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  • 1988  (12)
  • 1981  (10)
  • Inorganic Chemistry  (15)
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  • 1985-1989  (12)
  • 1980-1984  (10)
  • 1975-1979
  • 1930-1934
  • 1890-1899
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1119-1121 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Alkali Triazaphosphininolates  -  synthesis and ReactionsThe alkali triazaphosphininolates 2, 3, 4, and 6 are obtained by the reaction of 2,2-difluoro- or 2,2-dichloro-4,6-bis(trifluoromethyl)-1,3,5,2λ5-triazaphosphinine (1 and 5) with NaOCHMe2, NaOCMe3, KOCHMe2, or KOCMe3 and LiOSiMe3. NaOSiMe2CMe3 reacts with 1 in a molar ratio 1:1 or 2:1 to give the siloxy-substituted compounds 8 and 92). The 2-fluoro-triazaphosphinin-2-ol 72) is formed in the reaction of 4 with HF. 7 reacts with KOH to yield 2. The reaction of the sodium triazaphosphininolate 3 with ClSiMe3 leads to the formation of the siloxytriazaphosphinine 10. The N-lithiotriazaphosphinine-2-amines 13 and 14 are obtained from the aminofunctional compounds 11 and 12 and LiN(SiMe3)2. 14 reacts with ClSiMe3 to give LiCl and 15.
    Notes: Die Alkali-triazaphosphininolate 2, 3, 4 und 6 werden durch Reaktion von 2,2-Difluor- bzw. 2,2-Dichlor-4,6-bis(trifluormethyl)-1,3,5,2λ5-triazaphosphinin (1 bzw. 5) mit NaOCHMe2, NaOCMe3, KOCHMe2 oder KOCMe3 sowie mit LiOSiMe3 erhalten. NaOSiMe2CMe3 reagiert mit 1 im molaren Verhältnis 1:1 bzw. 2:1 zu den Siloxyverbindungen 8 und 9. Das 2-Fluor-triazaphosphinin-2-ol 7 entsteht aus 4 und HF. 7 kann mit KOH in 2 übergeführt werden. Natrium-triazaphosphininolat 3 reagiert mit ClSiMe3 zum Siloxy-triazaphospininolat 10. Die N-Lithio-triazaphosphinin-2-amine 13 und 14 entstehen aus den aminofunktionellen Verbindungen 11 und 12 mit LiN(SiMe3)2. 14 reagiert mit ClSiMe3 zu LiCl und 15.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1393-1398 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Highly Substituted 1-tert-Butyl-1-silacyclohexadienesSilacyclohexadienes with bulky ligands and good leaving groups are of interest for experiments concerning the synthesis of kinetically stabilized silabenzene derivatives. Here we describe the synthesis of 1-tert-butyl-1-silacyclohexadienes, which are substituted in 1-, 2-, 4-, and 6-position. From lithiated precursors, the trialkylsilyl- or tert-butyl-substituted silacyclohexadienes 6, 8, 9, 12, 13, 14, and 15 are formed by substitution reactions. The methoxysilane 1 is transferred with LiAlH4 to the hydrosilane 2. Si—H or C—H bond cleavage with N-bromosuccinimide results in the formation of the silacyclohexadienes 3 and 5, brominated in 1- and/or 4-position. In some substitution reactions isomerisation of the diene system is observed. The new compounds are characterized by their 1H-, 13C-, and 29Si-NMR spectra and by their MS data.
