Über die Struktur von geschmolzenem Selendioxid

About the Structure of Molten Selenium Dioxide The Raman spectra of molten and gaseous selenium dioxide are nearly identical. The number of bands indicates the existence of a temperature depending equilibrium of monomeric and dimeric selenium dioxide in the molten and the gaseous state. A chain structure as in the crystal could not be found. An oxygen-bridged planar ring seems most likely for the structure of the dimer. Broadening of bands two intense, polarized lines at ν = 955/966 cm^?1 indicate an equilibrium of the trans-(C_2h) with the cis-structure (C_2v).     

Über die Halogenaminierung von Diseleniden. Synthese und Struktur des achtgliedrigen Ring-Kations [Me2SN2SeMe]2++

On the Haloamination of Diselenides. Synthesis and Structure of the Eight-membered Ring Cation [Me₂SN₂SeMe]₂⁺⁺ N-halogen compounds of benzamidine and S,S-dimethylsulfone diimides react with diselenides by Se? Se-bond cleavage yielding different types of selenium-nitrogen compounds. With N-bromo-benzamidine the diazene derivatives RSeN(Ph)CN?NC(Ph)NSeR 2a, b (a : R = Me; b : R = Ph) are formed. In the reaction of N,N′-Dichloro-S,S-dimethylsulfone diimide, Me₂S(NCl)₂, with diselenides cyclic hetero-selenonium salts [(Me₂SN₂SeR)Cl]₂ ( 4a, b ) are obtained. The structure of the eight membered ring compound 4a was determined by x-ray crystallography (space group P1 , Z = 1) and compared with that of the isotypic sulfonium salt [(Me₂SN₂SMe)Br]₂ ( 3a ).     

Struktur und Eigenschaften quaternärer Chalkogenide MIAIIIBIVX. III. Über die Verbindungen AgTiZrTe4 und Ag2TiZrTe4

Structure and Properties of Quaternary Chalcogenides M^IA^IIIB^IVX . III. On the Compounds AgTiZrTe₄ and Ag₂TiZrTe₄ Preparation and properties of the compounds AgTiZrTe₄ and Ag₂TiZrTe₄ are reported. The structure deduced from X-ray diffraction diagrams is closely related to the structure of TiZrTe₄ showing an ordered accomodation of Ti and Zr atoms at the octahedral sites of the CdI₂ type structure. The interlayers free of Ti and Zr atoms are suggested to be in part occupied by Ag⁺ ions in an ordered sequency, which allows to explain the occurrence of 8 Te layers in the repeating unit.     

Über die Deammonisierung und Dehydroxylierung von NH4-Chabasit

Deammoniation and Dehydrosylation of NH₄-Chabazite The deammoniation of NH₄-chabazite is completely reversible. Compared to other investigated zeolites the hydrogen form of chabazite remains stable at higher temperatures and over a wider temperature range. Thermoanalytic and by IR spectrophotometry two types of OH groups with OH-stretching bands at 3565 and 3615 cm^?1 can be distinguished. Water saturation of H-chabazite at room temperature results in irreversible changes of the crystal structure. The thermostability of the deriving lattice is extremely low and no acidic OH groups are detectable any more. It is supposed that in the completely hydrated H-chabazite acidic H₃O⁺ ions solved out aluminium from the lattice which occupies some of the cationic lattice sites. The dehydroxylation is an irreversible process and is accompanied by a lattice collapse.     

Über die Eigenschaften des Xp-Teils von AnBXp-Kernresonanzspektren

The subspectral breakdown of the X-part in A_nBX_p-spectra is derived and the general properties of the subspectra are discussed. The nature of the asymmetry of X_p-spectra for n > 1 is explained and conditions for its disappearance are given. The degeneration of the X_p-part into deceptively simple spectra is described and degeneration conditions are derived. The determination of relative signs of coupling constants is discussed.     

