Syntheses of a series of S6 thioether cages and their coordination chemistry with Ag+.

The syntheses of four S6-cages with different cavity sizes are described. In regard of potential applications for radioimmunotherapy with 111Ag, their coordination behaviour towards Ag(i) was evaluated by studies of their reactivity in solution and of their crystal structures. All cages reacted differently with Ag(i). Whereas S6-cages based on 3,8,12,17,20,25-hexathiabicyclo[8.8.8]-hexacosane (14) and on 5,9,17,21,28,31-hexathiabicyclo[11.11.11]pentatriacontane (18) showed only external Ag(i) coordination, successive adaptation of the cage size, yielded ligand 24, based on 4,7,13,21,24,25-hexathiabicyclo[8.8.8]hexacosane, which gave a complex with internal-peripheral Ag(i) binding. [ABSTRACT FROM AUTHOR]