Concave carrier molecules: Selective transport of copper(II) and lead(II) nitrates through supported liquid membranes

Concave 1,10-phenanthrolines 1 are selective and efficient carrier molecule s for membrane transport of copper(II) and lead(II) ions. With competitive membrane transport experiments the selectivity patterns of three concave 1, 10-phenanthroline membrane carriers have been determined. Measurements with copper(II) and lead(II) nitrates confirmed the predicted selectivities and revealed high transport rates for la and Ib. While lb shows a high prefere nce for copper(LI) nitrate, la transports lead and copper nitrates equally well, but with much higher flux. In bulk liquid membranes, the carrier medi ated ion flux remained constant over an extended period, whereas it decreas ed significantly in reused supported liquid membranes, which indicates rapi d loss of carrier from the membrane under these conditions.