Photosensitized luminescence of novel β-diketonato Nd(III) complexes in solution

Photosensitized luminescence in the near-infrared region of five low vibrational beta-diketonato neodymium(III) complexes, tris(1,1,1,5,5,5-hexafluoroacetylacetonato)neodymium(III) (1), tris(4,4,5,5,5-pentafluoro-1-pentafluorophenyl-1,3-pentanedionato)neodymium(III) (2), tris(4,4,5,5,6,6,6-heptafluoro-1-pentafluorophenyl-1,3-hexanedionato)neodymium(III) (3), tris(4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-pentadecafluoro-1-pentafluorophenyl-1,3-decanedionato)neodymium(III) (4), and tris[bis(pentafluorobenzoyl)methanato]neodymium(III) (5), were examined by the selective excitation of the ligand moieties in THF-d(8). The intramolecular energy transfer efficiencies from the excited ligands to the central Nd(III) ion were determined and the order of 1 < 2 < 3 < 4 < 5 was obtained. The order of the overlap area between the phosphorescence due to the ligand moieties and the absorption due to Nd(III) in the 400-650 nm spectral region was also increased in the above order. These results suggest that the energy matching of the donor and the acceptor is decisive for the efficient photosensitized luminescence of Nd(III) complexes.