Anion Dependent Self-Assembly of Polynuclear Cd-Ln Schiff Base Nanoclusters: NIR Luminescent Sensing of Nitro Explosives

Two types of polynuclear Cd-Ln complexes [CdLnL(NO3)Cl2(DMF)2] [Ln = La (1) and Nd (2)] and [Ln2CdL2(NO3)2(DMF)2](OH)2 [Ln = La (3) and Nd (4)] were constructed using a new Schiff base ligand which has a long backbone with two phenyl groups. The Schiff base ligands show a “twist” configuration in 1–4. The crystal structures show that the molecular dimensions of 3 and 4 are about 6 × 10 × 15 Å. The Cd-Nd complexes 2 and 4 exhibit the typical NIR luminescence of Nd3+. Interestingly, 4 shows the luminescent sensing of nitro explosives and exhibits a high sensitivity to 2-nitrophenol at the ppm level