity and molecular weight of the polymers. The two catalytic systems are able to act jointly, producing different polymers, for which separate melting and crystallization temperatures are obtained. © 1998 John Wiley & Sons, Ltd.
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  • 132
    ISSN: 0268-2605
    Keywords: density functional calculation ; binuclear metal carbonyl ; Cr2(CO)6+ ; laser ablation ; molecular beam ; optimized structures ; dissociation energy ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Density functional calculations have been made on a binuclear metal carbonyl ion Cr2(CO)6+ found in our laser ablation-molecular beam (LAMB) experiment. Optimized structures are calculated for three different conformations: T33 of D3d symmetry with three terminal carbonyl groups on each chromium atom, B2T22 of D2h symmetry with two bridging carbonyl groups and two terminal carbonyl groups on each chromium atom, and B4T11 of D4h symmetry with four bridging carbonyl groups and one terminal carbonyl group on each chromium atom. The most stable conformation is T33 which is 36.76 and 286.44 kJ mol-1 lower in energy than B2T22 and B4T11, respectively. The difference of conformation exerts a significant influence on the internuclear distance between chromium and the carbon of terminal CO, but hardly on the Cr-Cr bond length. For B2T22 and B4T11, longer C-O distances for bridging carbonyls compared with those for terminal ones indicate effective π*-back donation from the chromium atom to the bridging carbonyl groups. Furthermore, the relative abundance of Cr2(CO)n+ (n = 0-6) observed in our previous experimental study can be explained qualitatively by comparison of the excess energy produced in the formation of a Cr+-Cr bond with the CO dissociation energy of Cr2(CO)6+. © 1998 John Wiley & Sons, Ltd.
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  • 133
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    Applied Organometallic Chemistry 12 (1998), S. 467-468 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 134
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    Applied Organometallic Chemistry 12 (1998), S. 468-468 
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 135
    ISSN: 0268-2605
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 136
    ISSN: 0268-2605
    Keywords: metal clusters ; quantum-size effect ; nanostructures ; size effects ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Meta-cluster compounds can be exploited advantageously to study the evolution, with increasing size of the molecules of the physical properties of metal clusters from molecular to bulk-metal behavior. The metal-cluster molecules are well-defined, stoichiometric, chemical compounds. The molecules consist of a metal core of a variable number of atoms, surrounded by a shell of ligand atoms or molecules. Depending on the compound, the type of metal atom may be varied, whereas the core size can be changed from a few up to several thousands of atoms. Accordingly, these materials provide excellent model systems for monodisperse metal particles, embedded in a dielectric matrix, and can be investigated by the well-known experimental techniques of solid-state physics. © 1998 John Wiley & Sons, Ltd.
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  • 137
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    Applied Organometallic Chemistry 12 (1998), S. 815-818 
    ISSN: 0268-2605
    Keywords: desilylation ; hydroxyquinones t-butyldimethylsilyl ethers ; potassium fluoride ; tetra-n-butylammonium fluoride ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Desilylation of a series of hydrolytically stable hydroxyquinone t-butyldimethylsilyl ethers was achieved in high yields by the use of potassium fluoride in the presence of catalytic amounts of aqueous 48% hydrobromic acid (HBr), or basic aluminium oxide (Al2O3), and tetra-n-butylammonium fluoride (Bu4NF) as cleaving agents. Copyright © 1998 John Wiley & Sons, Ltd.
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  • 138
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    Applied Organometallic Chemistry 12 (1998), S. 541-549 
    ISSN: 0268-2605
    Keywords: organotin speciation ; analytical validation procedure ; organotin sediment extraction ; Grignard derivatization ; organotin extraction stability ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of several extraction variables such as acid concentration and strength (e.g. for HCl and HOAc), the presence of complexing agents (e.g. tropolone, sodium diethyldithiocarbamate) in the extracting mixture, solvent polarity (e.g. hexane, toluene) and sonication time for native butyl- and phenyl-tin compounds from sediment was evaluated. A toluene-HOAc mixture (10:4) yields the highest extraction efficiency for all the analytes and minimizes the degradation of trialkyl- and triaryl-tins during the extraction under sonication. In addition, losses of underivatized monobutyltin and monophenyltin were minimized in several steps of the analytical procedure. The analytical procedure developed was validated against existing CRMs for butyltin determination. © 1998 John Wiley & Sons, Ltd.
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  • 139
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    Applied Organometallic Chemistry 12 (1998), S. 667-673 
    ISSN: 0268-2605
    Keywords: polysilanes ; poly(dimethylsiloxane) ; polyphosphazenes ; atom transfer radical polymerization ; controlled/‘living’ radical polymerization ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Recent advances in the synthesis of block, graft and star polymers containing inorganic macromolecular species are described. Anionic copolymerization techniques were used in the for-­mation of diblock copolymers of poly(styrene-block-methylphenylsilylene) and poly(isoprene-block-methylphenylsilylene) by the ring-opening polymerization of 1,2,3,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasilane initiated by living anionic polystyrene and isoprene respectively. Hydrosilation of an attachable initiator onto telechelic vinyl- or hydrosilyl-terminal or­-pendant poly(dimethylsiloxane) (PDMS) yielded a PDMS macroinitiator. This macroinitiator was used in atom transfer radical polymerization (ATRP) of styrene and isobornyl acrylate to produce ABA triblock copolymers. As a model for graft copolymers from a polyphosphazene backbone, chemical trans-­formation of hexachlorocyclotriphosphazene­resulted in hexafunctional molecules containing either benzyl bromide or bromopropionyl moieties. The initiator 1,1,3,3,5,5-hexakis[4-(2-bromopropionyloxymethyl)phenoxy]cyclotriphosphazene was used in the ATRP of styrene to yield a polymer with a narrow, monomodal molecular weight distribution. Chain extension of this star polymer with isobornyl acrylate is also described. © 1998 John Wiley & Sons, Ltd.
