A novel family of Ru(II) polypyridyl complexes containing benzocrown ether for Na+ and Li+ probing

Two polypyridyl ligands 4′-(imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzo-12-crown-4 (L1), 4′-(imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzo-15-crown-5 (L2) and corresponding complexes [(bpy)2RuL1–2](PF6)2 (1, and 2) and [Ru(L1–2)3](PF6)2 (3, and 4) have been synthesized. These complexes show metal-to-ligand charge transfer absorption at 458–468 nm and emission at 585–592 nm. Binding ability of the complexes with Li+ and Na+ were investigated by fluorescence and UV–vis titration.