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  • Articles  (163)
  • Articles: DFG German National Licenses  (163)
  • Inorganic Chemistry  (163)
  • 1
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Konjugiert-ungesättigte C18-Fettsäuren werden unter Verwendung von Osmiumtetroxyd zu den entsprechenden Polyhydroxy-Fettsäuren hydroxyliert. Diese liefern mit Aldehyden und Ketonen 2.4.5-substituierte 1.3-Dioxolan-Fettsäuren. Einfach hydroxylierte Fettaldehyde lassen sich über die Diazoketone nach der Grundmannschen Synthese herstellen. Kondensiert man die Hydrazide der Polyhydroxy-Fettsäuren mit Acetylaceton zu den 1-acylierten 3.5-Dimethyl-pyrazolen und unterwirft diese einer Hydrogenolyse, so erhält man die entsprechenden Polyhydroxy-Fettaldehyde.
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  • 2
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Hochalkylierte Cyclohexane. - Röntgenstrukturanalyse, Kraftfeld-Berechnungen und Konformationen von cis/trans-1,4-disubstituierten Cyclohexan-IsomerenDie Struktur von mesyliertem cis- und trans-Tetramethylshisool cis-2 und trans-2 wurde durch Einkristall-Röntgenmethoden aufgeklärt. In cis-2 nimmt die Isopropenylgruppe im Kristall eine axiale Stellung ein, und die erhaltenen Strukturdaten stehen in gutem Einklang mit Kraftfeldberechungen. In trans-2 wurden zwei Rotamere, die durch Rotation der Isopropenylgruppe entstehen, durch NOE-Messungen zugeordnet. Der Vergleich der spektroskopischen Daten mit denen anderer Tetramethyllimonenderivate zeigt, daß diese in Verbindungen mit bevorzugt äquatorialer und bevorzugt axialer Lage der Isopropenylgruppe eingeordnet werden können.
    Notes: The structures of mesylated cis- and trans-tetramethylshisool cis- 2 and trans-2 have been elucidated by single-crystal X-ray techniques. In cis-2 the isopropenyl group adopts an axial position in the crystal, and the structural data obtained are in good agreement with those from force-field calculations. In trans-2 the two rotamers arising from rotation of the isopropenyl group were assigned by NOE measurements. Comparison of the spectroscopic data with those of other tetramethyllimonene derivatives showed that these can be classified into compounds with preferred equatorial and preferred axial position of the isopropenyl group.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 321-327 
    ISSN: 0009-2940
    Keywords: Trifluororthocarbonates of potassium, rubidium, cesium ; Phase transitions ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Crystal Structures of Potassium, Rubidium, and Cesium Trifluororthocarbonate and a Remark Concerning the Barium Sulfate Type1)Crystals of potassium, rubidium, and cesium trifluororthocarbonate (9a, 9b, and 9c) have been grown by Ostwald ripening in CH3CN applying a COF2 pressure of 3 bar. According to X-ray single-crystal structure analysis, 9a, 9b, and 9c belong to the baryte-structure family with an pseudotetrahedral anion being dynamically disordered at room temperature. All of the title compounds undergo a phase transition into a monoclinic, completely ordered low-temperature form, which has been refined for 9c. The C - O bond seems to be shortened by polar interactions. The results obtained with 9a, 9b, and 9c at room temperature indicate that the type of disorder found in 9 might be generally present in baryte-type compounds.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 118 (1985), S. 2607-2625 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Deamination Reactions, 41. Reactions of Aliphatic Diazonium Ions and Carbocations with EthersAliphatic diazonium ions and carbocations were generated by deacylation of appropriate nitro-soureas (1, 5, 9) in alcohol-ether mixtures or in 2-alkoxyethanols. Ethers were generally inferior to alcohols in capturing cationic intermediates. Formation of trialkyloxonium ions led to alkyl exchange or ring opening. The observed reactivity orders were n-butyl〉isobutyl for the diazonium ions, allyl〉sec-butyl〉tert-butyl for the carbocations, methoxy〉ethoxy and oxirane〉oxetane〉tetrahydrofuran for the ethers, indicating the predominance of steric effects. Neighboring group participation in 4-methoxy-1-butanediazonium ions (58) and 4,5-epoxy-1-pentanediazonium ions (74) was detectable but inefficient (〈 20% of cyclic oxonium ions).
    Notes: Aliphatische Diazonium-Ionen und Carbokationen wurden durch Entacylierung der entsprechenden Nitrosoharnstoffe (1, 5, 9) in Alkohol/Ether-Gemischen oder in 2-Alkoxyethanolen erzeugt. Die Ether waren den Alkoholen beim Abfangen kationischer Zwischenstufen stets unterlegen. Die Bildung von Trialkyloxonium-Ionen führte zu Alkylaustausch oder Ringöffnung. Die Reaktivitätsabstufungen n-Butyl 〉 Isobutyl bei Diazonium-Ionen, Allyl 〉 sec-Butyl〉tert-Butyl bei Carbokationen, Methoxy〉Ethoxy und Oxiran〉Oxetan〉Tetrahydrofuran bei Ethern weisen auf das Vorherrschen sterischer Effekte hin. Nachbargruppenbeteiligung war bei 4-Methoxy-1-butandiazonium-Ionen (58) und 4,5-Epoxy-1-pentandiazonium-Ionen (74) nachweisbar, aber wenig effektiv (〈 20% cyclische Oxonium-Ionen).
