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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 23 (1995), S. 167-174 
    ISSN: 1573-1111
    Keywords: Amines ; amino acids ; liquid membrane ; macrocyclic ligands ; active transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The transport of some amines in protonated form was studied (viz. methylamine, dimethylamine, diethylamine andn-propylamine) and α-amino acids (l-leucine,l-methionine,l-isoleucine,l-phenylalanine,l-valine,l-α-alanine andl-cysteine). The following macrocyclic ligands were used as carriers throughout the experiments: 15-crown-5 (15C5), 18-crown-6 (18C6), benzo-18-crown-6 (B18C6), dibenzo-18-crown-6 (DB18C6), diazacrown ether [2.2] (1,7,10,16-tetraoxa-4,13-diazacyclooctadecane) and cryptand [2.2.2] (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo [8.8.8] hexacosane). The active transport, assisted by pH gradient, of amino acids and amines in protonated form as ion pairs in the presence of picrate anion was performed. The experiments suggested the influence of the ligand size, the donor atom type, and the substituents on the transport phenomena.
    Type of Medium: Electronic Resource
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  • 2
    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
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