Visible luminescent Ln42 nanotorus coordination clusters

Three thermodynamically stable nano-sized complexes containing 42 Ln3+ ions in a single molecule were synthesized via a self-assembly process. The compounds have torus or wheel-like architectures and have the general formula Ln42L14(OAc)82(OH)30 (Ln = Eu, Tb, Gd, L = deprotonated ortho-vanillin, OAc = acetate). The Eu and Tb complexes represent the first reported visibly luminescent lanthanide nanotoroids. The single crystal structures of all three complexes and their photophysical properties are reported.