Metal-controlled diastereoselective self-assembly and circularly polarized luminescence of a chiral heptanuclear europium wheel

The chiral dissymmetric tetradentate ligand (S)-6′-(4-phenyloxazolin- 2-yl)-2,2′-bipyridine-6-carboxylate (S-Phbipox) leads to the diastereoselective assembly of a homochiral Eu3+ triangle and a highly emissive (quantum yield = 27%) heptanuclear wheel that is the largest example of a chiral luminescent complex of Eu3+ reported to date. The nuclearity of the assembly is controlled by the solvent and the Eu3+ cation. All of the compounds show large circularly polarized luminescence with an activity that varies with the nature of the assembly (highest for the homochiral trimer). © 2012 American Chemical Society.