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  • 140
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    Applied Organometallic Chemistry 12 (1998), S. 695-705 
    ISSN: 0268-2605
    Keywords: poly(silylenemethylene) ; polycarbo-­silane ; silicon carbide ; precursor ; polysilaethy-­lene ; disilacyclobutane ; pyrolysis ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Work carried in the authors laboratory on Si-CH2-Si bridged polycarbosilanes is reviewed. In pursuit of high-yield polymeric precursors to silicon carbide, convenient synthetic routes to both linear and hyperbranched polycarbosilanes having a ‘[SiH2CH2]n’ compositional formula have been developed. The linear [SiH2CH2]n polymer was prepared by ring-opening polymerization of a substituted disilacyclobutane, and was studied both as an analogue of polyethylene and as a high-yield precursor to SiC. Elaboration of the methods employed to prepare this polymer has yielded a wide range of new poly(silylenemethylene)s (PSMs) of the type [SiRR′CH2]n, where R and R′ can be a wide range of different groups, including a series of symmetrically disubstituted polymers with R = R′ = F, alkyl and alkoxy which form crystalline solid phases and various amorphous, atactic polymers having different R and R′ groups. By using (Si)-Cl replacement reactions analogous to those developed previously for polydichlorophosphazene, as well as hydrosilation reactions similar to those used for [Si(H)(Me)O]n, a series of side-chain polymers having various groups attached to Si through Si-C or Si-O bonded linkages were obtained. Similar polymer modification reactions have recently been developed for the branched oligomer/polymer analogue of these linear polycarbosilanes, leading to hyperbranched species with functional substituents, including a di(ethyleneoxy) methyl ether-terminated derivative which readily dissolves lithium salts. The results of studies of these novel ‘inorganic/organic’ hybrid polycarbosilanes are described and their properties are compared with those of related carbon-backbone and siloxane polymers. © 1998 John Wiley & Sons, Ltd.
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  • 141
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    Applied Organometallic Chemistry 12 (1998), S. 787-792 
    ISSN: 0268-2605
    Keywords: tetrakis(dimethylamino)titanium ; amminolysis ; precursor ; pyrolysis ; titanium nitride ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Precursors possessing Ti-N bonds were prepared by the reactions between Ti(NMe2)4 and each of three diamines H2NCH2CH2NH2, Me(H)NCH2CH2N(H)Me, HN(CH2CH2)2NH (Ti(NMe2)4:diamine = 1:2), and were converted into ceramics by pyrolysis. The reactions with H2NCH2CH2NH2 and HN(CH2CH2)2NH led to the formation of insoluble solids, whereas a soluble oil was obtained by the reaction with Me(H)NCH2CH2N(H)Me. The pyrolyses under argon gave carbon-rich Ti(N,C,O) phases,­but those under NH3- N2 resulted in the formation of Ti(N,C,O) phases with higher nitrogen contents. Despite the difference in precursor structures the pyrolysis behavior of three precursors under argon was rather similar, suggesting that the precursor obtained from Me(H)NCH2CH2N(H)Me was effectively cross-linked during pyrolysis. © 1998 John Wiley & Sons, Ltd.
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  • 142
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 319-341 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Reaktivität des 3-Äthoxy-1.2-diphenyl-cyclopropenylium-Kations (1) gegenüber C-Anionen des Malodinitrils, Cyanessigesters, Benzylcyanids etc. wird systematisch untersucht. Das Nucleophil kann sowohl am C-3 als auch am C-1 von 1 angreifen; diese Konkurrenz ist von Solvens und Substituenteneffekten determiniert. Die entstehenden Produkte - Δ1-resp. Δ2-Cyclopropen-3-äthyläther 9 bzw. 10, Methylencyclopropen-Derivate (16) oder ringoffene 1 : 1-Addukte (20) - werden in ihrer Struktur aufgeklärt und ihr Bildungsmechanismus diskutiert.
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  • 143
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 374-375 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 144
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    Berichte der deutschen chemischen Gesellschaft 102 (1969) 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 145
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 23-30 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die protonenkatalysierte Umsetzung von Arylcyanaten mit Dimethylsulfoxid liefert im ersten Reaktionsschritt Carbamidsäureester, die bei längerer Reaktionsdauer oder erhöhter Temperatur durch intermediär gebildeten Formaldehyd zu N.N′-Methylen-bis-[carbamidsäurearylestern] (5) kondensieren. Der Mechanismus des Primärschritts wird als ein der Pummerer-Reaktion analoger Zerfall eines aktivierten Komplexes aus Arylcyanat, Dimethylsulfoxid und Proton erkannt.
