Synthesis, characterization and luminescence property of ternary rare earth complexes with azatriphenylenes as highly efficient sensitizers

A series of novel ternary rare earth complexes showing attractive luminescence properties were prepared with both neutral and anion ligands. Three azatriphenylene neutral ligands, 1,10-phenanthroline (phen), dipyrido [3,2-a: 2′,3′-c] quinoxaline (dpq) and dipyrido [3,2-a: 2′,3′-c] phenazine (dppz) were investigated systematically as sensitizers in the ternary rare earth complexes. Benzoate ions (BA−) and phenoxyacetate ions (POA−) were chosen as anion ligands. The compositions of these complexes were characterized by elemental analysis, rare earth coordination titration, molar conductivity measurement, IR spectroscopy, UV–vis absorption spectroscopy, 1H NMR spectroscopy and TGA–DTA. The luminescence spectra, luminescence decay time and quantum efficiency of the complexes were also studied. The very strong luminescence intensities and rather long luminescence lifetimes (typically > 1.0 ms) were achieved for both Eu3+ and Tb3+ ternary complexes with phen and dpq as neutral ligands. Moreover, high quantum efficiencies (40–60%) were also obtained for Eu3+ ternary complexes with phen and dpq as neutral ligands.

► We prepared novel ternary rare earth complexes with neutral and anion ligands.
► Three neutral ligands (phen, dpq and dppz) were investigated as sensitizers.
► Benzoate and phenoxyacetate ions were chosen as anion ligands.
► Eu3+ and Tb3+ complexes with phen or dpq exhibited strong luminescence intensities.
► Eu3+ ternary complexes with phen or dpq showed high quantum efficiency (40–60%).