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  • 1
    Electronic Resource
    Electronic Resource
    New Biphenylenophanes and Biphenylophanes - 1,8-Dimethylbiphenylene by Continuous Vacuum Pyrolysis (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1901-1906 
    Details
    ISSN: 0947-3440
    Keywords: Cinnoline pyrolysis ; Circular dichroism ; Cyclophanes ; Dimethylbiphenylene synthesis ; Sulfone pyrolysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 1,8-disubstituted biphenylenes by pyrolysis of azo compounds has been optimized. By means of a continuously working pyrolysis apparatus, the cis isomer 2 can be reliably produced on a gram scale. The chiral syn-[2.2]biphenylenophane 12 has been synthesized by an intermolecular cyclization reaction, subsequent oxidation of the sulfur atoms and pyrolytic extrusion of sulfur dioxide. In an analogous manner, the [2.2]biphenylophane 13 was obtained. The separation of the racemates of the hydrocarbons 12 and 13 could be achieved using a stationary chiral HPLC phase. Compound 12 preferentially adopts a syn conformation in the solid state. The CD spectra of 12 and 13 are compared.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970915
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  • 2
    Electronic Resource
    Electronic Resource
    The First 1,10-Diaza[2.2]metacyclophanes - Strained Medium Membered Heterocycles⋆ (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1471-1477 
    Details
    ISSN: 1434-193X
    Keywords: Cyclophanes ; Dilution principle ; Heterocycles ; Medium membered rings ; Ring strain ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The N-protected 1,10-diaza[2.2]metacyclo- and 1,10-diaza-[2]metacyclo[2](2,6)-pyridinophanes 4 and 5 have been synthesized for the first time using high dilution conditions. The free secondary diamine 7 was obtained from 4 by alkaline hydrolysis. - Quantum chemical calculations support the hypothesis that 7 is one of the most strained anti-hetera[2.2]metacyclophanes known. This is also evident from the 1H-NMR spectrum of 7, which shows one of the strongest high field shifts for the intraannular protons in comparison to other anti-[2.2]metacyclophanes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Structure/Chiroptics Relationships of Planar Chiral and Helical Molecules (1998)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1998 (1998), S. 1491-1509 
    Details
    ISSN: 1434-193X
    Keywords: Chirality ; Circular dichroism ; Cyclophanes ; Theoretical calculations ; Strained molecules ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The chiroptical properties of planar-chiral and helical molecules without stereogenic centres and with well-defined structure, strain, electronic properties and chirality are investigated by experimental and theoretical circular dichroism spectroscopy. We report on the synthetic and theoretical achievements made during the past 10 years in the field of rigid [2.2]metacyclophane propellers, as well as in the area of [n]para- and [n]metacyclophanes containing aliphatic parts like adamantane or unsaturated bridges. Results for carbo and hetero helicenes and helicene-related molecules like twisted phenanthrenes are presented. It is demonstrated how reliable theoretical calculations using configuration interaction and time-dependent methods in combination with density functional theory today are and how useful the interplay between theory and experiment stimulates the development of chiral molecules optimized for this purpose. Even for large molecules it is routinely possible to assign Cotton effects to electronic transitions, to evaluate chromophore contributions, to determine absolute configurations and conformational equilibria, and to discover intramolecular charge transfer effects.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chiral Pyridinophanes as Hydrogen-Bonding Supramolecular Building Blocks (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1221-1225 
    Details
    ISSN: 0947-3440
    Keywords: Aggregations ; Circular dichroism ; Cyclophanes ; Molecular recognition ; Supramolecular chemistry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Hydrogen-donor and hydrogen-acceptor substituted chiral cyclophanes with a [2](1,3)benzeno[2](3,5)pyridinophane framework have been synthesized, enantiomerically separated, and analysed by circular dichroism (CD). X-ray structure determination and CD analyses show that these cyclophanes are able to act as hydrogen-bonding donor/acceptor building blocks for the design of chiral supramolecular aggregates with suitable complementary partners. Starting from the pyridinophane N-oxide 4, selective reactions lead to the new chiral pyridinophanes 5-7 in high yields. The X-ray structure analysis of the pyridinophane-2-carbonitrile 5 reveals a multilayered herringbone structure as it forms dimeric aggregates. The CD analysis of the host 7 with the complementary guest molecules melamine and cyanuric acid elucidates the formation of supramolecular complexes in solution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970626
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  • 5
    Electronic Resource
    Electronic Resource
    Molecular Ribbons Containing Pyridine Rings (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 2115-2121 
    Details
    ISSN: 0947-3440