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  • 146
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 38-49 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phosphine können bei der Reaktion mit Aziden in α- oder γ-Position der Stickstoffkette angreifen. Für das in Substanz faßbare Staudinger-Addukt von Triphenylphosphin an Tosylazid belegen Infrarotspektren 15N-isotopenmarkierter Derivate eine unverzweigte R3P=Nγ—Nβ=Nα—X-Struktur. Bei der thermischen Zersetzung in Benzol zu N-Tosyl-P-triphenyl-phosphazen (4) wird nach massenspektroskopischen Untersuchungen ausschließlich γ.β-N2 abgespalten.
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  • 147
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 77-82 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Umsetzungen von Cl3-nFnCSCl (n = 1,2,3) mit F3CCO2Ag liefern in guten Ausbeuten Verbindungen vom Typ , die bei 20° unbegrenzt haltbar sind. Erhitzt man (1) im Bombenrohr auf 170°, so bilden sich Kohlendioxid und F3CSCF3, während beim Bestrahlen mit UV-Licht Perfluoracetanhydrid, F3CSSCF3 und F3CSO2SCF3 entstehen. Bestrahlt man mit (2) UV-Licht, so bilden sich CO2 und Cl2FCSCF3. Aus Thionylchlorid und Cl3-nFnCCO2Ag (n = 2,3) konnten nur die entsprechenden Anhydride und SO2 isoliert werden. Analog liefert Silberperfluorbutyrat mit F3CSCl die Zersetzungsprodukte F3CSSCF3, F3CSO2SCF3 und (C3F7CO)2O.
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  • 148
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 104-111 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bis-[β-chlor-β-alkoxy-äthyl]-sulfoxide 5 entstehen unter milden Bedingungen bei der Umsetzung von Thionylchlorid mit Vinyläthern im Molverhältnis 1:3. Bei der Reaktion C-substituierter Vinyläther mit Thionylchlorid sind nur 1 : 1-Additionsverbindungen isolierbar. - 5a bildet mit prim. und sek. Aminen Bis-[β-amino-vinyl]-sulfoxide 7, mit Triäthylamin das Eliminierungsprodukt 9 und durch intramolekulare Redox-Reaktion 10.
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  • 149
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 118-125 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Darstellung der zum trans-Pinansystem gehörenden Pinandiole-(2.3) (1 und 2) wird der konfigurative Zusammenhang der vier diastereomeren Pinandiole-(2.3) klar ersichtlich.
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  • 150
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 167-179 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Derivate des Hexahydro-1.2.4.5.3.6-tetrazadiborins (1a) entstehen bei der Einwirkung von Organylhydrazinen auf Diaminoborane oder Phenylbordichlorid. Physikalische Untersuchungen legen eine aplanare Ringstruktur mit Bevorzugung der Wannenform nahe.Die Hydrazinolyse von HB[N(CH3)2]2 mit CH3HN—NHCH3 und CH3HN—NH2 ergibt Dimere dieses Ringsystems. Es sind Methylderivate der pentacyclischen Käfigverbindung 20. Das aus Hydrazin und Bis(dimethylamino)-boran zugängliche polymere (HB-NH-NH)n zersetzt sich oberhalb von 110° unter N2-Abspaltung zu (H2B-NH-NH-BH2)n.
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  • 151
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 196-204 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das Dinucleotid 9 wurde aus dem Nucleotid 8 und einem Guanidinium-Salz des Adenosin-5′-phosphorsäure-amids zusammengesetzt. 8 erhielt man aus dem Silbersalz des 3-Carbamoyl-pyridons-(6) (1) und 2.3.5-Tri-O-benzoyl-D-ribofuranosylchlorid über die O-Verbindung (2), die zum N-Ribosid (3) umgelagert und nach Entbenzoylierung und Acetonierung in 2′.3′-Stellung des Ribosids 4a mit Cyanäthylphosphat und Dicyclohexylcarbodiimid in 5′-Stellung zum Nucleotid 8 phosphoryliert wurde. Die β-Verknüpfung in 4a (und damit in 9) wurde u. a. durch Korrelation mit dem analogen Glucosid 4b so gut wie sichergestellt.
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  • 152
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 243-254 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 6-Dimethylamino-fulven (1) wird von CH3OD im Sinne einer elektrophilen Substitution in 2- und 5-Stellung deuteriert; unter der Annahme einer Reaktion 1. Ordnung ergab sich in CH3OD/CDCl3 (3 : 1) bei 60° eine Halbwertszeit von 3.7 Stdn. H-3 und H-4 werden langsamer gegen Deuterium ausgetauscht, ebenso das Proton in der 4-Position von 6-Dimethylamino-2.3-benzo-fulven (15). Die π- und J-Werte von 1, 10, 15, 17 und 18 wurden ermittelt; die vicinalen Kopplungskonstanten der Fulvenprotonen erlauben Aussagen über die Beteiligung polarer Grenzstrukturen am Grundzustand.
