Enhanced Circularly Polarized Green Luminescence Metrics from New Enantiopure Binary Tris-Pyrazolonate-Tb3+ Complexes

Achieving superior circularly polarized luminescence brightness (BCPL) is an important subject and continuous challenge for chiroptical materials. Herein, by applying a binary molecular design for the synthesis of chiral organo-Tb3+molecules, a novel pair of mononuclear chiraltris-pyrazolate-Tb3+enantiomers, [Tb(PMIP)3(R,R-Ph-PyBox)] (2) and [Tb(PMIP)3(S,S-Ph-PyBox)] (5), have been synthesized and characterized. The three 1-phenyl-3-methyl-4-(isobutyryl)-5-pyrazolone (HPMIP) ligands play the role of efficient luminescence sensitizers and strong light-harvesting antennas, while the enantiopure 2,6-bis(4-phenyl-2-oxazolin-2-yl) pyridine ligand (R,R/S,S-Ph-PyBox) is employed as the strong point-chiral inducer. With the proper combination of theHPMIPandChiral-Ph-PyBoxwithin the Tb3+enantiomers, strong (PMIP)−-centered π-π*electronic absorption (ε263 nm= 38,400–39,500 M−1cm−1) and brilliant high-purity ligand-sensitized Tb3+-centered green luminescence (ΦPL= 47–48%) were observed. In addition, a clear circularly polarized luminescence (CPL) activity (|glum| = 0.096–0.103) was also observed, resulting in a strongBCPL(610–623 M−1cm−1) for the two Tb3+enantiomers from the hypersensitive transitions. Our results offer an effective path to develop high-performance chiroptical organo-Tb3+luminophores.