Two Chiral Yb Enantiomeric Pairs with Distinct Enantiomerically Pure N-Donor Ligands Presenting Significant Differences in Photoluminescence, Circularly Polarized Luminescence, and Second-Harmonic Generation.

Using enantiomerically pure bidentate and tridentate N-donor ligands (L/L and L/L) to replace two coordinated HO molecules of Yb(tta)(HO), respectively, two eight- and nine-coordinated Yb enantiomeric pairs, namely, Yb(tta)L/Yb(tta)L (/) and [Yb(tta)L]·CHCN/[Yb(tta)L]·CHCN (/), were isolated, in which Htta = 2-thenoyltrifluoroacetone, L/L = (-)/(+)-4,5-pinene-2,2'-bipyridine, and L/L = (-)/(+)-2,6-bis(4',5'-pinene-2'-pyridyl)pyridine. Interestingly, they not only present distinct degrees of chirality but also show large differences in near-infrared (NIR) photoluminescence (PL), circularly polarized luminescence (CPL), and second-harmonic generation (SHG). Eight-coordinated with an asymmetric bidentate L ligand has a high NIR-PL quantum yield (1.26%) and a long decay lifetime (20 μs) at room temperature, being more than two times those (0.48%, 8 μs) of nine-coordinated with a -symmetric tridentate L ligand. In addition, displays an efficient CPL with a luminescence dissymmetry factor = 0.077, being 4 × (0.018). In particular, presents a strong SHG response (0.8 × KDP), which is 8 × (0.1 × KDP). More remarkably, the precursor Yb(tta)(HO) exhibits a strong third-harmonic generation (THG) response (41 × α-SiO), while the introduction of chiral N-donors results in the switching of THG to SHG. Our interesting findings provide new insights into both the functional regulation and switching in multifunctional lanthanide molecular materials.