Development of a Functional Ruthenium(II) Complex that Can Act as a Photoluminescent and Electrochemiluminescent Dual-signaling Probe for Hypochlorous Acid.

A functional ruthenium(II) complex that can act as a probe for response to hypochlorous acid (HOCl) in aqueous media with photoluminescence (PL) and electrochemiluminescence (ECL) dual-signals, [Ru(bpy)2(DB-phen)](PF6)2 [bpy: 2,2'-bipyridine; DB-phen: 5-(2,4-dimethoxybenzylamino)-1,10-phenanthroline)], has been designed and synthesized. The complex is highly luminescent both under the light excitation and the electrochemical induction. It can specifically react with HOCl in physiological pH aqueous media to afford its chlorinated derivative, [Ru(bpy)2(DBCA-phen)](PF6)2 [DBCA-phen: 5-(2,4-dimethoxybenzyl-chloroamino)- 1,10-phenanthroline], accompanied by remarkable decreases in its PL and ECL intensities. The PL and ECL abatements of [Ru(bpy)2(DB-phen)](PF6)2 show good linear correlation to the concentration of HOCl with detection limits at low micromolar concentration level, and the PL and ECL responses of the complex to HOCl are highly specific without interferences of other reactive oxygen/nitrogen species. These features enabled [Ru(bpy)2(DB-phen)](PF6)2 to be used as a probe for the highly selective and sensitive detection of HOCl in aqueous media with PL and ECL dual-modes.