    Additional Material: 9 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 2007-2013 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclopentenone Derivative, XII1). - Studies on the Stereoselectivity of Intramolecular CycloadditionsChemical as well as stereochemical results of intramolecular cycloadditions in the cyclopentenone series are shown to depend very strongly on the nature of the connecting unit. With linking carbon chains as in 6 and 7, cycloaddition products 8 and 9 are formed with high but differing stereoselectivity, while the sulfur analogue 11 gives rise to a 1:1.4 mixture of steroisomers 12 and 13. Some stereoselective transformations of the cycloadducts are reported.
    Notes: Das chemische wie auch stereochemische Resultat intramolekularer Cycloadditionen in der Cyclopentenon-Reihe zeigt eine starke Abhängigkeit von der Natur des Verknüpfungsgliedes. Bei Überbrückung mit einer Kohlenstoffkette werden aus den Vorstufen 6 und 7 die Cycloadditionsprodukte 8 und 9 mit ausgezeichneter, wenn auch entgegengesetzter Stereoselektivität hervorgebracht. Einbau eines Schwefelatoms in die Kohlenstoffkette indessen führt vom Thioether-Analogon 11 zu einem 1:1.4-Gemisch der stereoisomeren Cycloaddukte 12 und 13. Einige stereoselektive Transformationen der Cycloaddukte werden mitgeteilt.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1383-1388 
    ISSN: 0009-2940
    Keywords: Phase-transfer catalysis ; Ozonides, ionic ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthetic Routes to New Ionic OzonidesNew synthetic routes to tetraorganylammonium ozonides involving exchange reactions with alkali metal ozonides were investigated. The previously reported reaction between tetraalkylammonium hyperoxides R4N+O2- (R = Me, Et) and alkali metal ozonides in liquid ammonia is severely hampered by the difficult synthesis of these hyperoxides; they are unknown for other quaternary ammonium cations. A similar reaction between the easily accessible chlorides of trialkylbenzylammonium ions and KO3 yields mixed ozonides/chlorides due to some solubility of KCl in liquid ammonia. The new compounds BzlMe3N+ (O3-)0.6Cl-0.4 (3), BzlEt3N+ (O3-)0.8Cl0.2- (4) and Bzl(nBu)3N+(O3-)0.5Cl0.5- (5) were prepared by this route. - The by far superior route to new ozonides utilizes macroreticular cation exchange resins in liquid ammonia. Batch equilibration between an excess of the appropriate ionic form of the resin and CsO3 produced Me3PhN+O3- (6), BzlMe3N+O3- (7), Bzl(nBu)3N+O3- (8), and (nPr)4N+ O3- (9) in almost quantitative yield. Compounds 4, 6, and 7 were studied by single-crystal X-ray analysis; the shortening of the ozonide bond length and the widening of the bond angle in comparison to the alkali metal ozonides as well as the possibility of C-H…O hydrogen bonding are discussed. Thermal stabilities were determined by DTA/TG methods, rapid decomposition starts at 59-79°C for 3, 6, and 7 and at 28-56°C for the remaining new ozonides which contain detachable β-H atoms.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 997-1001 
    ISSN: 0009-2940
    Keywords: Ionic ozonides ; Ammonium ion, bisquaternary ; C-H…O hydrogen bonds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bisquaternary ammonium ozonides Me3N+(CH2)n +NMe3(O3-)2 with n = 3, 4, 6 (1, 2, 3), Me3N+(CH2)3+NMe3(O3-)2 · 3 NH3 (1a), Me3N+(p-Ph)+NMe3(O3-)2 (4) and Me3N+(p-Ph)+NMe3(O3-)2 · NH3 (4a) were obtained in quantitative yields by cation exchange starting from CsO3. The compounds 1a and 3 have been studied by single crystal X-ray analysis. The influence of C-H…O and N-H…O hydrogen bonds on the bond length and the bond angle of the ozonide anion is discussed; earlier results are included. The difference between the two bond lengths within the O3- ion [137.4(3) pm and 129.5(3) pm] in 1a is unexpectedly large. Thermal stabilities determined by DTA/TG methods range from 24-83°C.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1761-1764 
    ISSN: 0009-2940
    Keywords: Endohedral ; Barium ; Fullerenes ; Dibarium fullerenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new route to endohedral fullerenes involving the evaporation of carbon and a metal at different positions, i.e. at different temperatures, in a radio-frequency furnace is described. For the first time, endohedral barium fullerenes within the composition range Ba@C74 to Ba@C136 have been produced in high yields as compared to hollow fullerenes, and have been extracted with CS2. Ba@C60, and Ba@C70, are only soluble in CS2 following sublimation. Furthermore, the first nonlanthanoid dimetallo fullerenes ranging in composition from Ba2@C88 to Ba2@C116 have been obtained. All endohedral barium fullerenes were characterized by mass spectrometry. Properties such as sublimation behaviour, solubility, and sensitivity to air have been studied.
