Abstract
Chiral lanthanide complexes, due to their high luminescence dissymmetry factor (g(lum)) and luminescent quantum yield, have become highly promising materials for circularly polarized luminescence (CPL). Herein, we report two novel pairs of lanthanide chiral complexes, which exhibit both a high g(lum) and high luminescence quantum efficiency. Photophysical and chiroptical investigations revealed that both (NEt(4))(2)[Eu(2)(L(1)(S))(4)] and (NEt(4))(2)[Eu(2)(L(2)(S))(4)] displayed intense CPL. Their g(lum) values for (5)D(0) → (7)F(1) transition reach + 1.34 and + 1.14, respectively, exhibiting high luminescence quantum yields of 37.43% and 30.30% for (5)D(0) → (7)F(J) transitions (J = 0 - 4). Through the analysis of the photophysical properties and X-ray single-crystal structures of (NEt(4))(2)[Eu(2)(L(1)(S))(4)] and (NEt(4))(2)[Eu(2)(L(2)(S))(4)], it was found that the modification of the ligand significantly affected the twist angle α of the coordination polyhedron, revealing the direct cause for achieving a high g(lum). This study provides a new design concept for the development of other lanthanide-based CPL materials with high g(lum) values and high luminescence quantum yields.