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.

Keywords:

• Ruthenium complex
• 2,2′-Bipyridine
• polypyridine
• 1,10-phenanthroline
• crystal structure

Funding

This work was supported by the Natural Science Foundation of China [grant number 21372007]; Science & Technology Department of Zhejiang Province [grant number 2013C31059], [grant number 2014C31149].