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  • 1
    Electronic Resource
    Electronic Resource
    The making of molecular belts and collars (1989)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 7 (1989), S. 227-245 
    Details
    ISSN: 1573-1111
    Keywords: Cavitands ; Diels-Alder reactions ; stereoelectronic control ; kohnkene ; clathrate formation ; chemical sensor ; [12]collarene ; [12]beltene ; [12]cyclacene ; organic zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This article relates the first encouraging steps towards the fulfilment of a long-standing research goal aimed at turning the chemistry of laterally-fused six-membered rings through 90° ... or, more specifically, the making of (i) beltenes, in which 1,4-cyclohexadiene rings are linked in a polycyclic array by lateral fusion through their carbon-carbon double bonds, (ii) collarenes, in which alternating benzene and 1,4-cyclohexadiene rings are fused to form macropolycyclic hydrocarbons and (iii) cyclacenes, which may be considered as two annulenes joined to each other by carbon-carbon single bonds between every other atom around the annulene rings. The synthesis of the key macropolycyclic compound, which is a potential precursor of [12]beltene and [12]collarene, exploits the amazing stereoelectronic control that exists in the Diels-Alder reaction between a bisdiene and a bisdienophile with the appropriate structural features and reactivity characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01060724
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  • 2
    Electronic Resource
    Electronic Resource
    The supramolecular structures and reactivities of some complexes of chiral crown ethers with borane ammonia (1985)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 3 (1985), S. 355-377 
    Details
    ISSN: 1573-1111
    Keywords: Chiral crown ethers ; glycopyranosides ; mannitol derivatives ; borane ammonia complexes ; crystal structures ; enantioselective reductions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Whereas 1 ∶ 1 crystalline complexes have been isolated between borane ammonia and methyl 4,6-O-benzylidene-2,3-dideoxy-α-d-galactopyranosido [2,3-b]-1,4,7,10,13,16-hexaoxacyclo-octadecane (1), methyl 4,6-O-benzylidene-2,3-dideoxy-α-d-mannopyranosido [2,3-b] (methyl 4′,6′-O-benzylidene-2′,3′-dideoxy-α-d-mannopyranosido [2′,3′-k]-1,4,7,10,13,16-hexaoxacyclo-octadecane (3), and (1R,2R,7R,24R)-3,5,8,11,14,17,20,23,26,28-decaoxatricyclo-[21.4.0.02,7]octacosane (4), the hosts, methyl, 4,6-O-benzylidene-2,3-dideoxy-α-d-mannopyranosido[2,3-b] 1,4,7,10,13,16-hexaoxacyclo-octadecane (2) and 1,4 ∶ 1′,4′ ∶ 3,6 ∶ 3′,6′-tetra-anhydro-2,2′ ∶ 5,5′-bis-O-oxydiethylenedi-d-mannitol (5) have yielded 2 ∶ 1 (guest:host) crystalline complexes with borane ammonia as guest. X-ray analyses of the supramolecular structures of BH3NH3 ·1, (BH3NH3)2 ·2, BH3NH3 ·3, BH3NH3 ·4, and (BH3NH3)2 ·5 have been carried out and BH3NH3 ·1, BH3NH3 ·2, and (BH3NH3)2 ·5 have been shown to reduce acetophenone with enantiomeric excesses of 5, 13, and 10% respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00655736
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  • 3
    Electronic Resource
    Electronic Resource
    X-ray Crystallographic Studies on the Noncovalent Syntheses of Supermolecules (1999)
    Springer
    Structural chemistry 10 (1999), S. 243-259 
    Details
    ISSN: 1572-9001
    Keywords: Noncovalent interactions ; pseudorotaxanes ; self-assembly ; solid-state structures ; supramolecular chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract An approach to the supramolecular syntheses of discrete multicomponent aggregates of noncovalently bound molecules, i.e., supermolecules, is described. This approach involved the careful analysis of X-ray crystal structures so as to permit a gradual increase in superstructural complexity. Many elaborate supermolecules were synthesized noncovalently from dialkylammonium-containing cations and crown ethers, following the initial observation that the dibenzylammonium ion threads through dibenzo[24]crown-8 to generate a singly stranded, singly encircled [2]pseudorotaxane, principally as a result of $$[{\text{N}}^{\text{ + }} - {\text{H}} \cdot \cdot \cdot {\text{O}}]$$ and $$[{\text{C}} - {\text{H}} \cdot \cdot \cdot {\text{O}}]$$ hydrogen bond formation. The scope of the fundamental recognition motif obtained from this initial observation was then broadened, through the use of thread-like ions with multiple dialkylammonium centers and/or larger crown ethers, so that multiply stranded and/or multiply encircled pseudorotaxanes could be prepared. Cations bearing both dialkylammonium and crown ether recognition sites were also used for the nocovalent synthesis of a discrete daisy chain supermacrocycle and the basic recognition motif was combined with other motifs for the production of a wide range of novel superarchitectures. As a greater understanding of the noncovalent interactions governing the self-assembly of the complex superarchitectures was acquired, new protocols for the noncovalent syntheses of doubly docked pseudorotaxanes and interwoven supramolecular bundles, including a supramolecular analogue of the photosynthetic special pair, were developed. The discovery that anions can play a prominent role in the solid-state self-assembly of some of the supermolecules was a valuable spinoff of the research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021844715425
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