Near Infrared Luminescence of Lanthanides in Complexes with Organic Dyes

Spectral-luminescence characteristics of Yb³⁺ and Nd³⁺ ions in water solutions of their complexes with some organic dyes of sulfophenylphthalexones group have been considered. Complexes can be efficiently excited with visible light (_exc = 532 nm). 4f-Luminescence as a result of energy transfer from the dye moiety to the lanthanide ion was shown. Complexation of new polydentate ligand L of sulfophenylphthalexones type increases the luminescence lifetimes because of the reduced solvation of the ion by water. They were determined as 12.60 s for complex Yb-L and 1.45 s for Nd-L.