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  • 153
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 289-296 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetrakis(diphenylphosphinomethyl)-methan, C[CH2P(C6H5)2]4, sowie Tetrakis(diphenylarsinomethyl)-methan, C[CH2As(C6H5)2]4, reagieren mit Halogenen zu Verbindungen des allgemeinen Typs C[CH2E(X)2(C6H5)2]4 (E = P, As; X = Cl, Br, J), in denen sämtliches Halogen im Festzustand und in Dichlormethan-Lösung kovalent gebunden ist. In stärker polaren Lösungsmitteln wie Dimethylformamid oder Acetonitril verhalten sich die Chlorderivate wie 1:2-, die Bromderivate wie 1 : 3- und die Jodverbindungen wie 1 : 4-Elektrolyte. Die aus sterischen Gründen mögliche Bildung von chlorverbrückten spirocyclischem, bromverbrückten bicyclischen und jodbrückenfreien Phosphonium- und Arsoniumkationen wird diskutiert.
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  • 154
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 342-350 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Phenyl-pyrrolidon (1b) wird durch UV-Licht in N-Phenyl-pyrrol (9) übergeführt. N-Phenyllactame mit mindestens 7 Ringgliedern (1d-f) lassen sich photochemisch in guten Ausbeuten in die Benz-aza-cycloalkenone 4d-f umlagern. Die Struktur der Photolyseprodukte wird spektroskopisch, durch Derivate und durch Abbau zu Anthranilsäure gesichert.
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  • 155
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 378-379 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 156
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 380-381 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 157
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 383-387 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Synthese von α-Pyridyl-glyoxal (2) (in Lösung) und einige Eigenschaften werden beschrieben.
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  • 158
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    Keywords: Chemistry ; Inorganic Chemistry
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    Notes: Die Solvolyse der Titelverbindungen ergibt ausschließlich Fragmentierung zu den entsprechenden Cycloalkenen, wenn Tosylat- und Aldehyd-Gruppe eine anti-periplanare Konformation einnehmen können. Ist dies ausgeschlossen, treten neben der Fragmentierung Ausweichreaktionen unter Wagner-Meerwein-Umlagerung ein.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 435-442 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus dem in flüssigem Ammoniak schwach sauren o-C6H4(C≡CH)2 (Ks1 ⋍ 7·10-6) werden durch die Neutralisationsreaktion (1) sowie die Verdrängungsreaktionen (2), (3) die Alkalisalze o-C6H4(C≡CM)2 (M=Li bis Cs) rein dargestellt und ihre IR-Spektren diskutiert. Durch konduktometrische Titration in flüssigem Ammoniak wird die intermediäre Bildung der Monoalkalisalze bei der Neutralisationsreaktion (1) nachgewiesen.
    Additional Material: 7 Ill.
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  • 160
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 459-468 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Amino-2-desoxy-D-glucit reagiert mit Aceton zur Diisopropylidenverbindung 9, die mit Chlorameisensäure-äthylester das cyclische Carbamat 11 liefert. Durch partielle Hydrolyse ist die 5.6-O-Isopropylidengruppe abspaltbar zu 12, welches durch Perjodatspaltung in die Pentose 13 übergeführt werden kann. Bei saurer Hydrolyse von 13 erfolgt spontan Ringschluß zur 4-Amino-4-N.5-O-carbonyl-4-desoxy-L-xylofuranose (17), einem Zucker vom Pyrrolidin-Typ. 17 und seine Derivate 15 und 16 zeigen eine Abweichung von der Hudsonschen Isorotationsregel.
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  • 161
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 522-527 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Umsetzung von α-Cyanzimtsäurederivaten (1a, 1b, 1c) mit Cysteamin (2) bzw. dem Thiazolinylessigester 3 entsteht das Oxo-tetrahydro-thiazolo[3.2-a]pyridin 8, das leicht zum Oxo-dihydro-thiazolo[3.2-a]pyridin 7 dehydriert wird.
    Additional Material: 2 Ill.
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  • 162
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 556-563 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Bis-trialkylphosphoranylidenamino-dialkyl-silanen (1 und 3) und doppelt-molaren Mengen Aluminium- oder Galliumtrialkylen werden ionisch aufgebaute Produkte (2, 4, 5, 8) gebildet, deren Kationen neuartige viergliedrige Ringsysteme enthalten. Diese kleinen Ringe vom Typ D sind Isostere der schon länger bekannten Verbindungsklassen A, B und C. Wie aus Konkurrenzexperimenten hervorgeht, werden Aluminiumatome den Galliumatomen als Ringglieder vorgezogen. Mit Indiumalkylen entstehen aus 1 nicht-ionische 2:1-Komplexe (9, 11), in denen jedes Stickstoffatom des zweizähligen Donators mit je einem Metallalkyl in Wechselwirkung tritt. Eigenschaften und NMR-Spektren der neuen Verbindungen werden angegeben und diskutiert.
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  • 163
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 568-574 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Unter sehr milden Bedingungen gelingt die Darstellung von Benzimidazolium- und Benzthiazoliumsalzen aus Carbonsäuren und o-substituierten N-Methyl-anilinen. Mit Ferrocencarbonsäure wurde ein Vertreter der bisher unbekannten Metall-π-Komplexe der Heteroanaloga des Sesquifulvalens erhalten.