Über die acetolysenprodukte der cyanhydrine von 4-pyridazoin und 4-pyridoin: Struktur und ungewöhnliche reaktivität 9. Mitteilung über pyridazine

4-Pyridazoinecyanohydrin was found to be converted into the 1,4-dihydropyridazine derivative 2a on treatment with acetic anhydride. Structures of 2a and the corresponding 4-pyridine derivative 2b were assigned on the basis of spectroscopic data. Chromatography of 2a on silica gel using methanol as eluent yielded methyl 4-pyridazinecarboxylate. The pyridine derivative 2b under similar conditions was converted into a mixture of methyl isonicotinate and 4-pyridinylmethyl acetate. Mechanisms of these unexpected reactions are discussed.     

Über die Herstellung des Methyl-α-D-fructopyranosides und die Struktur der dabei gebildeten Orthoester

Concerning the preparation of methyl α-D -fructopyranoside and the structure of the orthoester by-products Koenigs-Knorr glycosidation (AgClO₄/Ag₂CO₃) of the easily accessible p-nitrobenzoylated fructosylchloride 7 yields mainly the protected glycoside 3 which was deacylated to the known title compound 1 . The orthoesters 15 and 16 were formed as by-products in this glycosidation whilst the analogous orthoesters 21 and 22 are formed as main products in the glycosidation (Ag₂CO₃) of the benzoylated fructosylchloride 12 . The structure of these orthoesters was deduced mainly from their spectroscopic data, from those of their derivatives 17 , 18 , 19 , 20 , 25 and 26 and by comparison of the latter with the model compounds 31 and 34 .     

1,2-Diphospha-3,4-diboretane und 1,3-Diphospha-2,4,5-triborolan: Synthese und Struktur sowie Berechnungen zur Molekülstruktur Über den Einfluß von Substituenten auf die Struktur von 1,2-Diphospha-3,4-diboretan

1,2-Diphospha-3,4-diboretanes and 1,3-Diphospha-2,4,5-triborolane: Synthesis and Structure as well as Calculations on the Molecular Structure On the Effect of Substituents on the Structure of 1,2-Diphospha-3,4-diboretane [2 + 2]-Cyclocondensation reactions led to the synthesis of the 1,2-diphospha-3,4-diboretanes [(t-BuP)₂B₂(NMe₂)₂], 1 a , and [(t-BuP)₂B(NMe₂)B(NiPr₂)], 1 b . Their molecular structures have been determined by X-ray methods, and these are compared with the structure of [(t-Bu)P? BN(iPr₂)]₂, 2 a . Compounds 1 show a folded B₂P₂ four membered ring having tert.-butyl groups in anti-positions. Ab initio calculations on 1,2-diphospha-3,4-diboretanes demonstrate that two conformers with anti-orientation of the substituents at the phosphorus atoms can be expected. These differ by the relative orientation of the almost planar P₂BR groups to the BP₂ plane. The influence of substituents (H and NH₂ at the B atoms, and H and Me at the P atoms) on the ring conformation has been studied. Finally, the first derivative of a 1,3-diphospha-2,4,5-triborolane, 3 a , is reported.     

Über die Cyanamidolyse von Natriumtri- und -tetrametaphosphat

Cyanamidolysis Reactions of Sodium Tri- and Tetrametaphosphate Reactions of Na₂NCN with sodium tri- and tetrametaphosphate are leading to the formation of Na₃PO₃N₂C, NaPO₂(N₂(C)₂), Na₃PO₄, and Na₄P₂O₇, respectively. In alkaline aqueous solutions hydrolysis and cyanamidolysis reactions occur parallel. The course of the different reactions is discussed.     

Über einige Umwandlungsprodukte des «BLIX-Sulfatids» und die Herstellung von quartären Dihydro-sphingosinium-Salzen

In the sulfatide fraction of beef spinal-cord, isolated according to the method of BLIX [9] and LEES [14], there are also sulfatides present derived from 2S, 3R-1, 3-dihydroxy-2-amino-octadecane.     

