Homochiral Self-Sorted and Emissive IrIII Metallo-Cryptophanes.

The racemic ligands (±)-tris(isonicotinoyl)-cyclotriguaiacylene (L1), or (±)-tris(4-pyridyl-methyl)-cyclotriguaiacylene (L2) assemble with racemic (Λ,Δ)-[Ir(ppy)2 (MeCN)2 ]+ , in which ppy=2-phenylpyridinato, to form [{Ir(ppy)2 }3 (L)2 ]3+ metallo-cryptophane cages. The crystal structure of [{Ir(ppy)2 }3 (L1)2 ]⋅3BF4 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)2 }3 (L2)2 ]3+ having enhanced and blue-shifted emission when compared with [{Ir(ppy)2 }3 (L1)2 ]3+ .

Encapsulation of sodium alkyl sulfates by the cyclotriveratrylene-based, [Pd(6)L(8)](12+) stella octangula cage.

We have previously described a cyclotriveratrylene (CTV)-based complex, [Pd6L8](12+), that forms a highly symmetric stella octangula cage. Here we report on the ability of this system to host sodium salts of three alkyl sulfates; octyl (SOS), dodecyl (SDS) and tetradecyl (STS). (1)H NMR chemical shift and diffusion coefficient measurements reveal that two molecules of alkyl sulfate reside in the cage, though rapid exchange between cage and bulk solvent is apparent. Host : guest association constants have been determined and support for the internalisation of the sulfates is available from 2D ROESY and NOESY data.