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101.
Frank Bachmann Joachim Reimer Marcus Ruppenstein Joachim Thiem 《Macromolecular rapid communications》1998,19(1):21-26
Starting from 1,4:3,6-dianhydrosorbitol (DAS, 1 ), a five step monomer synthesis led to 2-deoxy-1,4:3,6-dianhydro-2-isocyanato-L -iditol, 9 , which by catalytic polyaddition gave polyurethane 13 . A second route required the synthesis of 2-azido-5-O-chloroformyl-2-deoxy-1,4:3,6-dianhydro-L -iditol, 11 . During catalytic hydrogenation, the intermediate 2-aminochloroformyl derivative 12 underwent spontaneous polycondensation. The structure of 13 was characterized by 1H and 13C NMR, IR spectroscopy and elemental analyses. Gel-permeation chromatography showed M̄n = 8 000–12 000 corresponding to a degree of polymerisation up to 70. Differential scanning calorimetry revealed the polyadduct to be semicrystalline with a glass transition at Tg = 118°C and a melting range of 190–200°C. The polycondensation product was found to be crystalline with a melting range of 140–180°C. 相似文献
102.
103.
Silica-supported TEMPO catalysts: synthesis and application in the Anelli oxidation of alcohols. 总被引:1,自引:0,他引:1
The application of silica-supported TEMPO as a recyclable catalyst in the Anelli oxidation of alcohols is reported. The catalyst is easily obtained in a one-step reductive amination procedure starting from a commercially available aminopropyl-functionalized silica. Details of the synthesis of the supported catalyst and its analysis by MAS NMR are presented. Various alcohol oxidations according to the Anelli protocol have been carried out and the stability of the applied silica-supported TEMPO has been studied. 相似文献
104.
W. Vonau F. Gerlach U. Enseleit J. Spindler T. Bachmann 《Journal of Solid State Electrochemistry》2009,13(1):91-98
Novel glass electrodes for the determination of cations with reversible internal solid contact are introduced. They are based
on a semiconducting zinc oxide layer with a maximum thickness of 1 μm in contact with ion selective glasses on one side and
with a metal layer on the other side. The metal oxide layer is thereby generated either by ultrasonic spray pyrolysis from
zinc acetate solution, by electrochemical deposition from zinc nitrate solution or by spin coating from a dispersion of ZnO
in an organic binder. A following activation in a palladium chloride solution allows the chemical reductive deposition of
NiP as electronic conductor. Dipping-type and flow through electrodes as well as planar glass electrodes in thick film technology
fabricated in the above-mentioned method are described. In this case gold electrodes are applied by screen printing on isolated
steel substrates. The zinc oxide layers, created in different manners, are covered afterwards with cation selective glasses
in thick film technology. They cause a stabilisation of the half-cell potentials of the all solid state indicator electrodes
proved by suitable measurements. 相似文献
105.
The lowest-energy optical transition of two-electron-oxidized porphyrinogens [L(Delta)M] is a ligand-based charge transfer. The color of the intermediary, two-electron mixed-valent oxidation state shifts from vermilion (lambdamax = 480 nm) to yellow (lambdamax = 270 nm) upon increasing the ionic radius of the central metal dication from Mg2+ to Zn2+ and Ca2+. Structural, spectroscopic, and computational studies establish that the relative energies of the highest occupied and lowest unoccupied orbitals, between which the intervalence charge-transfer optical transition occurs, are modulated by the molecular dipole moment, which in turn depends on the only structural variable among the [L(Delta)M] compounds, the position of M2+ relative to the dianionic dipyrrole unit. 相似文献
106.
Bachmann S Hellriegel C Wegmann J Händel H Albert K 《Solid state nuclear magnetic resonance》2000,17(1-4):39-51
Pure organic polyalkylvinyl ether phases were synthesized by suspension polymerization using different ratios and compositions of n-butylvinyl ether (C4VE) and n-octadecylvinyl ether (C18VE) with triethylene glycol divinyl ether or divinylbenzene as crosslinkers, respectively. These phases were investigated by means of solid-state 13C cross-polarization magic angle spinning nuclear magnetic resonance (NMR) spectroscopy and 1H high-resolution magic angle spinning (HR MAS) NMR spectroscopy in suspended-state. A comparison of these two methods showed the substantial advantages of 1H HR MAS NMR measurements. Structure elucidation was achieved using a 2D H,H-COSY NMR experiment performed under MAS conditions enabling full peak assignment of the 1H NMR spectra of these phases. The dynamic behavior of the polyalkylvinyl ether phases was determined by employing temperature-dependent measurements of spin–lattice relaxation times (T1) as well as accumulation of a 2D wide line separation NMR spectrum. 相似文献
107.
108.
109.
Monochromatic low power radiation of a CO2 laser (1.5 W) initiates in diborane B2H6 a chain reaction in the course of which icosaborane(16) B20H16 is formed as the main product. This reaction is accompanied by visible luminescence. 相似文献
110.
Ohne Zusammenfassung 相似文献