NIR-luminescence from ternary lanthanide [HoIII, PrIII and TmIII] complexes with 1-(2-naphthyl)-4,4,4-trifluoro-1,3-butanedionate

The ligand 1-(2-naphthyl)-4,4,4-trifluoro-1,3-butanedionate (Htfnd) has been employed to synthesize six novel ternary-lanthanide complexes in which the synergic ligands were 1,10-phenanthroline-5,6-dione (dione) and 4,5-diazafluoren-9-one (dafone), respectively. Two series of complexes Ln(tfnd)(3)dione and Ln(tfnd)(3)dafone (Ln=Ho, Pr, Tm) were obtained. These complexes were characterized by elemental analysis, Fourier Transform Infrared spectra and diffused reflectance. After ligand-mediated excitation, Ln(tfnd)(3)dione and Ln(tfnd)(3)dafone all show the characteristic NIR luminescence of the corresponding Ln(3+) ions (Ln=Ho, Pr, Tm). This can be attributed to the efficient energy transfer from ligands to central Ln(3+) ions, via an antenna effect. The indirect energy transfer in the complexes has been investigated and the differences in the luminescence intensity between Ln(tfnd)(3)dione and Ln(tfnd)3dafone were discussed in detail. The excellent luminescent performances enable these NIR-luminescent complexes to have potential applications in optical amplification operating at 1300 or 1500 nm. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.