Homochiral Self-Sorted and Emissive Ir Metallo-Cryptophanes.

The racemic ligands (±)-tris(isonicotinoyl)-cyclotriguaiacylene (L1), or (±)-tris(4-pyridyl-methyl)-cyclotriguaiacylene (L2) assemble with racemic (Λ,Δ)-[Ir(ppy) (MeCN) ] , in which ppy=2-phenylpyridinato, to form [{Ir(ppy) } (L) ] metallo-cryptophane cages. The crystal structure of [{Ir(ppy) } (L1) ]⋅3BF has MM-ΛΛΛ and PP-ΔΔΔ isomers, and homochiral self-sorting occurs in solution, a process accelerated by a chiral guest. Self-recognition between L1 and L2 within cages does not occur, and cages show very slow ligand exchange. Both cages are phosphorescent, with [{Ir(ppy) } (L2) ] having enhanced and blue-shifted emission when compared with [{Ir(ppy) } (L1) ] .