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  • 1
    Electronic Resource
    Electronic Resource
    m-Bromophenolic epoxy resins for electronic packaging (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 198 (1992), S. 51-60 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Meta-halogenierte Phenole sind bekanntermaßen chemisch und thermisch stabiler als ihre ortho- oder para-halogenierten Analoga. Die Verwendung eines reaktiven Zwischenproduktes, hergestellt durch Bromierung von 2,4,6-Trimethylphenol, als Alkylierungsmittel für den Einbau der stabilen m-Bromphenol-Einheit in verschiedene organische Substanzen und Polymere wird beschrieben. Bei der Anwendung als Verkapselungsmaterialien für elektronische Bauteile zeigten sich Epoxid-Derivate von Novolaken mit m-Bromphenol-Einheiten bezüglich hydrolytischer und thermischer Stabilität den konventionellen Tetrabrombisphenol-A-Epoxidharzen, die ortho- und para-bromiert sind, überlegen. Die m-Bromphenolgruppe verbessert die Bauteilzuverlässigkeit bei gleichzeitiger Erfüllung der Anforderungen an das Brandverhalten.
    Notes: Meta-halogenated phenols are generally known to be more chemically and thermally stable than their ortho- or para-halogenated counterparts. A reactive intermediate, produced by the bromination of 2,4,6-trimethylphenol is being used as an alkylating agent to incorporate this stable m-bromophenol moiety into varieties of organic compounds and polymers. In electronic encapsulation applications, epoxy derivatives of novolacs containing m-bromophenol have exhibited superior hydrolytic and thermal stability as compared with the conventional tetrabromo bisphenol-A epoxies which are ortho-brominated phenolics. The m-bromophenol moiety contributes to the extended device reliability while meeting flame retardency requirements as well.
    Additional Material: 5 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051980105
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  • 2
    Electronic Resource
    Electronic Resource
    Comparisons between oriented film and solution tertiary structure of various nucleic acids (1979)
    New York : Wiley-Blackwell
    Biopolymers 18 (1979), S. 1809-1820 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have considered whether or not the tertiary structure of a biomolecule is the same in a crystal (or an oriented film) as it is in solution. A methodology has been developed for comparing polarized absorption spectra obtained from a solid-state sample with those obtained from an oriented solute to further resolve this question. An electric dichroism instrument built in our laboratory was used to measure the solution dichroism signal which, along with the ordinary solution uv absorption spectra, yields polarized absorption spectra in the directions parallel and perpendicular to the applied electric field. These were then compared to polarized absorption data from oriented films of nucleic acids to determine whether the two sets of data could be rotated into coincidence. This rotation was accomplished using a computer program based on a nonlinear programming method. Four nucleic acids were studied and the film and solution data for three of these were found to be equivalent, requiring rotation through an angle of 3°-20°, depending on film humidity, to bring them into coincidence. For the fourth sample we were unable, perhaps because of signal-to-noise ratio limitations, to find a correlation. Flow dichroism and electric dichroism data were also found to be quite similar. Thus it is clear that the induced dipole moment is along the helical axis and that the physical, hydrodynamical, and electrical axes of the nucleic acid molecules are equivalent.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1979.360180717
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  • 3
    Electronic Resource
    Electronic Resource
    Sphärische ionotrope gele carboxygruppenhaltiger cellulosederivate als trägermaterialien für biologische wirkstoffe, IVTeil III cf.4.. Synthese von carboxycellulose und ionotrope gelbildung mit calciumionen (1990)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 178 (1990), S. 95-107 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Sodium carboxy cellulose with a degree of substitution up to 0.8 can be prepared by oxidation of cellulose with NaNO2/H3PO4 and subsequent treatment with NaBH4. The extent of oxidation increases with raising molecular weight ranging from 170 to 1500 of the starting material. IR and NMR studies show that only the C-6 atom of the anhydroglucose unit is oxidized. The sodium carboxy celluloses show a high tendency to form ionotropic gels even in spherical shape with calcium ions. The mechanically stable gels are characterized by investigation of the swelling behaviour and SEM.
