| Abstract |
The binding properties of two phenylketones ( 2a and 3a) and two ethylesters ( 2b and 3b) derived from p-tert-butyldihomooxacalix[4]arene or from p-tert-butylcalix[4]arene, in the cone conformation, towards transition (Ag+, Ni2+, Cu2+, Co2+, Zn2+, Fe2+ and Mn2+) and heavy (Cd2+, Hg2+ and Pb2+) metal cations have been determined by extraction studies with metal picrates and liquid membrane transport experiments with the same salts. The affinity of these ligands for Ag+ has also been investigated by H-1 NMR spectroscopy. Both ketones are better extractants than the esters, and show a strong preference for Ag+, while Cu2+ is the most extracted cation with the esters. H-1 NMR titrations with AgSO3CF3 indicate 1 : 1 complexes for all ligands, those with ketones are more stable, on the NMR time scale, than those with esters. Both esters are good carriers for Ag+, and 2b exhibits the highest transport rate (4.7 mumol h(-1)) found until now with dihomooxacalix[4]arene derivatives. |
