Fig. 3: The structures of Borromean rings.

a Size relationships between ligand L1 and the building units E4(OTf)2 and E5(OTf)2 in Borromean rings 4(OTf)12 and 5(OTf)12; b Chemical structure, c molecular structure, d three colours showing the π···π stacking interactions and e space-filling representations of Borromean ring 3(OTf)12. Most hydrogen atoms, anions and solvent molecules are omitted for clarity (N, blue; O, red; C, grey; S, yellow; Ru, aqua).