LAUSR

Abstract Four mono- and bi-nuclear lanthanide complexes [LnL1(NO3) (H2O)DMF] (Ln = Nd (1) and Yb (2)) and [Ln2 (L2)2(OAc)2] (Ln = Nd (3) and Yb (4)) were synthesized by using two new Schiff base ligands with long (CH2)2NH(CH2)2 backbone. The lengths of the Schiff base ligands are about 1.8 nm. The bi-nuclear lanthanide complexes 3 and 4 have nanoscale structures with sizes of approximately 0.7 nm × 1.1 nm × 1.6 nm. For 3, the molar ratio of Nd:Br:O obtained by the energy dispersive X-ray spectroscopy analysis is in agreement with the crystal structure. The chromogenic Schiff base ligands in 1–4 can efficiently transfer energy to lanthanide ions, thus, these complexes exhibit the typical NIR luminescence of lanthanide ions. Interestingly, 3 and 4 have higher NIR emission quantum yields (Φem) than 1 and 2, respectively.