Luminescence andMagnetic Properties of {Ln^IIICd^II₁₆} Metallacrown Complexes Centered withCompressed Tetragonal Antiprismatic Ln(III) Units

Metallacrown (MC) motifs are suitable elements for constructing functional lanthanide complexes, taking advantage of their versatile structural configurations and chemical tailoring capabilities. Herein, “triple-decker sandwich” MCs [LnCd₁₆(quinha)₁₆py₈](NO₃)₂(CF₃SO₃)·20H₂O·5DMF (<b>1-Ln</b>, Ln = Dy^III, Yb^III, and Nd^III) have been synthesized using the quinaldichydroxamic acid (H₂quinha) ligand. Structural analysis indicates that <b>1-Ln</b> comprises two [12-MC_Cd(II)-4] rings coordinated with Ln^III on the upper and lower sides and an outer [24-MC_Cd(II)-8] macrocycle. <b>1-Ln</b> possesses a compressed tetragonal antiprismatic coordination geometry with zenithal angles over 65°. <b>1-Yb</b> and <b>1-Nd</b> exhibit near-infrared emission with lifetimes of 23.55 and 7.12 μs, and the abnormal temperature-dependent intensity might be caused by the hot band absorption. <b>1-Dy</b> displays fast magnetization relaxation in the low-temperature region due to the inappropriate crystal field environment.