title: Enhancement of the luminescence efficiency of europium(III) tris(β-diketonato) complex in organic media by quaternary ammonium salts with anionic ligands.
abstract: Benzyldimethyltetradecylammonium (BA14(+)) salts with anionic ligands (X(-)), such as bis(2-ethylhexyl)sulfosuccinate, bis(2-ethylhexyl)phosphate (BEHP(-)), and benzotriazole (BTA(-)) anions, were prepared.  These salts were soluble in various organic solvents.  The luminescence emission spectra of organic solutions of a red luminescent, tris(1,1,1,2,2,3,3-heptafluoro-7,7-dimethyl-4,6-octadionato)europium(III) complex in the presence of the BA14X's were recorded.  The emission intensity of the Eu(III) complex was increased remarkably by the addition of BA14X (X(-) = BEHP(-) and BTA(-)).  This effect can be attributed to the formation of 1:1 X(-)-adducts of the Eu(III) complex, in which the asymmetry of the ligand field is increased so as to enhance the emission efficiency of the (5)D(0)→(5)F(2) transition.  The enhancement effect by BA14X was higher than that of charge-neutral ligands, such as tri-n-octylphosphine oxide and 1,10-phenanthroline, which have been used as second ligands to enhance the emission efficiency of tris(β-diketonato)europium(III) complexes.
authors.affiliation: Department of Bioscience, Fukui Prefectural University, Eiheiji, Fukui 910–1195, Japan. hajime@fpu.ac.jp
authors.forename: Hajime
authors.initials: H
authors.lastname: Katano
authors.forename: Kohei
authors.initials: K
authors.lastname: Uematsu
authors.forename: Toshihide
authors.initials: T
authors.lastname: Tsukatani
mesh_terms: D000838:Anions; D005063:Europium / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000838:Anions; D008024:Ligands; D000644:Quaternary Ammonium Compounds; D012997:Solvents; D005063:Europium