Self-assembly of one visible and NIR luminescent Sm(III) coordination polymer with flexible Schiff base ligand

Abstract

Two mononuclear lanthanide complexes [EuL1(NO3)(H2O)DMF] (1) and [SmL1(OAc)(H2O)EtOH] (2), and one lanthanide coordination polymer {Sm(L2)(OAc)}n (3) were synthesized by the use of two Schiff base ligands with a long (CH2)2NH(CH2)2 backbone. The crystal structures of 1–3 were determined by X-ray crystallography. The chromogenic Schiff base ligands in 1–3 can transfer energy to lanthanide ions and these complexes exhibit the typical luminescence of lanthanide ions. In 1 and 2, there is a H2O molecule coordinated with the Ln3+ ion, while there are no solvent molecules coordinated with the lanthanide ion in 3. Interestingly, for the Sm(III) complexes, the lanthanide coordination polymer 3 has longer emission lifetime and higher quantum yield (Φem) than the mononuclear lanthanide complex 2.