    Notes: Natriumcarboxycellulose mit einem Substitutionsgrad bis 0,8 kann durch Oxidation von Cellulose mit einem Polymerisationsgrad im Bereich von 170 bis 1500 mit NaNO2/H3PO4 und anschließender Behandlung mit NaBH4 hergestellt werden. Das Ausmaß der Oxidation steigt mit wachsender Molmasse des Ausgangsmaterials. IR-und NMR-Untersuchungen zeigen, daß nur das C-6-Atom der Anhydroglucoseeinheit oxidiert ist. Die Natriumcarboxycellulosen weisen eine hohe Tendenz zur ionotropen Gelbildung auch in sphärischer Form mit Calciumionen auf. Die mechanisch stabilen Gele werden durch Quellungsuntersuchungen und REM charakterisiert.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1990.051780107
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  • 4
    Electronic Resource
    Electronic Resource
    Präorganisierte Bis-ethine: Molekulare π-Pinzetten? (1990)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 123 (1990), S. 1097-1103 
    Details
    ISSN: 0009-2940
    Keywords: Bond formation, C-C ; Iron complexes ; Macrocycles ; Molecular tweezers ; Naphthalenophane ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Preorganized Bis-ethynes: Molecular π-Tweezers?1,8-Bis[(arylethynylphenyl)]naphthalenes of type V (e.g. 10, 11) and 1,8-bis[(arylethenylphenyl)]naphthalenes (6, 6a, 7, 7a) were synthesized for the first time. In contrast to the known 1,8-bis(arylethynyl)naphthalenes VI their “stereologs” 10 and 11 are thermally stabile. Yet they react with pentacarbonyliron to yield dinuclear transition metal complexes of the type 12, 13, i.e. a strained cyclophane macrocycle is formed by C-C bond formation. The X-ray analysis of the di-tert-butyl compound 11 shows that the peri substituents diverge, but with increasing distance from the naphthalene skeleton one of the arylethynyl units is bent to the opposite direction (Figure 2). The question whether the new molecular skeleton V can be viewed as molecular tweezers is discussed: as the hydrocarbons react irreversibly with transition metal carbonyls, they may rather be taken as “tweezers for single use”.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19901230524
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  • 5
    Electronic Resource
    Electronic Resource
    Vielgliedrige Donor-substituierte Kohlenwasserstoffringe (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2523-2531 
    Details
    ISSN: 0009-2940
    Keywords: Carbocycles ; Large rings ; Macrocycles ; [2n]Metacyclophanes ; Müller-Röscheisen reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Many-Membered and Donor-Substituted Hydrocarbon RingsThe preparation of large rings 2 of the [2n]metacyclophane type by the Müller-Röscheisen method is described. Yields of cyclic products, potential ligand or host character and ring size can be controlled by intra- and extraannular OCH3 groups. The 40-membered macrocyclus 24 containing eight substituted benzene rings is the largest ring compound of this series isolated so far in pure form. Large substituents OR in position 2 of the starting bis(bromomethyl) compounds lead to higher ring member numbers. The new macrocyclic compounds, with the exception of the “dimer” 7, are all conformationally flexible according to 1H-NMR spectra. X-ray structural analyses were performed of the macrocycles 10, 13, 17, and 18; the inclusion of solvent molecules is proven.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921251127
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  • 6
    Electronic Resource
    Electronic Resource
    all-Homocalixarene: Carbocyclische Wirtverbindungen mit intra- und extraannularen Ligandarmen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2483-2491 
    Details
    ISSN: 0009-2940
    Keywords: Carbocycles ; Homocalixarenes ; Calixarenes, Homo- ; Large rings ; Macrocycles ; [2n]Metacyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: all-Homocalixarenes: Carbocyclic Host Compounds with Intra- and Extraannular Ligand ArmsMethoxy-substituted [2n]metacyclophanes 1-10, obtained by Müller-Röscheisen cyclization, are converted into all-homocalixarenes 11-20 with free phenolic hydroxy functions. The well-soluble cyclic pentamer 11 and octamer 14 with endo-acidic host properties are investigated with regard to guest binding. They exhibit selectivity towards alkaline earth metal ions (Ba2+) in liquid/liquid extraction studies. Some of the macrocyclic oligophenols are transformed into homocalixarenes 21-25 with intra- or extraannular oxapropionate groups. The diester 22 and the tetraester 23 are converted into carbocycles 26 and 27 with two and four free oxapropionic acid groups. Complexation properties of the oligoesters in extraction studies and log K values in water are reported. X-ray structural analyses were performed of the [6]-, [8]- and [4]- homocalixarenes 9 and 21, 14 and 23; the inclusion of solvent molecules is proven.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931261123
