Constructing High‐Generation Sierpiński Triangles by Molecular Puzzling

Three generations of metalated trigonal supramolecular architectures, so‐called metallo‐triangles, were assembled from terpyridine (tpy) complexes. The first generation (G1) metallo‐triangles were directly obtained by reacting a bis(terpyridinyl) ligand with a 60° bite angle and Zn^II ions. The direct self‐assembly of G2 and G3 triangles by mixing organic ligands and Zn^II, however, only generated a mixture of G1 and G2, as well as a trace amount of insoluble polymer‐like precipitate. Therefore, a modular strategy based on the connectivity of ⟨tpy−Ru²⁺−tpy⟩ was employed to construct two metallo‐organic ligands for the assembly of G2 and G3 Sierpiński triangles. The metallo‐organic ligands L^A and L^B with multiple free terpyridines were obtained through Suzuki cross‐coupling of the Ru^II complexes, and then assembled with Zn^II or Cd^II to obtain high‐generation metallo‐triangular architectures in nearly quantitative yield. The G1–G3 architectures were characterized by NOESY and DOSY NMR spectroscopy, ESI‐MS, TWIM‐MS, and transmission electron microscopy.