Synthese und Eigenschaften von Polyacetylen

Polyacetylene is important because it can be transferred into metallic conducting phases by treatment with strong oxidizing or reducing agents (“doping”). The influence of the reaction conditions, especially of the polymerization catalyst, are investigated. The polymers obtained under normal conditions are always crosslinked. The morphology is independent of the polymerization method and can be described as an aggregation of lamellar particles with typical dimensions of a few 100 Å. The polymer chains are oriented perpendicular to the surface and chain folding is observed. The crystal structures of cis and trans polyacetylene are given. The consequences of the morphology on the mechanism of doping and charge transport are discussed using general structural principles.     

Synthese und Eigenschaften substituierter 1.4.2-Dithiazine

Synthesis and Properties of Substituted 1,4,2-Dithiazines Azidions react with 1,3-dithiolium salts to give the 2-azido-1,3-dithiolen 2 . In solution and at room temperature, 2-azido-2-methylthio-1,3-dithiols of the type 2a eliminate nitrogen forming N-methylthio-2-imino-1,3-dithiols 4 and 3-methylthio-1,4,2-dithiazines 5a, c–1 . The thermolysis of the more stable 2-azido-1,3-dithiol 2b proceeds in a less distinct way. Compounds 4 , exhibiting the properties of sulfenimides, easily yield the 2-amino-1,3-dithiolium salts 6 . The 1,4,2-dithiazines 5 are unstable at higher temperatures. They are converted to isothiazoles 11 with extrusion of sulphur. In a side reaction the compounds 5a, c–k eliminate methyl rhodanide, and 5b eliminates hydrogen cyanide. The formation of a dithiet or a dithioketone as an intermediate is proved by trapping with dimethyl fumarate. With strongly electrophilic reagents compounds 5 undergo ring contraction, yielding 1,3-dithiols, and with strong bases they react with ring opening.     

Synthese und spektroskopische Eigenschaften chiraler 1,3-Oxazolidine

Synthesis and Spectroscopic Properties of Chiral 1,3-Oxazolidines (1S,2S)-2-Amino-1-(p-nitrophenyl)-propan-1,3-diol 2a and the (1R,2R)-configurated isomer 2b react with N-substituted dithiocarbimidic acid diesters and ketenedithioacetals, respectively, to give the 2-substituted chiral 4-hydroxymethyl-5-phenyl-1,3-oxazolidines 4 and 7 . N-Carbmethoxy-dithiocarbimidic acid dimethylester yields under the same conditions the isomeric 1,3-oxazolidine 5 . On treatment of 4 and 7 with isocynantes crystalline urethanes 9 are formed.     

Synthese und Eigenschaften N-acylierter Thiophosphinsäureamide

Preparation and Properties of N-acylated Thiophosphinic Amides N-Acyl-, N-thioacyl- and N-sulfonyl-substituted thiophosphinic amides are prepared by the reaction of metallated acid amides with acid chlorides. The compounds exist as imides and form intermolecular hydrogen bonds. Their pK_a-values were potentiometrically determined and show a considerable acidifying influence of the thiophosphinic residues. Methylation of the imides with diazomethan gives predominantly S-methylesters of imidothiophosphinic acids.     

Fischer-Tropsch-Wachse Synthese,Struktur, Eigenschaften und Anwendung

Fischer-Tropsch-Waxes-Synthesis, Structure, Properties and Application Starting from the three general process directions of coal chemistry the application possibilities of synthesis gas as well in general as with respect to the Fischer-Tropsch-reaction, too, are discussed. The history of the development of the Fischer-Tropsch-synthesis, the reaction conditions and the process applied by SASOL is delt. Furtheron the structure of the Fischer-Tropsch-waxes, investigation possibilities as well as general relations (e. g. between molecular weight and characteristic values) are explained. Finally it is tried to derive from structural properties certain application properties.     

Synthese,Struktur und photophysikalische Eigenschaften von polyarylierten Imidazolen und Oxazolen

Synthesis, Structure, and Photophysical Properties of Polyarylated Imidazoles and Oxazoles 23 tetraphenylimidazoles 1,2 and 11 triphenyloxazoles 4,5 with amino, nitro, methoxy, hydroxy, or halogeno substituents chiefly in the para position were prepared. The absorption and fluorescence emission properties were investigated in ethanolic solution. The effects of the substituents in 1,2 on the spectral shifts show that the arrangement of the phenyl rings in 1 position is not coplanar in relation to the heterocycle whereas the phenyl rings in 2 position are more coplanar. The spectral changes of compound 2a in solvents of various polarity (dielectric constants 2,02–47,24) are almost negligible. The Stokes shift is moderately increased. A remarkable increase in the fluorescence quantum yield is observed by chlorine substitution in phenyl ring 2.     

