Abstract
This work aims to suggest a facile approach for induced circular dichroism (ICD) and induced circularly polarized luminescence (iCPL) of the optically inactive, dynamically racemic luminophore tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octanedionato)europium(III) (rac-Eu(fod)3), through deracemization by interaction with chiral block copolymers (BCPs*), polystyrene-b-poly(l-lactide) (PS-b-PLLA), and polystyrene-b-poly(d-lactide) (PS-b-PDLA)). In a dilute solution, rac-Eu(fod)3 exhibits no circular dichroism (CD) and a negligibly weak CPL in the presence of PS-b-PLLA and PS-b-PDLA. By contrast, significantly strong CD and CPL of the rac-Eu(fod)3 chromophore can be induced by the mesochiral self-assembly of BCPs* with the formation of a helical phase (H*) that mostly relies on a highly enantiomer-selective deracemization of the rac-Eu(fod)3 with propeller chirality (Delta or Lambda form) upon complexation with the BCPs*, resulting in a high-luminescence dissymmetry factor up to approximately 10-2. The vibrational circular dichroism (VCD) results reveal that the VCD signals of the chiral polylactide chains in H* can be remarkably enhanced upon complexation with the deracemized Eu(fod)3. The enhanced twisting of the packing of polylactide chains via interchain chiral interaction due to the presence of the nonracemic (deracemized) Eu(fod)3 provides a unique platform for the design of chiroptical devices in various applications.