Evaluation of circularly polarized luminescence in a chiral lanthanide ensemble

October 11, 2018


Evaluation of circularly polarized luminescence in a chiral lanthanide ensemble


Yoshinori Okayasu, Junpei Yuasa




Molecular System Design & Engineering


This work demonstrates a methodology for the evaluation of circularly polarized luminescence of a chiral europium(III) (EuIII) complex species in an ensemble system. The chiral EuIII complex species consists of chiral bis(oxazolinyl)pyridine [(R)- or (S)-iPr-Pybox] and β-diketonate ligands with a pendant nitro group (DK-NO2). The pendant NO2group in [iPr-Pybox](EuIII)(DK-NO2)3 (monometallic EuIII species) coordinates to the EuIIIcenter of another EuIII complex, giving rise to the generation of a chiral EuIII ensemble consisting of mono-, di-, and the other oligomeric EuIII species, {[iPr-Pybox](EuIII)(DK-NO2)3}n. The luminescence dissymmetry factors (glum) of the chiral EuIII ensemble have been successfully determined by using a commercially available fluorescence spectrophotometer attached with a rotatable λ/4 filter and a fixed linearly polarized plate. This study suggests that the chiral EuIII ensemble in solution displays a large circularly polarized luminescence (|glum| = 0.19) as compared to that of a reference monometallic complex [iPr-Pybox](EuIII)(DK-CN)3 (|glum| = 0.11–13). The larger glum is primarily attributed to the contribution of the dimetallic EuIII species exhibiting a high degree of circular polarization in luminescence (glum2 = 0.27) in the ensemble. Conversely, a large linearly polarized component was observed in luminescence from the chiral EuIII ensemble in the solid state (KBr pellet).




Fluorescence, Circularly polarized luminescence, Stereochemistry, Solid state, Coordination chemistry, Quantum yield, Inorganic chemistry