Trifluoromethyl-substituted 2,2'-bipyridine ligands. Synthetic control of excited-state properties of ruthenium(II) tris-chelate complexes

The synthesis of the novel bidentate ligands 4,4'-bis(trifluoromethyl)-2,2'-bipyridine (4,4'-BTFMB), 5,5'- bis-(trifluoromethyl)-2,2'-bipyridine (5,5'-BTFMB), and 4,4',5,5'-tetrakis(trifluoromethyl)-2,2'-bipyridine (4,4',5,5'-TTFMB) is reported. The photophysical and photochemical properties of a series of tris-chelate complexes [Ru(bpy) n (BTFMB) 3-n ] 2+ (n=0-2; bpy=2,2'-bipyridine) are described.