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  • 9
    ISSN: 0009-2940
    Keywords: Ruthenacycloalkanes ; Osmacycloalkanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal-Containing Heterocycles: Preparation, Properties, Reactions, LXIV1. - Preparation and Investigations about the Reactivity of η2-Olefin Complexes and Four- to Six-Membered Metallacycloalkanes of Ruthenium and OsmiumThe olefin complexes (η2-CH2=CHR)M(CO)4 (3a, b, 5a, b) [R = H (3), CH3 (5); M = Ru (a), Os (b)] and four- to six-membered metallacycloalkanes (7a, b, 9b) [R = H (7), CH3 (9)], (11a, b, 15a, b) [n = 2 (11), 3 (15)], (13a, b) are obtained by nucleophilic elimination-cycloaddition on the alkanediyl bis(trifluoromethanesulfonates) YCH2CHRY [R = H (2), CH3 (4)], (YCH2)2CR2 [R = H (6), CH3 (8)], Y—[CH2]n—Y [n = 4 (10), 5 (14)], cyclo-C6H10(YCH2)2 (12) (Y = CF3SO2O) with the divalent anions [M(CO)4]2- (1a,b). The corresponding osmium compounds are much more stable than their lower ruthenium homologues. On the basis of the 1H-NMR spectrum 7b has a planar conformation. According to an X-ray structural analysis 15b crystallizes in the triclinic space group P1¯ with Z = 2 and has a chair conformation. Heating of 7b results in the formation of cyclopropane (16). Under argon the ruthena- and osmacycloalkanes 11a, b and 15a, b decompose with formation of the olefins 17-23. In the presence of CO from 7b, 11a, b and 15b the three- to six-membered cycloalkanones 24-27 are isolated at elevated temperatures.
    Notes: Die Olefin-Komplexe (η2-CH2=CHR)M(CO)4 (3a, b, 5a, b) [R = 1H (3), CH3 (5); M = Ru (a), Os (b)] und vier- bis sechsgliedrigen Metallacycloalkane (7a, b, 9b) [R = H(7), CH3 (9)], (11a, b, 15a, b) [n = 2 (11), 3 (15)], (13a, b) erhält man durch nucleophile Eliminierungs-Cycloaddition an den Alkandiylbis(trifluormethansulfonate) YCH2CHRY [R = H (2), CH3, (4)], (YCH2)2CR2 [R = H (6), CH3 (8)], Y—[CH2]n—Y [n = 4 (10), 5 (14)], cyclo-C6H10(YCH2)2 (12) (Y = CF3SO2O) mit den zwei-wertigen Anionen [M(CO)4]2- (1a, b). Die entsprechenden Osmiumverbindungen sind viel stabiler als ihre niedrigeren Rutheniumhomologen. Aufgrund des 1H-NMR-Spektrums hat 7b eine planare Konformation. 15b kristallisiert nach einer Röntgenstrukturanalyse in der triklinen Raumgruppe P1¯ mit Z = 2 und besitzt Sesselkonformation. Beim Erhitzen von 7b bildet sich Cyclopropan (16). Unter Argon zersetzen sich die Ruthena- und Osmacycloalkane 11a, b und 15a, b unter Bildung der Olefine 17-23. In Gegenwart von CO isoliert man aus 7b, 11a, b und 15b bei höheren Temperaturen die drei- bis sechsgliedrigen Cycloalkanone 24-27.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1711-1714 
    ISSN: 0009-2940
    Keywords: 2,4,6,8,10-Hexaoxa-1,3,5,7-tetraphosphatricyclo[3.3.1.1]decane 1-sulfide, molecular and crystal structure ; P4O6 derivatives ; Calculations, SCF, for P4O7 and P4O6S ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: P4O7 and P4O6S, Comparison of Molecular and Crystal StructureSingle crystals of P4O6S were grown for the first time. By X-ray diffraction the space group (P21/c), the unit cell [α = 813.5(1), b = 938.3(1), c = 993.1(1) pm; β = 90.27(1)°], and the crystal and molecular structure have been determined. As compared to P4O7, the geometry of the P4O6 cage remains virtually unchanged upon substitution of the terminal oxygen atom by a sulfur atom. Calculated charge distributions clearly confirm the experimental results. With the exception of P(1), to which the additional chalcogen atom is attached, the effective charges at all other atoms seem not to be affected by an exchange of the terminal oxygen atom by a sulfur atom.
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