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  • 7
    Electronic Resource
    Electronic Resource
    A Macrocyclic Tetraazapolyene - Synthesis and Configuration (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 671-672 
    Details
    ISSN: 0009-2940
    Keywords: Azines ; Bis(azines) ; Macrocycles ; Tetraazapolyenes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The new macrocyclic bis(azine) 2 forming yellow microcrystals has been prepared in 72% yield by treating the diketone 1 with hydrazine hydrate under high-dilution conditions. In contrast to the UV/Vis spectrum of the “open-chain” azine 4, that of 2 shows characteristic features of a polyene chromophore containing (Z)-configurated double bonds.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240335
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  • 8
    Electronic Resource
    Electronic Resource
    Konkave Makroheterocyclen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1713-1721 
    Details
    ISSN: 0009-2940
    Keywords: Concave molecules ; Cyclophanes ; High-dilution principle ; Macrocycles ; Spheriphanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Concave MacroheterocyclesMacrocyclic compounds of the general type 2 having a spherical shape and a molecular cavity have been synthesized. A „fold and paste“-type cyclization step generates the macroheterocycles 4, 10, 11, 14, and 21. Since this approach is difficult to apply for O-substituted derivatives, the „spheriphane“ 24 was synthesized by intermolecular cyclizaiton. The X-ray structure analysis of 11 shows intermolecular interactions („dimer formation“) in the crystal.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260731
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  • 9
    Electronic Resource
    Electronic Resource
    Auf dem Weg zu makrocyclischen para-Phenylenen (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1723-1732 
    Details
    ISSN: 0009-2940
    Keywords: Cyclohexanes ; Cyclohexanones ; Cyclophanes ; Macrocycles ; Paracyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the Way to Macrocyclic para-PhenylenesStrategies are presented to synthesize the hitherto unknown [On]Paracyclophanes 1. Open chain belt-type molecules based on 1,4-connected carbocyclic six-membered rings were prepared. Functionalization of the outer rings in 4-position is the prerequisite for cyclization or lengthening of the molecular belts. In order to obtain the macrocyclic target molecules 1, well preorganized cis-isomers of 1,4-disubstituted cyclohexanes were prepared. X-ray structural analyses reveal the static stereochemistry of the intermediates 8, 9, 17, 18, and 24. The macrocyclic hydrocarbon 29 containing five cyclohexylidene units was detected.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260732
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  • 10
    Electronic Resource
    Electronic Resource
    Ein neues, Deltaphan und bandförmige Cyclophane (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 2089-2096 
    Details
    ISSN: 0009-2940
    Keywords: Aza-phanes ; Cyclophanes ; Molecular belts ; Macrocycles ; CH-π interaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A New Deltaphane and Ribbon-Shaped CyclophanesThe reaction of the fourfold functionalized [3.3][3.3]metacyclophane 8 with tosylamide monosodium salt leads to a new deltaphane in quantitative yield. An X-ray analysis confirms the belt-shaped structure of 3. Moreover, a series 10-15 of well-soluble belt-shaped macrocycles with up to 21 interconnected benzene rings were detected. The intermediate [3.3][3.3]metacyclophane 4 shows remarkably short distances to enclosed toluene, one toluene molecule acting twice as a π acceptor and once as a π donor. Competition experiments with benzene demonstrate the dependence of conformational behaviour on the solvent.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941271035
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