ISSN:
1573-1111
Keywords:
calixarenes
;
alkali metals
;
complexation
;
extraction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The binding properties of cone-5,11,17,23-tetra-tert-butyl-25,27-bis(diethylcarbamoyl-methoxy)-26,28-bis(diphenylphosphinoylmethoxy)calix[4] arene (cone-1) towards alkali metals have beencompared with those of the corresponding partial-cone conformer (paco- 1). Bothhybrid ligands form stable complexes with alkalipicrates in tetrahydrofuran having a 1 : 1cation/ligand ratio. Regarding extractability, thatpresented by cone-1 decreases continuallyon-going from Li/Na to Cs, while that for paco-1 presents a peak selectivity for Na (withthe following order Na 〉 K 〉 Rb 〉 Li 〉 Cs).These selectivities parallel, respectively, resultsobtained for extraction and transport experiments. Thekinetics of the alkali metal thiocyanate transportthrough a bulk liquid membrane containing theseligands in 1,2-dichloroethane could be rationalised interms of a simple mathematical model. The lowertransfer coefficients found for paco-1 relative to cone-1 reflect the larger sizeof the diffusing paco-complex.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008192012881
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