    Keywords: Cyclophanes ; Macrocycles ; Phanes ; Pyridinophanes ; Ring compounds ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first synthesis of the ribbon-like compounds 6-10 is described. The new building block diethyl 2,6-bis(bromomethyl)pyridine-3,5-dicarboxylate 1 was prepared and characterized. Single-crystal X-ray structure analyses indicate that these ribbon-like molecules arrange in a folded conformation, with the pyridine and benzene units being folded in a face-to-face manner, and the tosyl units of 8-10 pointing outwards. The “intramolecular self-assembly” (folding) of these molecular ribbons is primarily attributable to the energetically more favourable syn conformation of both the [3.3]metacyclophanes and the pyridinophanes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961225
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  • 6
    Electronic Resource
    Electronic Resource
    Adamantan als Baustein neuer Araliphane Synthese, Spektroskopie und Kristallstrukturen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 915-922 
    Details
    ISSN: 0009-2940
    Keywords: Adamantane ; Adamantanophanes ; Cyclophanes ; Medium-membered rings ; Sulfone pyrolysis ; Phanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Adamantane as a Building Block of New Araliphanes - Synthesis, Spectroscopy, and Crystal StructuresExchange of benzene units for aliphatic building blocks in cyclophanes leads to new molecules of the “araliphane” type. With adamantane the araliphanes 2 - 4 are synthesized. Their stereochemical behavior as shown by NMR studies and X-ray crystallographic analyses differs significantly from that of their aromatic counterparts. The signals of the intraannular adamantane hydrogens are strongly shifted upfield up to δ=- 2.18 (in 2). 4 is obtained as a racemic mixture of enantiomers (in the crystalline state) and shows a boat-like deformation of the benzene moiety.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240436
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  • 7
    Electronic Resource
    Electronic Resource
    Deformierte chirale [n]Metacyclophane (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 759-765 
    Details
    ISSN: 0009-2940
    Keywords: Chirality ; Circular dichroism ; Conformational mobility ; Cyclophanes ; [n]Phanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deformed Chiral [n]MetacyclophanesThe new dithiametacyclophane 3c and the thiaazametacyclophanes 6a, b are chiral, but do not contain chirality centres. They are obtained by cyclization of 1,3-propanedithiol (2), or of the thiaza precursors 5a, b, with the bis(bromomethyl) compounds 1, 4a, b. The dynamic behaviour of the aliphatic chains in 3c, and 6a, b (flipping/rotation) have been studied by dynamic NMR. X-ray analyses of 3c and 6a document the out-of-plane deformation of the boat-shaped benzene ring. The circular dichroism of enantiomer-enriched 3c is reported.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270427
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  • 8
    Electronic Resource
    Electronic Resource
    Neue [m.n]Cyclophane durch sukzessive Ketonpyrolyse (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 2477-2482 
    Details
    ISSN: 0009-2940
    Keywords: Pyrolysis ; Decarbonylation ; Ketone pyrolysis, successive ; Cyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New [m.n]Cyclophanes by Successive Ketone PyrolysisThe new cyclophane ketones 7, 10, 11, 13, 14, and 16 and the known hydrocarbons 8 and 15 are obtained by successive thermal elimination of carbon monoxide with C-C bond formation from the known [3n]cyclophane(ones)n and the new terphenylophanedione 4. X-ray structure analyses of the ketones 3 and 4 and the anti-isomer of the ketone 7a are performed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931261122
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  • 9
    Electronic Resource
    Electronic Resource
    Chiral Metal Carbene Modified [2.2]Metacyclophanes: Synthesis, Structure, and Chiroptic Properties (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1105-1111 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes ; Chromium ; Cyclophanes ; Chirality ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Pentacarbonyl(4-[2.2]metacyclophanyl(methoxy)carbene)-chromium(0) (6) was prepared according to the Fischer route from 4-bromo[2.2]metacyclophane. Aminolysis with non-chiral and chiral amines affords aminocarbene complexes 7-12. X-Ray structure analyses for 6 and its aminocarbene analogs 7 and 8 indicate that the incorporation of the chromium-carbene fragment has no significant influence on the deformation of the [2.2]metacyclophane skeleton.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300812
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  • 10
    Electronic Resource
    Electronic Resource
    Verklammerte Tolane (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2533-2538 
    Details
    ISSN: 0009-2940
    Keywords: Alkynes, strained ; Cyclophanes ; Cyclopropenylium cation ; Tolanophanes ; Wittig reaction ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The tolanophanes 1, 2 and 3 are prepared by Wittig cyclization reactions. The corresponding “stilbenophanes” 21 and 13 are also isolated. The X-ray structure analysis of 1 revealed a bending of the acetylene triple bond by 11 degrees. Attempts to aim at the “superphane” 23 by reaction with transition metal complex catalysts were unsuccessful; reaction with phenyl-carbene lead to the cyclopropenyl cation 22.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921251128
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