Actinide expanded porphyrin complexes

Abstract In this article the uranyl cation (UO 2 2+ ) coordination chemistry of several prototypic expanded porphyrins is reviewed. The ability of certain expanded porphyrins, large polypyrrolic ligands, to stabilize complexes containing the uranyl cation is contrasted to that of the porphyrins. These latter systems, well-recognized for their ability to stabilize a range of transition metal complexes, among others, have hitherto been shown to form structurally characterized complexes with only uranium(IV) and thorium(IV) cations among cations of the actinide series. Possible reasons for these differences in cation complexation behavior are discussed.