Enhanced Electrogenerated Chemiluminescence of ruthenium and iridium coordination compounds using melatonin
The effect on the coreactant Electrogenerated Chemiluminescence (ECL) of (bpy)2Ru(DC-bpy)2+ (bpy = 2,2'-bipyridine and DC-bpy = 4,4'-dicarboxy-2,2'-bipyridine), (bpy)2Ru(DM-bpy)2+ (DM-bpy = 4,4'-dimethyl-2,2'-bipyridine), and Ir(ppy)3 (ppy = 2-phenylpyridine) when melatonin (N-acetyl-5-methoxytryptamine; MLT) is present in aqueous buffered solution is reported with tri-n-propylamine as the coreactant. Micromolar concentrations of melatonin generate up to 1.4-fold enhancement of (bpy)2Ru(DC-bpy)2+/TPrA ECL and (bpy)2Ru(DM-bpy)2+/TPrA ECL, and 1.7-fold enhancement Ir(ppy)3/TPrA ECL. Photoluminescence (PL) emission efficiencies and spectra do not change in the presence of melatonin unless the melatonin solution has undergone electrochemical bulk oxidation, at which point PL and ECL are nearly indistinguishable. Electrochemical and spectroscopic experiments indicate that the mechanism involves the scavenging of oxygen by melatonin oxidation products that prevents the quenching of excited states by dissolved oxygen in solution.
electrogenerated Chemiluminescence (ECL), coreactants, enhanced ECL, melatonin
Roughton, Sarah, and Mark M. Richter. "Enhanced Electrogenerated Chemiluminescence of ruthenium and iridium coordination compounds using melatonin." Inorganica Chimica Acta 454 (2017): 58-61.
Inorganica Chimica Acta