NMR-spektroskopische Untersuchungen an Mercaptophosphazenen. II. NMR-spektroskopische Untersuchungen an 15N-markierten Mercaptophosphazenen

N.M.R. Spectroscopic Investigations of Thiophosphazenes. II. N.M.R. Spectroscopic Investigations of ¹⁵N Labelled Thiophosphazenes Completely ¹⁵N labelled compounds of the type ¹⁵N₃P₃Cl_6?n(SR)_n, R = Et or Ph; n = 0, 2, 4, or 6, and of the type ¹⁵N₄P₄Cl_8?n(SR)_n, R = Et; n = 0, 4, or 8, were prepared and investigated by means of both ³¹P n.m.r. spectroscopy and ¹⁵N n.m.r. spectroscopy respectively. The coupling constants ²J_PP, in some cases only found by simulating the spectra, and the coupling constants ¹J_PN are given. The values of these coupling constants and their relation are discussed. The general tendency is visible, that with increasing coupling constant ¹J_PN the coupling constant ²J_PP decreases. With increasing grade of substitution n the ¹⁵N chemical shifts are changed to higher fields.     

Triaziridine. 6. Mitteilung. Substituententransformationen an Triaziridinen

Substituent Transformations on Triaziridines Several novel triaziridines were prepared by substituent transformations starting from the known dialkyl-triaziridine-carboxylates 1a – c , with the aim to study the influence of the substitution pattern on the properties of the triaziridine ring. The dialkyl-triaziridines 2a – c were obtained by (t-BuO^?)-mediated demethylation and decarboxylation and the dialkyl-triaziridine-methanols 4a – c by LiAlH₄ reduction. Further reduction of the tosylates of 4a , b with LiAlH₄ gave the methyl-dialkyl-triaziridines 3a , b . The dialkyl-triaziridines 2a , c could not be N-methylated directly with CH₃I, but the anions 10a , c , obtained from 2a, c with CH₃Li, yielded 3a , c . N-Methylation of 2a with (CH₃)₃OBF₄ did not afford 3a but rather the methyl-triaziridinium salt 11 . The dialkyl-triaziridine 2c has pK_a > 14, its protonated species < 2. A concept that the electron pairs on the triaziridine N-atoms are more strongly localized than on amine N-atoms explains (a) that the dialkyl-triaziridine 2c is hardly basic, (b) that the LiAlH₄ reductions of the esters 1 stop at the stage of the methanols 4 , and (c) that the methanols 4a , b do not cleave like aminomethanols.     

Rheooptische Untersuchungen an Hochpolymeren. 20. Mitt

Ohne Zusammenfassung     

Strukturuntersuchungen an Paramyosin. 1. Mitt.: Wasserstoffionen-Gleichgewichte

Ohne Zusammenfassung     

Reaktionen an Ziegler-Natta-Katalysatoren. 14. Mitt. Anwendung der Olefin-Metathese zum Nachweis einer Grignard-Wurtz-Reaktion an hydrobromiertem Polybutadien

Ohne Zusammenfassung     

Untersuchungen an oxidischen Katalysatoren. XLV. Umwandlung von Aromaten an dealuminierten ZSM-5-Zeolithen

Studies on Oxide Catalysts. XLV. Conversion of Aromatics on Dealuminated Zeolites ZSM-5 The catalytic properties of zeolites ZSM-5 dealuminated by hydrochloric acid are investigated in the isomerization of m-Xylene, the disproportionation of toluene and in the alkylation of toluene with methanol. Besides the increase of the Si/Al ratio, the dealumination leads to an inversion of the Si/Al concentration gradient in crystallites, to a shift of acidity spectrum and consequently to a change in catalytic activity and selectivity.     

Spektralanalytische Untersuchungen an Wolframerzen, 2. Mitt.

Zusammenfassung Es wurde das für Wolframit ausgearbeitete Verfahren in modifizierter Weise für die Bestimmung von Spurenelementen in Scheeliten angewendet. Es gelang, Kobalt, Nickel, Kupfer, Vanadium, Zinn, Wismut, Arsen, Chrom und Blei bis herab zu 0,001% zu bestimmen, der Nachweis von Antimon und Molybdän reichte nur bis 0,03%. Der mittlere Fehler betrug zwischen 3 und 9%.Da die direkte spektralanalytische Bestimmung von Phosphor in Wolframmineralien unbefriedigend sst, wurde ein chemisches Anreicherungsverfahren ausgearbeitet, wobei der Phosphor schließlich quantitativ in eine Aluminiumoxydmatrix überführt und mit spezieller Technik auf Kohleelektroden aufgenommen wurde; die Nachweisempfindlichkeit betrug etwa 0,003% P₂O₅ im Ausgangsmaterial bei einem Anreicherungsverhältnis 120. Als Bezugselement bewährte sich Gallium sehr gut, welches Reproduzierbarkeiten von 5% und darunter liefert.Mit 7 Abbildungen     

Untersuchungen an oxidischen Katalysatoren. XLIII. Thermoanalytische und katalytische Untersuchungen an platinhaltigen H-ZSM-5-Zeolithen

Studies on Oxide Catalysts. XLIII. Thermoanalytic and Catalytic Investigations of Platinum-Containing Zeolites H-ZSM-5 By impregnation with H₂PtCl₆ from ethanolic solution, after reduction a higher metal dispersion in zeolites Pt/H-ZSM-5 is achieved than by impregnation from aqueous solution. Over such samples, bifunctional catalyzed reactions are more favoured than over zeolites Pt/H-ZSM-5 obtained by impregnation with H₂PtCl₆ from aqueous solution.     

