Enhanced Electrogenerated Chemiluminescence of ruthenium and iridium coordination compounds using melatonin

Abstract

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.

Department(s)

Chemistry and Biochemistry

Document Type

Article

DOI

https://doi.org/10.1016/j.ica.2016.02.030

Keywords

electrogenerated Chemiluminescence (ECL), coreactants, enhanced ECL, melatonin

Publication Date

2017

Journal Title

Inorganica Chimica Acta

Link to Full Text

Share

COinS