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  • 164
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Freie 4-Amino-4.5-didesoxy-L-xylose und 4-Amino-4-desoxy-L-xylose wurden durch alkalische Spaltung aus ihren Derivaten 7 und 6 dargestellt und in ihren Reaktionen untersucht. Beide Verbindungen weisen in Lösung ein Gleichgewicht zwischen Pyrrolidin-Formen 11, 12, Δ1-Pyrrolin-Formen 13, 14 und den Dimeren 9, 10 auf, in dem die Dimeren 9, 10 weit überwiegen. Die Struktur der erhaltenen Dimeren 9, 10 folgt aus den NMR-Spektren von 9 und seiner Derivate und aus der Spaltung des N-Acetats 20 in 12 und 15. Die Dimeren werden durch Hydrierung, mit Schwefeldioxid und mit Blausäure glatt in monomere Derivate zerlegt. Sie sind gegenüber Salzsäurebehandlung überraschend stabil und bilden keine Pyrrolderivate.
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  • 165
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 528-547 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das spirocyclische Phosphoniumsalz 1 reagiert mit Lithiumalanat oder Natriumboranat zu Bis-2.2′-biphenylylen-phosphoran (2), das ungewöhnliche Spektraldaten aufweist. 2 kann seinen Wasserstoff als Proton, als Hydrid-Ion und überraschenderweise auch spontan als Atom abgeben! Das Bis-2.2′-biphenylylen-phosphoranyl-Radikal (3) liefert ein ESR-Dublett mit aP = 17.9 Gauß und dimerisiert u. a. zu einem Produkt 5 mit tri- und pentakoordiniertem Phosphor. Das durch Protonenabstraktion aus 2 erhältliche Phosphoranyl-Anion 4 steht im Gleichgewicht mit einem Phosphin-Carbanion 13, das auch unabhängig darstellbar ist.
    Additional Material: 2 Ill.
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  • 166
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 785-791 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das von Hattori und Mitarbb. erstmals aus den Blüten von Poncirus trifoliata isolierte und von Horowitz als Isosakuranetin-7-neohesperidosid aufgeklärte Poncirin 1a) wurde a) durch Kondensation von Phloracetophenon-4-neohesperidosid (2b) mit Anisaldehyd und Cyclisierung des primär erhaltenen Chalkonglykosides (3), b) durch Direktkupplung von Isosakuranetin (1) mit α-Acetobromneohesperidose nach Koenigs-Knorr und c) durch partielle Methylierung von Naringin (1c) synthetisiert. Die auf verschiedenen Wegen erhaltenen Glykoside stimmten untereinander und mit dem natürlichen Poncirin überein. Damit ist die Struktur 5.7-Dihydroxy-4′-methoxy-flavanon-7-β-[2-O-α-L-rhamnopyra nosyl-D-glucopyranosid] (1a) für das Poncirin bewiesen.
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  • 167
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 815-819 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Konstitution von 2exo-Methyl-norbornanol-(5exo) und -(6exo) (11 und 6) wird durch eine eindeutige Vergleichssynthese des 2exo-Methyl-norbornanols-(5exo) (11) bewiesen. 2exo-Methyl-norbornanol-(6exo) (6) wird in geringer Menge bei der Umlagerung von tertiärem 2endo-Methyl-norbornanol-(2exo) (9) mit Ameisensäure erhalten.
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  • 168
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 2835-2850 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Im Sinne einer Diels-Alder-Reaktion mit inversem Elektronenbedarf geben Cumalinsäureester (1) mit Ketenacetalen 1:1-Addukte der Struktur 3. Ihre Thermolyse führt führt zu 4-Alkoxy-benzoesäureestern, die Solvolyse zu 4-Alkoxy-isophthalsäuren bzw. -estern. 1 nimmt 2 Mol Äthylvinyläther (als elektronenreiches Dienophil) unter CO2-Abspaltung auf. Mit 1.1-Bis-[p-dimethylamino-phenyl]-äthen (13) und 1 unterbleibt die Dien-Synthese; es erfolgt vermutlich Anlagerung an die 5.6-Doppelbindung des Pyronringes zu 15.Aus Ketendiäthylacetal und Isodehydracetsäure-äthylester bzw. seinem 3-Nitroderivat entstehen unmittelbar die Benzoesäure-äthylester 10a bzw. 10b. Auch Ketenaminale, Keten-O.N-acetal oder das Inamin 16 reagieren mit Cumalinsäureestern entsprechend zu 12a, 12b und 17.Als 1.3-Dipolarophil addiert das Addukt 3c Diazomethan bzw. Phenylazid zu tricyclischen Reaktionsprodukten der vermutlichen Struktur 18 bzw. 20, deren Pyrolyse untersucht wird.
