Jean-Claude Bunzli - N-Aryl Chromophore Ligands for Bright Europium Luminescence

Version 1

      Publication Details (including relevant citation   information):

      Shavaleev,N.M., Eliseeva,S.V., Scopelliti,R., Bunzli,J.C.G.   Inorganic Chemistry 2010 49  (8) 3927-3936

      Abstract: Sterically hindered   N-aryl-benzimidazole pyridine-2-carboxylic acids (aryl = phenyl,   4-biphenyl, 2-naphthyl) readily form homoleptic, neutral,   nine-coordinate europium complexes which display efficient   sensitized luminescence in solid state and in dichloromethane   solution with quantum yields reaching 59% and have   monoexponential and nearly temperature-independent lifetimes as   long as 2.7 ms. The ligand-centered absorption band with a   maximum at 321-342 nm and intensity (50-56) x 10(3) M(-1)cm(-1)   ensures efficient harvesting of excitation light by the   complexes. Variation of N-aryl chromophore enhances the ligand   absorption at 250-350 rim without changing its triplet state   energy which amounts to (19.2-21.3) x 10(3) cm(-1). Photophysical   properties of europium complexes benefit from adequate protection   of the metal by the ligands against non-radiative deactivation   and efficient ligand-to-metal energy transfer exceeding 70%. A   correlation is observed between the sensitized luminescence   quantum yields of europium and the ligand triplet state energy;   in certain cases it points to the presence of a second-sphere   quenching of Eu(III) by co-crystallized water in the solid state

      Address (URL): WOS:000276556900049