A binuclear ruthenium polypyridyl complex: synthesis, characterization, pH luminescence sensor and electrochemical properties

Abstract

The binuclear ruthenium complex [Ru2(bpy)4L](PF6)4 [Ru1(PF6)4, where L = 9,10-bis(3-(1H-imidazo[4,5-f] [1,10] phenanthrolin-2-yl)phenyl)anthracene and bpy = 2,2′-bipyridine], was designed and synthesized as pH sensing probe. The spectroscopic data displayed the anthryl-moiety characteristic absorptions at 353 nm, 373 nm and 394 nm, respectively, and MLCT absorptions at 428 nm and 457 nm. The acid–base properties of the Ru complex ion were characterized, and the ground- and excited-state acid ionization constants were derived by UV–visible absorption and emission spectra. The results showed the luminescence of Ru1 decreased obviously with the increases of pH. The electrochemical properties of Ru1 were discussed, showing one Ru (II)-centered oxidation at around 1.31 V and three ligand-centered reductions.