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  • 169
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1347-1356 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Urorosein entsteht durch Polykondensation von Indolyl-(3)-glykolsäure und anschließende Oxydation, wobei sich der α.β′-Diindolylmethen-Chromophor bildet. α.β′-Diindolylmethen (1-5) werden durch Reaktion von α-freien und β-freien Indolen mit Glyoxylsäure, α.β′-Diindolymethene (10-12) aus α-Formyl-indolen mit β-freien Indolen gewonnen. Oxo-β.β′- (13-16) und Oxo-α.β′-diindolylmethene (17-20) entstehen aus β-bzw. α-Formyl-indolen mit Oxindolen.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1357-1362 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Einwirkung von Vilsmeier-Reagenz auf Phthalimidine im Verhältnis 2 : 1 bilden sich Halogen-formyl-isoindole 3. Als Zwischenprodukte kann man Isoindolenine 2 bzw. deren Salze 1 isolieren. Bei Reaktion im Verhältnis 1 : 1 entsteht Verbindung 4.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 2881-2888 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bisher schwer zugängliche Äther verschiedener natürlich vorkommender Polyhydroxystilbene werden mit 60-95% Ausbeute durch Wittig-Reaktion erhalten.
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  • 172
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 2889-2899 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkoxy-diazenium-Salze 1 bzw. 2 reagieren nach Gl. (1) mit Carboxylaten zu Aryl- oder Alkyl-acyl-diazenen 4. Die Reaktion besitzt große Variationsbreite und erlaubt die Vereinfachung der Peptidsynthese über phenyldiazen-aktivierte Carboxylgruppen. Aus 1 und Cyanat-Ionen entstehen 3-Hydroxy-1.2.4-triazole (24a-c). Die Existenz des als Zwischenstufe postulierten 1.3-Dipols 9 wird durch Abfangen mit Acetylen-dicarbonester zu Pyrazolen 27a, b wahrscheinlich gemacht.
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  • 173
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 2922-2929 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 14 weiter neue p-fluor-phenylsubstituierte Organophosphorverbindungen wurden dargestellt und aus ihren 19F-NMR-Spektren die Hammettschen σp-Werte bestimmt. Von dem nun insgesamt vorliegenden Material wurden die Parameter und σRm berechnet und diskutiert, um damit die phosphorhaltigen Substituenten hinsichtlich ihres induktiven und mesomeren Verhaltens quantitativ festlegen zu können.
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  • 174
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1418-1421 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Synthese der Titelverbindung (2) sowie ihre Umsetzung mit o-Phenylendiamin und Amidrazonen zu den Heterocyclen 4-6 wird beschrieben. Unter den Bedingungen der Benzilsäureumlagerung und beim Versuch der alkalisch katalysierten Kondensation mit Dibenzylketon entstehen unerwartete Produkte.
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  • 175
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1410-1417 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2.3-Bis-alkylimino-oxetane (3) reagieren mit Verbindungen HX zu den offenkettigen Amiden 6, während sie in Gegenwart von Lewis-Säuren zu den ungesättigten Amiden 5 isomerisiert werden können. Die Abhängigkeit beider Möglichkeiten von der Struktur des Oxetans und den Reaktionsbedingungen wird herausgestellt. Von Aldehyden abgeleitete Oxetane (3, R1=H) reagieren mit Carbonsäuren unter Acylwanderung zu den Enolamiden 21. Weitere Reaktionen von Carbonylverbindungen mit Isonitrilen werden in einer Übersicht zusammengefaßt.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1422-1430 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Brom-1-phenyl-cyclobutendion reagiert mit o-Phenylendiaminen zu 1-Phenyl-2.8-dihydrocyclobuta[b]chinoxalinonen-(2) 1. Der Strukturbeweis wird mittels spektroskopischer Methoden und durch alkalischen Abbau geführt. Bei Verwendung unsymmetrischer o-Diamine wird die differenzierte Basizität der Aminogruppen als ausschlaggebend für die Stellung der Substituenten erkannt. Das Auftreten von Nebenprodukten 2 beim Einsetzen von symmetrischen o-Diaminen gibt Aufschluß über den Reaktionsmechanismus.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1431-1438 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Titelverbindung bildet mit primären und sekundären aromatischen Monoaminen und p-Diaminen die vinylogen Amide und Bis-amide 1-5. Dimethylanilin wird in p-Stellung elektrophil substituiert (6). Phenylcyclobutendion liefert mit Dimethylanilin unter 1.4-Addition das Arylierungsprodukt 7.
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  • 178
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3082-3087 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Methylierung des 1-Phenyl-5-p-tolyl-formazans (1) führt zu zwei isomeren N-Methylderivaten (2 und 3). 3-Methyl-1-phenyl-5-[4-nitro-phenyl]-formazan (4) bzw. 1.3-Diphenyl-5-diphenylcarbamoyl-formazan (7) ergeben unter gleichen Bedingungen nur ein N-Methylderivat (5 bzw. 8).
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3094-3101 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Natrium-trimethylsilanolat reagiert bereits bei Raumtemperatur mit N-Trimethylsilyl-carbonsäureamiden zu Natrium-carbonsäureamiden und Hexamethyldisiloxan. Mit Imidchloriden bildet es unter ähnlich milden Bedingungen  -  über die nicht faßbare Stufe der Natriumcarbonsäureamide  -  Hexamethyldisiloxan und acylierte Amidine. Diese sind auch aus Natrium- oder N-Trimethylsilyl-carbonsäureamiden und Imidchloriden zugänglich.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3122-3126 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Acyl-Umlagerung von 4-Acetoxy-cumarin (2) zu 4-Hydroxy-3-acetyl-cumarin (3) wird in Abhängigkeit von der Temperatur mit und ohne Lösungsmittel untersucht. Durch Abfang-und Kreuzversuche sowie durch Verwendung von deuterierten Verbindungen wird gezeigt, daß in allen untersuchten Fällen einem intramolekularen Mechanismus der Vorzug zu geben ist.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3139-3147 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus Bis-[2-chlor-äthyl]-amin (HN-Lost) und Derivaten aromatischer β-Hydroxy-vinylketone resultieren Bis-[2-chlor-äthyl]-[2-acyl-vinyl]-amine 6. Das Reaktionsverhalten dieser vinylogen Stickstofflost-Amide wird untersucht und der Einfluß von Substituenten auf ihre Stabilität im schwach sauren Medium diskutiert.
