Synthese und Reaktionen desDiels-Alder-Addukts aus Pyren und Hexachlorcyclopentadien

TheDiels-Alder adduct2 from pyrene and hexachlorocyclopentadiene exhibits a different substitution pattern than pyrene itself, namely that of phenanthrene. By reactions with the adduct following Retro-Diels-Alder splitting, pyrene substitution products are accessible that cannot be obtained by direct substitution of pyrene. This is demonstrated by the synthesis of 4-chloropyrene (5) and 4-bromopyrene (6).

Herrn Prof. Dr.Oskar E. Polansky zum 60. Geburtstag gewidmet.     

Das Pyren und der Einfluß von Substitution oder Komplexie-rung auf seine Geometrie und Packung im kristallinen Zustand

The crystal structures of pyrene and substituted and complexed derivatives of pyrene have been investigated by X-ray and neutron diffraction. The geometry of the pyrene skeleton has been determined experimentally with high accuracy and calculated by quantum chemical methods. In the cases reported in the literature and cited here the pyrene skeleton has the molecular symmetry mmm or mm2 with values for the bond lengths of the six symmetrically independent bondsa, b, c, d, e, f differing significantly in the limits of error. Mean values of a number of experimental and theoretical bond lengths are given and can be considered as standard values for the mm2 symmetric pyrene skeleton. In the case of substitution of the pyrene in 3-position with a polar heterocyclic molecule of the azomethine-imine type the mm2 symmetry vanishes, a C–H ... N intramolecular hydrogen bond arises and the directly neighbouring pyrene units are not packed parallel with their planes to each other, but they are considerably tilted. Relatively narrow intermolekular C-C contacts, 3.314 and 3.368 Å, have been observed. The conclusion is drawn that the asymmetry of the pyrene molecule and a tilt of directly neighbouring pyrene units in the crystal packing can be induced by substitution e. g. with suitable polar heterocycles.

Juli 1985.     

Die Komplexe Pyren · 2 SbCl3 und Phenanthren - 2 SbBr3 Phasenverhalten,Präparation und Kristallstrukturen

Complexes Pyrene · 2 SbCl₃ and Phenanthrene · 2 SbBr₃: Phase Behaviour, Preparation, and Crystal Structures The melting diagrams of the systems pyrene-SbCl₃ and phenanthrene-SbBr₃ were studied by DTA. They are quasibinary and display one intermediate phase each of molar ratio 1:2 and melting congruently at 143 and 114°C, respectively. Their structures were determined by X-ray diffraction using single crystals obtained by sublimation. In pyrene. 2 SbCl₃ the two halogenide molecules are arranged on different sides, in phenanthrene - 2 SbBr₃ on the same side of the plane of the aromatic molecule. Sb ?π interactions lead to distances of the Sb atoms from this plane of 315 to 323 pm.     

Nachweis und Bestimmung von Hydrastin und Berberin in Drogen und Extrakten

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Physikalische und physikochemische Mikromethoden und -apparate

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Titan und Eisen in Titan-, Eisen- und Zirkoniumerzen und -konzentraten

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Darstellung und strukturuntersuchungen von dimethylmetallacet- und acetimidohydrazinderivaten des galliums und indiums

Trimethylgallium and trimethylindium react with N′,N$\text{-}\text{?}$ dimethylacethydrazine and N′,N″,N′″-trimethylacetimidohydrazine, respectively, to form as a first step, monomeric dimethylmetal derivatives with five-membered ring skeletons. These heterocyclic compounds immediately add a further alkylmetal molecule. The ¹H NMR, IR and Raman spectra of these compounds are discussed and the results of X-ray structure determinations of two of the adducts are given.     

Acyclische und cyclische Silylhydrazone und Hydrazonylsilane

Acyclic and Cyclic Silylhydrazones and Hydrazonylsilanes Dimethylketone-di-tert-butylmethylsilylhydrazone ( 1 ) is obtained in the reaction of the silylhydrazine and dimethylketone by condensation. Di-tert-butyldifluorosilane reacts with lithiated hydrazones to give fluorosilylhydrazones 2–4 , (CMe₃)₂SiF? NH? N = CRR′, ( 2 : R=Me, R′=CMe₃; 3 : R,R′=CHMe₂; 4 : R,R′=Ph). The bis(hydrazonyl)silane 5 , (CMe₃)₂Si(NH? N=CPh₂)₂, is formed in a molar ratio 1:2. Tris( 6 )- and tetrakis(hydrazonyl)silanes ( 7 ) are obtained from CMe₃SiF₃ ( 6 ), SiF₄ ( 7 ), and lithiated tert-butylmethylketon-hydrazone. The lithium derivatives 8–11 are formed in the reaction of 1–4 with butyllithium. Bis(silyl)hydrazones ( 12–15 ) are the result of the reaction of halogensilanes and the lithium derivatives of 1(8), 2(9) and 3(10); 12 : (CMe₃)₂SiMe(CMe₃SiF₂)-N? N=CMe₂, 13 : (CMe₃)₂MeSi(PhSiF₂)N? N=CMe₂, 14 : (CMe₃)₂SiF(Me₃Si)N? N=C(Me)(CMe₃), 15 : (CMe₃)₂SiF (SiMe₃)N? N=C(CHMe₂)₂. Saltelimination out of 10 und 11 leads to the formation of the first bis(imino)-2,2,4,4-cyclodisilazanes, 16 :[(CMe₃)₂ SiN? N=C(CHMe₂)₂]₂, 17 : [(CMe₃)₂SiN? N=CPh₂]₂. Cyclisation occurs in the reaction of 12 und 14 with tert-butyllithium, 2-silyl-1,2-diaza-3-sila-5-cyclopentenes ( 18 and 19 ) are formed. Dilithiated 1 reacts with SiF₄ to give the spirocyclic compound 20 . HF-elimination from 18 and dimerisation of the intermediate diazasilacyclopentadiens lead to the formation of the tricyclus 21 .     

Intra- und intermolekulare elektronische und Schwingungsrelaxation

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Zur Anreicherung und Bestimmung von Platin und Palladium in Erzen und Konzentraten

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Struktur und retentionsverhalten von offenkettigen und cyclischen kohlenwasserstoffen und deren einfacher substitutionsprodukte

Modern hydrocarbon and especially olefin chemistry is concerned with the stereospecificity of catalytic reactions. Mixtures resulting from these reactions must be analyzed for all possible isomers. Only gas chromatography with high resolution and mainly open tubular columns is able to separate the different isomers of unsaturated hydrocarbons present in such mixtures. The identidcation of the separated species is difficult, as the modern combination of mass spectroscopy with capillary columns supplies spectra which are not characteristic enough for identification of such unsaturated hydrocarbons. However, the interpretation of retention data of hydrocarbons may be successful, because small structural variations correspond to definite differences of retention data. The chemical history of the analyzed products and, in the case of methyl-substituted isomers, data on the methylene insertion reaction, make it possible to obtain a relative correlation of separated species.