LIGANDS FOR EU-III, FE-III, SR-II, AND UO2II BASED ON CMPO-FUNCTIONALIZED RESORCINARENE CAVITANDS - SYNTHESIS AND EXTRACTION

Partially functionalized cavitands (7a-d) have been synthesized starti ng from the tetrakis(bromomethyl)cavitand 6. New cavitand-based cation Ligands, with one to three carbamoylmethylphosphane oxide (CMPO) moie ties (11a-d), were prepared in good (66-90%) yields. The ligands 11a-d extract Eu-III, but do so less effectively than the tetra-CMPO cavita nd 1. The decreasing number of CMPO groups which result in decreasing extraction percentages for Eu-III, also decrease the selectivity of Eu -III over that of Fe-III, Sr-II, and UO2II. There is a difference in e xtraction behavior, determined by radio-tracer experiments, between th e distal and proximal disubstituted ligands, 11b and 11c, respectively . The extraction constants for the 1:1 complex of 11b and 11c with Eu- (picrate)(3) are K-ex = 6.7.10(8) M-4 and 3.7.10(9) M-4, respectively.