Synthesis, crystal structures and near-infrared luminescent properties of three lanthanide-based enantiomeric pairs

Three lanthanide-based enantiomeric pairs formulated as Ln(dbm)3LR/S (Ln = Nd3+ (R-1 and S-1), Er3+ (R-2 and S-2) and Yb3+ (R-3 and S-3), R- and S-configuration complexes containing the LR and LS ligands, respectively, and dbm = dibenzoylmethanate) have been obtained successfully upon the reaction of corresponding lanthanide precursors Ln(dbm)3·H2O with enantiopure chiral ligands (−)/(+)-4,5-pinene bipyridine (LR/S), respectively. Their structures were characterized by X-ray single-crystal analyses, elementary analyses and IR spectra. The circular dichroic (CD) spectra verified their chiroptical activities and enantiomeric natures. The photoluminescence investigations demonstrated that they display characteristic near-infrared (NIR) emissions of corresponding Nd3+, Er3+ and Yb3+ ions with notable lifetime values, representing the first example of chiral lanthanide β-diketonate complexes with NIR luminescent property.