    Additional Material: 3 Ill.
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  • 182
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1449-1452 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Darstellung und Eigenschaften von 2.2″-Äthano-m-terphenyl (1) werden beschrieben. Aus dem temperaturabhängigen 1H-NMR-Spektrum kann auf zwei nebeneinander ablaufende innermolekulare Bewegungsvorgänge (A ⇌ B und A ⇌ C) geschlossen werden. Der Prozeß A ⇌ B besteht in einem Durchtreten des inneren aromatischen Wasserstoffatoms durch das Neunring-Innere; dabei muß wegen der sterischen Behinderung durch die gegenüberliegende H2C—CH2-Bindung eine Energiebarriere überwunden werden. Der Vorgang A ⇌ C läßt sich als eine Ringinversion auffassen, in deren Verlauf die quasiaxialen H-Atome der CH2-Gruppen in eine quasiäquatoriale Stellung übergeführt werden und umgekehrt.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3205-3216 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oxydation von O-Acetyl-N-[3-amino-2-hydroxy-4-methyl-benzoyl]-L-threonin-methylester (20h) mit Kaliumhexacyanoferrat(III) liefert zu 90% ein chromatographisch trennbares Gemisch aus 2.5 Teilen Pseudo-actinocinyl-bis-[O-acetyl-L-threonin-methylester] (21b) und 1 Teil N.N′-[2-Hydroxy-4.9-dimethyl-phenoxazon-(3)-dicarbonyl-(1.6)]-bis-[O-acetyl-L-threonin-methylester] (22b). Da nach diesem Kondensationsverlauf bei der Synthese von Pseudoactinomycinen (z. B. 13a) analoge Trennungen wie die von 21b.22b erforderlich werden und diese am Schluß der Synthese am einfachsten sind, ist für die Darstellung von Pseudo-actinomycinen die oxydative Kondensation von N-[3-Amino-2-hydroxy-4-methyl-benzoyl]-pentapeptid-lactonen wie 11a das Verfahren der Wahl.
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3235-3237 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3238-3240 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3241-3247 
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    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-[2-Dialkylamino-vinyl]-phthalhydrazide 1 werden, ausgehend von 3-Methyl-phthalsäuredimethylester, über 3-[2-Oxo-äthyl]-phthalhydrazid synthetisiert. Sie sind Vinyloge der sterische Resonanzhinderung aufweisenden 3-Dialkylamino-phthalhydrazide und übertreffen letztere hinsichtlich der Chemilumineszenz bei der alkalischen Oxydation, erreichen jedoch das Luminol (3-Amino-phthalhydrazid) bei weitem nicht, vermutlich wegen ihrer leichten Hydrolysierbarkeit.
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  • 187
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1480-1484 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: o-Hydroxyamino-benzoesäure-äthylester (1) bildet mit Methylisocyanat in Abwesenheit eines Katalysators das N-Carbamoylderivat 2; dieses cyclisiert mit Hilfe von Phenyldiazomethan zum 2.1-Benzisoxazolonderivat 3b. In Gegenwart von Triäthylamin als Katalysator reagiert 1 mit Methylisocyanat unter Bildung des Dicarbamoylderivats 4; in Gegenwart von Phenyldiazomethan dagegen liefert es über 4 hinaus je nach den Mengenverhältnissen Derivate des 1-Hydroxy-chinazolins (5b) oder des 2H-[1.2.4]Oxadiazolo[2.3-a]chinazolins (7), eines neuen heterocyclischen Systems.
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  • 188
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3127-3134 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Chlorierung des Perchlorvinylacetaldehyds (3) bei -45° führt zu n-Perchlorbutanal (9). Das von Böeseken und Mitarb. beschriebene „9“ muß eine andere Konstitution besitzen. Perchlorbuttersäure (7) ist durch Chlorierung von Perchlorvinylessigsäure oder durch Umsetzung ihres aus dem Methylester 2 und Chlor erhältlichen Chlorids 4 mit DMSO in Methylenchlorid gut zugänglich. 7 ist thermisch noch ziemlich stabil, aber überaus leicht hydrolysierbar. 9 zersetzt sich schon bei Raumtemperatur allmählich und wird durch Basen ebenso wie 7 zu Hexachlorpropen abgebaut.
    Type of Medium: Electronic Resource
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  • 189
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3148-3158 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1-Aza-bicyclo[1.1.0]butane 3 werden aus 1.3-Dibrom-2-amino-propanen 2 durch zweifachen intramolekularen Ringschluß dargestellt. Die Reaktion mit Säurechloriden, Säureanhydriden, Thiophenol, sek. Aminen, Chlorwasserstoff und Acetylendicarbonsäureester führt unter Spaltung der 1.3-Bindung zu Azetidinen 9. 1-Aza-bicyclo[1.1.0]butane 3 lassen sich katalytisch unter Aufnahme von 2 Moläquivv. Wasserstoff zu primären Aminen 15 hydrieren.
