[en] In order to extract and separate metal ions contained in high-level spent fuel from nuclear reactors, novel hosts capable of organizing the structure on transition metal complexation were synthesized and their properties toward metal ion binding were characterized. The metal-organized hosts hitherto developed were modified so that they could extract f-orbital metal ions. A linear prehost having two salicylic acids at both ends of an oligoether chain was organized by uranyl in the presence of alkaline earth metal hydroxides into a pseudo crown ring. The reaction was found to proceed smoothly in the presence of template metal ions such as Sr²⁺. The resulting pseudo crown entrapped Sr²⁺ in the host cavity having two minus charges provided by four negative from two salicylates and two positive from uranyl. This organized host showed strong binding ability toward various metal ions, alkali, alkaline earth, lanthanides as well as actinides. An NMR titration method analyzed a large selectivity for Sr²⁺ among alkaline earth families, which were favored compared to alkali metals. The host showed large binding constants toward lanthanide and actinide metal ions and selectivity as well. The Sr²⁺ binding was much efficient when compared to (2.2.1)cryptand. (author)