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  • transport  (2)
  • 1H-NMR mononuclear and dinuclear species  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Multifunctional Calix[4]arenes Containing Pendant Amide and Phosphoryl Groups: Their Use as Extracting Agents and Carriers for Alkali Cations (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 127-140 
    Details
    ISSN: 1573-1111
    Keywords: Alkali cations ; calixarene ; amide ; phosphine oxide ; complexation ; extraction ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The complexing, extracting and mobile carrier properties of the tetra(phosphine oxide)-calix[4]arene 1 and the hybrid diamide-di(phosphine oxide)-calix[4]arene 2 were studied. Both ligands give 1 : 1 complexes with alkali cations in THF as shown by the picrate method. 1H NMR experiments were run to follow encapsulation of sodium and potassium cations. The corresponding spectra indicate C2-symmetrical structure. The observed extraction orders of the alkali picrates were as follows K+〉Rb+〉Li+〉Cs+〉Na+ for 1 and Li+〉Na+〉K+〉Rb++ for 2. Transport kinetics was analysed by means of a model which assumes pure diffusion and which allows the evaluation of mass transfer coefficients in all systems. These coefficients and their influences on the transport rate are discussed in terms of size of the transporting species in the liquid membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007975928021
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  • 2
    Electronic Resource
    Electronic Resource
    Solvent Extraction of Sodium and Potassium Ions by Dicarboxylated Calix[4]arenes (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 27 (1997), S. 155-168 
    Details
    ISSN: 1573-1111
    Keywords: Dicarboylated calix[4]arenes ; sodium and potassium complexes ; solvent extraction ; selectivity ; 1H-NMR mononuclear and dinuclear species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The extraction of sodium and potassium ions by 25,27-dicarboxymethyl-26,28-dimethoxy-5,11,17,23-tetra-tert-butyl calix[4]arene (L1H2) in chloroform shows the formation of MLIH and M2LI complexes (M = Na, K). In 1,2-dichloroethane, the MLIH species are formed in the acidic pH range, while only the Na2LI species is found at high pH values. The corresponding extraction equilibrium constants K11 (M) and K21 (M) have been evaluated and show a selectivity in favour of Na+ as compared to K+, whatever the nature of the complexes. In chloroform, this selectivity is much more pronounced considering the 2 : 1 complexes: K11(Na)/K11(K)≪ K21(Na)/K21(K). The coexistence of 1 : 1 and 2 : 1 metal : ligand complexes is also shown in the extraction of sodium in 1,2-dichloroethane by the 25,27-dicarboxymethyl-26,28-dimethoxyethoxy-5,11,17,23-tetra-tertbutyl calix[4]arene (LIIH2), locked in the cone conformation. Structural data of the complexes are discussed on the basis of 1H-NMR spectra. In particular, for LIH2, a conformational change from cone to partial cone upon metal complexation has been evidenced for the complexes KLIH, K2LI and Na2LI.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007993200050
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  • 3
    Electronic Resource
    Electronic Resource
    Calix[4]arenes with Pendant Amide and Phosphine Oxide Functionalities: Use as Extractive Agents and Carriers for Silver (I) Ions (1997)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 29 (1997), S. 137-151 
    Details
    ISSN: 1573-1111
    Keywords: Calixarene ; amide ; phosphine oxide ; silver ; extraction ; transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The solvent extraction properties towards Ag+ of5,11,17,23-tetra-tert-butyl-25,27-diX-26,28-bis(diphenylphosphinoylmethoxy)calix[4]arenes (X = CH2C(O)NEt2 (1), CH2P(O)Ph2 (2), CH3 (3), CH2C(O)Et (4))have been studied. Each ligand forms a 1 : 1 complex with silver(I). Ligand1, which bears two amide functionalities, is the most efficacious,emphasizing the crucial role played by the polar amide groups. The rate oftransport of AgNO3 through a bulk liquid membrane with this ligand ascarrier was shown to be superior to that of DC18C6, a structurally-relatedmulti-oxygen donor carrier. NMR and IR data suggest that Ag+ is coordinatedto each of the oxygen atoms in the ligand leading to an encapsulatedstructure [Ag ⊂ 1]+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007980931959
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    Paper (German National Licenses)
    Fulltext
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