The synergistic extraction of lanthanide ions by a mixture of calix[4]resorcinarene or its dimethylamino-, piperidyl- or trimethylammoniummethylated derivatives and 1,10-phenanthroline in n-heptanol

The alkylaminomethylated calix[4]resorcinarene derivatives, modified by dim ethylamino-, piperidyl- and trimethylammonium moieties, have been synthesis ed to investigate their extractability towards lanthanide ions and to compa re with the extractability of calix[4]resorcinarene. Both calix[4]resorcina rene and its derivatives have been shown to synergistically affect lanthani de ion extraction from neutral aqueous solutions by 1,10-phenanthroline thr ough outer-sphere interaction of lanthanide bis-phenanthrolinate cations wi th deprotonated forms of calix[4]resorcinarene. The derivatives with dimeth ylamino- and piperidylmethylated moieties are shown to be more effective ex tractants in comparison with the unsubstituted one.