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Acridone‐Benzimidazole Ring‐Fused Ligands: A New Class of Sensitizers of Lanthanide Luminescence via Low‐Energy Excitation
Author(s) -
Deiters Emmanuel,
Gumy Frédéric,
Bünzli JeanClaude G.
Publication year - 2010
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200901148
Subject(s) - chemistry , luminescence , lanthanide , chromophore , ligand (biochemistry) , acridone , europium , photochemistry , acetonitrile , ion , benzimidazole , crystallography , stereochemistry , organic chemistry , biochemistry , physics , receptor , optoelectronics
Two monotopic tridentate ligands, namely H L AB1 and H L AB2 have been synthesized which feature an acridone chromophore fused on a benzimidazolepyridine framework. They differ from each other by their connection points between a N ‐methylacridone and a N ‐methylbenzimidazole chromophoric moieties. Both ligands self‐assemble with Ln III ions in neat acetonitrile to form thermodynamically stable neutral complexes of general formula [Ln( L ABX ) 3 ] (log β 13 in the range 22–25). Subsequent photophysical investigations conducted in the same solvent demonstrate that ligand H L AB1 sensitizes europium luminescence ( Q L Eu = 10 % and τ Eu = 0.93 ms) whereas ligand H L AB2 sensitizes the luminescence of NIR‐emitting Ln III ions, in particular Yb III ( Q L Yb = 0.86 % and τ Yb = 29.3 μs). The sensitization efficiencies η sens of both ligands have been determined for these two complexes and found to be around 50–60 %. The main advantage of these ligands is their excitation wavelength which lies in the visible range (410–430 nm).