Synthese und Eigenschaften kristallin-flüssiger Derivate des Rhodanins

Synthesis and Properties of Liquid Crystalline Derivatives of Rhodanine Substituted benzylidene-rhodanines 3 – 8 were prepared both by condensation of 1 a – f with suitable aldehydes and by acylation of 2a – g with substituted benzoyl chlorides or cinnamoyl chlorid. The mesomorphic properties of the compounds are discussed in respect to molecular structure with the aid of i.r.-, Raman- and u.v./vis-spectra of 3d , 3k , 4 , 5 , 6g , 8a . We have investigated the dielectric and electrooptic behaviour of 31 .     

Untersuchungen zur Synthese und den Eigenschaften von amphiphilen Polymeren

Investigations of the Synthesis and Properties of Amphiphilic Polymers By reaction of propylene/maleic anhydride copolymers with the sodium salt of α-dodecyl-ω-hydroxy-trioxyethylene ionic polymers with different shares of long aliphatic side chains were prepared. The properties of these amphiphilic polymers were studied. Like micelles they are able to solubilize nonpolar probe molecules (N,N-dimethyl-aminoazobenzene). Viscosity measurements show the dependence of the conformation of the polymeric chain in solution on the share of aliphatic side chain and the degree of protonation. The polymers from micelle-like aggregates. It is supposed that the polymer with a high share of aliphatic side chains froms several local aggregates per polymer chain, while the polymer containing only few side chains seems to form intermolecular aggregates between different polymer chains. These investigations were performed with pyrene as probe molecule. Pyrene was also used to examine the micropolarity of the aggregates. Like polyelectrolytes the amiphilic polymers are able to cause the aggregation of opposite charged dyes (thionine).     

Synthese und Eigenschaften von 2-Methoxycarbonylmethylen- und 2- (Formyl-methoxycarbonylmethylen)-2H-Thiopyran-3-carbonsäureme-thylester

Synthesis and Properties of Methyl-2-methoxycarbonylmethylene- and -2-(formyl- methoxycarbonylmethylene)-2H-thiopyran-3-carboxylates Dimethyl-2-chloro-propene-l,3-dicarboxylate is a easily available reactive C₂-building block for the synthesis of 2H-thiopyran derivatives la — n in good yields via [C₃S + C₂]-cyclisation reactions using β-thioxoaldehydes and their derivatives as C₃S-synthons. The structure of the stable red products with Z-configuration (side chain in position 2 of the ring) is elucidated by means of several analytical and spectroscopic methods including X-ray analysis of compounds 1h and lk . Treating of 1 with Vilsmeier reagent yields title compounds 2 with a remarkable less reactive formyl group at the exo-methylene group. There is obviously a shielding effect of the carboxylate groups.     

Synthese und Eigenschaften von Trimethincyaninen mit verbrückten Ketten

Synthesis and Properties of Trimethinecyanines with Bridged Chains The effects of meso-substituents (H, morpholino, ethoxy) and hydrocarbon bridges, on the light absorption and the electrochemical properties of trimethinecyanine dyes ( 4a--f , 8a–c 10a–f ) are investigated. The results are in a good agreement with the predictions of the perturbation theory. Methods for the preparation of the dyes involving reaction of methylthio quaternary salts ( 1a , b ) with enamines ( 2a , b ) are described.     

Synthese und Eigenschaften von Dian-Epoxidharz-Kompositen unter Verwendung eines latenten Beschleunigers

The synthesis of tertiary amine salts used as latent accelerator in the investigated diene composites of hardened epoxy resins prepared from modified Diels-Alder adducts of terpene hydrocarbons and maleic anhydride is described. The mechanical, electrical and thermal properties of cured resins have been examined. Out of a selected composite, with the help of the injection moulding method, a number of insulators was produced which were then subjected to further investigation. The composite under examination proved to be fully suitable for making electrical insulating materials with the traditional method as well as with the injection moulding method.