Outer-Sphere Coordination of Uranyl Carbonate by Modified Cyclodextrins: Implications for Speciation and Remediation

摘要

The characterization of two outer-sphere ligands with uranyl carbonate are presented. The ligands are based on a- and b-cyclodextrin architectures, with amine hydrogen bonding groups appended to the 1 ° hydroxyl ring of the cyclodextrin. Binding affinities for uranyl carbonate are Ka = 253 M-i and 838 M-i for per-(6-(ethylenediamino)]-6-deoxy-a-cyclodextrin (1) and per-[6-(amino)]-6-deoxy-bcyclodextrin (2) respectively. These ligands are able to complex uranyl carbonate in seawater to an appreciable extent, and influence the speciation of the metal complex.