Anil-Synthese. 23. Mitteilung. Über die Herstellung von Styryl- und Stilbenyl-Derivaten des Pyrimidins

Preparation of Styryl and Stilbenyl Derivatives of Pyrimidines 2- and 4-(p-Tolyl)-substituted pyrimidines react with anils of hetero-aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide or potassium t-butoxide to yield the corresponding 2- and 4-[4″-(heteroaryl)stilben-4′-yl]pyrimidines or the 2- and 4-[a-(heteroaryl)-4′-styryl]pyrimidines respectively (‘Anil synthesis’). Furthermore, the Schiff′s bases derived from p-chloroaniline and 4-(pyrimidine-2-yl and 4-yl)benzaldehydes give, with methyl- and with p-tolyl-substituted heterocycles, the corresponding heterocyclic substituted styryl and stilbenyl derivatives. Alkyl-, alkoxy- or phenyl-substituted pyrimidines undergo also the ‘Anil synthesis’.     

Über die absolute Konfiguration der Cantharsäure und des Palasonins

The absolute configurations of (+)-cantharic acid, a chiral derivative of the achiral insect defensive substance cantharidin ( 1 ), and of palasonin, a lower homologue of 1 occurring in the plant Butea frondosa, were shown to be represented by formulas 2 and 3 , respectively (scheme 1). These results were obtained by application of the Horeau method (table 1) on the (+)-cantharic acid derivatives (+)- 5 , (?)- 7 , and (?) 11 (scheme 2), and the palasonin derivatives (+)- 29 and (+)- 30 (scheme 4), as well as by comparison of the chiroptical properties (tables 2 and 3) of a number of derivatives, prepared from either cantharic acid or palasonin. – Attempts to incorporate various radioactively labelled precursors into palasonin ( 3 ), using young and adult plants, have been so far unsuccessful.     

Über die Ozonisierungsreaktion von Iod in starken anorganischen Oxosäuren: Darstellung und Struktur von Iodosylverbindungen [1]

On the Ozonization Reactions of Iodine in Strong Inorganic Oxoacids: Preparation and Structure of Iodosyl Compounds The oxidation of elemental iodine with ozone in strong inorganic acids is a mild method for the preparation of iodosyl compounds. The formation of iodosyl sulfate in conc. sulfuric acid, of iodosyl fluorosulfate in fluorosulfonic acid and of iodosyl nitrate in non-aqueous nitric acid are described. The vibrational spectra of these compounds will be discussed.     

Zur Kenntnis der neuen Phosphorsulfidphase P4S9. II. Über verschiedene Methoden zur Darstellung und über die Eigenschaften und Konstitution des P4S9

Both, reaction of red phosphorus, P₄S₃ or P₄S₇ with sulphur, and elimination of sulphur from P₄S₁₀ yield the new phosphorus sulphide phase P₄S₉. This phase exists in two modifications. The properties and constitution of the P₄S₉ phase are described.     

Über die Matrixisolation von AsCl4F

Matrix Isolation of AsCl₄F The gasphase components during the sublimation of [AsCl₄]⁺[AsF₆]^? are characterized by means of mass and IR matrixisolation spectroscopy. The primary vaporization products are AsF₅ and the new halide AsCl₄F. The IR spectra of AsCl₄F and PCl₄F are compared and the calculated force constants are discussed. Other mixed halides of arsenic are formed under suitable conditions.     

Über die mechanische Aktivierung von Natriumchlorid und Natriumbromid

Mechanical activation (vibration milling) of NaCl and NaBr. Determination of primary particle size, lattice disturbance and lattice distortion by X-ray methods. Determination of surface area by the BET method. Oxidation of halogenide in activated salt in presence of bayerite. Catalytic HCl-abstraction from i-propylchloride on NaCl. The changes in chemical and catalytical behaviour of the activated samples are a function of the disorder of the solid.