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  • 190
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3192-3204 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Massenspektren der nicht enolisierbaren Thioketone 1b-6b, bei denen die Thiocarbonylgruppe nicht Bestandteil eines Ringes ist, unterscheiden sich von denen der ihnen entsprechen den Ketone durch einen neuen Fragmentierungstyp. Dieser ist durch einstufige, radikalische Abspaltung der Sulfhydrylgruppe gemäß Schema (5) gekennzeichnet, die zur Bildung eines Fluorenyl-Kations führt. Der Vergleich der Massenspektren von Thiobenzophenon (1b) und 9-Mercapto-fluoren (16) weist darauf hin, daß vor der (M—SH)-Fragmentierung des Thioketons die Fluorenstruktur durch Umlagerung und Cyclisierung vorgebildet sein muß Die Massenspektren der Thioketone 7b-14b, bei denen die Thiocarbonylgruppe Bestandteil eines Ringes ist, zeigen keine Sulfhydrylabspaltung. Einige dieser Thioketone weisen gegenüber den entsprechenden Ketonen eine intensivere (M—1)-Fragmentierung auf.Die untersuchten Diazoverbindungen zeigen primär (M—N2)-Fragmentierung und sekundär Wasserstoffabspaltung. Diese Sekundärfragmente der Diazomethane 1c-6c haben die Struktur eines Fluorenyl-Kations.Fragmentierungsmechanismen und Vergleiche mit thermo- und photochemischen Reaktionen dieser Verbindungen werden diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 191
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3224-3228 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch Umsetzung des labilen Ammoniakats von Kupfer(I)-acetylacetonat CuC5H7O2·2.5 NH3 mit Phenylisocyanid, Triphenylphosphin bzw. 1.2-Bis-diphenylphosphino-äthan konnten die stabilen Komplexe CuC5H7O2·2 CNC6H5, CuC5H7O2·2 P(C6H5)3, CuC5H7O2·(C6H5)2P [CH2]2—P(C6H5)2 als praktisch farblose, diamagnetische Substanzen erhalten werden. Die IR-Spektren dieser monomeren Nichtelektrolyte werden diskutiert.  -  Die Reaktion des CuC5H7O2·2.5 NH3 mit 1.10-Phenanthrolin (phen) hingegen führt zu dem rotvioletten, kristallinen, diamagnetischen [Cu phen2]C5H7O2. Die salzartige Struktur dieses Acetylacetonats ergibt sich aus Leitfähigkeitsmessungen sowie aus den Absorptionsspektren im IR- und sichtbaren Bereich.
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  • 192
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3230-3232 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 193
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1513-1522 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Der Zerfallsmechanismus einiger monomerer Lignin-Bauelemente (1-13) mit verschiedener Struktur der Seitenkette wird beschrieben.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 194
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 1523-1528 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aus N-Fluorformyl-schwefeldifluoridimid (1) und Quecksilber-bis-schwefeldifluoridimid (4) dargestellt. Durch thermische Zersetzung von 4 läßt sich Thiazylfluorid in präparativem Maßstab sehr rein gewinnen. Mit Chlor und Brom reagiert 4 bei Raumtemperatur zu N-Chlor- bzw. N-Brom-schwefeldifluoridimid, mit Jod entsteht vermutlich N-Jod-schwefeldifluoridimid.
    Additional Material: 2 Ill.
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  • 195
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3229-3229 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 196
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ausgehend vom ungesättigten Keton 1 gelingt die stereoselektive Totalsynthese mehrerer heterocyclischer Indol- und Oxindol-Alkaloide. Speziell der stereoselektive Aufbau der C-19-Konfiguration sowie der Einfluß dieses Zentrums auf die Folgereaktionen werden diskutiert. Die Massenspektren der verschiedenen stereoisomeren Zwischenprodukte werden gegenübergestellt.
    Additional Material: 3 Tab.
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  • 197
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3599-3602 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 198
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3605-3605 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 199
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3298-3303 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Der Hauptinhaltsstoff von Chrysanthemum frutescens L. wird nach dem Vorbild der biogenetischen Bildung synthetisch dargestellt. Struktur und Konfiguration der Zwischenprodukte sowie der Mechanismus der für die Aromatisierung entscheidenden Chlorierung werden diskutiert.
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  • 200
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    Berichte der deutschen chemischen Gesellschaft 102 (1969), S. 3304-3309 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die aus Cyclooctatetraen und Azodicarbonsäure-diäthylester über mehrere Stufen zugängliche Hydrazoverbindung 3 liefert bei der Dehydrierung an Stelle der Azoverbindung 4 Bicyclo[4.2.0]octatrien-(2.4.7) (5). Die leicht erfolgende Stickstoffeliminierung aus 4 wird mit einem elektrocyclischen Mechanismus im Sinne einer Retro-Diels-Alder-Reaktion erklärt.
    Type of Medium: Electronic Resource
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