ISSN:
1573-1111
Keywords:
Partial cone conformation
;
crown ether
;
anion effect
;
cavity size effect
;
conformational change
;
calix[4]arene
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract A novel compound, 25, 27 - N,N′ - di - ((2 -ethoxy)benzyl)butylenediamine - p - tert- butylcalix[4]arene, 1, has beensynthesized by reducing its Schiff base derivative. Inclusion studies by1H-NMR spectroscopy in a mixed solvent (CD3OD/CDCl3) of25,27-N,N′-di-((2-ethoxy)benzyl)propylenediamine-p-tert-butylcalix[4]arene,2, and 1 with Zn(II) ions, where counter anions are Cl-, Br-, I- and NO 3 - ,show that both ligands can bind Zn(II) to a different extent depending onthe counter anions and the cavity size of the ligands. The stabilityconstants of ZnX2–1 (ZnX2-2) complexes where X = Cl-, Br-, I- and NO 3 - are 1.4 ± 0.1 (1.6 ± 0.1), 1.7 ± 0.1 (1.9 ±0.1), 2.2 ± 0.1 (2.7 ± 0.1) and 4.7 ± 0.1 (6.0 ±0.1), respectively. The calix[4]arene unit of the ligand 2 was found to havea structural change from cone to partial cone conformation upon binding toZnCl2, ZnBr2 and ZnI2.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007933919762
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