Electrochemistry and Electrochemiluminescence of [Ru(II)-tris(bathophenanthroline-disulfonate)]4− in Aprotic Conditions and Aqueous Buffers

In this work, the electrochemical and ECL properties of tris[1,10-phenanthrolinediyl-4,7-di(benzenesulfonate)]Ru(II) ([Ru(BPS)3]4−) have been addressed in both strictly aprotic conditions and aqueous buffers. A combined theoretical and experimental approach is presented to focus thermodynamics and kinetic effects of electro-generated species possessing highly negative charge. The complex, prepared as the sodium salt by using a newly developed procedure, was subsequently converted to the tetrabutylammonium salt by ion exchange, thus making it soluble in organic media and allowing, for the first time, its thorough electrochemical investigation in ultra-dry aprotic media. The electrochemically induced luminescence (ECL) of Na4[Ru(BPS)3] in phosphate buffer, using the co-reactant method (tripropylamine), was investigated as a function of the electrode material and halide addition, and ECL intensities six times higher than that of [Ru(bpy)3]2+ were found. In addition, the ECL behavior of this promising dye for biomolecule recognition was investigated in aprotic media and, for the first time, the direct radical anion−radical cation annihilation ECL was obtained.coregae