    Notes: Mit sperrigen Liganden und guten Abgangsgruppen versehene Silacyclohexadiensysteme sind für Versuche zur Darstellung von kinetisch stabilisierten Silabenzolderivaten von Interesse. Wir berichten hier über Synthesen von in 1-, 2-, 4- und 6-Stellung substituierten 1-tert-Butyl-1-silacyclohexadienen. Aus lithiierten Vorstufen entstehen durch Substitutionsreaktionen die Trialkylsilyl- bzw. tert-Butyl-substituierten Silacyclohexadiene 6, 8, 9, 12, 13, 14 und 15. Das Methoxysilan 1 wird mit LiAlH4 in das Hydridosilan 2 übergeführt. Si—H- bzw. C—H-Spaltung mit N-Bromsuccinimid führt zur Bildung der in 1- und/oder 4-Stellung bromierten Silacyclohexadiene 3 und 5. Bei einigen Substitutionsreaktionen wird eine Isomerisierung des Diensystems beobachtet. Die erstmals beschriebenen Verbindungen sind durch ihre 1H-, 13C- und 29Si-NMR-Spektren sowie durch MS-Daten charakterisiert.
    Additional Material: 2 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 114 (1981), S. 3634-3642 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Au55[P(C6H5)3]12Cl6- a Gold Cluster of an Exceptional sizeThe reduction of (C6H5)3PAuCl with B2H6 in benzene yields Au9,2[P(C6H5)3]2Cl which is characterized by means of molecular weight determinations as Au55[P(C6H5)3]12Cl6. A simple model, based on an arrangement of close-packed gold atoms, leads to a gold cluster the structure of which is in good agreement with the unusual chemical composition. The Mößbauer spectrum of the compound shows four different kinds of gold atoms: a metallic part (Au13-nucleus), Au atoms coordinated by P(C6H5)3 and Cl ligands, resp., as well as uncoordinated surface gold. The complex can be decomposed by bromine and iodine to (C6H5)3PAuCl, (C6H5)3PAuBr(I), and metallic gold. The thermolysis at 50°C leads to [(C6H5)3P]2AuCl and gold quantitatively.
    Notes: Die Reduktion von C6H5)3PAuCl mit B2H6 in Benzol ergibt Au9,2[P(C6H5)3]2Cl, das mittels Molmassebestimmungen als Au55[P(C6H5)3]12Cl6 charakterisiert wurde. Ein einfaches Modell, beruhend auf einer Anordnung dichtest gepackter Goldatome, führt zu einem Goldcluster, dessen Aufbau mit der ungewöhnlichen chemischen Zusammensetzung in guter Übereinstimmung ist. Das Mößbauer-Spektrum der Verbindung zeigt vier Sorten von Goldatomen: einen metallischen Anteil (Au13-Kern), durch P(C6H5)3-bzw. Cl-Liganden Koordinierte Au-Atome, sowie unkoordi-niertes Oberflächengold. Mit Brom und lod läß sich der Komplex zu (C6H5)3PAuCl, (C6H5)3 PAuBr(I) und metallischem Gold abbauen. Die Thermolyse bei 50°C führt quantitativ zu [(C6H5)3P]2AuCl und Gold.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 559-560 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arsaphosphenyl and Diphosphenyl Complexes of Chromium and MolybdenumThe reaction of the (pentamethylcyclopentadienyl)(Cp*)-substituted arsaphosphene Cp* As=PAr (2, Ar = 2,4,6-tri-tert-butylphenyl) with M(CO)3(CH3CN)3 (M = Cr, Mo) in toluene affords the novel arsaphosphenyl complexes (η5-C5Me5)(CO)3MAs = PAr (M = Cr: 4; M = Mo: 5) via a transfer of the Cp* ligand from arsene to the metal centre. The corresponding diphosphenyl complex (η5-C5Me5)(CO)3CrP=PAr 3 is obtained analogously from Cp*P=PAr 1 and Cr(CO)3(CH3CN)3. The compounds were characterized by spectroscopic methods.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 917-922 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Stereochemie planarchiraler Verbindungen, 11.  -  Statische und Dynamische Stereochemie von 10,10′-Dibrom-2,2′-bi(1,6-methano[10]annulenyl)Bei der Kupplung von 2,10-Dibrom-1,6-methano[10]annulen mit Cu(II)-chlorid (über die Mono-Li-Verbindung) entsteht eine Mischung der meso- und Racemat-Form von 10,10′-Dibrom-2,2′-bi(1,6-methano[10]annulenyl) (2), die durch Chromatographie an Kieselgel getrennt wurde. Die Konfigurationszuordnung der Diastereomeren erfolgte durch 1H- und 13C-NMR-Spektroskopie und durch Racematspaltung. Die Rotationsbarriere von meso-2 wurde durch temperaturabhängige 1H-NMR-Spektroskopie mit 58 kJ mol-1 bestimmt. Nach chromatographischer Enantiomerentrennung von rac-2 in die optisch aktiven Gleichgewichtsmischungen der Rotameren ([α]D = +525 bzw. -525 in Ethanol) konnten diese bei 0°C an Kieselgel (im Verhältnis von 3.6:1) aufgetrennt, ihre CD-Spektren bei -10°C gemessen und die Rotationsbarrieren (85 bzw. 88 kJ mol-1) sowohl durch CD- als auch 1H-NMR-Kinetik (durch Äquilibrierung der Rotameren) bestimmt werden. Die stereochemischen Konsequenzen des Vorliegens von 2 Chiralitätselementen in 2 (Torsions- und Annulen-Chiralität) sowie mögliche Gründe für die (verhältnismäßig) hohe Differenz der Rotationsbarrieren zwischen meso- und Racemat-Form werden diskutiert.
    Notes: Coupling of 2,10-dibromo-1,6-methano[10]annulene with Cu(II) chloride (via the mono-Li derivative) affords a mixture of the meso and racemic forms of 10,10′-dibromo-2,2′-bi(1,6-methano[10]-annulenyl) (2) which were separated by chromatography on silica gel. Their configurational assignments followed from 1H- and 13C-NMR spectroscopy and optical resolution. The rotational barrier of meso-2 was established as 58 kJ mol-1 by temperature-dependent 1H-NMR spectroscopy. After chromatographic resolution of rac-2 into the optically active equilibrium mixtures of the rotamers ([α]D = +525 and -525 in ethanol), they could be separated on silica gel at 0°C (in a ratio of 3.6:1); their CD spectra were recorded at -10°C and the rotational barriers (85 and 88 kJ mol-1, resp.) were established by CD as well as by 1H-NMR kinetics (equilibration of the rotamers). Stereochemical consequences of the presence of two elements of chirality (torsional and annulene chirality) as well as possible reasons for the (relatively) high difference in the rotational barriers for meso and racemic forms are discussed.
    Additional Material: 5 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 627-630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substitution and Isomerization of λ5-Triazaphosphinines2,2-Difluoro-4,6-bis(trifluoromethyl)-1,3,5,2λ5-triazaphosphinine (1) reacts with CMe3NH2 and MeOH with cleavage of HF to give the substituted compounds 3 and 4. By addition of released HF, the hybrid-ionic compound 5 is formed. A stable 2-fluoro-2-hydroxytriazaphosphinine, N(CCF3N)2PF(OH) (6), is synthesized by the reaction of 1 with CMe3OH, CMe3SiMe2OH, or (CMe3)2Si(OH)2, alkyl fluorides or silyl fluorides being cleaved of. 2,2-Dichlorotriazaphosphinine 2 reacts with (CMe3NH)2SiMe2 to give N(CCF3N)2P(Cl)NHCMe3 (7). N(CCF3N)2P(F)NRSiMe3, R = C6H5 (8), SiMe3 (9), is formed by the reaction of 1 with (Me3Si)2NR. Interaction between 1 and heptamethylsilazane in the molar ratio 1:2 yields the disubstituted product 10 with an exocyclic P=N double bond. The reaction of alkoxides, silanolates, and thiolates with 1 gives mono- (11-17) and disubstituted (18-23) compounds. A migration of methyl and ethyl groups, with formation of an exocyclic P=O bond, is observed (11, 12).
