Dynamic chiral Eu(III) complex emitters with molecular rotor‐regulated aggregation‐enhanced antenna effects for high‐resolution bioimaging

Abstract In this study, the arrangement, configuration, and distance of molecular rotors in the chiral Eu(III) complex structure were regulated to achieve an aggregation‐enhanced antenna effect, substantially improving the luminescence intensity, circularly polarized luminescence (CPL), and bioimaging performance of Eu(III) complexes. In the aggregated state, the rotor structure of R/S ‐Eu‐YZZ‐1 was anchored inside the structure and could not rotate due to the combined effects of strong hydrogen bonding, π–π interactions, and steric effects, which promoted intersystem crossing and enhanced the “antenna effect,” thereby improving their emission intensity, luminescence asymmetry factor ( g lum ), and CPL brightness ( B CPL ). The g lum and B CPL of R/S ‐Eu‐YZZ‐1 were simultaneously improved, reaching values as high as 0.011/0.047 and 82.10/342.92 M −1 cm −1 , respectively. The optical imaging performance of the monolayer chiral isomer R/S ‐Eu‐YZZ‐1 was considerably better than that of the bilayer R/S ‐Eu‐YZZ‐2 in both in vitro cellular and zebrafish in vivo experiments, indicating that the aggregation‐enhanced antenna effect could enhance the bioimaging applications of chiral Eu(III) complexes.