The interaction of actinides, such as U(VI) and Th(IV), with amino acids are of interest due to their prevalence in environmental and biological systems and their potential use in advanced materials for separations technologies.1 Previous studies have focused on the behavior of actinide amino acid complexes in solution, but there is a limited understanding of the structural aspects of these species. Of the 20 proteinogenic a-amino acids, only three U(VI) and zero Th(IV) compounds have been structurally characterized. Here we present the synthesis, structural determination, and chemical characterization of five new actinide glycine and L-alanine compounds. Hydrolysis of the metal center leads to the formation of three infinite chains ([(UO2)3(Gly)2(O)2(OH)2](OH2)6, [(UO2)5(Gly)4(O)3(OH)3](OH2)11NO3, [(UO2)3(Ala)2(O)(OH)3](OH2)3NO3) one 2-D sheet ([(UO2)2(Gly)(O)(OH)2](OH2)1.5) and a molecular cluster (Th6(Gly)12(O)4(OH)4(OH2)x) (Gly = glycine, Ala = L-alanine). The nature of the structural water molecules within these compounds is quite unique and includes a helical arrangement within the open pores of the [(UO2)3(Gly)2(O)2(OH)2](OH2)6 compound. Additional aspects of the hydrogen bonding within these structures will be discussed, including the importance of the zwitterionic amino acid chelators in the development of novel bio-inspired materials.

Actinide a-amino acid complexes

246th National Meeting (2013)

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