Untersuchungen an Zinnverbindungen. XVII. Infrarot-, RAMAN-, Mossbauer- und massenspektroskopische Untersuchungen an Triorganozinnfluoriden

The IR, in the solid state (33 to 4000 cm^?1) and in gaseous state, the RAMAN , MÖSSBAUER and mass spectra of (CH₃)₃SnF, (C₂H₅)₃SnF, (n-C₃F₇)₃SnF, (n-C₄H₉)₃SnF and (C₆H₅)₃SnF were recorded. The frequencies of the vibrational spectra were almost completely assigned. By means of this methods the properties of the triorganyl tin fluorides, which differ considerably from the other organyl tin halides, were examined. The difference in their properties are due in all cases to strong intermolecular interactions.     

Zur Erinnerung an R. Fresenius

Ohne Zusammenfassung     

Kernresonanzuntersuchungen an zeolithischen Heptagermanaten, 2. Mitt.

Zusammenfassung An zeolithischen Heptagermanaten der FormelMe ₃HGe₇O₁₆·xH₂O, (Me=NH₄, Li, Tl, Cs und Na;x=0–6) wurden Kernresonanzuntersuchungen durchgeführt. Es wurden Messungen an¹H und¹⁴N in Ammoniumzeolith sowie an⁷Li,²⁰⁵Tl,¹³³Cs und²³Na zwischen Zimmertemp. und der Temperatur des flüssigen Stickstoffs ausgeführt. Es zeigt sich, daß die Kationen Diffusionsbewegungen ausführen, die sowohl durch höhere Temperatur als auch durch das Vorhandensein von Wassermolekülen begünstigt werden.

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NMR investigation of zeolitic heptagermanates, II

Zeolitic heptagermanates with compositionMe ₃HGe₇O₁₆·xH₂O, (Me=NH₄, Li, Tl, Cs and Na;x=0–6) have been investigated by NMR. Measurements on¹H and¹⁴N in ammoniumzeolites and on⁷Li,²⁰⁵Tl,¹³³Cs and²³Na have been performed between room temperature and liquid nitrogen temperature. It is observed that the cations execute diffusional motions, which are favoured by higher temperature as well as by the presence of water molecules.

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Mit 9 Abbildungen     

Strukturelle Abwandlungen an Kohlenhydraten, 7. Mitt.

The synthesis of the title compound from 1,2:5,6-Di-O-isopropyliden-α-D-glucofuranose (1) via 1,2:5,6-Di-O-isopropyliden-α-D-gulofuranose (4) is reported. The key-step is the introduction of the azido function into4 which is achieved by using Triphenylphosphane/Diethylazodicarboxylate/HN₃.     

NMR-untersuchungen an piperidinen—III. 1H-messungen an alkylpiperidinen

The ¹H-220 MHz spectra of several alkylpiperidines are reported. Almost complete assignments for all ring protons are possible. The effects of N-methyl and C-methyl groups on adjacent ring protons are discussed in detail.     

Hydroxidgruppen an Zeolithen. I. Zahl und Eigenschaften von Hydroxidgruppen an CaNaY- und MgNaY-Zeolithen unterschiedlichen Austauschgrades

Hydroxide Groups on Zeolites. I. Number and Properties of Hydroxide Groups on CaNaY and MgNaY Zeolites of Different Degree of Ion Exchange The number of hydroxide groups was studied on CaNaY and MgNaY zeolites by D₂ exchange in dependence on the degree of exchange, and their properties were examined by infrared spectroscopy. At these zeolites there exist five types of hydroxide groups which differ by their concentration, their acidic strength, and their thermal stability. The OH-groups are produced mainly by dissociative chemisorption of water at the bivalent cations. The concentration of OH groups shows a characteristic dependence on the degree of ion exchange. There are OH groups which are strongly acid BRÖNSTED centers, capable of protonisation of pyridine, and others which are only capable of weak interactions with pyridine. The number of the acid BRÖNSTED centers increases with the degree of ion exchange analogous to the total number of the hydroxide groups and is highly dependent on the species of the cations exchanged and on the preheating temperature. Compared with CaNaY zeolites, MgNaY zeolites posess a greater number of hydroxide groups which are thermally more stable.