Ruthenium (II) Complexes of Mono-, Di- and Tripodal Polypyridine Ligands: Synthesis, Characterization, and Spectroscopic Studies

Mono-, di- and tripodal polypyridine ligands 4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenol (L1), 2-(4-(2-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzyloxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L2), 2-(4-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzyl oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L3), 2-(4-(4,6-bis(4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenoxy)-1,3,5-triazine-2-yloxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L4), and their Ru (II) complexes have been synthesized and characterized. All the ligands (L1-L4) gave the emissions at three shoulder at 278 nm, 315 nm, and 328 nm and the complexes (C1-C4) exhibit Ru (II) metal centered emission at 265 nm, 288 nm and 328 nm in acetonitrile solution at room temperature. Maximum d-pi* transition seen at 462 nm for all the complexes.