Construction of a Large High-Nuclearity Cd–Sm Schiff Base Cluster with Nanoscale Inner Cavity as Luminescent Probe for Metal Cations

Two Cd–Ln clusters [Ln8Cd24L12(OAc)48]·(solvent)n (Ln = Sm (1), Gd (2)) were synthesized from a specifically designed Schiff base ligand with a long (CH2)11 chain backbone. 1 and 2 show drumlike structures (24 × 24 × 26 Å3), which have nanoscale inner cavities (10 × 12 × 12 Å3). The inner cavities of the clusters are large enough to capture some guest molecules. Interestingly, 1 has visible and near-infrared emissions of Sm3+ and shows luminescent sensing behavior to metal ions, especially to Zn2+ and Fe3+ ions