    Notes: 2,2-Difluor-4,6-bis(trifluormethyl)-1,3,5,2λ5-triazaphosphinin (1) reagiert mit CMe3NH2 und MeOH unter HF-Abspaltung zu den Substitutionsverbindungen 3 bzw. 4. Freigesetztes HF addiert an 1 unter Bildung des Zwitterions 5. Das stabile 2-Fluor-2-hydroxytriazaphosphinin N(CCF3N)2PF(OH) 6 entsteht bei der Reaktion von 1 mit CMe3OH, CMe3SiMe2OH und (CMe3)2SiOH)2, wobei Fluoralkan bzw. -silan abgespalten wird. 2,2-Dichlortriazaphosphinin 2 reagiert mit (CMe3NH)2SiMe2 zu N(CCF3N)2(PCl)NHCMe3 (7) und 1 mit (Me3Si)2NR zu N(CCF3N)2P(F)NRSiMe3, R = C6H5 (8), SiMe3 (9). Aus Heptamethyldisilazan und 1 im molaren Verhältnis 2:1 wird ein Disubstitutionsprodukt 10 mit exocyclischer P=N-Bindung isoliert. Alkoholate, Silanolate und Thiolate reagieren mit 1 unter Mono (11-17) und Disubstitution (18-23). Methyl- und Ethylgruppenwanderung, unter Ausbildung einer exocyclischen P=O-Bindung (11, 12), wird beobachtet.
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  • 7
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Syntheses of Biologically Important Carbohydrates, 251) On the Regioselectivity of Sharpless Reaction; The vic. cis-Oxyamination of Unbranched and 3-C-Branched Ald-2-and Ald-3-enopyranosidesThe configurations and the ratios of regioisomeric amino sugars obtained by vic. cis-oxyamination of unsaturated carbohydrates 1, 4, 9, 16, 19, 21 are determined. Due to the ratios of amino sugars from the ald-3-enopyranosides 9 and 16 it is obvious that the regioorientation is probably not directed by the electron density at the double bonds.
    Notes: Die Konfigurationen und die Verhältnisse regioisomerer Aminozucker bei der vic. cis-Oxyaminierung von ungesättigten Kohlenhydraten 1,4,9,16,19,21 werden bestimmt. Die Isomerenverhältnisse der Aminozucker aus den Ald-3-enopyranosiden 9 und 16 zeigen, daß die Regioorientierung wahrscheinlich nicht durch die Elektronendichte an den Doppelbindungen gesteuert wird.
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  • 8
    ISSN: 0009-286X
    Keywords: Anemometrie ; Leitfähigkeitssonden ; Zweiphasenströmung ; Bioreaktor ; Turbulenz ; Blasensäule ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 9
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The gas phase reaction of 1,2,4,5-tetracyanobenzene (3) with metal sheets like Cu, Ni, Co, Fe, and Ti exhibits the in situ formation of polymeric phthalocyanine coatings 1. The electrochemical behaviour of layers of 1 is investigated by means of cyclic voltametric measurements. Determination of layer-thickness and electrical resistance is also performed.
    Additional Material: 3 Tab.
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  • 10
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyetheresteramides (PEEA) on the basis of polyamide 12 and oligotetrahydrofuran (OTHF) may be referred to as intrinsically plasticized and intrinsically impact strength toughened thermoplastic elastomers. This is due to their special 4-phase morphology consisting of two pure crystalline and two mixed amorphous phases, which was completely analysed by various TEM preparation techniques. PEEA containing more than 50% PA 12 hard segments exhibit a space filling dendritic superstructure of lamellar crystallized hard segments. In the range of 50 - 30% PA 12, the dendrites become more and more isolated, and below 30% PA 12 only single lamellae can be observed. The matrix in all PEEA is an amorphous, PA 12-rich mixed phase (“OTHF-plasticized PA 12”) located between the hard segment lamellae. An amorphous OTHF-rich mixed phase is very finely dispersed in PEEA and acts as an intrinsically impact strength toughening modifier. Lamellar crystallized soft segments could be imaged by TEM in this dispersed phase, but only in PEEA products with a higher molecular OTHF and at sufficient low temperatures.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
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