Heteroleptic ruthenium(II) polypyridine complexes with a series of substituted 2,2′-bipyridine ligands

Abstract

Five substituted-2,2′-bipyridine ligands L, (4-(p-methylphenyl)-6-phenyl-2,2′-bipyridine (L1), 4-(p-bromophenyl)-6-(p-bromophenyl)-2,2′-bipyridine (L2), 4-(p-bromophenyl)-6-phenyl-2,2′-bipyridine (L3), 4-phenyl-6-(p-bromophenyl)-2,2′-bipyridine (L4), and 4-(p-fluorophenyl)-6-(p-fluorophenyl)-2,2′-bipyridine (L5) were synthesized by stepwise formation. Reaction of cis-[RuCl2(bpy)2]⋅2H2O or cis-[RuCl2(phen)2]⋅2H2O and the substituted-2,2′-bipyridine ligands in the presence of KPF6 afforded the corresponding cationic polypyridine-ruthenium complexes of the type [(bpy)2Ru(L)](PF6)2 (bpy = 2,2′-bipyridine, 1–5) or [(phen)2Ru(L)](PF6)2 (phen = 1,10-phenanthroline, 6–10), respectively. All complexes have been spectroscopically characterized by UV–vis, luminescence, and electrogenerated chemiluminescence. The structures of 1⋅CH3COCH3, 3⋅CH3COCH3, 5⋅2CH3COCH3, 6, 8, 9, and 10 have been determined by single-crystal X-ray diffraction.