New Class of Bright and Highly Stable Chiral Cyclen Europium Complexes for Circularly Polarized Luminescence Applications

High glum values of +0.30 (ΔJ = 1, 591 nm, in DMSO) and −0.23 (ΔJ = 1, 589 nm, in H2O) were recorded in our series of newly designed macrocyclic europium(III) complexes. A sterically locking approach involving a bidentate chromophore is adopted to control the formation of one stereoisomer, giving rise to extreme rigidity, high stability, and high emission intensity. The combination of a chiral substituent on a macrocyclic chelate for lanthanide ions opens up new perspectives for the further development of circulary polarized luminescent chiral tags in optical and bioapplications.